The penis is one of the end-artery organs in the human body. The blood supply of the penis depends on the internal pudendal artery, which arises from the anterior division of the internal iliac artery. Subsequently, the penis is one of the organs that are highly affected by peripheral vascular disease. Furthermore, erectile dysfunction is a clinical sign that might precede coronary heart disease. Artificial entrapment of the blood into the cavernous bodies is one of the treatment options for erectile dysfunction. In addition, the same concept might be utilized in some sex aids to increase self-pleasure; hence, penile rings are widely used in some cultures. We present here a case of metal penile ring entrapment, which was managed successfully with the help of the hospital maintenance team. Therefore, it is of tremendous importance in unusual cases to seek advice from all possible resources. Such complications should be highlighted to increase the awareness of the users and the medical professionals as well. Sex aids, also known as sex toys, refer to tools or devices that are used mainly to facilitate human sexual pleasure. The use of sex aids for more than 30,000 years has been reported by archeologists . MoreoveA 61-year-old male presented to the emergency ward with painful edematous swelling of the penis along with urine retention. The patient developed these symptoms after the insertion of a penile ring 24 hours back for enhancing penile erection and sexual performance. The patient failed to remove or cut the ring with either a metal saw or grinder. The patient had a history of ED for the last two years. On physical examination, it was revealed that the patient developed penile lacerations at the ring site along with ecchymosis and edema Figures . In addiTherefore, the patient was transferred to the operative theatre to remove the penile ring under general anesthesia. Given the fact that the metal ring was very thick, several failed efforts lasted longer than five hours. The iron saw and metal wire were employed. In addition, orthopedic instruments were utilized without fruitful results.Eventually, the hospital maintenance team was summoned, and they used a special iron cutter to shatter the metal ring Figure . To emptThe use of metal rings to sustain a penile erection is unique, and the ring might become entrapped on the penis . BecauseThere are no conventional procedures or guidelines for removing an entrapped penile ring, and it can be done with non-medical instruments. Some cases of penile ring entrapment are challenging to cure and need creativity and a multidisciplinary approach ,10. The Aspiration decompression is an invasive procedure for draining blood from distended corpora. This shrinks the penis, allowing the ring to be removed . BecauseIn our patient, under general anesthesia, we tried most of the procedures, and the hospital maintenance team was eventually summoned, and they used a special iron cutter to shatter the metal ring after the failure of all the above protocols.The use of a metal ring for the penis should be revaluated and scientific discussion should be made about the harms of its use. These types of rings are being used and applied in the absence of medical supervision. However, in case of overwhelming complications, the medical team would be responsible for dealing with the problem, which leads to more strain on the limited health system resources. This case might be an example of how to deal with the problem with a severe lack of guidance methods.


This study aims to compare the early development of professional value between the students in the traditional programme (BSN) and those in the accelerated BSN (ABSN) programmes.A longitudinal design was conducted.Data were collected from three schools of nursing during one academic year. A total of 117 BSN students and 101 ABSN students completed the survey of demographic information and the Nurses’ Professional Values Scale–Revised questionnaires. All data were analysed by IBM SPSS‐Statistics 22.Results showed that, in the beginning of the first professional nursing course, both students in the BSN and the ABSN programmes reported similar level of professional values. However, after one academic year, the changes in the professional value varied both between these two programmes and among the three different nursing schools. The increased professional value in school A represented the possibility for students to improve during their first‐year professional nursing programme. As educators, we should redesign our teaching strategies according to the different conditions of students in each programme. Although lots of strategies have been implied, nursing shortage is still a worldwide challenge in the healthcare system, especially during the pandemic of the COVID‐19 recently  and from each school first. Then, we contacted with the class leaders in each programme and arranged meeting schedules with the whole classes. We explained the purpose of the study and issues of voluntary participation. Once subjects agreed and signed the informed consents during that meeting, questionnaires were distributed to them immediately. Researcher waited and collected questionnaires after the students completed. A total of 101 students in the ABSN programme and 117 students in the BSN programme completed and returned their questionnaires during the study period. A power of 0.89 was achieved by this data set.3.33.3.1The collected demographic data included age, gender, religion, marriage status, types of educational programmes and pre‐ABSN educational programme.3.3.2Cronbach's alpha (0.70–0.92) were conducted, and the validity and reliability were verified upon this updated scale. It consists of 26 items that address the following subscales as caring; professionalism; activism; trust; and justice.Based on the American Nurses Association's (ANA) code of ethics with interpretive statement, Weis and Schank  revised Cronbach's alpha was 0.73–0.84.The responses are based on the 5‐point Likert scale, with the score of each item ranging from 1 (“not very important”) to 5 (“very important”). The range of total score is between 26 and 130, a higher score indicates the respondent's greater familiarity with the professional values. NPVS‐R has been translated into many languages in order to measure the professional nursing values in different cultures. In the present study, the range of 3.4Paired t test, t test and ANOVA were performed to verify the expected relationships among variables. A p value <.05 was set as significant.All data were handled by the IBM SPSS‐Statistics 22. The descriptive statistics were conducted to describe the characteristics of each variable. 44.1t test showed that subjects in the ABSN programme were significantly older than subjects in the BSN programme . Nevertheless, comparison of age for subjects in the BSN programme within three schools showed no differences among them . Similar results were also found for the subjects in the ABSN programme .Subjects in the BSN programme within three sites were characterized as female, no specific religion, unmarried and unemployed Table . Subject4.2The results of the total score and each subscale of the NPVS‐R for the BSN and the ABSN in each semester were shown in Table 4.3Four types of comparisons were performed, which were comparison of all subjects between the ABSN and the BSN programmes at the same semester; self‐comparison between the first and the second semesters for each programme in three schools; comparison of each programme of the ABSN and the BSN among three schools in each semester; and comparison between the BSN and the ABSN at the same semester in the same school respectively.4.3.1p > .05) in the first and the second semesters respectively. It showed that similar responses towards the total scale and each subscale were reported in the first semester in the subjects of the BSN and the ABSN. Meanwhile, similar relationship was found in the second semester.No significant difference existed in the comparison of the total scale and each subscale between the BSN and the ABSN .For the subjects in the ABSN programme, the significantly difference only existed in one subscale of the NPVS‐R in the school A and C. In addition, a significantly higher score was reported in the first semester than that in the second semester for trust and professionalism subscales respectively (4.3.3p > .05; Table p = .04; Table Comparison of the BSN programme among three schools showed that no significant differences of the total scale and all subscales of the NPVS‐R existed at the first and the second semesters respectively (4.3.4t tests showed that the only significant differences of the NPVS‐R were existed in the second semester in the School A (p < .05; Table p < .05; Table Results of 55.1The only significant difference of demographic characteristics was that the subjects in the ‘ABSN’ programme were significantly older than the subjects in the ‘BSN’ programme. This fits the fact that the subjects in the ABSN programme need to obtain their first bachelor degree; then, they are qualified to enter this new ASBSN programme.Some students in the ABSN worked as part‐time, even full‐time, while they were studying this new nursing programme, it might indicate the independent needs and financial burden of these students as found in other countries (Kowitlawakul et al., 5.25.2.1Various types of results were reported for the NPVS‐R in literature. For example, some studies reported the total score only (Alfred et al., In this study, the range of mean score of the NPVS was 106.38 ~ 110.64. Similar mean score was reported in the nursing students from America as 109.2 ± 12.3 (Alkaya et al., Meanwhile, the subjects in both the BSN programme and the ABSN programmes reported a similar level of the professional value when they began their learning of professional nursing. In the western literature, students in the ABSN programme were recognized as highly independent and motivated (Penprase & Koczara, The results of present study also found that the total score and two subscales of the NPVS in the first semester were significantly higher than those in the second semester for subjects both in the BSN programme and the PBSN programmes. For each school, similar nursing courses and learning experiences were provided during the study period. These subjects received their fundamental nursing and the first clinical practicum during the second semester. To learn and to see the reality of nursing theory and practice might break their imagination and dream of ‘Angel in white’. These might reduce their professional value in return. However, the reduced dimensions of the NPVS in the BSN programme and the PBSN programme need further exploration.The self‐comparisons in the BSN programme, except in the school C, reported higher values in certain subscales and the total scale in the NPVS‐R in the 1st semester even though our follow‐up was one semester only. Similar trend was found in one subscale of the NPVS‐R in the ABSN programme in school A and C. Contradictory results were found in literatures that the professional values increased with time Fisher, . As mentThe subjects in the school B, both the BSN pram and the ABSN programme, reported a similar level of the NPVS‐R. Literature did find that there was no difference during school year (Caldwell & Katie, Present study showed that no significant differences existed in the NPVS‐R for the BSN subjects in three schools at the first and the second semesters respectively. It might be associated with the facts that the Ministry of Education in Taiwan regulates the curriculum of each nursing school in order to fulfil the requirements of the Nursing License Examination. Subjects in the BSN programme received similar nursing courses and learning experiences after they passed the National Entrance Examination and entered into these nursing programs. In addition, these three schools are experienced in teaching this program. Similar levels of the professional value are acceptable.For the ABSN programme, the subjects in the school A reported a lower score in the NPVS‐R than those in the school B and C in general. However, in the second semester, only the subjects in school A reported significantly lower activism than the subjects in school B. We have mentioned that the school A just started this new programme. Each school recruited their students in the ABSN programme independently. Different sources of students, previous learning and working experiences of students, and their lived experiences might have impact on their learning experiences and perception of nursing. Thus, levels of the professional value might be differently reported even though they just started their leaning in nursing profession. After one semester's learning, the students in school A catch up with the students in the other two programs, and activism was the only subscale reported lower than the students in school B. The improvements might be associated with the teaching and coaching efforts of faculties in school A that has been recognized as top one in Taiwan. It also indicated that progression of the professional values is possible through education.Our study showed that, in school A, subjects in the ABSN programme reported a higher level of professional value then subjects in the BSN programme. It was supported by literature (Feller et al., Similar curriculum and environments existed in these three schools, except the school A is a public school and just starts their first year of teaching for this new ABSN programme and the other two schools are private schools with 2 years’ experiences of teaching this new programme. Will the policy of school, environments, characters and experiences of facilities make the differences? Further exploration is needed.5.3The limitation of the present study was that these results cannot be generalized into the whole nursing programmes during the whole academic years because it only collected one class of subjects from 3/5 nursing schools and during one academic year. Larger sample sizes and longer duration of follow‐up are strongly suggested for further study. Thus, we can get a whole picture of the development of the professional value for students both in the BSN programme and the ABSN programme that have never been explored yet. Improving the professional value was possible from our findings with 1‐year follow‐up. Redesign teaching strategies to fit the characters of the students in the ABSN programme was strongly suggested. These might promote the development of the professional value and help the students in this new programme reach the ultimate goals of learning in nursing profession.6New type of the nursing educational programme was implemented in Taiwan recently. Students in the BSN and the ABSN programmes were purposely sampling and recruited during one academic year. The returned questionnaires showed the various patterns of changes in the professional value in each comparison with types of programmes and schools of nursing. Also, the increased professional value in the school A showed the possibility of improvement during the first learning of professional nursing. As educators, we must redesign our teaching strategies according to the different conditions of the students in each programme.The authors declare that they have no competing interests.Hui‐Ping Lin; Hsueh‐Erh Liu: Conceptualization and design of the study, and manuscript writing and revision. Tsai‐Hsiu Chang, Hsiu‐Fang Lee, C.W Chang and Hui‐Chu Chiang: Data collection. Hsiu‐Fang Lee, Yu‐Hsia Tsai, C.W Chang and Hui‐Chu Chiang: Data analysis. Tsai‐Hsiu Chang and Hsueh‐Erh Liu: Supervision of the whole study process. All the authors have read and approved the final version of the manuscript.


This review identifies and synthesizes literature related to the awareness of and attitudes towards sustainability and climate change from the perspective of nursing students and educators.A systematic integrative review.The review will follow the five stages outlined by Whittemore and Knafl: problem identification, literature search, data evaluation, data analysis and presentation. The data analysis will be based on inductive content analysis developed by Elo and Kyngäs. Principles of the Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) will also inform the review process.This review will offer insights about sustainability and climate change in relation to an important target population: the future nursing workforce and those educating its members. Findings might inform curriculum development, potentially contributing to a nursing profession that looks after the health of the planet and the health of the population inhabiting it. The use of the concept of sustainability includes environmental considerations at all levels. The implementation of sustainability will contribute to a development that maintains an environment that does not harm current and future generation’s opportunities for good health. Anåker and Elf  argue thCruz et al.  suggest Arguably, having an awareness of climate change, accompanied by a positive attitude towards sustainability, are important aspects of nursing and, therefore, nursing education. In view of this, this integrative review aims to explore the awareness of and attitudes towards sustainability and climate change from the perspective of nursing students, and from nursing educators.1.1This integrative review aimed to identify research on the awareness of and attitudes towards sustainability and climate change from the perspective of nursing students and educators.22.1We will undertake an integrative review of the literature to analyse and synthesize results from studies  framework  where the screening will take place based on inclusion and exclusion criteria listed in Table The search results from each database search will be imported into EndNote and transferred to Rayyan  that were retrieved at the initial screening phase will be manually reviewed for primary studies that might meet the inclusion criteria.Disagreements between reviewers in the abstract or full‐text screening phase will be resolved through discussion until an agreement is reached. If necessary, a third reviewer will be used to resolve any discrepancies as a measure of investigator triangulation, whereby decisions are made collaboratively to reduce biased decisions (Polit & Beck, All reviewers will inspect the final list of included studies, before progressing to the next stage of the review. A PRISMA flow diagram (Page et al., 2.2.3All included articles will be critically appraised independently by two members of the review team, using the Mixed Methods Appraisal Tool (MMAT, Hong et al., 2.2.4A data extraction Excel spreadsheet based on Cochranes framework (Cochrane Library, A narrative synthesis will be performed to explain the findings based on inductive content analysis developed by Elo & Kyngäs . This da2.2.5Findings will be presented under the headings of main categories from the data analysis, with examples from primary sources to ensure authenticity (Elo & Kyngäs, The study will be reported in accordance with the PRISMA guidelines (Page et al., 2.3Research Ethics Committee approval or patient consent will not be required as this is a protocol for an integrative review of published papers.3This integrative review will seek to comprehensively synthesize the existing body of research related to the awareness of and attitudes towards sustainability and climate change from the perspective of nursing and educators. The findings of the review could be considered when planning nursing curricula in relation to intended learning outcomes and pedagogies. Although some higher education institutes across Europe and elsewhere are already incorporating sustainability in nursing education (Richardson et al., Munn et al.  highligh3.1There are some potential limitations in the study design. The integrative review may not identify all relevant studies, because of difficulties in defining the concepts awareness and attitudes. To overcome this, we have identified a wide range of synonyms as search terms, to include as many definitions as possible Appendix . AdditioThe study will include quantitative and qualitative studies and few critical appraisal tools for mixed study reviews are available. We chose MMAT since it has shown content validity and reliability (Crowe & Sheppard, There is no specific reporting guideline for integrative or mixed‐method reviews. The use of review methods and a clear report of decision‐making will ensure a transparent review process. The use of the PRISMA checklist for systematic reviews (Page et al., We will adopt a narrative synthesizing of data. The interpretation of data may be open to bias but the involvement of the whole review team, with multiple perspectives during the entire process, will limit the risk of bias.3.2The findings of this integrative review might inform curriculum development, potentially contributing to a future nursing workforce made up of responsible global citizens who look after the health of the planet, and the health of the population inhabiting it.None declared.Jennie Aronsson made substantial contributions to conception and design of the study. She was involved in drafting the manuscript, revising it critically for important intellectual content and giving final approval of the version to be published. She is accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Andy Nichols has made contributions to the conception and design and has been involved in drafting the manuscript and given final approval of the version to be published. Paul Warwick has made contributions to the design of the study and been involved in the drafting of the manuscript and given final approval of the version to be published. Marie Elf made contributions to conception and design of the study. She has been involved in drafting the manuscript and revising it critically for important intellectual content and given final approval of the version to be published.


Chemists have followed this trend and incorporated 3D printers in their research laboratories and lecture halls, demonstrating the possibilities of this technique in a plethora of academic publications [Notwithstanding the versatility of the printed educational resources, their applicability in the analytical chemical laboratory has not yet attracted much attention because of the limited chemical compatibility –8 of theGiven the potential of 3D printing and the leading role that chemists will play in its development, the presentation of this technique to the young generation of chemists at the undergraduate level is not only capital but also fostered by the new guidelines of European Higher Education Area , 17 as aThe solid-liquid extraction of hydrophobic compounds from environmental solids is an analytical application very well suited to the analytical chemistry laboratory in which 3D prints can be leveraged because it avoids light eluotropic solvents and very high temperatures. To this end, we herein introduce a laboratory exercise for the “Integrated Analytical Chemistry Laboratory” (last semester of the BSc in Chemistry (year 4) at the University of the Balearic Islands, Spain) that aims to exploit 3D printing in extraction technologies. The students will design and prototype their own Soxhlet extractor by SLA whereupon it will be employed in a sediment analysis workflow, by attaching it to standard glassware, such as an Erlenmeyer flask and Liebig condenser, for extraction of polycyclic aromatic hydrocarbons (PAHs) using hexane prior to high-performance liquid chromatographic (HPLC) analysis.The abovementioned points referring to 3D printing (i to iv) will be implicit in the laboratory exercise, which will follow a (constrained) guided inquiry structure: The idea behind it is to engage the students in elucidating the possibility of replacing the standard glassware for low-cost, tailorable 3D prints. The students are expected to learn the CAD/CAM software, fabricate the extractor, and compare the performance with a glass counterpart, and even with a third extraction approach for validation purposes. The benefits of customization will be exemplified by designing a smaller working Soxhlet that permits less solvent and energy consumption than conventional counterparts and can be fabricated in 2 days. The disadvantages will be found when the addition of ≥5% acetone as additive to the extractant is proven incompatible with the resin, or the boiling temperature of the toluene is too high for use with the 3D resin. Detection and quantification of fluoranthene will be compromised when the unspecific leachates of the resin overlap with that analyte in the chromatogram. Finally, all the abovementioned points will have to be explained by the students from the chemical point of view  in their final report in which the pivotal position of chemistry in the developments of this still evolving tool will be demonstrated.The first session of this exercise 4 h) is organized in a separate computer classroom. Prior to starting, the students are provided with two previous papers from the authors describing the use of 3D printing in the analytical laboratory [ h is orgDuring the first hour, the students are trained by the instructor or a PhD student on the variety of standard operations enabled by the software . The teaAfter this first hour, a glass Soxhlet body is given to the students and they are asked to model it with a reduced inner volume. To foster the guided inquiry model, a broken Soxhlet can be given as well and ask them to fabricate a replacement for the second part of the exercise. In our case, the justification of the exercise is to compare whether the 3D printed labware can substitute the conventional glassware. In some instances, a given student had previous experience with CAD software as a hobby or attendance of freely configurable subjects as “technical drawing.” In those cases, the group required less attention, and this particular student was given the duty to assess that all of the individuals within the team commanded the software at equal times, in an example of 2-phase collaborative learning . They arWe realized that most of the groups invested too much time in small morphological features that have no practical relevance, so we decided, in some instances, to provide them with the Soxhlet CAD model from the instructor Fig.  after inThe first students’ Soxhlet printed did not work out because the syphon was blocked, and this was difficult to observe in the CAD model. Therefore, this group used the 3D printed Soxhlet provided by the instructor (see SI for specific details of the CAD design). Other problems experienced during the authors’ previous trials were the gargling effect in the syphon if the inner diameters were not big enough, and the excess of resin consumption. Because of time constraints, we suggest that unless the students’ prototype will obviously work, students print the model designed by the instructor . The importance of moving, rotating, and adding supports to the CAD model is explained. Briefly, the move action prevents the laser from degrading a section of the silicon film of the tank prematurely; tilting the model prevents failures due to strong overhangs, and the addition of supports allows printing those that are unavoidable, as well as separating the model from the platform, since the first layers are usually printed with increased exposure time for enhanced adherence to the printing platform. The model is afterwards loaded in the printer and a brief description of the working principle is presented. UV polymerization is also linked to organic chemistry subjects.Our model required 7 h and 42 min to get printed, and thus could not be done during the duration of the laboratory session. We decided to start printing in the morning, so the students from that group could see the end of the printing during the laboratory session. The starting time was negotiated with the students, so if they wanted, they could be present in the first minutes of the print. This attendance was not mandatory, but for three out of the four groups, all the members were available. At the end of the print, the almost finished extractor can be seen entering repeatedly into the resin tank, as well as the UV laser scanning the different layers, which is much more stimulating for the students than the initial printing hours, when the operation of the printer cannot be easily understood. Note that the orange cover of SLA printers prevents eye damage by the UV laser. Afterwards, the instructor retrieves the print from the moving platform followed by cleaning in an isopropanol bath and curing in a UV oven for 1 day (see SI for further details). Students are required to watch the cleaning process. Note that it is not possible to use the Soxhlet until 2 days after the design, so this exercise must be interleaved with another lab exercise, depending on the practicum schedule.In the second session (4 h), the students (i) assemble the Soxhlet extraction system, (ii) rinse it with appropriate solvent pending use, (iii) perform the solid-liquid extraction of PAHs from a real environmental solid sample, and (iv) analyze the extracts and process the chromatographic data. Two students work with the 3D printed Soxhlet and two with the glass counterpart in parallel. During the unattended Soxhlet extraction of the solid material, students perform together an ultrasound-assisted extraction using a probe system with the aim of introducing the concept of validation resorting to a different extraction approach, that is, the results from the 3D printed Soxhlet and the glass counterparts might be statistically identical, but different from another extraction methodology.The low-cost extraction system is assembled with the 3D printed Soxhlet body and off-the-shelf components: a 30-cm Liebig condenser, a 100-mL Erlenmeyer flask, and a heating plate. The conventional extraction system is assembled with a Soxhlet body, Dimroth condenser, round-bottom flask, and electric mantle. A thimble is created by wrapping a piece of laboratory filter paper, which is introduced into the Soxhlet body. Hexane is selected as the extraction medium instead of other common mixtures, such as hexane-acetone or toluene because of the greater hydrophobicity and lower boiling point, respectively. The solvent reservoir is filled with 2 syphoning volumes  of hexane through the Soxhlet and the system (without sample) is run for 30 min  for preventing carryover or unspecific interfering compounds leached from the printed material. A suspension of white flakes can be observed in the reservoir of the low-cost setup and is attributed to the reactivity of the solvent at increasing temperatures toward the still-green 3D printed module but does not jeopardize further applicability. Those first volumes are exchanged with fresh hexane, the thimbles filled with 1.00 g of PAH-containing sediment , and the heating elements turned on again. After 2 h of operation, the 3D printed and glass Soxhlet systems are stopped, the bodies detached from the flasks, and the latter kept on the heating elements for gentle drying of the extracts in the fume hood. Students may require help for disassembling the heated apparatus without exposing their skin to the hexane vapors . When the flasks are cooled at room temperature, the residues are reconstituted in 5 mL of acetonitrile, recovered with a glass syringe, filtered through a 0.45-μm Nylon filter, and made up with acetonitrile to 10 mL using a volumetric flask.−1 standard is injected by the students, which is already prepared (time constraints). A 5-level calibration curve is provided afterwards for data interpolation. HPLC conditions used in this work are available in SI. Examples of chromatograms for the 3D printed and classical glass Soxhlet are shown in Fig. While both Soxhlet systems are running, the students complete the ultrasonic probe-assisted extraction: 1.00 g of sediment is introduced in a 50-mL beaker along with 10 mL of acetonitrile and sonicated for 5 min. The suspension is recovered and filtrated through a 0.45-μm nylon filter with a 10-mL glass syringe and made up with acetonitrile to 10 mL. Thereafter, the students start equilibrating the HPLC column and analyze a standard solution. HPLC theory and applicability is taught in other lectures in analytical chemistry and instrumental analysis and lab courses as well including “Experimentation in analytical chemistry” (6th semester) or “Advanced chemistry laboratory” (7th semester), so students have an active role, yet always supervised by a technician. The guided inquiry format is respected as far as the time constraints enable: the students must scrutinize available literature and national/international norms to decide whether a standard method for PAHs is available or rather they must create their own. Only one 100 μg LAfter completing the two lab sessions, the students must fill an online questionnaire based on convergent, evaluative, and multiple-choice questions that was designed as a formative assessment tool to evaluate the achievement of the aims proposed in the introduction and the students’ ability of connecting 3D printing with other subjects of the chemistry syllabus. We paid special attention to introduce in the laboratory exercises all the concepts that would be asked for in the questionnaire. Critical thinking is expected in order to complete the post practicum questionary, such as not to neglect the power consumption of the printer to evaluate costs of the 3D printed Soxhlet, recording the syphoning frequency of both Soxhlet apparatus for comparing their energetic efficiency or observing the need to retighten the 3D printed system during warming, to name a few. To guide students toward the correct answers, they could see the questions previously and check literature  before submit the answers online. They had up to 3 attempts to answer all the questions, from which they receive a feedback every time. Yet, a point was subtracted from the final qualification in every second and third attempt. Final qualifications  were 10 for 44% of the students, 9 for 31%, 8 for 13%, and 7 for 12%. In no case, the questionary lowered the grades of the students. The questionary was reviewed upon the application to other audiences ; and thus, improved (and expanded) questionnaires were generated, from which a model test can be found in SI.Given the strong relationship between 3D printing and analytical chemistry, we have herein proposed an integrated laboratory practicum in which the students are engaged to design a Soxhlet extractor with CAD/CAM software followed by fabrication of the prototype using an inexpensive SLA 3D printer, for further application to the analysis of an environmental solid. The fast prototyping by 3D printing makes this proposal amenable to the students’ laboratory time and opens the door of 3D printing to educational applications as a cost-effective alternative to dedicated glassware because it (i) allows customization of volumes and shapes, (ii) yields transparent components readily compatible with grounded glassware, and (iii) enables integrating several functionalities in a single print. The results demonstrate that the prints are completely compatible with non-polar solvents at moderate temperatures. The extracts however might contain some interfering compounds resulting from leached monomers/oligomers, but the comparison against a classical glass Soxhlet and acetonitrile-based ultrasound-assisted extraction revealed no significant differences for most of the target analytes. The guided inquiry format of lab courses paved the way for introducing a hands-on exercise with the CAD/CAM software and 3D printing in the frame of analytical chemistry, and to relate the technical details of such manufacturing process with the underlying chemistry principles learned in previous semesters.ESM 1(DOCX 142 kb)


Verbeamtung). Attention will be payed to the fact that this success relied on the activities of mediators, who translated and conveyed the patients’ interests to society at large. This victory was concordant with similar initiatives in other fields of the diabetic life, including sexuality and lifestyle management. Therefore, efforts to achieve civil servant employment for diabetic patients were constitutive of a broader initiative that changed the image of the disease and promoted the integration of diabetic patients into West German society.Patient history has enriched medical history since about the 1980s. But there are still research gaps in certain periods and themes, especially in topics related to the medical history of West Germany. This paper deals with the efforts of patients, lay persons, and medical advisors (diabetologists) to enable diabetics to secure employment as civil servants ( Since about 1985, when the path-braking paper of Roy Porter was published, teaching and research on the history of the patient attracted increasing attention. This approach to patient history was very much embedded in cultural history; it involved examining the dependency of diagnostics and treatment on national habits and attitudes. Researchers focused mainly on low status social groups who stood at the margins of society and favored alternative healing systems Porter . This paEspecially when looking at these marginalized patient groups, one still comes across significant research gaps, especially with respect to those historical periods and locations which have generally received little attention.3In the following, we will explain these circumstances using the example of diabetic patients. This group is exemplary due to its long-lasting history of empowerment. By tracing the group’s activities in West Germany, we can examine the interrelations of time-bound social affairs, medical problems and the development of group consciousness. In spite of the surge in research interest on medicine in the early Federal Republic after the collapse of Nazi Germany, with its focus on the mode and strategies of the reinstatement of the physician-patient relationship after 1945, the field demands further attention  in the period from 1950 to approximately 1970. The paper wants to elucidate how patients, lay-people and therapists translated a new concept of the disease of diabetes for an audience of politicians. This translation was necessary not only to achieve acceptance and tolerance in general, but also for securing employment in post-war Germany. This engagement was shaped by the socio-political conditions in West Germany after 1945, since the process of democratization corresponded with an increasingly influential media landscape in which the specific interests of social groups could be articulated (Bösch & Frei This article examines to what degree diabetic patients were successful in obtaining access to the position of civil or public servants (The Diabetic (Der Diabetiker) as the organ of the self-help society The German Diabetic Association (Deutscher Diabetiker Bund). Also, unprinted material from different ministries of the Federal Republic will be considered . These files are kept by the German Federal Archive in Koblenz. Based on this material, it is possible to develop a much more detailed description and analysis of the path to civil service than exists in the short comments within the literature to date.The basis of this enquiry is a hermeneutic analysis of printed sources and especially the journal In the following, I will first describe important preconditions of the process while concentrating on diabetes and its history up to 1945. I then deal with the status of diabetic patients in West Germany after 1945 and explore first initiatives by diabetics to gain access to civil servant positions in 1958. In the third subsection, I focus on new discussions that arose in 1969 and led to a more subtle understanding of diabetes and diabetic patients in the political sphere. Finally, in a fourth subsection, I analyze my findings and make some concluding remarks.Only in the last decades of the nineteenth century did the signs and symptoms of diabetes become interpreted into modern terms. Physicians located the origins of the disease in the pancreas, which became incapable of producing enough insulin. This condition resulted in problems utilizing glucose and inhibited the processing of fats. Around 1900, a person with diabetes had a life span of approximately 15 years and could expect to die of starvation. The only medical measure available to combat the disease was a strict low-calorie diet with severe restriction of carbohydrates. Managing the disease was only possible on the basis of a close cooperation between patient and physician. This cooperation was embedded in a system of paternalistic medicine where the patient received clear directives from his medical supervisor Feudtner : 6–21.Volksgemeinschaft). Maintaining individual health was subordinated to contributing to victory at war. Insulin was rationed and hardly available. Diabetic patients in the “Third Reich” were reduced to the old image of the starving patient with a life expectancy of only a few years. This image came to dominate popular attitudes towards diabetics and survived the end of World War II  und Charles Best (1899–1978) successfully extracted and isolated insulin. Although the impact of “medical discoveries” should not be overestimated, there is no doubt that the isolation of insulin changed lives and transformed the social context of diabetic patients tremendously. By substituting insulin, patients could nearly reach the age of physiologically healthy persons. This treatment required careful attention to the regular supposition of insulin and the observance of strict dietary measures. Caring for diabetic patients shifted from accompanying a dying human to accompanying a chronically-ill patient by treating the long-term consequences of her disease—e.g. blood vessel damage or damage to the retina. The shift of treatment and appearance of diabetes began in the 1920s and set off a wave of research interest in diabetes. II Roth : 4–9.Deutscher Diabetiker Bund, DDB) in 1951. The aim of this association was to support patients and their families and to advocate for the integration of diabetic patients in West German society.After 1945, amid a surge of new philanthropic ventures, an initiative for diabetes was started by the journalist Robert Beining 1898–1961). Already during the 1930s Beining dealt with problems of nutrition and he became one of the early pioneers of diabetic nutrition in West Germany, promoting this innovative field of interest. In doing so, Beining acted an agent who could bridge the gap between diabetic patients and German society. Together with six other people he founded the German Diabetic Association (1. AlreadThe Diabetic (Der Diabetiker) to discuss the health as well as the social problems facing diabetic patients. Very soon thereafter, Beining asked physicians to join the editorial board of the journal. Already in 1951, a medical advisory board (Beirat) was founded.8Also in 1951, Beining and his colleagues founded the journal From its early days, Robert Beining and the Diabetic Association agitated against the idea that a diagnosis of diabetes meant continuous starvation. Combining dietary measures together with the application of insulin could now enable patients to lead an ordinary life with an almost normal life expectancy. By being informed and disciplined, the patient could manage his work just as healthy colleagues did. In light of this improved management, Beining held, it was wrong to declare diabetic patients unfit for work in an early stage of their career. In April 1956, Richard Boll, the district-chairman of the DDB Hamburg, pointed out in his speech on “the social duties of the German Diabetes Association” that “educated and disciplined diabetics have no major non-productive time compared with other men. Also, they need not to be declared disabled prematurely.”The Diabetic. His transfer to a civil servant position was refused by the administration of a German town since “early disability has to be envisaged because of diabetes.” The patient now asked for help and especially for an acknowledgement of the new perspectives on the diabetic working life:… many colleagues are already taken over into civil service […] I would like to ask you, whether—from your point of view—there are really no options to become a civil servant as diabetic. Aren’t attitudes about early disability of diabetics outdated? Do you know, how these matters are handled elsewhere? What would be your further advice?10Because this attitude did not correspond with the public image of the diabetic patient, the job situation of diabetes patients remained precarious, especially in the case of civil servants. In 1956, a 26-year-old patient sent a letter of complaint to the journal This patient—one of many—was not only concerned about adequate dietary measures and the accurate insulin dose. At stake was his work life and his working place. So he took the initiative to change his labor conditions.News of improved treatment management fueled the debate on discrimination against diabetic patients. In 1957, the chairman of the DDB district group in Düsseldorf, the physician Paul Schwenger, aggressively advocated for the right of diabetic patients to work and to be accepted as regular workers. Schwenger’s speech received significant attention since it was held on the occasion of the foundation of the Düsseldorf Group. Schwenger promised that he could “offer the Ministry of Labor a reserve work force of 200,000 to 300,000 out of the community of diabetic citizens.”Although physicians played their part in promoting the productivity of diabetes patients, it was the layperson Robert Beining who launched the decisive initiative to improve the options of diabetic patients in the public service. In April 1958, he wrote a letter to the Federal Minister of Labor and Social Affairs.15Entstehung und Entwicklung des Beamtenrechts in Deutschland, 2021). This “Framework Law to Unify Civil Servant Law” (Rahmengesetz zur Vereinheitlichung des Beamtenrechts/Beamtenrechtsrahmengesetz—BRRG) stipulated that “Appointments should be made on the basis of aptitude, ability and professional competence without consideration of sex, origin, race, believe, religious or political attitudes, origin or personal relationships.”At this point it is important to consider the background of diabetes patients’ problems with civil servant positions and the reasons for Beinings’s appeal. As “state servants” these civil servants had a special position, which had their origins in the eighteenth-century efforts of the local elite to build up a reliable staff for territorial administration. In these positions, they were bound to the sovereign for their whole lives. In exchange they also enjoyed special privileges, such as a life-long income and other advantages. After 1945, these posts became disreputable since they had been abused to pursue the racist policy of the Nazi regime. Nontheless, it was decided to keep up the civil servant system. Different laws in the German states were bound together in 1957 when the Federal Republic set out civil servants’ activities when creating a specific law, which assimilated regional specifities within a general guideline for administering civil servant posts (Deutscher Handwerkskammertag) sent a reply with the comment that they had no data regarding the problem. Also, the German Industry and Trade Company (Deutscher Industrie- und Handelstag) mentioned that they had “no material.”The Ministry mentioned received Beining’s letter (Department No. I) and did not react for a month. Remarkably, in May 1958, the matter then was delegated to the Department No. II, which was in charge of care for “disabled persons.” This delegation illustrates the image of diabetic patients as disabled that still prevailed. Nonethless, Beining’s request was taken seriously. Plans were made to evaluate the matter and to include the Federal Ministry of Internal Affairs for further decisionmaking.Bundesgesundheitsamt).21In the course of July 1958, the matter was handed over to the Federal Ministry of Internal Affairs, which at the time acted as a department the Federal Health Office , and in case of increased carbohydrate intake not more than 20 g per day. There should be no disposition to cetonuria.Admittance to a civil service post should take place only if the applicant is over 25 years old and her diabetes is under permanent control for at least two years. Hiring on probation for one to two years with final evaluation should be performed in cases with low risk but not enough evidence.Applicants with diabetes fulfilling the prerequisites mentioned above should be admitted to the pension fund without any further limitations. Usually, the fitness for employment should be clarified individually by expert medical assessment.Diabetic patients with the necessary education and knowledge, who need no insulin, can carry out the respective job like someone else.Diabetic patients who need insulin should avoid jobs with irregular working hours  to avoid changes to insulin and dietary plans. Also—for reasons of security—they should not be committed to activities which endanger themselves and others in case of hypoglycemia .Every diabetic patient should be examined in intervals, which should be determined on a case-by-case basis. Generally, these intervals should not exceed 12 weeks. Every year, a thorough general medical examination should be carried out.In case of complications, which do not restrict the working capability of the respective person but suggest the change of the working place, this change should be arranged by the medical health officer responsible.24Nonetheless, diabetologists backed the attempt of the Diabetic Association to have the issue addressed. Increasingly diabetes management was viewed in line with Gerhard Katsch’s views as a psychosomatic and holistic process that required collaboration with the patient as well as her integration into the labor world. Although Katsch worked at the University of Greifswald within East Germany, his voice was still heard in the west. He was still active until his death in 1961 shortly before the erection of “the wall” Falk : 80–84. In summary, these guidelines represented a compromise between the needs of governmental institutions to secure the employment of healthy candidates and the right of diabetes patients to be acknowledged as candidates who are able to fulflil the demands of civil service. The role of the medical expert and his authority was embedded in this scheme, yet the medical expert also acted as a spokesman of patient rights. In conclusion, he served as a mediator between the state and the patient.The combined initiative of the DDB and physicians exerted pressure on the Ministry of Internal Affairs. The latter agreed—with only minor amendments—to the new guidelines for employment of diabetic patients as a recommendation for future use in almost all ministries of the Federal Republic. These guidelines provided the basis for the employment of diabetic patients who where at least 25 years old and had their disease under medical control at least for two years and with no long-term damages. The adoption of these guidelines represented a historic break, because now diabetic patients could be appointed as civil servants.25Although successful, the guidelines did not solve problems in the long run. They remained too general. Prejudices surrounding the employment of diabetic patients could be revived if necessary. Therefore, critics called for amendments and changes. Eleven years later, in 1969, one specific event promoted new discussions about the guidelines. Its starting point were the activities of Hellmut Mehnert (*1928), a diabetes specialist and medical pioneer in diabetes treatment in Munich. Mehnert had worked as a guest physician in the USA, where he had collaborated with Elliott P. Joslin. In 1969, Mehnert was appointed director of the Third Medical Department of the Clinic Munich-Schwabing. Later, he became a nationally and internationally well-known physician and scientist, who stood for patient-adjusted medical practice.26Deutsche Diabetes Gesellschaft, DDG) as the preeminent body of diabetes specialists,29In 1969, Mehnert was asked to evaluate the status of an applicant for a civil servant position at the Federal Postal Service. The Postal Service administration urged Mehnert to perform specific food tests and above all to determine the fasting value of blood sugar. Mehnert was embarrassed by the request and sent a complaint to the administration, on the basis that the tests were outdated and they would endanger the patient’s good health based on a well-belanced blood glucose value.Berliner Diabetiker-Sozialwerk)  Kurow : 23–27.The Diabetic. In June 1970, the story of an employee of an insurance company  was published. The employee’s application for public servant appointment had been rejected by Public Health Officers and only a second medical reference based on the support of the German Diabetic Association had enabled the employee to achieve the position wanted  were excluded from possible governmental service. Patients had the obligation to maintain their health status in regular consultation with their diabetes specialist.34This means that the clarifications and improvements for patients were accompanied by loss of self-management. The price the “diabetics” paid was a more rigorous medical observation with regular medical examinations. Specific activities such as driving machines in public were excluded as job options and there was a more subtle differentiation between insulin dependent diabetic patients and older ones, who merely required dietary measures. Most remarkably, all patients deemed “not cooperative” . He therefore argued at the ministerial level against this “Danaian gift” (Danaer Geschenk). Kurow argued that it would be possible to adjust treatment effectively to avoid complications and thus to enable state service. The status of “severe disability,” in contrast, hampered all legislative efforts to grant diabetics protection, since it led to a general, fundamental discrimination against them. Kurow supported his statement with the attachement of patient files.37Therefore, discussions about the guidelines did not cease. In conclusion, two key aspects that fueled the continuous discrimination of diabetes patients can be identified. The first one was the question of diabetes patients’ status as “severely disabled” on the basis of a certain certificate which allowed them to apply to public servant posts successfully. Since it was more convenient to have the certificate than to quarrel and discuss with employers, diabetes patients often decided in favor of this document. Since about 1976, the new diabetes guidelines were successively hampered by the disability option. In accepting the certificate, diabetic patients agreed to their own pathologization in order to secure a job. Günther Kurow tried to convince his fellow diabetics to resist taking this step. In his view, it torpedoed all the efforts of the Amtsärzte) was one important hindrance to improve diabetic patients’ rights regarding civil servant appointments. This group acted as the “gate keepers” to jobs in governmental health institutions, backed by a long tradition of state-supported conservative policy. They proved to be a decisive backbone of public health policy during the Nazi period as they were adherents of a segregationist racial hygienist agenda (Labisch & Tennstedt Erbfehler) in the family of the patient. Health officers continued to use this justification, even when the diabetic patient was the only one in the family with no hints of any hereditary origins of the disease. The request for compensation was rejected with the remark that hereditary laws would be too complicated for laypeople to understand and that there would be latent (hidden) hereditary defects  and tried to convince his health officer colleagues that a diabetic patient with finely adjusted insulin dosage and dietary measures could do her job over the course of three or four decades without problems. Kühnau further argued that persons with diabetes would behave extremely responsibly; he used traffic accident statistics to make his point.DDG to give more details about criteria for estimating adequate healthcare in young diabetic patients.41Based on these racial hygienist thoughts, many health officers interpreted the guidelines in their own way. To a certain extent, they abused them to prevent the employment of young diabetic patients as public servants. During the 1970s this led to a conflict between patients and health officers. Diabetologists tended to support their patients. The conflict between patients and diabetologists on one side and health officers on the other side finally escalated in 1978. The diabetologist Joachim Kühnau visited the sessions of the Panel of Medical Assessment of the Committee of Excecutive Health Officers  Statista , discussAfter 1945, diabetic patients were confronted with old prejudices even in the democratic society of West Germany. The challenge for these patients was to improve their situation. Patients, lay supporters, and physicians could decipher outdated views on the disease and translate modern diagnostic and therapeutic values. Together with their supporters, diabetic patients constructed a new view of the disease, creating the image of a patient who was no longer a victim of starvation, but instead a “conditionally healthy” person with average life expectancy. This change of perspective extended access to diverse domains of social life for diabetics.Beamte). Beining’s initiative was successful, because the guidelines set up by the Insulin Committee of Diabetologists were accepted by diverse West German ministries. He was the first mediator within our context, who brought the intitiative for diabetic patients one step forward.This story of empowerment overlaps with the history of other patient organizations in Germany after 1945. Though every organization worked in a unique context that strongly depended on the disease or problem, there are certain commonalities that can be observed , also a diabetes patient, had widened the scope of his biochemical work into the sphere of diabetes treatment, thereby pioneering the foundation of patient self-help groups. Similar to Kurow’s later work, Lawrence had tried to mobilize diabetic patients to improve their situation when networking in society and politics Prüll : 1367f..Mehnert, Kurow, and Lawrence in Britain were advocates of diabetes patients in matters of lifestyle. On the other hand, they never gave up their ideas about professional medical conduct. In order to improve the guidelines of 1959 and the prospects for employment, they needed to promote the idea of medical control of diabetes patients. Through this mediator work, both patients and physicians benefited from their collaborative translation of knowledge about diabetes. Diabetic patients gained a foothold in the sphere of civil service, while diabetes specialists extended their interpretative role and consolidated their influence as indispensable therapists and consultants. Collaboration between patients and physicians involved more than simply granting patients freedom to perform their own medical insulin dosage research.The successful attempts to fight against the discrimination of diabetic patients promoted by the likes of Beining, Mehnert and Kurow was accompagnied by other initiatives, which also aimed at the advanced integration of diabetes patients into societal life. Therefore, the story of the diabetes patients’ struggle to obtain civil servant positions appears as the final chapter of this story. First attempts to integrate this group into social life involved the initiative of patients to improve their living conditions related to marriage and sexual life. During the second half of the 1950s, diabetic patients forced a discussion about intimacy and sexuality on their physicians, who often claimed marriage between diabetes patients and healthy citizens would result in diabetic offspring. According to the prejudices of the health officers, even diabetes specialists had concerns regarding hereditary origins of diabetes. Therefore, they tried to convince their patients to avoid marriage with diabetic patients. But the latter resisted and forced the editors of the diabetes journal to promote marriage and engagement advertising. This way they could increase their chances of partnership in spite of the burdens of their disease. These processes were also based on negotiations and discussions between diabetes patients and diabetologists, who needed to be convinced to follow the ideas of their patients: diabetic patients advocated for the acceptance of their own needs and attitudes. As early as 1956, the taboo subject of sexuality was brought out into the open. Through patients’ initiatives, which were soon embraced by diabetologists, they changed both the treatment and the therapeutic concepts of the disease itself. This process in turn promoted the democratization of medicine, as the empowerment of the patient was accompanied by other similar processes in the first decades of the Federal Republic. Prüll .The second project taken up by patients was related to diabetes therapy itself, namely dietary measures. It involved diabetic patients redefining their “sense of life” as an expression of growing self-esteem; in many cases they cultivated their dietetic life as a counterpoint to hedonistic glutony of West German society in the 1950s. Based on the sense-of-life theory of the philosopher Paul Tiedemann, who focused on self-awareness as a cornerstone of a satisfying life experience, it was possible to analyze the reaction of diabetes patients to the increasingly well-to-do lifestyle in West Germany: Diabetes patients praised the resistance to the temptation of luxury foods, smoking and drinking. Moreover, they held themselves up as “ideal” members of society. One diabetic stated in 1957: “We do not live for eating, but we choose our food in a way to be able to fulfill our duties to society and to the family we have founded” (Prüll The matter of civil service employment forms a third part of this history, since the patients together with their helpers and advocates remolded the image of the disease diabetes. Achieving the path to civil service employment was another step on the way to integrating diabetic persons into the job market and work life. Although employment guidelines came out of compromise with diabetologists, the improvement of employment prospects for diabetic patients as civil servants can be understood as emblematic of a significant development in patient rights and a departure from the long shadow of nineteenth-century paternalistic medicine and the excesses of Nazi Germany.


In order to derive accurate concentration–response relationships, it is important to determine the local concentration of nanoparticles to which the cells are actually exposed rather than the nominal concentration of nanoparticles in the cell culture medium. In this study, the sedimentation–diffusion process of different sized and charged gold nanoparticles has been investigated in vitro by evaluating their settling dynamics and by developing a theoretical model to predict the concentration depth profile of nanoparticles in solution over time. Experiments were carried out in water and in cell culture media at a range of controlled temperatures. The optical phenomenon of caustics was exploited to track nanoparticles in real time in a conventional optical microscope without any requirement for fluorescent labelling that potentially affects the dynamics of the nanoparticles. The results obtained demonstrate that size, temperature and the stability of the nanoparticles play a pivotal role in regulating the settling dynamics of nanoparticles. For gold nanoparticles larger than 60 nm in diameter, the initial nominal concentration did not accurately represent the concentration of nanoparticles local to the cells. Finally, the theoretical model proposed accurately described the settling dynamics of the nanoparticles and thus represents a promising tool to support the design of in vitro experiments and the study of concentration–response relationships.The biological response of organisms exposed to nanoparticles is often studied  In the pharmaceutical sector, for example, dose–response analysis is essential to estimate the dose at which a drug can have a therapeutic or adverse effect in patients . One of Gold nanoparticles are of great interest for a number of biomedical applications since they are a promising carrier for the targeted delivery of therapeutic, diagnostic and imaging agents in the human body . They arIn vitro studies of nanoparticles typically involve exposing a monolayer of cultured cells that are adhered to the bottom of a well in a microtiter plate. Frequently investigators use the nominal concentration of nanoparticles in the cell medium as a basis to determine dose–response relationships without taking into account that the concentration may not in fact be homogeneous in the well over time. This is due to the fact that nanoparticles in solution are subject to gravitational sedimentation forces, Brownian diffusion forces and inter-particle forces which affect the transport of nanoparticles within the medium. This in turn controls the concentration of nanoparticles local to the cells that can influence cellular uptake and toxicity [toxicity ,9. Krug,toxicity . The aim. 1.1a). After a certain time, an unstable equilibrium is achieved, and nanoparticles are randomly but homogeneously distributed in the medium (b). Gravitational sedimentation becomes relevant for dense particles  with a diameter larger than 10 nm, causing a concentration gradient from the bottom to the top of the solution [c) [Nanoparticles dispersed in solution tend to sediment, diffuse and aggregate as a function of intrinsic properties  and as a function of system properties . Once injected in solution, the process dominating the dynamics of nanoparticles is the diffusion process and nanoparticles tend to move from zones of high concentration to zones of low concentration a. After e medium b. Gravitsolution . This cotion [c) . The timMost studies described in the literature attempt to experimentally investigate the sedimentation–diffusion equilibrium process by acquiring UV–visible absorption spectra over time in an attempt to determine the behaviour of the nanoparticles in solution –15. UV–vIn this study, we investigated the sedimentation–diffusion process and evaluated the settling time of gold nanoparticles in a range of simple and biological solutions. Nanoparticles were tracked by exploiting the optical phenomenon of caustics, and the nanoparticle concentration profile was directly evaluated by acquiring consecutive optical sections from the bottom to the top of the solution and counting the number of particles in each section over time.Investigators have also developed theoretical models to predict the observed sedimentation–diffusion behaviour of nanoparticles in solution . The mosIn this study, we investigated the settling dynamics of different sized gold nanoparticles in water and cell culture medium at a range of different temperatures by exploiting the optical phenomenon of caustics ,27. The . 2. 2.18 particles ml−1. Nanoparticle dynamics in solution were monitored in a standard optical inverted microscope  mounted on antivibration feet  to isolate the sample from the environment. The microscope was equipped with a stage-top incubation system  to control the temperature and the amount of CO2 present during the experiments. To generate caustic signatures of the nanoparticles, some simple adjustments to the normal set-up of the microscope were made following the procedure described by Patterson & Whelan [z-direction [Spherical, citrate-capped, negatively charged gold nanoparticles (pH 7.7) were purchased from BBI Solutions, with nominal diameters of 60 nm, 80 nm, 100 nm and 150 nm. Spherical positively charged gold nanoparticles were purchased from nanoComposix, with a nominal diameter of 100 nm. The as-supplied concentrations were reduced by adding the concentrate to ultrapure-deionized 0.2 µm membrane filtered water as appropriate to obtain a constant working concentration of 10& Whelan . The cau& Whelan ,27. The . 2.2n is the normalized nanoparticle concentration, D is the diffusion coefficient and V is the sedimentation velocity . The initial condition was n = 1 for all z and t = 0. The boundary condition was based on an assumption of nanoparticle conservation in the system, expressed by no particle flux across the top and the bottom of the solution (at z = 0 and L being the depth of the solution).The objective of the predictive analysis was to calculate the height profile of the nanoparticle concentration in the solution as a function of time. It was achieved by solving the Mason–Weaver convection–diffusion differential equation :2.1∂n is not correct and needs to be derived supposing a function of the form D). We can start with Fick's second law:J is the flux of nanoparticles. In our scenario:DJ is the diffusion flux defined by Fick's first law:SJ is the sedimentation flux expressed asFollowing the assumption that the diffusion coefficient D:z coordinate was first transformed to a non-dimensional form:Combining (2.2) to (2.5), we get the Mason–Weaver equation with a non-constant diffusion coefficient, L/100 so the non-dimensional Δz = 0.01, and the time step Δt = 0.4 s was chosen to maintain a stable solution of the equation over time.Then equation (2.6) was solved using the Euler explicit method where the derivatives were approximated by finite differences. The space and time domains were uniformly partitioned in a mesh. The space step was ut. The equation (2.6) after the approximation by finite differences becomesu, we can obtain the concentration at time u + 1 :The points To calculate the nanoparticle concentration at the boundaries, we apply the boundary condition that there is no particle flux across the top and the bottom of the solution. By combining equations (2.2) and (2.3), the Mason–Weaver equation is obtained as a function of the nanoparticle fluxes:L (j = 100), these four fluxes, depicted also in the computational stencil (b), are as follows:At the top boundary, z =  stencil b, are asz = 0 (j = 0), the four fluxes c) are as follows:Consequently, the equation (2.11) at the top boundary takes the form and JS′ c are as D(n) as a function of the normalized local concentration of the nanoparticles n can be expressed asDexp = 5 × 10−13 m2 s−1 is the experimental value of the diffusion coefficient measured at a low concentration of nanoparticles in the solution at 23°C and StEinD is the diffusion coefficient according to the Stokes–Einstein equation [n50 = 1.5 and k = 30, representing the nanoparticle relative concentration normalized at which the transition happens and the slope of the transition, respectively.The diffusion coefficient equation . The traThe modified version of the Mason–Weaver equation is used in this paper to theoretically predict only the settling dynamics of nanoparticles in solutions at 23°C because of the lack of data concerning the experimental diffusion coefficient exhibited by nanoparticles in solution at higher temperatures.. 3. 3.1The effect of nanoparticle size on the equilibrium of the sedimentation–diffusion process is shown in a). As expected, the Mason–Weaver equation, with the Stokes–Einstein diffusion coefficient and Stokes sedimentation velocity, is not able to accurately predict the experimental results. The theoretical upward diffusion flux, which opposes the downward sedimentation flux of nanoparticles, is higher than the experimental one, leading to an overestimation of the concentration of the nanoparticles not settled once equilibrium is attained. The main factor affecting the diffusion flux in the Mason–Weaver equation is the diffusion coefficient evaluated using the Stokes–Einstein equation. Coglitore et al. [8 particles ml−1, the diffusion coefficient of the nanoparticles was at least one order of magnitude smaller than the theoretical value predicted by the Stokes–Einstein equation and was independent of nanoparticle size.The reliability of the classical Mason–Weaver equation in describing the concentration profile of the nanoparticles in solution over time has been assessed by plotting the concentration of not-settled nanoparticles together with the Mason–Weaver predictions a. As expe et al.  found byet al. [et al. [Another limitation of the model is the assumption that the sedimentation velocity and diffusion coefficient exhibited by the particles in solution are constant with time, without taking into account that the concentration gradient formed once equilibrium is achieved can directly affect the sedimentation and diffusion behaviour of the nanoparticles. Ganguly & Chakraborty  demonstret al.  explaineet al. ,31. On t [et al.  reported [et al. .−13 m2 s−1, as reported in previous studies for gold nanoparticles at concentrations less than or equal to 108 particles ml−1 [figure 4b, the modified model predicts the experimental data more accurately than the classical Mason–Weaver model and can be used to simulate the settling dynamics and estimate the nanoparticle concentration over time. The model presented in this work is also able to approximate the concentration profile of nanoparticles in solution. As shown in A modified Mason–Weaver theoretical model has been developed to overcome the limitations of the classical Mason–Weaver equation, taking into account the experimental evidence and physical hypotheses discussed above. The distinctive feature of the model proposed in this study is the dependence of the diffusion coefficient on the local concentration of the nanoparticles (equation (2.6)). The diffusion coefficient for each particle size tested has been set equal to the experimental value of 5 × 10les ml−1 –24, and The minor deviations between the modified Mason–Weaver model and the experimental data can be explained by the fact that the sedimentation velocity in the model has been kept constant at a value that gives the best fit for each size of nanoparticle tested and did not vary with their concentration . The sedimentation velocity was kept constant to reduce the mathematical complexity and computational requirements of the modified model, but also because of the lack of experimental measurements. The latter was due to the impossibility of measuring the sedimentation process independently from the diffusion process at different time steps with the technique used in this study. Moreover, the original Mason–Weaver equation does not take into account forces that are considered to be dominant at the nanoscale .. 3.2a). The results obtained demonstrate that at 37°C the sedimentation velocity increased and that the solution reached the sedimentation–diffusion equilibrium 30 min before the same solution at 23°C. The higher temperature directly influences the aggregation kinetics of gold nanoparticles, enhancing their aggregation rate in solution [b). At higher temperatures aggregates of particles form at an increased rate and sediment faster than monodispersed nanoparticles in solution due their larger mass. The nanoparticle solution kept at 37°C exhibited a more evident depletion of the primary absorption peak and a higher secondary absorption peak when compared with the same solution kept at 23°C. The depletion of the primary absorption peak has been extensively reported as an indication of the reduced number of monodispersed nanoparticles in solution [The effect of temperature on the sedimentation–diffusion equilibrium was evaluated by testing 100 nm diameter negatively charged gold nanoparticles in water at 23°C and at the biologically relevant temperature of 37°C a. The resolution . Colloidsolution . The UV–solution ,36. The solution . Hence, solution .Figure a. There is no apparent difference between the sedimentation rate exhibited by these two types of nanoparticles; but positively charged nanoparticles exhibit a higher concentration of not-settled particles with respect to their negatively charged counterparts at equilibrium. This behaviour can be explained by considering the colloidal stability of the positively charged nanoparticle solution used in this investigation. The UV–visible analysis (figure 8b) confirmed the presence of fewer aggregates in solution at 23°C after 4 h when compared to the solution of negatively charged nanoparticles kept at the same temperature for the same time (i.e. less evident depletion of the primary absorption peak and no secondary absorption peak at longer wavelengths). Hence, more monodispersed particles are free to diffuse back into solution from the sediment leading to a higher concentration of not-settled nanoparticles at equilibrium.The comparison between the sedimentation–diffusion behaviour of oppositely charged 100 nm gold nanoparticles in water at 23°C is shown in figure 8. 3.3To characterize nanoparticle behaviour in biologically relevant solutions, the dynamics of sedimentation–diffusion equilibrium has been investigated by dispersing 100 nm diameter negatively charged gold nanoparticles in Dulbecco's modified Eagle medium (DMEM) with 10% fetal bovine serum (FBS). This solution was chosen because it is commonly used to support the growth of a range of mammalian cells and to understand the concentration of nanoparticles delivered at the cellular level. The potential presence of a two-dimensional adherent cell monolayer is expected to have an impact on the dynamics and concentration of nanoparticles in close proximity to the cell  due to uptake internalization as well as potential excretion by the cells.. 4in vitro studies using adherent two-dimensional cultures, where the actual concentration of nanoparticles interacting with cells is needed to characterize and evaluate the cellular response. The theoretical model presented in this work shows good agreement with experimental data and is able to accurately describe the settling dynamics and concentration profile of nanoparticles in solution, making it a promising tool for the design of in vitro experiments and the study of concentration–response relationships.In this paper, we have presented an experimental investigation of the process of achieving sedimentation–diffusion equilibrium for nanoparticles in solution and developed a theoretical model able to predict the settling dynamics of nanoparticles over time. The experimental results demonstrate that nanoparticle size, colloidal stability and solution temperature drive the sedimentation–diffusion equilibrium of nanoparticles in solution and that, for particles larger than 60 nm in diameter, the target dose differs significantly from the administered dose in both water and cell culture medium. This evidence should be taken into account when performing Click here for additional data file.


GNSS Reflectometry (GNSS‐R) measurements over inland water bodies, such as lakes, rivers, and wetlands exhibit strong coherent signals. The strength of the coherent reflections is highly sensitive to small‐scale surface roughness. For inland waters, this roughness is primarily due to wind‐driven surface waves. The sensitivity of the coherent reflections to surface roughness can be leveraged to estimate wave height profiles across inland waters. Coupled with a wind wave model, an approach to retrieve a wind vector is described using a forward model, which is potentially able to predict scattered power profiles for different wind speeds and directions and choosing the minimum‐squared error solution. The ability for spaceborne or airborne GNSS‐R to measure an inland water wind vector and wave heights could contribute to scientific applications focused on understanding nearshore ecosystems, monitoring climate change effects on inland waters, sediment resuspension, biomass production, fish habitat, and others. This paper presents a novel approach to potentially retrieve wind vector and wave heights over inland waters using GNSS‐R and discusses the issues with performing such retrievals using simulation and very few available raw signals recorded from CYGNSS satellites. Global Navigation Satellite Systems (GNSS) signals reflected from inland waters exhibit coherent scattering properties that make them highly sensitive to water surface roughnessWind‐induced roughness will vary across a water body, with a strong dependence on wind speed, wind direction, and the water depthDiscuss potentials of a novel model‐based approach for retrieval a of wind vector and surface wave heights over lakes using CYGNSS data The significant roughness of typical ocean and land surfaces at L‐band frequencies commonly results in diffusely scattered GNSS reflections. However, it has been observed that the surfaces of lakes, rivers, wetlands, and other inland water bodies are often sufficiently smooth to produce coherent reflections. Coherent reflections are of particular interest for remote sensing due to their high‐reflected power, fine spatial resolution, and phase information. Utilizing these reflections enables a unique capability to monitor surface water (even obstructed by dense vegetation) in all weather conditions including rain and clouds. The NASA CYGNSS mission is a constellation of 8 small satellites in low Earth orbit that carry GNSS‐R receivers , traverses a water body and infer the wind speed and wind direction  based on this profile. To achieve this, it is necessary to develop a forward scattering and inland water wave model to describe the interaction between wind and waves.Measurements of the wave heights in inland waters by GNSS‐R are relevant for applications involving estimation of hydrological and biological processes such as sediment resuspension , While the surface temperature and associated trends of inland water bodies can be accurately measured (for clear sky conditions) with thermal infrared data from satellite instruments , and the Rayleigh parameter Ra can be rewritten in terms of Hs asRa leads to a reduction in the coherent signal amplitude. The attenuation in the coherent signal power due to surface roughness (ψ) is given by . Lower frequencies, such as L2  or L5 , will have slightly lower attenuation for the same wave heights, given their larger wavelengths. Incidence angle (shown by the color of the curves) will also affect the total loss through Equation Hs < 15–20 cm. Also of note is that at lower incidence angles, increasing roughness will attenuate signals more quickly.One of the most significant parameters that determine the magnitude of the coherent return is the surface roughness. The amount of height variation across a surface–relative to the incidence angle and wavelength–will determine the amount of power that is coherently reflected. The relative electromagnetic roughness is typically described by the Rayleigh parameter  is the Woodward Ambiguity Function (WAF), R1 and R2 are the distances from transmitter to a point on the surface, and from the surface to the receiver respectively, γ is a vegetation attenuation parameter, dS is a differential surface area, and σpq0 is the normalized bistatic radar cross section (NBRCS). The total received power can be split between coherent and non‐coherent components , produce a coherent component.The general form of the power of the bistatic signal measured by a GNSS‐R receiver can be written as , most variables in Equation S and the roughness attenuation ψ. For the purpose of this paper we will assume that the inland water geometry S is known or well‐observed .where In the next section, we discuss the forward model used to describe the wind/wave interaction and examine how different geophysical parameters such as fetch, wind speed, and wind direction will affect the reflected signal.3ψ over the entire surface area S. To achieve this, this work applies a water wave model developed by the Coastal Engineering Research Center (CERC) of the U.S. Army Corps of Engineers to calculate surface roughness  is the wind stress factor, g is the gravitational acceleration m/s2, d is the water depth (m), and F is the fetch (m). The variable U10 is the wind speed (m/s). It is important to note that there are three main factors affecting the wave heights in this model. They are U10, d, and F. In the context of this model, fetch is defined as the distance from a given location to the shoreline in the up‐wind direction. This model was developed for shallow water conditions, which is considered to be less than 90 meters deep. The model estimates Hs, which is then combined with the incidence angle θ and wavelength λ to form the roughness Ra.In this equation, The CERC model is a relatively simple wave height model. Other wave models–such as SWAN  measurements. The DDM is the primary measurement made by GNSS‐R receivers, and represent the measured power as a function of varying delay and Doppler values, as seen in Equation As the wind direction changes, the value of fetch across the surface of an inland water body also varies. This change in fetch allows for a change in the wave heights across the surface and a change in the surface roughness. Figure 4.2Generally, the range of wind speeds that the coherent signal will be sensitive to is based on the interaction between the wind and the water surface. Significant wave heights greater than 15–25 cm will greatly attenuate a GPS signal at ∼19 cm wavelength for most incidence angles. At higher incidence angles, the surface roughness attenuation is reduced and leads to coherent reflections that are still strong at higher wave heights. This, in turn, will reduce the sensitivity to lower wind speeds as the effective roughness will be minimal. Generally, the range of wind speeds that a reflection will be sensitive to will be highly dependent on the water body itself  as well as the reflection geometry.Before attempting to retrieve wind speed or wind direction, an analysis was performed to test what sensitivity to wind speed and direction of the DDM peak power is present in the CYGNSS Level‐1 data CYGNSS, . First, 4.3The sensitivity in the reflected power to the wind speed and direction can be leveraged to make estimations of these two parameters using the modeled wave height profiles. It is expected that, over a certain range of effective roughness (given by the Rayleigh parameter), the coherent signal will be attenuated in unique ways along a particular track across an inland water body. A forward model is used to estimate a set of received power profiles that can be used along with the measured power profile within a least squares error algorithm.Tc where Tc is the coherent integration time) for comparison with the measured data  is used from a specular track over Lake Ilopango from July 13, 2019, illustrated in Figure The red line in Figure Another possible complication in a wind vector retrieval is the possibility of ambiguity between wind vectors for select tracks. While the reflected power profiles are highly dependent on the inland water body topography, certain shapes may produce an ambiguous return. One could imagine a scenario where a good fit exists for a number of measured power curves and the modeled power curve. For example, if the specular track were to cross through the center of a water body of symmetric shape, an ambiguity in the wind direction will arise. The top of Figure The sensitivity of the received power tracks to the wind direction and magnitude provides the possibility to estimate both the surface wave height profile and the associated wind vector. First, a set of power curves for varying wind vectors is generated using the forward model. Then, the residuals are calculated by taking the difference between the measured power curve and the simulated curves. The simulated curve that gives the minimum squared residual is then our estimated surface height profile and wind vector. Because the sensitivity of the received power with wind direction is highly dependent on the shape and size of the water body, it is expected that the retrieval accuracy of the wind magnitude is likely to be greater than the wind direction.Figure In addition to the estimation of the wind vector, this method potentially retrieves a surface wave profile. With the selection of a wind speed and direction, the underlying surface wave heights that gave the best fit forward‐modeled power curve is also selected. Figure 4.4The previous section demonstrated successful retrieval of wind speed; however, it was based on a single raw signal CYGNSS recording over the lake. Thus far, a total of 3 recordings have been made from CYGNSS over this lake and are compared below. Details of each track are summarized in Table For this comparison, GNSS reflections from Lake Ilopango were simulated using the same coherent scattering model presented previously. The local topography was considered when recalculating the specular point track over the lake. No wind speed or wind direction retrieval was performed on these additional tracks. Rather, the point is to highlight the features in all tracks available over the lake.Figure 4.5Due to the surface roughness caused by the wind, a non‐coherent component of the scattered signal also exists alongside the coherent reflection. The strength of the bistatically scattered diffuse signal is dependent on the surface roughness spectrum , the traditional methods of calculating the NBRCS using Geometrical Optics (GO) are inaccurate  across the surface is assumed. The calculated σ0 across the surface using SSA1 is shown in Figure For larger inland water bodies, the diffuse component will be more significant since the scattering area is larger and larger waves will be supported. To quantify when the non‐coherent component will be significant, the coherent and non‐coherent contributions to the total received power for increasing values of Hs of 27 cm. As expected through the attenuation factor ψ, the coherent power reduces quickly with increasing Hs. Also of note, the diffuse power increases quickly with Hs, reaches a peak, then slowly reduces. In addition, at low wave heights, the coherent power is several orders of magnitude greater than the diffuse power, even at the diffuse power's peak value.Figure Since we are using an infinite surface, the total surface area contributing to the diffuse power in this scene is constrained by the size of the WAF. If we consider reflections from smaller inland water bodies than the size of the WAF (such as the previous example in Figure 5The method described in this paper indicates that information about the wind magnitude and direction is contained within the shape of the measured signal as a specular point transects an inland water body, almost independently of the absolute magnitude. It was shown that the coherent signal is highly sensitive to roughness variations over the water surface. The surface roughness depends on the wind‐driven wave heights, which vary predictably over the surface for different wind speeds and wind directions. It has been observed that the CYGNSS Level‐1 peak SNR data over an inland water body such as Lake Ilopango exhibits clear dependence on wind vector. The forward model for the scattered power in combination with a wave model demonstrates potential for the retrieval of wave heights and wind vector. This new source of wind vector data is very valuable to investigate the lake surface heat balance, in particular for cloudy/rainy conditions and non‐instrumented areas. The CYGNSS raw signal data were used to validate a retrieval of wind speed using a mean‐squared error minimization approach with promising results. The scattering effects of the lake edges and/or the possible ambiguity given by the geometry likely complicate the retrieval of wind vector. Finally, we have shown evidence that the coherent component of the reflection from small inland waters is dominant as compared to the non‐coherent scattering. However, if the water body is large, non‐coherent reflection becomes the dominant scattering mechanism when the surface roughness increases.Results in this paper were based on a simple example lake with no vegetation. In such cases, the interaction between the wind and the water surface can be described by wave models, and these models work well in unprotected inland waters. However, vegetated inland waters such as wetlands and marshes are of significant scientific interest, and vegetation will have a significant influence on the final surface roughness. Work is underway to identify and incorporate several vegetation effects on inland surface water roughness into our GNSS‐R coherent scattering model.