The effect of pre-corrosion pits on residual fatigue life for the 42CrMo steel (American grade: AISI 4140) is investigated using the accelerated pre-corrosion specimen in the saline environment. Different pre-corroded times are used for the specimens, and fatigue tests with different loads are then carried out on specimens. The pre-corrosion fatigue life is studied, and the fatigue fracture surfaces are examined by a surface profiler and a scanning electron microscope (SEM) to identify the crack nucleation sites and to determine the size and geometry of corrosion pits. Moreover, the stress intensity factor varying with corrosion pits in different size parameters is analyzed based on finite element (FE) software ABAQUS to derive the regression formula of the stress intensity factor. Subsequently, by integrating the regression formula with the Paris formula, the residual fatigue life is predicted and compared with experimental results, and the relationship of the stress intensity factor, pit depth, and residual fatigue life are given under different corrosion degrees. The fatigue life predicted by the coupled formula agrees well with experiment results. It is observed from the SEM images that higher stress amplitude and longer pre-corroded time can significantly decrease the residual fatigue life of the steel. Additionally, the research work has brought about the discovery that the rate of crack extension accelerates when the crack length increases. The research in this paper also demonstrates that the corrosion pit size can be used as a damage index to assess the residual fatigue life. Most engineering materials are subject to corrosion, and corrosion research has received much attention from different perspectives ,4,5,6,7.In recent years, fatigue performance of pre-corroded metallic alloys has been studied extensively. For example, recent works ,16,17,18In this study, the effect of stress distribution around corrosion pits on the stress intensity factor is firstly investigated. The crack nucleation sites and the geometry of corrosion pits are examined by a surface profiler and a scanning electron microscope (SEM), and then the relationship between the fatigue life and the maximum applied stress is obtained by fatigue tests of different pre-corroded specimens. Based on experiment results, an FE model is conducted to investigate stress distribution around corrosion pits, and regression formula of the stress intensity factor varying with corrosion pits in different size parameters is then derived. Subsequently, by coupling the regression formula with the Paris formula , the fatTo better understand the stress intensity factor varying with corrosion pits in different size parameters and to accurately depict the residual fatigue life of 42CrMo steel subject to corrosion, it is necessary to quantitatively investigate the effects of pre-corrosion levels on the fatigue behavior of 42CrMo steel. Experimental specimens were fabricated using the 42CrMo steel (American grade: AISI 4140), which was provided by Baowu Steel Company . Specimens were manufactured in the form of flat bare sheets with a thickness of 6 mm by wire cutting machine, the sizes of specimens are provided in Twelve smooth samples were numbered and divided into four groups. The accelerated neutral salt spray corrosion experiment was established to achieve the pre-corroded steel plates based on the standard of JIS H 8502.5 . A schemIn this study, the pre-corroded experiment procedure can be devised as four main steps: (1) the pure NaCl crystals of 50 g were weighed by an electronic balance and poured into one liter of deionized water and stirred with glass rod at an ambient temperature of (25 ± 1 °C) for 5 min; (2) four groups of numbered samples were alternately immersed in 5% NaCl solution at an ambient temperature of (25 ± 1 °C) for 0 h, 24 h, 48 h, and 96 h, respectively; (3) the corrosion products were removed by membrane removal solution ; (4) all surfaces of samples were rinsed with deionized water and dried by a blower for pit depth measurement.φ is the depth of a pre-corroded pit (μm) and t is the pre-corroded time (h).To achieve the morphology of the corrosion surface and to determine the size and geometry of pre-corrosion pits, a non-contact Dektak150 surface profiler  and an S-4800 scanning electron microscope  were used in this study. A region of 30 mm × 20 mm  for each specimen was approximately arranged at the area of pre-estimated fatigue fracture. It is noted that the rate of corrosion changes steadily with the increase of pre-corroded time , thus thBased on the standard of ASTM E468-90 , the fatIK is the stress intensity factor of the crack, σ is the external stress under the plane stress state, and a is the crack length and b is the specimen width.The pre-corrosion pit reduced the fatigue life substantially, particularly the interacting pits and sharp pits . In thisThe FE analysis model of the 42CrMo steel in the form of a corroded flat sheet with a thickness of 6 mm was created using the HyperWorks software . On the basis of the experiment test, a single semi-elliptical pit model was conducted, and the symmetry plane of the flat sheet and refined mesh around the pit are shown in The CPS8 quadrilateral element type was adopted in the FE model and cracks were prefabricated on the surface through the use of an assigned seam function that was provided by HyperWorks. The sweeping method  was used2+ in the metal to form a soluble clathrate, which resulted in the anodic dissolution of the metal surface and the formation of corrosion pits. With the increase of pre-corroded time, more metal dissolved in the anode and the size of corrosion pit became larger and larger [When the 42CrMo specimens were immersed in NaCl solution, the Cl element in the solution adhered to the surface of specimens and reacted with the Fed larger . The speAccording to To obtain the effect of the stress distribution around corrosion pits on the stress intensity factor and the residual fatigue life of corroded steel, the size of pre-corroded pits should be accurately assessed and the depth of pre-corroded pits can be measured by a surface profiler. The schematic diagram of pre-corrosion pits under the pre-corroded times 24 h, 48 h, and 96 h is shown in Pre-corrosion not only reduces residual fatigue life, but also leads to the change of the stress intensity factor. Under the cyclic load with a frequency of 10 Hz, the local stress concentration around the corrosion pits accelerated the process of fatigue damage and resulted in the reduced fatigue life of the specimen. Three constant stress levels  were carried out to pre-corroded specimens for 0 h, 24 h, 48 h, and 96 h. The fatigue testing results of specimens with different exposure times are shown in Based on Equations (1)–(3), ABAQUS was applied to compute the stress intensity factor corresponding to different corrosion pit morphology characteristics, which were depicted in the previous section. The same material properties and loading conditions in The ashy area in By the adoption of Equations (2) and (3), the stress intensity factor around the crack tip in the process of crack propagation for non-corroded specimens can be calculated and compared with the stress intensity factor that was computed by ABAQUS software to validate the accuracy of the FE simulation results. A comparison of the stress intensity factor by theoretical Paris formula and FE simulation is shown in The maximum percentage error of the calculated stress intensity factor between the theoretical Paris formula and the FEM is 4.7%, which indicates that the theoretical calculation agreed well with the simulated results. Through the integration of the ashy area around the crack tip in KIS is the pre-corroded stress intensity factor, KI0 is the non-corroded stress intensity factor, and φ is the depth of corrosion pits. The fatigue life can be estimated according to the Paris formula [da/dN is the fatigue crack propagation, ΔK is the stress intensity factor at the tip of cracks, and C and m are the equation coefficients, respectively. For the 42CrMo steel, the coefficients of C and m are taken as 4.349 × 10−12 and 3.07, respectively [ formula . The Parectively . ThroughCN is the fatigue life of pre-corroded specimens and N0 is the fatigue life of non-corroded specimens.By combining Equations (4) and (6), the relationship between the fatigue life of pre-corroded and non-corroded specimens can be written as:Under different stress ranges and corrosion degrees, the residual fatigue life of pre-corrosion specimens is predicted through the use of Equation (7). The comparison of predicted fatigue life and experimental fatigue life is summarized in In this research, the effect of pre-corrosion pits on the residual fatigue life of the 42CrMo steel was experimentally and numerically studied. It was demonstrated in this paper that the corrosion pit size can be used as a damage index to assess the residual fatigue life. Therefore, the monitoring of corrosion pit size is important not only to know the corrosion status, but also to predict the residual fatigue life of the steel. With the recent development of structural health monitoring technology ,42,43,44In summary, this study investigated the effect of pre-corrosion pits on the residual fatigue life of the 42CrMo steel. It was found that higher stress amplitude and longer pre-corroded time significantly decreased the residual fatigue life of the steel. The investigation of the residual fatigue life of pre-corrosion specimens was conducted through the use the regression formula and experimental measures, and the fatigue life predicted by the regression formula agreed well with experiment results. Moreover, it was found that the rate of crack extension accelerated when the crack length increased. It is also demonstrated in this paper that the corrosion pit size can be used as a damage variable to assess the residual fatigue life. The recommendation for future research is to monitor corrosion pit characteristics and to predict the residual fatigue life of the 42CrMo steel.


The interest in renewable energies obtained from the resources availed in the ocean has increased during the last few years. However, the harsh atmospheric conditions in marine environments is a major drawback in the design of offshore structures. The protective systems that are employed to preserve offshore steel structures are regulated by several standards , which classify the corrosivity category of offshore installations as C5-M and Im2. In this work, three coatings employed in offshore components protection have been evaluated according to these standards by performing weathering aging tests in different climatic cabinets. The coatings studied were a thermally sprayed carbide coating with an organic sealant (C1), a thermally sprayed aluminum (TSA) coating with an organic topcoat (C2), and an epoxydic organic coating reinforced with ceramic platelets (C3). The only coating that reached the higher categories in all the tests was the C2 coating. The C1 coating presented ferric corrosion products coming from the substrate in some of the tests, and blistering was detected in the C3 coating. Atmospheric zone: This zone is located above the sea level, and the severity of corrosion is related to the time of wetness, during which electrochemical processes take place. There is a direct relationship between atmospheric salt content and corrosion rate. Materials are also exposed to solar radiation, which deteriorates the performance of organic coatings.Splash zone: This section in the structure is intermittently wetted, due to tides and the wind. The corrosion rate of metals in this zone is the highest, due to the aerated condition, which makes the access of dissolved oxygen for electrochemical reactions easy. Since it is continuously being wetted, chlorides can concentrate on the surface while the water films dry. Furthermore, the impinging of seawater containing sand and other flowing matter adds a mechanical component to the materials’ deterioration in this exposure zone.Tidal zone: The materials are alternately submerged and exposed to the splash zone, as the tide fluctuates. In the submerged condition, materials are exposed to a well-aerated seawater, which favors the attachment and growth of biofouling. The corrosion rate is influenced by the tidal flow, with higher corrosion rates with increasing movements.Submerged zone: The section of the structure that is always immersed in the sea. The corrosion rate in this zone depends on the availability of oxygen to be transported to the cathodic sites of the materials’ surfaces. As oxygen concentration varies with depth, decreasing with increasing distance to the surface, the corrosion rate is also slower at higher depths.Subsoil: In the buried structure, the oxygen concentration is low, and hydrogen sulfide may be present.The marine environment is a very aggressive working atmosphere, where structural materials and components are exposed to ultraviolet radiation, a chloride-rich salty environment, frequent wetting and drying cycles, high humidity, the attack of biological microorganisms and marine bacteria, etc. ,2,3,4,5.Low (L): 2 to 5 yearsMedium (M): 5 to 15 yearsHigh (H): 15 to 25 yearsVery High (VH): >25 yearsThe most employed structural material in offshore applications is steel—usually mild or low-alloyed—due to its superior mechanical properties ,12,13. HThe categories required for a protective system in an offshore installation are C5-M and Im2, for non-submerged and submerged components, respectively. In order to obtain these protection grades, the ISO 12944 standard recommends employing multilayer coatings with thicknesses between 320–500 µm for a C5-M category in the atmospheric zone, and between 480–1000 µm for the splash zone and submerged components (Im2). According to the standard, these specifications should be enough to ensure a durability of 15 years for a coated component  does notThe selection of protective coatings for the marine environments strongly depends on the exposure zone and must provide the system with specific properties to assure infrastructures’ durability. The typical coating systems that are employed in offshore applications  with theIn this work, three coatings used in offshore component protection have been evaluated. The selected coatings are commercial coatings that are currently used in the protection of steel submerged components in mooring line systems. In a previous work, the corrosion and tribocorrosion (wear+corrosion) behavior of the three coatings was evaluated . FurtherC1)Thermally sprayed carbide (WC–CrCo) with an organic sealant (C2)Arc thermally sprayed aluminum (TSA) with an organic topcoat (C3)Epoxy-based organic coating reinforced with ceramic particles  steels ,8,21. Th2, which were mechanized to obtain samples of 100 × 75 mm2. The uncoated backside and edges of the panels were isolated with an insulating wax to avoid corrosion of the steel substrate to affect the results. The exposed area of these samples was of 71 cm2.The three coatings evaluated in this work were applied on R4 steel grade panels of 100 × 150 mmThe mean thickness and porosity values measured for the three coating systems in the previous work is presented in The ISO 12944 and the NORSOK M-501 standards propose several accelerated aging tests such as immersion (ISO 2812-2 ), water In all the tests, visual inspections were performed periodically in order to detect the presence of any defect such as blisters, cracks, delamination of the coating, or corrosion of the substrate. All the samples were kept in the chambers for the maximum duration to achieve the C5-M high or Im2 categories, unless premature failure of the coating due to the appearance of defects was detected (ISO 4628 1-5 ).The resistance of the coatings to immersion was analyzed according to the ISO 2812-2 standard  Table 4Table 4. Condensation atmosphere with constant humidity (CH)Condensation atmosphere with alternating humidity and air temperature (AHT)Condensation atmosphere with alternating air temperature (AT)A water condensation test was performed according to the ISO 6270-2 standard  to analyThe conditions of the three tests are summarized in Corrosion aging tests in a neutral salt spray chamber were performed under the conditions specified in the ISO 9227 standard  Table 4Table 4 istandard .The coatings were aged by alternating the exposure to different climatic environments, in accordance with the procedure described in the NORSOK M-501 and ISO 12944-9 standards. The test consisted of combining the exposure to UV radiation and condensation , with tThe results of the weathering corrosion aging tests for the three coatings in the different climatic chambers, and their categorization in accordance with the ISO 12944 and NORSOK M-501 standards are briefly recapitulated within this section.Immersion tests were performed to evaluate the resistance of the coatings to water immersion. The surface state of the coatings at different evaluation times is presented in In the first evaluation after 168 h of immersion, C1 coating samples presented some decolorized zones in the surface. This could be a consequence of the partial removal of the organic sealant of few µm  20] app app20] aIn the case of the C2 coating, the presence of ferric corrosion pits was detected close to the edges in the first evaluation at 168 h. These pits corresponded to the oxidation undergone by some metallic particles that were embedded in the surface of the coatings during machining processes, i.e., contaminants. After 672 h, the apparition of white salts resulting from the oxidation of the aluminum layer beneath the organic topcoat was observed. The state of the coating remained unaltered in the following evaluations at longer immersion times. The final surface state of the coating was similar to that of the untested sample, in terms of color and brightness, and no presence of ferric corrosion coming from the steel substrate was detected.C3-sample No.1: 4 (S4)C3-sample No.2: 2 (S4) (removed from the chamber after 504 h of immersion)C3-sample No.2: 4 (S5)The samples of C3 coating presented a loss of brightness from the first evaluation at 168 h of exposure, showing a considerably paler tone. After 504 h, blisters appeared in one of the three samples , which wThe C1 and C2 coatings passed 3000 h of immersion, achieving the Im2 (high) category (ISO 12944-6), whereas the C3 coating did not pass the immersion test, not even reaching 2000 h of immersion required for an Im1 (medium) category , alternating temperature and humidity (AHT), and alternating temperature (AT). The evolution of the coatings surface at different evaluation times is presented in In the three exposure atmospheres, the C1 coating presented some decolorized zones in the surface after several hours in the cabinet, which was a consequence of the partial elimination of the sealant applied on top of the sprayed carbide. This was observed after 110 in the CH test, and after 278 h in the AHT and AT tests. Furthermore, ferric corrosion was observed to appear in all the samples close to edges. As previously explained for the samples of the immersion tests, this corrosion phenomenon arose from the cavitation effects in the edges of the insulating wax, and was not considered as a coating failure. In the three test atmospheres, the color of the coating changed with increasing exposure, which was a consequence of the sealant degradation, acquiring a more reddish tone . In the In the case of the C2 coating, all the samples presented some red spots on the surface, corresponding to ferric oxides. However, these oxides did not come from substrate corrosion, but rather from the corrosion of metallic particles that were embedded in the coating surface during the sample machining process. No significant changes were observed in the coating during the exposure to any of the three condensation atmospheres in terms of ferric corrosion, blistering, cracking, or color change. In the CH test, the presence of white salt deposits arising from the oxidation of the aluminum layer was detected after 614 h. In the case of the AHT tests, the three coated samples were intact after 720 h of exposure, even without the presence of white salts. Finally, in the AT test, white salt deposits appeared after 336 h in one of the three samples. Therefore, considering the minor changes undergone at the three testing atmospheres, the C2 coating passed the three condensation tests, achieving a C5-M (high) category (ISO 12944-6).C3-sample No.1: 2 (S3)C3-sample No.2: 2 (S4)C3-sample No.2: 2 (S4)The samples of the C3 coating showed color and brightness loss after several hours of exposure, but no presence of ferric corrosion, cracks, or other defects was detected during the evaluations. The only defects appeared in the CH test samples, which presented a significant part of the surface covered by blisters. However, in the AHT and AT tests, no blister appeared in any of the coated samples after 720 h in the chamber. According to the UNE EN-ISO 4628-2 standard , the bliConsequently, the C3 coating was classified within the C5-M (high) category for the AHT and AT tests, and with a C4 (high)/C5-M (medium) category for the CH test, corresponding to an optimal surface condition of the coating for 480 h of exposure to constant humidity (ISO 12944-6) /C5-M (low) categories (ISO 12944-6). However, the C2 coating overcame the 1440 h of exposure to salt spray, showing no ferric corrosion coming from the steel substrates, and proving an effective protection in such an aggressive atmosphere. Thus, the C2 coating was classified as belonging to the C5-M (high) category (ISO 12944-6)  and Im2 (H) categories specified in the ISO 12944-6 standard corresponding to high corrosivity atmospheres, the results obtained for the three coating systems evaluated in this work is summarized in The thermal sprayed carbide layer with a thin organic sealant of few nanometers (C1) was found to present ferric corrosion pits in some of the testing atmospheres. Coherently with the results obtained for the C1 coating in a previous work, in which the electrochemical corrosion response of the coating was evaluated in synthetic seawater , the orgIn the case of the arc thermally sprayed aluminum with an organic topcoat (C2), this was the only protective system that overcame all the weathering tests successfully. In this coating system, the thickness of the organic topcoat of several nanometers acted as an adequate barrier against the aggressive environments evaluated. In some of the tests, e.g., the immersion tests, the condensation tests (CH and AT), and the salt spray tests, white deposits corresponding to aluminum oxides were detected. In these tests, which constituted high humidity atmospheres during the whole exposure period, water penetrated through the conductive paths generated in the organic coating. Once the humidity reached the sprayed layer, the aluminum reacted to form aluminum oxides or hydroxides in the form of white salts. These results are in coherence with those observed in previous works in which the thermally sprayed aluminum layer with  and withFinally, the organic coating reinforced with ceramic platelets (C3) presented blistering in the tests comprising the highest humidity atmosphere during the whole test duration, i.e., the immersion, condensation (CH), and salt fog tests. The formation of blisters is closely related to the delamination of organic coatings on the coating/substrate interface as a consequence of a low adhesion of the coating allowing the penetration of water. In the electrochemical corrosion tests performed in the previous work for this coating , the corFrom the immersion tests (ISO 2812-2), the only coating that did not reach 4000 h of immersion was the C3 coating. Blisters were detected to appear after 504 h in one of the samples, and after 672 h in the other two samples. The C1 and C2 coatings were classified as IM2 (high), overcoming the 4000 h of exposure without the appearance of any defect.Regarding the water condensation tests (ISO 6270), the C1 and C2 coatings obtained the C5-M (high) category in the three water atmospheres. However, C3 was classified as C5-M (high) in the AHT and AT atmospheres, and as C4 (high)/C5-M (medium) for the CH test due to the apparition of blisters after 614 h of exposure.In the case of the salt spray tests (ISO 9227), C2 was the only coating reaching the C5-M (high) category. The C1 and C3 coatings were classified as C4 (medium)/C5-M (low), after the detection of ferric corrosion (480 h) in the C1 coating and blisters (972 h) in the C3 coating. The adherence that was measured for the C2 and C3 coatings in the samples with incision was 4A/5A, according to the ASTM D3359 standard. The adherence of the C1 coating was not measured, since the incision could not be made in the hard carbide layer.With respect to the combined aging tests , the C1 coating did not pass the test, since the surface of the samples was covered by a considerable amount of ferric corrosion at the end of the last test cycle. On the other hand, the C2 and C3 coatings passed the test, showing just some discoloration and loss of brightness, maintaining the protective properties.Finally, the only coating that reached the higher category and overtook all the test atmospheres was the C2 coating. The combination of both the aluminum layer and the organic topcoat providing a two-layered protection by means of a sacrificial aluminum anode and the high corrosion resistance of the organic layer.In the present work, the effectiveness of three coatings for the corrosion protection of offshore structural steel has been evaluated, according to the ISO 12944 and NORSOK M-501 standards. The corrosivity category of the coatings was determined for each aging test condition (ISO 12944). The conclusions of this work were the following:


Concentrated Growth Factors (CGF) is a concentration of second generation autologous growth factors compared to platelet rich plasma (PRP) and represents a multifactorial stimulation system that can be used for the management and treatment of chronic skin ulcers.The aim of this work is to evaluate the additional benefits of the CGF compared to the standard of dressing and its effects on the dynamics of the healing process.Autologous CGFs were obtained from 100 patients with chronic mixed ulcers (venous ulcers in patients with II stage claudication) of the lower limbs in a multicentric controlled randomized study.The results showed a significant advantage in the use of CGF in association with cleansing and selective compression in the healing time and stabilization of mixed ulcers of the lower extremities.These results support the CGF’s clinical use for improving clinical outcomes in mixed ulcers of the legs. It represents a multifactorial stimulation system as it uses all phases of the blood. It is proposed for the ancillary treatment of chronic skin ulcers.The advantages of CGF found in literature are the immediate hemostatic action, biocompatibility, fast epithelial regeneration  and a high antimicrobial effect due to the high concentration of leukocytes , 2, 3, 4Progress in the management of chronic skin wounds has led to high rates of recovery , 6, 7 buThe CGF represents an evolution of the PRP. Its application is progressively spreading in the clinical field. CGF and PRP are based on the release of platelet growth factors, mainly contained in alpha granules, which exert a stimulating action on the reparative processes of skin lesions. Few studies have been published, hence the literature provides a low level of similarity in cases and protocols ,9.1.1The current work aims to evaluate the additional benefits of the CGF compared to the standard dressing and compression of chronic leg ulcers and its effects on the dynamics of the healing process.2A multi-centre randomized controlled trial has been performed for patients with mixed ulcers: i.e. on a population with venous insufficiency  and chronic obstructive arterial disease . The protocol consisted of the application of CGF in addition to a standard wound dressing and elastic compression, performed once a week, for a 12 weeks period  and followed by a 6 months follow-up. None of the patients enrolled underwent surgery for venous or arterial disease, as they were considered not suitable or they refused the treatment: these kinds of mixed ulcers are usually characterized by a significantly slower healing time compared with ulcers that are just venous. The trial was preliminarily approved by the Institutional Review Board Independent Ethics Committee (IRB-IEC) as the Ethics Committee of the Inter-University Centre of Phlebo-lymphology (CIFL), with a positive result (protocol: ER: ALL.2016.03A). The study was conducted by recruiting patients from among ten vascular centres of Southern Italy - reported in “Supporting Info”- under the control of the authors as members of the “SIMCRI Group for the study of CGF in the treatment of Mixed Ulcers”, and coordinated by the CIFL researcher’s group.It should be noted that both comparative study groups have previously applied procedures in clinical use: specifically, we refer to CGF as a recent method of preparing platelet gel that enriches the dressing of growth factors present in platelet granules , 14, 15.It is also correct to specify that no significant methodological changes have been made after the start of the trial.Patient enrollment took place between December 2016 and December 2017. The clinical trial and related evaluation analysis were completed in July 2018. The primary end-point was identified in the reduction of the surface of the ulcerative wounds within 12 weeks of treatment. Secondary end-points were the presence and variation of ulceration pain and the reduction of bacterial load during treatment.2.1Following a selection of 143 patients with mixed ulcers of the legs initially enrolled and after excluding 43 patients , 100 patients  with chronic mixed ulcers of the legs (over three months lasting) were recruited into the Vascular Units participating in the study. These patients were randomized into two homogeneous groups: a group (A) of 53 patients who received CGF dressing in addition to standard treatment, and a group (B) of 47 patients which received a standard wound treatment as later described.As a criterion for a correct management of the lesion, the principles of wound bed preparation have been applied. ,17, and All the patients participating in the study were informed about the aims of the study and an informed consent was provided and stored in the records of each participating centre. Once informed consent has been obtained, a clinical data collection form, common to all participating centres, has been compiled.2.2The exclusion criteria applied in the recruitment of patients were the following: recent outcomes of myocardial infarction, dialysis, a serious infection of the lesion (with extension to the surrounding tissues), reduced life expectancy, cachexia. Drugs already in use for other pathologies of each patient were not considered exclusion criteria, except in cases of significant modification of the therapy, necessary during the study itself. The reasons for the exclusion from the study were reported.The exclusion criteria expected for the study was the following: extension or onset of severe ulcer infection and amputation or revascularization surgery.2.3The primary outcome of the study was surface reduction and ulcer healing after 12 weeks of treatment, while secondary outcomes were sought in the reduction of wound-related pain and in the reduction of the bacterial component in the ulcer: these outcomes did not change during the trial.2.4In order to define the characteristics of the lesion in terms of surface, the presence of fibrinous material (slough) or granulation tissue, comparable and quantifiable photographic images of the lesions were acquired, subjected to the evaluation of two external neutral observatories: at the beginning of the protocol and for each medication (both in the treatment and group phases in the monthly follow-up).Complete ulcer healing was defined by both clinical and photographic documentation of complete skin epithelialization.2.5CGF was produced by the patient’s blood without addition of exogenous substances through the use of a special centrifuge Phase Separator . After taking 10 ml of blood from an arm vein, under aseptic conditions, the blood centrifugation / separation process followed an automatic program with alternate speeds that prevented platelet degranulation. The centrifugation duration was 14 minutes, with the following program: - 2 minutes at 2700 rotations per minute (rpm) (to obtain the separation of blood components); - 4 minutes at 2400 rpm (to obtain cell lysis); - 4 minutes at 2700 rpm (to get the aggregation of the blood components); - 3 minutes at 3000 rpm (to get homogenization of blood components).Other characteristics of centrifugation were: Acceleration in about 29/30 sec. from 0 to 2700 rpm with Fg 25 (to avoid any damage to the blood components); Stop in 33 sec. from 3000 to 0 rpm with Fg 87/88 (to avoid the mixing of the fractions obtained); Use of glass test-tube (CE certificate 0476) (“red cap”) to obtain a product with characteristics of gel, for elastic and suturing membranes.4. Use of glass tube with red cap with addition of 18/20 units Sodium Heparin (“Sodium Heparin”) to keep all phases in liquid state: allows to obtain different fractions  in the liquid state, therefore not gelled. This tube “Sodium Heparin” allows for the different fractions in liquid to form at room temperature for about 8 hours at a temperature of 4 ° C for about 40 hours. In addition, Sodium Heparin aggregates the platelets for a better release of the growth factors [3Patients were randomized by selecting enrolled patients for Group A (CGF supplementary treatment) and Group B (standard treatment as control group), by a software-generated procedure provided by a computerized randomization program with audit trial. Randomization was implemented by the single coordinator for randomization and was controlled by the principal investigator at University of Naples “Federico II”. Randomization was also indicated in the patient record.3.13.1.1The dressing was carried out with the following protocol: 1. Cleansing with physiological solution at a temperature between 34 and 37° C; 2. Dakin’s solution pack (sodium hypochlorite diluted 0.05%) for 5 min.; 3. Direct application of the CGF gel on the wound; 4. Covering of CGF with gauze containing hyaluronic acid; 5. Subsequent covering with an advanced absorbent and impermeable medication (Allevyn Adhesive ®); 6. Application of a containment sock (day and night) and of an elastic leg , only during the day.3.1.2The dressing was carried out with the same protocol, devoid of only point 3, the CGF application.The dressings were scheduled every week for twelve weeks, and a follow- up of a further twelve weeks where a standard weekly dressing was applied to all patients, if the healing of the ulcers had not yet occurred. When healing was completed, elastic compression already in place (with monthly check- up) was prescribed.3.2Dressings and follow-up have been performed at the participating centres, by those responsible for the protocol application. Failure to comply with the prescribed dressing time for an advance or delay of more than one day, or the accumulation of deviations from the scheduled dressing cadence above a total of two days throughout the duration of the protocol were considered a lack of adherence to the protocol and valid reasons for exclusion from the study.3.3Pain assessment was performed at enrolment and at each dressing change by evaluating pain intensity according to the Wong-Baker scale, as in Patients, however, were allowed to treat pain with home therapies using non-steroidal anti-inflammatory drugs, when necessary.3.4The evaluation of the bacterial load was performed, with a semi-quantitative buffer, in all the patients enrolled in the study during the first dressing (T0) and during the following dressings after 3-6-9 weeks (T3-T6-T9). Bacterial growth values of 4+ or higher were considered positive for wound infection, while lower values were considered indicative of a non-infected wound.3.52), were compared with paired samples t-test among consecutive times of the study period.All statistical analyses derived from this study were performed using Medical statistical software. Visual histograms and analytical methods (Student’s t-test) were used for the determination of normal distribution in all the expected outcomes. The statistical significance threshold was set to * P <0.05. Continuous variables were expressed as mean ± standard mean error. Paired values for planimetric data, including wound area  during the first 12 weeks of observation: in 11 patients. (20.7%) after 5 weeks, in 14 patients (26.4%) in 6 weeks, in 10 patients (18.8%) in 7 weeks, in 8 patients (15.0%) in 8 weeks, in 7 patients (13.2%) in 9 weeks, in 2 patients (3.7%) in 10 weeks, and in 1 patient (1.8%) in 11 weeks. Ulcers healing in group B occurred in the first phase of the study  only in 32 out of this 47 patients (68% of cases), with the following timing: in 2 patients (4.2%) in the first 5 weeks; in 1 patient (2.1%) in 6 weeks, in 3 patients (6.3%) in 8 weeks, in 5 patients (10.5%) in 9 weeks, in 7 patients (14.8%) in 10 weeks, in 6 patients (13.9%) in 11 weeks, in 8 patients (18.6%) in 12 weeks, while in 15 patients (31.9%) wound healing was achieved over 12 weeks.Evolution of the healing times in the two groups of treated patients is described in The overall evaluation of pain intensity by means of the Visual Analogue Scale (VAS), using the Wong-Baker scale, initially homogeneous in the two study groups (5.38 +/- 1.35 in Group A and 5.16 +/- 1.94 in group B) showed a significant improvement (p <0.001) of pain symptoms in Group A patients compared to those of Group B, starting from the second week of treatment , progressively improved in the following weeks No complications or undesirable effects of GCF  have been observed in any of the Group A patients.4.1In the cost / benefit analysis applicable to the use of the CGF for the treatment of difficult ulcers of the lower limbs, the average cost of the CGF application procedure in the study carried out was first evaluated. The costs relating to the application of the CGF consists of the following: Peripheral blood collection (10 cc) in a dedicated sterile test tube: collection was carried out by the nursing staff responsible for dressing the ulcers and only includes the costs of the collection set and the special sterile test tube: 3.15 € (euro). Specific centrifugation with Phase Separator Centrifuge : the cost of centrifugation is represented by the amortization of the centrifuge and can be considered of about 2.80 € (used for an average of 1500 procedures). Aseptic preparation of CGF for topical application : 1.55 €. The total cost of each procedure for applying the CGF as an additional treatment for ulcers of the lower limbs was therefore 7.50 €.In the analysis, finally, for the time necessary for the procedure with CGF, we must consider on average 3 minutes for the blood collection, 14 minutes for the centrifugation and another 3 minutes for his preparation and application on the wound, for an average total time of 20 minutes. Time spent for the dressing performed with CGF in group A of patients was therefore higher on average by 10 minutes compared to the medication performed in group B of control patients . Even if the dressing provided with CGF has a higher unit cost than the standard dressing, the total cost of the treatment is very advantageous since the number of dressings necessary for healing is generally largely reduced.5The presence of a chronic non-healing ulcer is a condition of discomfort for each patient because of the painful symptomatology and the impairments that limit their daily habits in terms of social life or work. The healing of leg ulcers, that are mainly caused by venous insufficiency, makes favourable use of physical methods aimed at the reduction of venous ankle hypertension, whereby the patient extended position, the use of elastic stockings or bandages, combined with the cleaning of the ulcer, leads to healing of the ulcer in variable times ,17. The The social cost of treatment must also involve the costs of home self- dressing, medical examinations and possible hospitalizations for specific procedures.Furthermore, most patients belong to the category of geriatric patients and may have numerous co-morbidities that influence the course of the wound and interfere with the healing pathway .In fact, the limits of the study can be found in the multi-factoriality of pathologies that support mixed ulcers: they occur especially in the elderly population, both from the point of view of chronic venous insufficiency and for chronic peripheral artery disease, but also for the effect of pharmacological therapies (that each patient practiced at the same time during the study period for these pathologies) or for concomitant chronic pathologies such as diabetes, hypertension and coronary heart disease,: their time of onset, their severity of concomitant diseases, the quantity and quality of associated drug therapies could represent subgroups of study that have not been evaluated in this trial, but have not been considered preventively determinants for the sought therapeutic effect.A recent controlled critical review, produced with the Cochrane Collaboration method , indicatTherapeutic effects of the application of autologous growth factors of blood derivation have found a wide space of application in several sectors of medicine and surgery , both in vitro and in vivo, with various mechanisms: induction of cell proliferation, stimulation of inflammatory cells, increase of collagen deposition and angiogenesis, through the enhancement of enzymatic fibrinolysis and stimulation of protein synthesis , 27, 28.Further analytical and interpretative assessments of the role of autologous growth factors are beyond the scope of this article, but further information can be derived from future studies in this field.The regenerative properties of blood are related to the presence of platelets, leukocytes, mononuclear cells and growth factors. The platelets contain in fact numerous active substances that play an important role in tissue regeneration through the recruitment and activation of mesenchymal cells, such as osteoblasts, fibroblasts and endothelial cells. The active substances are located in different sub-cellular structures: alpha-granules, dense granules, lysosomes and micro-peroxisomes. Alpha-granules contain chemiotactic and mitogenic growth factors important in tissue regeneration, including PDGF, TGF-beta 1 and -beta 2, VEGF, EGF, IGF and FGF. Undoubtedly, personalized compression therapy , in the context of mixed ulcers, and also for those exclusively of venous origin, represents a fundamental step in treatment, and it is reported as a high-grade recommendation in all the guidelines produced in the vascular field.6The results of this multicentric study on the effects of CGF in the treatment of mixed ulcers of the lower limbs showed a significant advantage in the use of CGF in association with cleansing and selective compression in the healing and stabilization of this kind of ulcers. Pain was also significantly reduced comparatively in the group of patients who were treated with CGF, and furthermore the cost / benefit analysis of the use of this product indicates significant advantages in favour of this procedure. In the treatment of difficult mixed ulcers, CGF has been therefore proved useful and effective in obtaining a faster, less painful, longer lasting and overall cheaper healing of the ulcer. For these reasons, the enhancement of treatment with CGF to all the chronic ulcerative manifestations with a tendency to chronicization is considered valid and suggested by the authors.


Flood has an important effect on plant growth by affecting their physiologic and biochemical properties. Soybean is one of the main cultivated crops in the world and the United States is one of the largest soybean producers. However, soybean plant is sensitive to flood stress that may cause slow growth, low yield, small crop production and result in significant economic loss. Therefore, it is critical to develop soybean cultivars that are tolerant to flood. One of the current bottlenecks in developing new crop cultivars is slow and inaccurate plant phenotyping that limits the genetic gain. This study aimed to develop a low-cost 3D imaging system to quantify the variation in the growth and biomass of soybean due to flood at its early growth stages. Two cultivars of soybeans, i.e. flood tolerant and flood sensitive, were planted in plant pots in a controlled greenhouse. A low-cost 3D imaging system was developed to take measurements of plant architecture including plant height, plant canopy width, petiole length, and petiole angle. It was found that the measurement error of the 3D imaging system was 5.8% in length and 5.0% in angle, which was sufficiently accurate and useful in plant phenotyping. Collected data were used to monitor the development of soybean after flood treatment. Dry biomass of soybean plant was measured at the end of the vegetative stage (two months after emergence). Results show that four groups had a significant difference in plant height, plant canopy width, petiole length, and petiole angle. Flood stress at early stages of soybean accelerated the growth of the flood-resistant plants in height and the petiole angle, however, restrained the development in plant canopy width and the petiole length of flood-sensitive plants. The dry biomass of flood-sensitive plants was near two to three times lower than that of resistant plants at the end of the vegetative stage. The results indicate that the developed low-cost 3D imaging system has the potential for accurate measurements in plant architecture and dry biomass that may be used to improve the accuracy of plant phenotyping. Soybean  is the sMany researchers have studied the morphological responses of crops under flood stress. The formation of adventitious roots is highlighted as a common response of flood-tolerant species . Flood tr = 0.95 and 0.95, respectively, p < 0.0001). However, the visual rating is labor-intensive and subjective due to human vision. In modern soybean breeding programs, the stress tolerant cultivars are selected by planting diverse germplasms in stress environments using the criterion of the minimum yield reduction ,10, whic2R = 92% and root mean square error = 9.4 mm) between the manual and automated method. However, it is difficult to measure the leaf (petiole) angle of single soybean plant because the overlapping effects were observed between adjacent plants at the 14th day after emergence and stems were hard to be generated in three-dimensional (3D) point cloud data [Currently, the state of art plant-phenotyping technologies allows measuring crop morphological traits in an efficient and effective manner. An et al.  developeoud data  when soy2R = 0.85 − 0.97) to manually measurements, however, the laser device is not cost-efficient compared to visible imaging systems. Lou et al. [2R = 98.4% and 84.5% with a mean absolute percentage error of 3.7% and 6.2%, respectively). However, the binocular stereo is usually used in reconstructing canopy structures, and it will be hard to recover soybean stems where most of them are covered by canopy leaves from the top view.To quantify crop geometric traits, O’Neal et al.  developeu et al.  developeu et al.  tested au et al.  establisThe overall goal of this study was to develop a low-cost 3D imaging system to measure morphological traits of interest for quantification of the plant variations in soybean due to flood stress at early growth stages. The specific objectives were (1) to develop a low-cost imaging system for the 3D model reconstruction of soybean plants; (2) to evaluate the accuracy of the developed 3D imaging system in measuring the plant height, plant canopy width, petiole length and petiole angle of soybean plants; and (3) to evaluate the potential in estimating biomass using the extracted image features. A flood experiment was conducted at a greenhouse of the University of Missouri, Columbia, MO, USA, from May through July in 2018. Two types of soybean cultivars with known flood tolerance ability, i.e. NIL211 as the flood resistant and NIL147 as flood sensitive cultivar , were plwww.omc-stepperonline.com), a motor driver, a micro-controller (Arduino Uno), and a bearing pair. The angle between the beam and the support is adjustable, and so as the height from the ground. A camera arm made of an aluminum stick in a diameter of 5 mm was connected to the stepper motor through the bearing pair and a shaft coupling. The arm was bent using a bending machine to a predefined angle of 145° to the center line of the motor shaft. The camera arm allowed the camera moving at a defined trajectory of a circle in a plane determined by three vertexes of C, F and H of a cube, as shown in www.dfrobot.com) was used to control the camera to move and take the images of plants from different viewpoints. The materials used for developing the imaging system were from local hardware store or low-cost off-the-shelf products. The total cost of the imaging platform, including the digital camera, aluminum stand and support, the stepper motor and control, was less than $400, the detail can be found in A 3D imaging acquisition system was developed to collect images of plants from different viewpoints to reconstruct 3D models of plant. The architecture of the imaging system is shown in LCG) of the cube determined the imaging distances from the camera to plants, and it was found that a minimal length of 40 cm was required to cover the whole plants. The dimensions of the cube LCG was determined by the motion trajectory of the camera, which was a function of the length of the camera arm LAC :In this study, we selected the length of the camera arm as The 3D models of soybean plants were reconstructed based on the method of structure from motion (SfM) that is a low-cost photogrammetric method for 3D reconstruction using a series of overlapping images. It applies a highly redundant, iterative bundle adjustment procedure, based on a database of features automatically extracted from the set of multiple overlapping images to resolve the target’s structure . The arrwww.cloudcompare.org) for further processing, including calibrating the dimension, removing the background (soil and plant pots) and taking measurements. The geometric calibration was conducted by comparing the measurements of the diameter of the plant pots using both the imaging system and a tape measure. The measurement of the four traits was conducted in CloudCompare manually because of the complicity of automated processing. In this study, we focused on system development and validation of usefulness of the developed system in plant phenotyping. The system will be optimized and automated processing algorithms will be developed in the future study. The measurement procedure is shown in The change in the morphological parameters of plants under different treatments was quantified using the image features of the plant height, plant canopy width, petiole length, and petiole angle, which were extracted from the 3D models of each plant on different days. The dense point cloud data were exported from Agisoft to an open source software CloudCompare , including linear regression analysis, analysis of variance (ANOVA). The measurement accuracy of plant height and petiole angle from the imaging system was calculated by comparing the data collected manually, and a linear regression analysis was conducted. Data are the plant height, plant canopy width, petiole length, and petiole angle on the i = 1, 2, 3, 4 or 5 time of data collection. Then the average change rate of the plant height, plant canopy width, petiole length, and petiole angle in four groups was calculated using all plants in each group. At the end of the vegetative stage V5, dry biomass of 48 plants was collected, and a one-way ANOVA was conducted to evaluate the significance in the difference between four groups. The average change rates of the plant height, canopy width, petiole length, petiole angle and dry biomass were used to explore the variation of growth and accumulation of biomass at the early vegetative stage (V1).In this study, imaging data were collected on five days during stage V1, i.e., 2nd, 4th, 6th, 8th and 10th of April, 2018, which were divided into four growth periods, i.e., 2–4, 4–6, 6–8 and 8–10. To quantify the amount of plant growth in the four growth periods, change rate (CR) in each growth period of each plant was calculated using Equation (3) for each image feature.R2 = 0.88 and 0.96) for plant height and the petiole angle at a 0.05 significance level, indicating that the 3D imaging system has potential in measuring morphological traits of interest for soybean plants at early stages.The agreement between the image measurements and the manual measurements was shown in p-value < 0.05) than that under controlled environment and the flood-sensitive cultivar under both conditions, which is consistent with the observations of Cox et al. (2003). The average change rates of the four traits  at four growth stages of all groups were shown in The average change rates in plant height of the other three groups were similar in each growth period. On the other hand, the same flood treatment did not affect the growth of the sensitive cultivar (Group III) and no significant difference was observed in the plant height between the two cultivars in the controlled groups (Group II and IV). In summary, flood on soybean plants at vegetative stage V1 had a significant effect on their growth speed of plant height and petiole angle for the cultivar resistant to flood, but limited on the plant canopy width, the petiole length. Therefore, the extracted image features are able to quantify the response in soybeans in different cultivars to flood at vegetative stage V1.p-value < 0.05), however, no significant difference was found between two cultivars in the same treatment (treated or control), as shown in The biomass of each plant and the mean of each group are listed in PH is the plant height, CW is the canopy width, BL is the petiole length and PA is the petiole angle. The data of the plant height, canopy width, petiole length, and petiole angle of all 48 plants collected using the 3D imaging system on the five selected days were used to analyze the correlation between image features and the biomass. A linear regression analysis was conducted to find the regression functions of the five days. Equation (4) shows the regression function for the data of the last day.The statistical analysis results of the multiple linear regression analysis for Day 5 that had the highest correlation, are shown in This study developed a cost-effective 3D imaging system to quantify the variation in soybean growth and biomass due to submergence stress at the early growth stage. The developed system collected plant architecture information of soybean plants, including plant height, canopy width, petiole length, and petiole angle, five times at early growth stages. Meanwhile, the biomass of each plant was measured using the oven dying method by cutting the above-ground plant shoots after the last data collection. The multiple linear regression was conducted to estimate the potential of estimate plant biomass using the developed image features. Compared with the 2D imaging system, the developed 3D imaging system is more accurate in measuring architectural information of plants and may quantify the variation of plant development due to biotic and abiotic stresses. The developed method is simple and low-cost for data acquisition compared with other 3D imaging systems. However, it also has some limitations that are needed to be further investigated, for example, inefficiency in data acquisition and image process. The developed 3D imaging system may be not suitable for a high-throughput platform .The plant growth and yield of soybeans can be significantly affected by flood stress . When soA cost-effective 3D imaging system was developed to take measurements of plant architecture of soybeans at the early growth stage. The developed system was evaluated in quantifying four plant traits, including plant height, plant canopy width, petiole length and petiole angle, in a flood study. The results show that flood-stress (submergence stress) during the vegetative stage V1 had significantly affected the development of soybean plant in the plant height and canopy width, which led to two times to three times reduction in the dry biomass at the end of vegetative stage V5 compared to the plants under control. The low-cost 3D imaging system was able to measure the linear length with an error of 5.78%, and angle of 4.99%, which considered accurate and useful to quantify the plant variation. On the other hand, linear regression analysis indicates that the extracted image features were able to estimate the dry biomass, especially using the data collected on the last day. This study shows that the developed 3D imaging system has the potential for the accurate measurement of plant architecture and estimation in dry biomass, and it may be useful to acquire plant traits for breeding programs.


Fracture of anterior teeth is the most frequent type of injury in the permanent dentition. Composite materials have made possible the use of adhesive materials and techniques, but storage of fragment in the media can enhance the bond strength. The purpose was to evaluate the influence of storage media and duration of the fragment in the media on the bond strength of the reattached fragment of teeth.A total of 104 permanent maxillary central incisors were included. Samples were divided into four groups of 26 teeth each, further divided into eight groups of 13 teeth each and sectioned 3 mm apical to the incisal edge and stored in four storage media—tap water, artificial saliva, sodium fluoride, and Tooth Mousse at 12 and 24 hours. The bond strength was measured by universal strength testing machine.Tooth Mousse showed statistically significant difference  compared with sodium fluoride, artificial saliva, and tap water when stored in both 12 and 24 hours’ duration.Tooth Mousse was a better storage media when compared with sodium fluoride, artificial saliva, and tap water.Tooth Mousse can be considered as a best storage media for fragment reattachment.How to cite this article: Jalannavar P, Tavargeri A. Influence of Storage Media and Duration of Fragment in the Media on the Bond Strength of the Reattached Tooth Fragment. Int J Clin Pediatr Dent 2018;11(2):83-88. Coronal fractures of permanent incisors represent 18 to 22% of all the traumas affecting dental hard tissues; of these, 96% involve maxillary incisors.2 Although composite resin restoration is indicated in the management of fractured anterior teeth, reattachment is an excellent option when the fragment is available. With the development of adhesive dentistry came the concept of “fragment reattachment.”3 Reattachment offers the advantages of being a highly conservative technique and does not involve any kind of preparation that promotes the preservation of natural tooth structure, good esthetics, and acceptance by the patient who receives the treatment. Prognosis of the fragment reattachment depends on the firm attachment of the fragment to the tooth with strong bonding between the two segments and the tooth preparation. Various studies have been carried out using different materials and tooth preparation designs employed for the union of fractured segments.4The treatment of coronal fracture is a considerable challenge for the dentist because they have to fulfill the parameters, like form and dimension, opacity, and trans-lucence of the original tooth to obtain a successful restoration.7 So, successful fragment reattachment depends on the intact retrieval of the fragment at the time of injury and adequate hydration of the fragment outside the mouth. Hydration maintains the vitality and original esthetic appearance of the tooth. The hydrophilic characteristic of adhesive systems also means that hydration acts to ensure adequate bond strength.3 The reattachment time can affect the bond strength of these reattached fragments because dentin moisture is also essential for achieving the high bond strength between the fragments and composite resin.8 Very few studies have been reported on the kinds of environments like saliva, water, or normal saline, in which patients may store fractured parts of teeth, like what should be done in case of avulsed teeth.3 The focus of the study was to examine the influence of different storage media and duration of the fragment in the media on the bond strength of the reattached fragment of teeth.One of the factors that play an important role in the success of fragment reattachment is the type of storage of the fragment following trauma. Most of the case reports have highlighted the importance of hydrating the fractured segments.In this experimental study, 104 extracted permanent maxillary central incisors were selected. All the extracted teeth were cleaned with ultrasonic scaler and samples were randomly and equally divided into four groups of 26 teeth each. Groups were further divided into eight groups of 13 teeth each  and wereAfter 12 and 24 hours, in group I, fragments were rinsed, dried, and bonded to a respective apical portion of a tooth. Both the fractured surfaces were etched by 37% phosphoric acid for 15 seconds and rinsed with water for 15 seconds and dried with paper towel. Then the bonding agent was applied on both the etched surfaces and cured with light curing unit. The fragments were held with the help of gutta-percha stick and approximated with their respective apical portion using a flowable composite by pressing both the parts together and curing for 40 seconds. Reattached samples were kept in distilled water. A similar procedure was carried out respectively for groups II, III, and IV .All the samples were mounted on an acrylic block up to 1 mm apical to the cingulum and specimens were loaded on the universal strength testing machine . In order to evaluate the impact, a crosshead speed of 0.5 mm/minute was selected and the compressive load was applied on the incisal third of teeth specimen at 90° using universal strength testing machine to simulate the impact from a fall . The bon1 and IV2, and and III2, but the mean value of bond strength of these groups was higher than that of other groups. The mean value of bond strength was lesser in groups II1 and II2 and groups I1 and I2 at 12 and 24 hours respectively , especially groups III1, and IV1 in group III2 and groups I1, II1, III1, and IV1 in group IV2. Whereas groups I2 and II2 showed similar statistically significant values (p 0.05) when compared with the groups I1, II1, III1, and IV1 , which had highest mean values of bond strength compared with any other experimental groups at 12 and 24 hours. On comparison within the groups, bond strength of Tooth Mousse exhibited high statistically significant difference with other groups, showing 15.68 and 18.74 kg when compared with sodium fluoride, which was 12.23 kg and 15.13 kg (III2) at 12 and 24 hours respectively; it could be because Tooth Mousse contains a high percentage of essential elements like calcium and phosphate. These findings were corroborating the results found by Shirani et al,13 where they proved that milk elements, such as calcium and phosphate can harden and stiffen both demineralized and healthy dentin by permeating the surface. This is probably the reason why enhanced bond strength was observed in the groups which were rich in calcium and phosphates. Even these results also substantiate the findings of other studies by Shirani et al,14 where the selection of storage conditions was based on publicly accessible materials, particularly milk and egg white, as these have been recommended for storing the avulsed tooth. Again, these media were rich in calcium and phosphate, which enhance the bond strength of reattached fragment. In addition, Borges et al15 also reported that fragments treated with Tooth Mousse paste prior to the application of Adper SE Plus presented statistically improved bond strength compared with nontreated samples, as confirmed by the lower frequency of adhesive failures and the higher frequency of cohesive failures in composite. Adper SE Plus presents phosphoric acid esters that are capable of bonding chemically to hydroxyapatite. Thus, this adhesion potential could have been improved by increased calcium availability after dentin treatment with Tooth Mousse paste.The best storage media, as observed in the present study, was Tooth Mousse  of 6.51 and 8.31 kg and tap water (I1 and I2) about 5.17 and 7.21 kg; the possible reason could be the formation of fluorapatite crystals within the fragment which strengthen the reattached fragment. Moreover, artificial saliva and tap water contain minor percentage of essential elements like calcium and phosphate or fluoride; hence, they play a role in hydration of the fragment rather than the enhancement of bond strength.In the present study, it was observed that sodium fluoride in contrast to Tooth Mousse has lower bond strength because most fluoride salts produce a reaction product which inhibits the flow of resin into spaces in and around enamel prisms, and thus decreases the mechanical retention and produces weak product-to-resin junction bond strength.2, II2, III2, and IV2 demonstrated the highest bond strength mean values compared with the 12-hour groups I1, and IV1, which suggests that longer the duration of fragment in the media, higher the bond strength. These results support the findings of Farik et al.8One more parameter evaluated in this study was the duration of fragment in the media on the bond strength of the reattached fragment. It was observed that 24-hour groups I8 recommended that fragments that were initially kept in a dry environment should be kept moist (in water) for at least 24 hours prior to their reattachment. But these findings disagree with the study done by Yilmaz et al17 and Capp et al,3 where they have found that the fracture resistance of tooth fragments that were kept in a dry environment for 48 hours followed by a 30-minute rehydration were not significantly different from those teeth that had been kept in tap water for 24 hours prior to their reattachment. These data were encouraging, as a 30-minute rehydration would be clinically convenient. Hence, considering the findings of above-mentioned studies, storing the fragments for a short duration is equivalent to the 12 hours’ duration in our study.It has been reported that the strength of the bond between the fragment and tooth is reduced when the fragment is kept in a dry environment for more than 1 hour prior to its reattachment. Farik et al15 However, in those investigations, the Tooth Mousse paste was left in place on dentin for 60 minutes per day and this application was repeated daily for 7 days. But the procedure described above to treat dentin with a Tooth Mousse paste is not clinically viable. On the contrary, this study highlights the possibility of using a shorter duration (3 minutes) to actively apply Tooth Mousse paste immediately after cavity preparation, which can be applicable for clinicians as a novel step for adhesive procedures.On the contrary, in our study, it was evident that groups at 24 hours showed improved bond strength, especially Tooth Mousse group, which significantly influenced the bond strength, corroborating with Borges et al.Therefore, when individually considered, none of the factors (storage media and duration) were capable to restore the original strength of the teeth. However, an appropriate association between type of storage media and sufficient duration can enhance the bond strength of the reattached fragment. In this study, the appropriate association was found between Tooth Mousse and 24 hours’ duration.Hence, the findings of above-mentioned studies support the fact that storage of the fragment in a media before reattachment would be desirable, especially calcium-rich media which can further enhance the bond strength of the reattached fragment. The lowest bond strength values were found when artificial saliva and tap water were used to store the fragment. In this way, inappropriate storage media, which have low percentage of calcium and phosphate, leads to fragility of the reattached fragment, with high risk of debonding. The amount of load required to fracture the reattached fragment is influenced by the media and duration where the fragment is stored before reattachment. The best result is obtained when the fragment is stored in Tooth Mousse. Tooth Mousse can be considered as a best storage media for fragment reattachment.Tooth Mousse can be considered as a best storage media for fragment reattachment, as it increases the bond strength.


An experimentally validated mathematical model of a microfluidic device with nozzle-shaped electrode configuration for realizing dielectrophoresis based 3D-focusing is presented in the article. Two right-triangle shaped electrodes on the top and bottom surfaces make up the nozzle-shaped electrode configuration. The mathematical model consists of equations describing the motion of microparticles as well as profiles of electric potential, electric field, and fluid flow inside the microchannel. The influence of forces associated with inertia, gravity, drag, virtual mass, dielectrophoresis, and buoyancy are taken into account in the model. The performance of the microfluidic device is quantified in terms of horizontal and vertical focusing parameters. The influence of operating parameters, such as applied electric potential and volumetric flow rate, as well as geometric parameters, such as electrode dimensions and microchannel dimensions, are analyzed using the model. The performance of the microfluidic device enhances with an increase in applied electric potential and reduction in volumetric flow rate. Additionally, the performance of the microfluidic device improves with reduction in microchannel height and increase in microparticle radius while degrading with increase in reduction in electrode length and width. The model is of great benefit as it allows for generating working designs of the proposed microfluidic device with the desired performance metrics. Microfluidic devices employ channels with hydraulic diameters smaller than 1 mm and this brings about certain advantages such as low sample and reagent requirement, small footprint, portability, and low power consumption . MicroflfCM) is dependent on the permittivity and conductivity of the medium and microparticle as shown in Equation (2); Equation (3) presents the relationship of conductivity of microparticle to its bulk and surface conductivities [Re[CMf] determines whether a microparticle will experience pDEP or nDEP; when Re[CMf] is positive, then the microparticle will experience pDEP and if Re[CMf] is negative, then the microparticle will experience nDEP.The real part of the Clausius–Mossotti factor  and silica microparticles  [It can be noticed from Equation (2) that as Regarding the electrode configuration shown in Researchers have developed DEP based microfluidic devices for 3D-focusing of microparticles. Morgan et al.  modeled Several electrode configurations have been developed in the past for DEP-based focusing ; howeverThe model corresponding to the microfluidic device shown in The initial conditions associated with the Equation (4) include the initial displacements and velocities as represented in Equations (5) and (6), respectively ,16,17. TFrom Equation (4) it is evident that information on the electric field and velocity of the medium are required for solving the same. The information on electric field can be determined only if information on electric potential inside the microchannel is available. Information on electric potential inside the microchannel will be available upon solving Equation (7). Afterwards, solving Equation (8) will provide information on electric field inside the microchannel ,16,17.(7The boundary conditions associated with Equation (7) include applied electric potential on the electrodes and electrical insulation elsewhere. All governing equations, i.e., Equations (4), (7) and (8), are numerically solved. The finite difference method (FDM) is used for solving Equations (4) and (7). For implementing FDM, second order central difference scheme replaces the first order differential term of Equation (4) while the second order central difference scheme of Equations (4) and (7) replaces second order central differential term. In order to evaluate the electric field, the first order differential terms of Equation (8) are replaced by second order difference schemes. The time step for Equation (4) is held at 0.00001 s. The node-to-node distance in the x-and z-directions are set at 25 μm and 1 μm, respectively. The node-to-node distance in the y-direction is determined based on the node-to-node in the x-direction and the electrode dimensions; this approach allows for having a structured grid inside the computational domain even though the electrode has a triangular shape. The details of implementing FDM to solve Equations (7) and (8) can be found in Alnaimat et al. ,16 and MThe velocity of the medium is dictated by the Navier–Stokes equations and the continuity equation. Additionally, the flow is usually fully developed at the start of the electrode configuration and this allows for reducing the governing equations to a simplified version of one of the components of the Navier–Stokes equation. The velocity of flow under these conditions is provided in Equation (10) . Since tThe performance of the microfluidic device used for 3D-focusing is quantified in terms of Equations (11) and (12). Equations (11) and (12) represent the degree of 3D-focusing of microparticles. Mathematically, Equations (11) and (12) represent the standard deviation associated with the final position of the microparticle from the ideal 3D-focused position of the microparticle; performance of the microfluidic device studied by Morgan et al.  for 3D-fpp) and documented the trajectories for all electric potentials. Holmes et al. [pp the axial velocity of microparticles is 1.05 mm/s after achieving cent percent 3D-focusing. For applied electric potential of 20 Vpp, the microparticles are 3D-focused near the center of the microchannel and this coupled with the fact the microparticles are transported axially by the medium allows for assuming the centerline velocity of the medium to be same as the velocity of the microparticles. Based on the assumption that the centerline velocity of the medium to be 1.05 mm/s, the volumetric flow rate is determined and employed in the model. Holmes et al.  developes et al.  conductes et al. ; howeverThe model detailed here is based on several assumptions all of which are detailed in Mathew et al.  and inclmε = 78.5oε, ρm = 998 kg/m3, mμ = 10−3 Pa·s) [The ability of the microfluidic device in achieving 3D-focusing is investigated in this section. Studies are carried out using polystyrene microparticles suspended in water (From the equations presented in the previous section of the article it is evident that the performance of the microfluidic device depends on parameters such as microchannel height, electrode width and length, volumetric flow rate, and applied electric potential. In the following part of this article, the influence of these parameters are investigated.Additionally, it can also be noticed from z-component of nDEP force acts on the microparticle. It can be noticed form The influence of the electrode width on the vertical and horizontal focusing parameters is analyzed in Regarding the vertical focusing parameter, it remains almost constant with an increase in electrode width before significantly reducing at high electrode width; the vertical focusing parameters at low electrode widths is almost equal to the vertical focusing parameter in the absence of nDEP forces, i.e., ca. 13 μm. With an increase in electrode width the number of microparticles occupying the space between the top and bottom electrodes increase along with the increase in degree of non-uniformity of the electric field. These are the reasons for the observed trend in the variation of vertical focusing parameter with electrode width. Since microparticles are uniformly distributed over the cross-section of the microchannel, the distance between each sidewall and the nearest column of microparticles is 30 μm, while that between each sidewall and the nearest second and third columns of microparticles are 60 μm and 90 μm, respectively. Thus, for electrode width of 25 μm no microparticles are present in the space between the top and bottom electrodes while for electrode widths of 50 µm and 75 µm the number of columns of microparticles present in the space between the electrodes are one and two, respectively. For an electrode width of 125 µm, the first four columns of microparticles from each sidewall occupy the space between the electrodes and this coupled with enhancement z-component of nDEP force, associated with the increase in electrode width, leads to strong vertical focusing as depicted in This article presents a nozzle-shaped electrode configuration for dielectrophoresis-based 3D-focusing of microparticles. A mathematical model of this microfluidic device is developed and used for studying its feasibility in achieving 3D-focusing. Additionally, the mathematical model is used for parametric study to understand the influence of operating/geometric parameters on the 3D-focusing efficiency of the device. The parameters analyzed include applied electric potential, volumetric flow rate, electrode width and length, and microchannel height. The performance of the microfluidic device is quantified in terms of horizontal and vertical focusing parameters which are mathematically equivalent to the standard deviation of the horizontal and vertical positions of the microparticle evaluated at the exit section on the microfluidic device. The focusing parameters decrease with an increase in applied electric potential, thereby indicating enhancement in performance of the microfluidic device. The focusing parameters increase with an increase in volumetric flow rate, which is indicative of the degradation in performance of the microfluidic device. An increase in electrode width and length improves the focusing parameters, thereby indicating the enhancement in performance of the microfluidic device. An increase in microchannel height generally increases the focusing parameters, thereby leading to degradation in performance of the microfluidic device. The focusing parameters are influenced by the radius of the microparticle such that an increase in radius of microparticle reduces the focusing parameters, thereby indicating improvement in the performance of the microfluidic device. The model is particularly useful in selecting the geometric and operating parameters of the proposed microfluidic device so as to operate it at the desired performance metrics, i.e., focusing parameters.


He identified criteria for each type of symmetry and discussed, using concrete examples, the limits of the infrared method in determining the symmetry of the cycle . Recently, at the Laboratory, studies have been undertaken by A. ABOUIMRANE et al. [1] for the calculation of the normal IR frequencies of the P3O9 cycle for the ideal and real symmetries: D3h, Cs and C3 .By taking the IR spectra of several cyclotriphosphates of a resolved structure, has subsequently shown that it is possible to characterize the PPublished by Elsevier Inc. This is an open access article under the CC BY license https://doi.org/10.1080/10426507.2017.1333507. The percentages of the two groups, P-Oi-P and POe2 of the ring, were calculated from the successive isotopic substitutions 31P–33P, 16Oi-18Oi and 16Oe-18Oe. It has been assumed that internal oxygens are not involved in POe2 movements and that oxygens outside the cycle are not involved in POiP movements. The behavior of the eigenvectors, the displacement of the atoms with respect to their equilibrium position, and therefore of the relative movements at each normal frequency, with respect to the elements of symmetry of the group of the isolated P3O9 cycle, makes it possible to specify their symmetry and consequently the normal modes Corresponding. The assignment of the cycle frequencies is made without any a priori hypothesis and without vibrational spectra 3h, Cs and C3 respectively were confirmed by the IR and Raman vibrational spectra of the compounds containing the P3O9 cycles of symmetry Cs  3O9 cycle, the geometric variations of the elongations and angular deformations of the 12 P3O9 ring atoms corresponding to each were calculated. These movements made it possible to attribute the twelve fundamental valence frequencies, for which the variations of distances, P-Oe or P-Oi, are the most important at the 12 highest frequencies. Whereas for the other 18 vibrations of angular deformations the variations of the distances are zero or very small. On the basis of the atomic displacements, the valence frequencies and the deformation frequencies of the P3O9 cycle were distinguished and assigned.For the calculated normal frequencies of the P


The objective of this study was to determine the best approach for handling missing records of first to successful insemination (FS) in Japanese Black heifers.Of a total of 2,367 records of heifers born between 2003 and 2015 used, 206 (8.7%) of open heifers were missing. Four penalty methods based on the number of inseminations were set as follows: C1, FS average according to the number of inseminations; C2, constant number of days, 359; C3, maximum number of FS days to each insemination; and C4, average of FS at the last insemination and FS of C2. C5 was generated by adding a constant number (21 d) to the highest number of FS days in each contemporary group. The bootstrap method was used to compare among the 5 methods in terms of bias, mean squared error (MSE) and coefficient of correlation between estimated breeding value (EBV) of non-censored data and censored data. Three percentages  were investigated using the random censoring scheme. The univariate animal model was used to conduct genetic analysis.−4, 0.879×10−4, 0.876×10−4 and 0.866 ×10−4 for 5%, 8.7%, 10%, and 15%, respectively, of the missing records. Thus, C4 showed the lowest and the most stable MSE of heritability; the coefficient of correlation for EBV was 0.88; 0.93 and 0.90 for heifer, sire and dam, respectively.Heritability of FS in non-censored data was 0.012±0.016, slightly lower than the average estimate from the five penalty methods. C1, C2, and C3 showed lower standard errors of estimated heritability but demonstrated inconsistent results for different percentages of missing records. C4 showed moderate standard errors but more stable ones for all percentages of the missing records, whereas C5 showed the highest standard errors compared with non-censored data. The MSE in C4 heritability was 0.633×10C4 demonstrated the highest positive correlation with the non-censored data set and was consistent within different percentages of the missing records. We concluded that C4 was the best penalty method for missing records due to the stable value of estimated parameters and the highest coefficient of correlation. Reproduction traits are important components from various breeding aspects, which have a large bearing on production and profitability. As in other livestock species, reproductive traits of beef cattle tend to be of low heritability . ReproduThe interval from first to successful insemination (FS) is the number of days between the first insemination and the insemination that results in conception. The FS in heifers has moderate heritability and high genetic correlation with the reproductive performance of cows, especially with FS and days open . A problFor solving the problem of missing records, several penalty methods have been proposed by animal geneticists: Adding 21 days to the largest record within a contemporary group, has been proposed based on the estrous cycle of female cattle . Adding Reproduction records of Japanese Black heifers were obtained from Artificial Insemination Center of Northern Okinawa. A data set consisted of records of artificial insemination, calving events and FS in heifers. The data set was edited by the following requirement: heifers born between 2003 and 2015, first insemination of heifers between 2005 and 2016, and farms with a minimum of five records. The final data set comprised 2,367 records of heifers from 164 farms, including 206  missing records. The data structure is presented in . The FS Two penalty approaches were used in this study: i) based on the number of inseminations, ii) based on the estrous cycle of female cattle. The FS days tend to be prolonged with the increasing number of inseminations, and based on this relationship, four penalty methods, coded C1, C2, C3, and C4, were set up. The last penalty method (C5) was based on the estrous cycle of female cattle [x, where nx is the average number of FS days at the number of times till the last insemination plus one.C1: average FS according to the number of inseminations. P = nm, where nm = 359.C2: constant number of days (359), derived from the highest expectation of FS in the records, P = nn, where nn is the maximum number of FS days to the nth insemination.C3: maximum number of FS days to each insemination. P = nx and nm, where nx is the average number of FS days at the number of times till the last insemination.C4: average of ng+ 21, where ng is the maximum number of FS in each contemporary group.C5: a constant number (21 d) was added to the highest number of FS days in each contemporary group. P = nThe general linear model (GLM) procedure of SAS 9.3 software  was usedyijklmn is the observation of FS, Fi the ith fixed effect of farm, Yj the jth fixed effect of year of insemination, Mk the kth fixed effect of month of insemination, Tl the lth fixed effect of artificial insemination (AI) technicians, Am the mth fixed effect of age class of heifers and eijklmn the random residual of yijklmn.where Genetic parameters were estimated using the univariate animal model by restricted maximum likelihood; estimated breeding value (EBV) for animals was predicted by the BLUP method using Asreml software . Statisty = a vector of observation, b = a vector of fixed effect of farm and AI technician, X = an incidence matrix for the fixed effects, u = a vector of random genetic additive effect, Z = an incidence matrix for the random effect, and e = a vector of random residuals.where, y, u, and e areThe expectations for The variance-covariance structure of random effects isA is the numerator relation matrix, I the identity matrix and The bootstrap method is one of the most powerful variance estimation techniques applied to complex sample statistics, whereby simulation is conducted to generate multiple data sets from an original data set . The priIn the present study, the bootstrap method was used to compare five penalty methods in terms of bias, mean squared error (MSE) and the accuracy of EBV. Resampling was generated 100 times from the original data. The bias and error variance computation requires between 50 and 200 resamplings . The numGenerate a resampled data set 100 times from the original (non-censored) data.Choose 8.7% of missing records within each resampling data set by the random censoring scheme.Estimate genetic parameters and predict EBV for each data set.Calculate the average of genetic parameters and predicted EBV.Compare the penalty methods by bias and MSE of heritability and correlation of EBV with a non-censored data set.Repeat steps 1 to 5 for three other percentages  to assess the influence of different proportions of missing records on the inference.Results of GLM of non-genetic effects for FS with the use of non-censored data are presented in Additive genetic variances, error variances and heritability for non-censored data and five different penalty methods are shown in Bias of estimated heritability in five penalty methods is pre sented in The MSE of estimated heritability in five penalty methods is presented in The average correlation between the EBV of the five pen alty methods and the EBV from the non-censored data set is shown in Heifers that have a true FS are those with successful insemination, gestation and calving. Eliminating an open heifer from the data set would yield biased or underestimated genetic parameters . In the In the present study, heritability of a non-censored data set was 0.012±0.016, lower than the average estimates in C1, C2, and C3, but slightly higher than those in C4 and C5. Standard errors of heritability of penalty methods were all higher than the heritability of a non-censored data set. Compared with previous reports, our heritability estimates were within the range of estimates in the literature. For Holstein heifers  and AyrsIn the present study, all of the penalty methods showed posi tive bias in heritability estimates. The bias in C5 was higher than that in the other penalty methods, making its error variance five times higher than the other penalty methods.The MSE is the most important criterion in evaluating the performance of a predictor or an estimator; it is also useful in acquiring the concepts of bias and accuracy in statistical estimations . EstimatIn the present study, 8.7% of the records were missing, and 5%, 10%, and 15% were designed to assess the influence of the missing records. The genetic and error variances in C1 and C5 tended to increase as the percentage of missing records increased; in C2, C3, and C4 they were inconsistent in the 10% and 15% missing records; in C4 they were the lowest in 5%, 8.7%, and 15% as compared with the other methods; however, in 10% of the missing records, the lowest variance was observed in C3. The reason for the fluctuation in genetic and error variances in 10% and 15% of the missing records was attributable to changes in pedigree structure. This phenomenon may be due to the deletion of key animals with regard to pedigree.C1 showed the lowest MSE in 5% and the highest in 8.7% compared with the other percentages. In C2 MSE tended to be similar to those in C3 and C4, where the lowest MSE occurred in 5% and increased as the percentage of missing records became higher. In C4 MSE was lower than in the other methods at all percentages of missing records. C5 showed the highest and the most unstable MSE among the different percentages. When the percentage of missing records rises up to 15%, heritability tends to be lower because genetic variance decreases, while error variance increases. The change in genetic and error variances is reinforced with higher missing percentages in conjunction with changes in the data structure .The coefficient correlation of EBV for heifer was lower than that for sire and dam, whereas it was higher for sire in 8.7%, 10%, and 15% of the missing records. In 5% of the missing records, it was higher in C1 for heifer than for sire, whereas in C2 it was higher for heifer than for dam or sire. In the other percentages, it was lower for heifer than for sire or dam, which may be attributable to the decreased accuracy for heifer EBV at higher percentages of missing records.The coefficient correlation in C3 was lower than in C4 but higher than in the other three methods. In C4 it was consistent and highest for heifers, sires and dams at all the percentages of missing records. In C5 it was the lowest for heifer and parents among the five penalty methods. The penalty in C5 was based on the highest number of FS days, as identified in each contemporary group plus the constant number (21 d). Thus the penalty by the simple addition of certain days resulted in a less accurate EBV and a lower correlation than the other methods. This phenomenon could be due to changes in EBV ranking when penalty data are implemented . SmallerThis study indicates that C4 is the best penalty method for missing records because it has the lowest MSE and the average of standard errors for heritability. It also demonstrated the highest accuracy for EBV and consistent results for all the percentages of missing records.