Moreover, due to the powerful ability in handling high-dimensional data and complex system, deep learning has efficiently promoted the applications of artificial intelligence in drug discovery and design. In this review, deep learning methods that tailor to precision drug design are carefully discussed. When a drug molecule is discovered, the development of specific targeted drug delivery system becomes another key aspect of precision drug design. Therefore, state-of-the-art techniques of drug delivery system including antibody-drug conjugates (ADCs), and ligand-targeted conjugates are also included in this review.Since Human Genome Project (HGP) revealed the heterogeneity of individuals, precision medicine that proposes the customized healthcare has become an intractable and hot research. Meanwhile, as the Precision Medicine Initiative launched, precision drug design which aims at maximizing therapeutic effects while minimizing undesired side effects for an individual patient has entered a new stage. One of the key strategies of precision drug design is target based drug design. Once a key pathogenic target is identified, rational drug design which constitutes the major part of precision drug design can be performed. Examples of rational drug design on novel druggable targets and protein–protein interaction surfaces are summarized in this review. Besides, various kinds of computational modeling and simulation approaches increasingly benefit for the drug discovery progress. Molecular dynamic simulation, drug target prediction and  As this initiative launched, precision drug design has entered a new stage. Cell-based HTS method has been widely used to obtain drug candidates, however, the hits identified by this method are usually difficult to undergo further optimization because of their bad lipophilic characteristic  was selected to undergo further structural optimization. Its derivative 17  was then found to be the most active one, which inhibited PRMT5 enzymatic activity at nanomolar concentration (IC50 = 330 nM) and displayed potent anti-proliferative effects on MV4-11 cells  that served as a therapeutic lead which was devoid of many side effects of current opioids , could disrupt the EZH2-EED interaction, destabilize the PRC2 complex and inhibit its methyltransferase activity in cancer cell lines  inhibitors has been well reviewed elsewhere . In anot11 cells . In 2016 opioids . To devell lines . This stll lines . Identifll lines .in situ fragment assembly are three broad strategies for converting fragments into hits and leads  as a fragment starting point in the discovery of Aurora kinase inhibitors, Howard et al. performed fragment-based drug design  for the treatment of cancer targeting on Aurora kinase was finally identified after optimization of the cellular activity and physicochemical properties of the initial fragment  that inhibited the RSK2 CTD by forming a reversible covalent bond with cysteine 436  found in only 11 of the 518 human protein kinase  that exhibited high ligand efficiency and selectivity for MSK/RSK-family kinases  conjugates were employed as small molecule prodrugs to selectively release anticancer drugs under the mechanism of the PCPA-induced LSD1 inhibition. PCPA-tamoxifen conjugates 1a  and 1b  that could release 4-hydroxytamoxifen (an anti-estrogen agent for breast cancer treatment) in the presence of LSD1 in vitro were designed as PCPA-drug conjugate prototypes. As expected, 1a and 1b exhibited anticancer activity in LSD1 overexpressed breast cancer cells. Further analysis showed that the simultaneous inhibition of LSD1 and the estrogen receptor and the release of 4-hydroxytamoxifen triggered by the inhibition of LSD1 together contributed to the anticancer effectiveness  and oseltamivir  were designed to mimic the transition state of the natural substrate sialic acid , which leaded to the improved activity and specificity on human neuraminidase (NA). To overcome drug resistance, there is an urgent need for the development of novel scaffold of NA inhibitors. Based on the finding that influenza NAs employ a covalent mechanism by using DFSA  as a substrate, Kim et al. explored difluorosialic acids (DFSAs) as a possible novel covalent mechanism-based influenza therapeutic agent  showed an IC50 value comparable to those for zanamivir and oseltamivir. In addition, DFSAs showed good inhibition of NAs for zanamivir or oseltamivir-resistant influenza virus strains   was found with strong antitumor activity but poor stability. Under natural light, it is inclined to undergo cis–trans isomerization, resulting in decreased activity. cis–trans isomerization by performing quantum chemistry calculation. Inspired by their quantum chemistry calculation results, they designed a series of compounds with improved stability and activity. Among them, compound 1  displayed potent antitumor activity in human colon cancer HT-29 xenograft model  . A potenft model .Figure 6A) (IC50 = 12 nM) was found by HTS  has been widely used to modulate ligand selectivity as it displays higher variability in shape and length  showed potent inhibitory activity (IC50 = 0.0039 nM) and high selectivity over other MMPs   strategy in which a ligand simultaneously occupies the ATP binding site and a unique pocket outside the ATP cleft has been employed to identify selective kinase inhibitors as both tool compounds and potent therapeutic candidates . The advd by HTS . The strd by HTS ,b. The Sd length . A seriend TACE) . X-ray cnd TACE) . BesidesFigure 7A) that could overcome mTOR resistance mutations by exploiting the unique juxtaposition of two drug-binding pockets  to create a bivalent interaction. In order to simultaneously occupy the ATP binding site and rapamycin-binding site, a bivalent mTOR inhibitor which contained rapamycin, a linker and MLN0128  was designed and synthesized. This compound could potently inhibit tumor growth and mTOR signaling in wild-type mTOR-expressing cells as well as in cells that have acquired resistance to rapalogs or ATP-competitive inhibitors, or both ( or both . This st or both .Table 1). Here, we summarize computational modeling and simulation approaches that give a helping hand in various drug development process.Given the complexity of biological process and life system, computational approaches that deal with multifarious parameters and features have played essential roles in analyzing systemic response of agents, identifying drug targets, and predicting novel therapeutic strategies . In addiMolecular dynamics simulations have been long proposed to unravel novel cryptic binding sites of the targets as well as provide insight into protein dynamics beyond that available crystallographic information. By performing MD simulations on their constructed complex structures of M2 muscarinic acetylcholine receptor (M2 receptor) with its allosteric modulators, in silico mutation studies, they identified an important network module and a combinational anti-cancer strategy which targeted ceramide and PI3K-AKT pathway consistently. They further utilize chemical tools to experimentally validate their prediction and successfully observed the synergistic effects in colon cancer cells. Hopefully, the network model could further assist researchers with mechanism studies and drug target prediction. In addition to network analysis, there are many good web servers that can be easily accessed to and be used to predict the drug target and small molecule-protein interactions (Table 2). SuperDrug2 provides comprehensive information of approved and marketed drugs and allows similarity and substructure search to obtain target information  based on support vector machine method and a large chemical dataset . Model ain silico prediction and in vivo validation. The above work is a good attempt that utilizes agent-based models to help discover new drug. Owing to the ideal flexibility and feasibility of agent-based modeling approach in immunology, it is promising to further design patient specific model for the prediction of immunology treatment.In the field of immunology, differential equation-based models and agent-based model have been utilized in modeling immune system. Differential equation-based approach is a mathematical model that describes organism-wide cell population dynamics in continuous time. Differential equation-based models are usually more effective in grabbing the dominating cellular and molecular change under bacterial or viral attack . HoweverFigure 8 (de novo molecular design by Schneider’s group and they utilized RNN with long short term memory (LSTM) cells to construct a SMILES-based compound generation model . They exploited both the information of peptide sequences and the residues of HLAs within 4.0 Å of the binding nanomer peptides, to construct an ANN with only one hidden layer. After training and optimizing the ANN model, NetMHCpan could achieve good prediction results. Of note, NetMHCpan was not intended to predict possible neoantigens at that time, though it is now used to perform peptide-binding prediction as part of the pipeline for neoantigen discovery and design. The latest version can be found here3. In 2017, a remarkable clinical research about personal neoantigen vaccine reported that four out of six vaccinated patients with melanoma had no recurrence within 25 months, and the other two patients who underwent disease recurrence then received anti-PD-1 therapy and finally achieved complete tumor regression (in silico methods like NetMHCpan.The human MHC is synonymous with human leukocyte antigen complex (HLA), which can be divided into three classes. Amongst, MHC-I can be recognized by CD8 co-receptors of T cells, while MHC-II can be recognized by CD4 co-receptors . MoreoveA-A∗0204 . Then inA-A∗0204 ; Table 2gression . This woWith the renaissance of deep learning in recent years, whether it could be used to predict peptide binding to MHCs has drawn wide attention, especially because of the potential application of tumor neoantigen. Researchers from Johns Hopkins University have developed five machine learning approaches, including MHCnuggets-GRU, MHCnuggets-LSTM and three CNN-based prediction methods, to predict peptide binding affinity to MHC-I . In the The advancement of computing power especially accelerated GPU as well as the great breakthrough of deep learning algorithms has made artificial intelligence become an active research area. Increasingly accumulated biological data like clinical samples and high-throughput sequencing data provides massive information while deep learning approaches could make full use of these data to find potential connections, which could be of great importance for precision medicine. In addition to the analysis of genetic variants and neoantigen prediction, deep learning could also be helpful in predicting possible metabolic sites of drugs and the polymorphism of metabolic enzymes to provide basis for clinical medication . NeverthFigure 9.In the development of ADCs, a monoclonal antibody which targets on a specific antigen expresses in certain cancer cells is often conjugated by a highly potent cytotoxic payload via a suitable linker . The binGemtuzumab ozogamicin  is a typical example of the first generation ADCs that suffer from the heterogeneity problem and toxicity issues . Mylotarin vivo and has limited ability to exhibiting secondary immune functions, such as antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity  compromises a microtubule polymerization inhibitor DM1 that is conjugated via a stable thioether linker to a humanized IgG1 anti-HER2 mAbs . In 2013The main improvements of second generation ADCs are preferable drug quality controls and minimal toxicity effects. Though FDA has added a warning label including hepatotoxicity, cardiac toxicity and embryo-fetal toxicity to T-DM1 packaging, less patients suffered from severe toxic effects than who received standard therapy (lapatinib + capecitabine) in clinical trials . The reaBesides, most second generation ADCs select IgG1 isotype as their mAbs owing to its cost-effective manufacture and the ability to support ADCC . The tarAnother second generation ADC that has been approved is Brentuximab vedotin . Brentuximab vedotin has the same antibody isotype (IgG1) and shares the properties of heterogeneity as T-DM1 but differs in its protease-cleavable linker and the cytotoxic warheads which contains monomethyl auristatin E (MMAE) moieties . BrentuxIn summary, the second generation ADCs have improved stability and showed better CMC  characteristics owing to the improved linkers and the change of IgG1 isotype, but are still in a dilemma about the heterogeneity and systemic toxicity.Vadastuximab talirine (Seattle Genetics) delivers the cytotoxic payload specifically to malignant cells bearing CD33 antigens . Just liTable 3.In addition to the site-specific technologies, other state-of-the-art technologies have also been used in the development of third generation ADCs . TechnolHowever, whether the aforementioned novel technologies could assist in the development of more potent, stable, homogenous and tolerable ADCs is eagerly expected by both academia and industry as well as doctors and patients who count on novel treatment methods and technologies to extend their lives.Figure 9). Many aspects have to be considered in design of ligand-targeted drugs including the targeting ligand (concerning an appropriate cell target), the proper linker and the toxic payloads  of a ligand for its receptor should be approximately 10 nM or lower so that a desired therapeutic effect may be achieved. Also, the coupling between the ligand and the linker should have little influence on the ability of ligands to bind to their receptors . Following are several typical examples of ligand-targeted drugs both for treatment and diagnosis application.All in all, the requirements for each part of ligand-targeted drugs are very strict. Several key factors related to potency, selectivity and physicochemical properties should be carefully optimized in order to achieve a successful conjugate  etarfolatide, contains a folate receptor-targeting ligand which is specially used for imaging of folate receptor overexpressing tumors . OTL38 cIn summary, although currently no product of ligand-targeted drugs has entered into the market, it still holds great hope for the development of these conjugates for treatment and especially diagnosis of patients with specific biomarker . TogetheThe discovery of potent and selective modulators will continue to be central to revealing the physiological functions of isozymes and to the development of new therapeutic or diagnostic agents for many diseases. In this review, we focused on strategies and applications for precision drug design. SBDD, computational modeling and simulation approaches, deep learning based genetic variant discovery and neoantigen prediction, ADCs, and ligand-targeted conjugate drugs, as well as ligand-targeted imaging agents are discussed in detail. Through combination of various kinds of strategies, novel therapeutic strategies based on precision drug design are highly expected. Recently, screening for inhibitor specificity using multiprotein complexes rather than purified proteins or the addition of requisite protein-protein interaction assay is advocated. Strikingly, a comprehensive understanding of the complex physiological function of isoforms and cell-type specific protein complexes with their substrates and modulators becomes essentially important in the design of highly potent and selective inhibitors.With the increasingly fundamental role of precision medicine in drug discovery and development, it could benefit for both targeted drug design and clinical trial design. In the meantime, personalized approach provides new challenges for better consideration of biomarker related clinical indication. In addition to the various targeted drug design strategies, precision immunotherapy approaches especially monoclonal antibodies targeted tumor-specific antigens, cell-based therapy like chimeric antigen receptor (CAR) T cell therapy, and vaccines are also important for precision therapies. In addition, various drug combinations could make great contributes to overcoming drug resistance and providing better efficacy. We believe that by integrating all kinds of strategies, it is promising to design highly selective bioactive molecules for specific molecular recognition in complex biological systems and will ultimately provide precision medicine beneficial for human.All authors made significant contributions to the preparation of the manuscript and approved it before submission. CL and KZ developed the paper design, and finalized the manuscript. CW and PX wrote the manuscript, edited the references, and revised the style of the manuscript. JH and LZ helped to collect the data, complete the table, and revise the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Administrative data are used to generate estimates of sepsis epidemiology and can serve as source for quality indicators. Aim was to compare estimates on sepsis incidence and mortality based on different ICD-code abstraction strategies and to assess their validity for sepsis case identification based on a patient sample not pre-selected for presence of sepsis codes.International Statistical Classification of Diseases (ICD) coding strategies for sepsis based on primary and secondary discharge diagnoses , explicit coding  and implicit coding (combined infection and organ dysfunction codes)). For the validation study, a stratified sample of 1120 adult patients admitted to a German academic medical center between 2007–2013 was selected. Administrative diagnoses were compared to a gold standard of clinical sepsis diagnoses based on manual chart review.We used the national DRG-statistics for assessment of population-level sepsis incidence and mortality. Cases were identified by three previously published In the validation study, 151/937 patients had sepsis. Explicit coding strategies performed better regarding sensitivity compared to R-codes, but had lower PPV. The implicit approach was the most sensitive for severe sepsis; however, it yielded a considerable number of false positives. R-codes and explicit strategies underestimate sepsis incidence by up to 3.5-fold. Between 2007–2013, national sepsis incidence ranged between 231-1006/100,000 person-years depending on the coding strategy.In the sample of a large tertiary care hospital, ICD-coding strategies for sepsis differ in their accuracy. Estimates using R-codes are likely to underestimate the true sepsis incidence, whereas implicit coding overestimates sepsis cases. Further multi-center evaluation is needed to gain better understanding on the validity of sepsis coding in Germany. Acknowledging that sepsis is the leading cause of death from infection and affecting more than 30 million patients globally , the WorICD coding strategies for sepsis in claims data were selected based on a review of international studies applying ICD abstraction strategies . Codes fValidation of ICD coding strategies was performed against a gold standard of manual chart review of patients admitted to a large university hospital in Germany . We planned the sample size for the validation sample based on considerations for the width of a two-sided 95% confidence interval (CI) for sensitivity of explicit sepsis codes. We expected a sensitivity of 10%  and aimeNational sepsis incidence and mortality were analyzed between 2007 and 2013 using the nationwide German DRG statistics, which includes inpatient claims data from all acute-care hospitals in Germany and is accessible by the Federal Statistical Office . We iden® 20.0 and 23 and the statistical package R [Interrater-agreement in the manual chart review was assessed by the S statistic for dichotomous data for the diagnosis of infection and by the S statistic with linear weighting for the diagnosis of sepsis  , an imprackage R .Of 1120 cases selected by stratified sampling 937 charts were available; 183 charts were inaccessible for accompanying parents, diagnostic or therapeutic day cases without inpatient charts or when charts were not available at the archive at the time of review. Inter-rater-agreements were high both for diagnosis of infection and sepsis . 151 patients had sepsis, including 81 patients with severe sepsis/septic shock. For patient demographics, see From 70 cases clinically defined as sepsis without organ dysfunction according to the “sepsis-1” criteria in the validation cohort, the majority (98%) had no organ dysfunction as defined by SOFA change and thus was classified non-septic according to the new definitions Click here for additional data file.S2 File(DOCX)Click here for additional data file.


Quantifying the bond strength between fibre-reinforced-polymer (FRP) composites and substrates is essential to the design of FRP retrofit systems. This paper collates a database of 1583 individual tests across 56 published experimental campaigns investigating the FRP-to-masonry bond strength through shear pull-tests. Included in the database is all available information characterizing the test arrangement, geometric and mechanical properties of the constituents, as well as the failure load and failure mode. Specifications tableValue of the data•Quantification of bond strength is essential to the design of FRP retrofit systems for strengthening structures.•The database presented collates the results of 1583 bond strength tests from 56 published studies.•The data can be used as the basis for the calibration of new bond strength design rules.•The data can be used as a benchmarking dataset for comparing new and existing design rules.1Through an extensive literature review, an experimental database of 1583 individual shear pull-tests on masonry specimens was compiled from across 56 published studies 1.1unit prism consisting of a single brick or block, or a masonry prism consisting of individual units bonded together using mortar joints. Both of these are shown in A generic pull-test specimen consists of a fibre-reinforced-polymer (FRP) composite plate adhesively bonded to a substrate prism over a particular lap length. The substrate prism can be either a A test is performed by applying an increasing tensile force to the FRP plate until the plate eventually debonds from the prism. Typical debonding failure involves the detachment of the plate along with a layer of the substrate material. Alternate failure modes , or a combination of these.The test results summarised in the compiled database include the maximum load and a description of the observed failure mode. Note that the various possible forms of instrumentation can include the measurement of strain along the plate using strain gauges, slip (displacement) between the plate and the prism, or full-field deformation by techniques such as digital image correlation. However, as the focus of the database is the bond strength, these are beyond the scope of the data.1.21.2.1Tested substrate materials include clay brick, limestone, tuff, concrete block, calcium silicate brick, sandstone, and mortar specimens. Data for each test includes the mechanical properties of the substrate material including its compressive and tensile strength. The tensile strength is further subcategorised in terms of the type of test performed as either direct, flexural, splitting, or unspecified.1.2.2The database covers both externally-bonded (EB) and near-surface-mounted (NSM) retrofits, as shown in Composite materials include carbon FRP (CFRP), glass FRP (GFRP), basalt FRP (BFRP), steel-reinforced polymers (SRP), aramid FRP (AFRP), and natural flax FRP. The majority of tests use epoxy adhesive but some also use polyurethane or cementitious adhesive.1.2.3P as shown in Tests within the database are split approximately evenly between single-lap and double-lap arrangements, with the latter being further subcategorised into a single block and a double block variant. Each of these are shown in The majority of tests in the database use monotonic loading. However, a small number of tests used cyclic loading comprising separate loading, unloading and reloading phases.1.3•Specimens subjected to effects such as temperature and moisture •Tests in which additional anchorage between the FRP and substrate was provided. For example those with nails, fans or cogs •Tests in which the FRP was bonded to plaster instead of directly to the masonry substrate •Non-quasi-static loading conditions such as impulse loads •Plates manufactured from textile-reinforced mortars or fibre-reinforced cementitious mortars.The database includes only tests conducted under standard conditions, that is, where the plate is bonded directly to the masonry substrate and subjected to quasi-static loading. The data therefore excludes the following:These exclusion criteria were applied to individual tests, and as such, control specimens found in the aforementioned studies are still included. Note that some studies have intentionally opted not to report the failure load for tests where the mode of failure was not by interfacial debonding—such tests are still included as long as the mode of failure was reported. Additionally, where the same tests were identified to have been reported in multiple sources, they are only included once.•Tests with confining pre-compression (30 tests) •Curved specimens (10 tests) •Specimens that were repaired after an initial test and re-tested (98 tests) The database also includes tests with the following special conditions, which are specifically identified in the database:1.4The compiled database is provided as a CSV (comma separated variable) spreadsheet in


The aim of the present study was to investigate the effects of the type and thickness of the zirconia material on the microhardness of the underlying dual-cure resin cement.α=.05). Eight disk-shaped zirconia specimens with a 4-mm diameter and four varying thicknesses  were fabricated from two different monolithic zirconia materials: posterior monolithic zirconia (Prettau) and anterior monolithic zirconia (Prettau Anterior). Dual-cure resin cement specimens with a 4-mm diameter and 5-mm height were prepared using Teflon cylinder molds and activated by light beneath the eight zirconia disks and without any zirconia disk for 20 s (n=12). A total of 108 specimens were embedded in acrylic. Vickers hardness of each specimen was measured at three different depths using a microhardness device with a 50-g load. All data were statistically evaluated using three-way ANOVA, one-way ANOVA, independent samples t-tests, and Bonferroni corrected post hoc tests ( Dual-cure resin cement's microhardness was significantly higher for the samples polymerized beneath anterior monolithic zirconia compared to posterior monolithic zirconia. The hardness decreased as the thickness increased for both types of zirconia; the latter was attributed to an attenuated curing efficiency. Microhardness of the dual-cure resin cement is influenced by both the type and the thickness of the monolithic zirconia restoration. Polymerization efficiency for resin cement cured under anterior monolithic zirconia may be superior to cured beneath posterior monolithic zirconia. Densely sintered yttria-stabilized zirconia ceramics (Y-TZP) have been widely used as alternatives to metal-ceramic restorations because of their superb mechanical properties and favorable esthetic characteristics , 2. TheyEither type of zirconia-based restorations can be cemented using either conventional or adhesive techniques . AdhesivVarious novel monolithic zirconia materials with different compositions and relatedly translucencies are available in the dental market. However, the effect of their type and thickness on the polymerization competence of resin-based cements remains to be a subject of interest. Therefore, the purpose of the current study was to investigate the microhardness of dual-cure resin cement used underneath anterior and posterior monolithic zirconia materials with different thicknesses. The null hypothesis of the study was that the microhardness of dual-cure resin cement is not affected by the type and the thickness of the overlying monolithic zirconia material.Eight disks with a 4-mm diameter and varying thicknesses were prepared from two types of monolithic zirconia materials ; four PRThe total thickness of all zirconia disks was measured by a digital caliper. Then, the outer disk surfaces were glazed  in accordance with the manufacturer's directions.2 was used with an exposure time of 20 s. Calibration of the curing device was checked before polymerization by contacting the tip of the light to a built-in light meter.In total, 108 resin samples were prepared by the placement of dual-cure resin cement  in cylindrical polytetrafluoroethylene (PTFE) molds with standard dimensions (4.0-mm diameter and 5.0-mm height). For the preparation of resin specimens, a glass slide placed against a black background was used in order to support the surface and reduce the reflectance of the subjacent surface against each sample. A transparent film strip was placed on the glass slide to avoid bonding of the material. Equal amounts of base and catalyst were mixed according to the manufacturer's recommendations. The PTFE cylinder mold was filled with resin cement. One more transparent film strip was placed on top, followed by another microscope slide, using finger pressure. Excess cement material was removed from the mold by pressing the film strips between the glass slides. Following removal of the excess cement, one of the eight ceramic disks was placed on top, and the tip of the light source was smoothly located on top of the zirconia disk. This would allow light to pass through the disk over the material . Resin sSubsequently, the resin cement samples were taken out of the PTFE molds, and a plastic spatula was used to remove the uncured material according to ISO 4049 guidelines . The curμm below this zero point using a microhardness tester  with a 50-g load applied for 15 s in the cross-sectional area. Three measurement depths were set by using the positioning knobs on the tester machine and the indentations were conducted by a pyramid-shaped microdiamond tip in order to give the hardness value  in cylindrical molds . To prep Figures  and 4. Tα=.05).VHNs obtained at different depths of dual-cure resin cement samples under different types and thicknesses of zirconia disks were statistically analyzed using three-way ANOVA in order to determine the effect of the zirconia type, specimen thickness, and measurement depth on VHN. The two-way interaction among groups was analyzed using independent sample t-tests, one-way ANOVA, and Bonferroni corrected post hoc tests   on VHN of the resin cement. According to three-way ANOVA, the analysis model was significant, with an Rμm  and VHN values of the dual-cure resin was significantly higher with PRA disks than with PRZ disks at measurement depths of 100, 300, and 500 μm . VHN showed a significant decrease with an increase in the measurement depth (p<0.001) for all groups polymerized under both PRA and PRZ discs whereas the difference was not significant for 100- and 300-μm measurements of control group. For the groups polymerized beneath PRZ and PRA disks, VHN at a 100-μm depth was significantly higher than that at 300- and 500-μm depths, that at a 300-μm depth was significantly higher than that at a 500-μm depth  was used in order to keep the focus on the difference between anterior and posterior monolithic zirconia. However, there are more factors that could affect the polymerization of the resin cement cured beneath zirconia-based restorations. In order to develop clinical recommendations, further studies are needed to confirm our results through comparisons of monolithic zirconia materials with different brands, compositions, and shades when luted using resin cements with differing ratios of chemical and light-activated components.Within the limitations of the study, the following conclusions can be drawn: microhardness values of dual-cure resin cement samples polymerized beneath PRA based materials were higher than that of resin cement samples polymerized under PRZ based materials for the same material thickness and measurement depth. Increase in zirconia thickness leads to significantly lower microhardness values for the underlying resin cement for both PRA and PRZ materials. Clinicians should consider that an increase in the thickness of both PRA and PRZ based restorations could result in insufficient light transmission, which affects the long-term durability of the resin cement and restoration. On the basis of this finding, clinicians can select a better material for each given situation, and they should also consider the efficiency of light curing under thicker zirconia restorations.


Modern Latin American populations were formed via genetic admixture among ancestral source populations from Africa, the Americas and Europe. We are interested in studying how combinations of genetic ancestry in admixed Latin American populations may impact genomic determinants of health and disease. For this study, we characterized the impact of ancestry and admixture on genetic variants that underlie health- and disease-related phenotypes in population genomic samples from Colombia, Mexico, Peru, and Puerto Rico.We analyzed a total of 347 admixed Latin American genomes along with 1102 putative ancestral source genomes from Africans, Europeans, and Native Americans. We characterized the genetic ancestry, relatedness, and admixture patterns for each of the admixed Latin American genomes, finding a spectrum of ancestry proportions within and between populations. We then identified single nucleotide polymorphisms (SNPs) with anomalous ancestry-enrichment patterns, i.e. SNPs that exist in any given Latin American population at a higher frequency than expected based on the population’s genetic ancestry profile. For this set of ancestry-enriched SNPs, we inspected their phenotypic impact on disease, metabolism, and the immune system. All four of the Latin American populations show ancestry-enrichment for a number of shared pathways, yielding evidence of similar selection pressures on these populations during their evolution. For example, all four populations show ancestry-enriched SNPs in multiple genes from immune system pathways, such as the cytokine receptor interaction, T cell receptor signaling, and antigen presentation pathways. We also found SNPs with excess African or European ancestry that are associated with ancestry-specific gene expression patterns and play crucial roles in the immune system and infectious disease responses. Genes from both the innate and adaptive immune system were found to be regulated by ancestry-enriched SNPs with population-specific regulatory effects.Ancestry-enriched SNPs in Latin American populations have a substantial effect on health- and disease-related phenotypes. The concordant impact observed for same phenotypes across populations points to a process of adaptive introgression, whereby ancestry-enriched SNPs with specific functional utility appear to have been retained in modern populations by virtue of their effects on health and fitness.The online version of this article (10.1186/s12864-018-5195-7) contains supplementary material, which is available to authorized users. Homo sapiens sapiens – originated in sub-Saharan Africa ~ 200,000 years ago and began to migrate out of Africa and spread throughout the world starting ~ 70,000 years ago [The modern human species – ears ago , 2. Afteears ago , 4. Distears ago , wherebyThis pattern of human evolution was turned upside down upon the arrival of Columbus in the New World a mere 500 years ago, which is less than 1% of the elapsed time since humans emerged from Africa. Columbus’ voyages precipitated the so-called ‘Columbian Exchange’ – a massive transfer of life forms, which had evolved separately for millennia, between the Old and New World hemispheres , 7. The Latin American genomes can thus be considered to represent a recent innovation in human evolution. Indeed, genomes from modern Latin American populations are evolutionarily novel in the sense that they contain combinations of genetic variants (haplotypes) that never previously existed together on the same genetic background. Our group is interested in trying to understand the implications of the recent advent of novel Latin American genomes, particularly as it relates to the genetic determinants of health-related phenotypes. In other words, we are asking what it means when genomes that were separated for many thousands of years are suddenly brought back together and what the implications of this process are for human health and fitness.Our group and others have employed an approach that we call ancestry-enrichment analysis to address these kinds of questions via population-level studies of admixed American genomes . This apA number of recent studies have used ancestry-enrichment analysis to show evidence of adaptive introgression in admixed American genomes. The first study of this kind showed an excess of African ancestry at the major histocompatibility locus (MHC) in a sample of Puerto Rican genomes , and a fAll of the previous ancestry-enrichment studies were distinguished by their interrogation of the ancestral origins of individual haplotypes, i.e. physically linked sets of genetic variants that are inherited together. For this study, we developed and applied a novel method based on individual genetic variants – single nucleotide polymorphisms (SNPs) – in an effort to expand our view of the relationship between genetic ancestry, admixture and health in Latin American populations. Our approach entails the detection of SNPs that are found at anomalously high frequencies in admixed populations compared to what is expected based on their frequencies in the ancestral source populations, i.e. ancestry-enriched SNPs. To find such ancestry-enriched SNPs, we consider the proportional contributions of ancestral source populations to admixed Latin American populations, together with SNP frequencies in the ancestral populations, to derive expected SNP frequencies for the Latin American populations. These expected frequencies are compared to observed frequencies in order to identify statistically significant ancestry-enriched SNPs; the connection between ancestry-enriched SNPs and health-related phenotypes is then explored via analysis of the functional annotations of the SNPs and their linked genes. In particular, we interrogated the impact of ancestry-enriched SNPs on disease, metabolism and immune system pathways. This approach uncovered signals of ancestry-enrichment in health- and disease-related traits shared among all four of the Latin American populations that we analyzed, raising the possibility of shared selective pressures among them.n = 94), Mexico (n = 64), Peru (n = 85), and Puerto Rico (n = 104) – were taken from the 1000 Genomes Project (1KGP) phase 3 data release [http://www.internationalgenome.org/data/. Genome sequences from the four Latin American populations were compared to whole genome sequences and whole genome genotypes of global reference populations from African, European, and Native American continental population groups to characterize their patterns of genetic ancestry and admixture Exp can be calculated as:Ancestry-enriched SNPs were characterized as SNPs found in higher frequencies in admixed Latin American populations compared to what is expected based on (1) their frequencies in the ancestral source populations, and (2) the proportion of ancestry derived from each ancestral source population. For any given SNP, in any given Latin American population, the expected frequency of the SNP f(SNP)Pop is the frequency of the SNP in a specific ancestral source population and P(Anc)Pop is the proportion of ancestry in the modern Latin American population derived from that same ancestral population. Ancestry proportions were computed using the reduced, merged set of SNPs described above, with African and European reference populations from the 1KGP and Native American reference populations from HGDP. SNP frequencies were computed using whole genome sequences, in order to provide more complete coverage of variants genome-wide, using the YRI African and IBS European reference populations with the most closely related East Asian population CHB taken as a surrogate for Native American ancestry.Obs) to expected (Exp) frequencies of the reference (Ref) and alternate (Alt) alleles for any given SNP as shown here:The statistical significance of SNP ancestry-enrichment calculated this way was determined by comparing the observed  q-values were used to account for multiple statistical tests. The SNPs that had significant FDR values (q < 0.05) were considered to be ancestry-enriched in the Latin American population, i.e. present at a higher frequency than expected based on the population ancestry profile.The Anc) that gave rise to the pattern of enrichment were also determined by jointly minimizing the frequency difference between the SNP in the Latin American population and a single ancestral source population while maximizing the distance between that single source population and the other two ancestral populations:For ancestry-enriched SNPs, the individual ancestry components (f(SNP)Popx is the frequency of the SNP in each of the ancestral source populations and f(SNP)Obs is the frequency of the ancestry-enriched SNP in the Latin American population.where P-values were computed for each gene set using the Wilcoxon signed-rank test.Ancestry-enriched SNPs were mapped to genes if they mapped within the NCBI RefSeq  gene modftp://ftp.ebi.ac.uk/pub/databases/microarray/data/experiment/GEUV/E-GEUV-1/analysis_results/. A total of 445 RNA-seq samples were used in the analysis, including 87 African and 358 European individuals. The RNA-seq data correspond to gene expression levels for the same lymphoblastoid cell lines, i.e. Epstein–Barr virus (EBV) transformed B-lymphocytes, which were used for the 1KGP DNA-seq characterization. RNA-seq sample preparation, sequencing experiments and read-to-genome mapping were performed as previously described [RNA-seq data were taken from the GUEVADIS RNA sequencing (RNA-seq) project for 1KGP samples escribed . The reaescribed . Gene exescribed , 30.Matched whole genome sequencing based SNP genotype calls were obtained for the same 445 individuals from the phase 3 release of the 1KGP . Only SNMeta-analysis was used to evaluate the overall ancestry-enrichment for sets of SNPs that are implicated in specific health- or disease-related pathways. For any given ancestry-enriched SNP that mapped to a gene found in an overrepresented pathway, a log odds ratio was calculated as:Obs) versus expected (Exp) frequencies (f) are compared for the SNP reference (Ref) versus alternate (Alt) alleles. Then for each pathway, the set of individual SNP log odds ratios was combined to yield pathway-specific log odds ratio values along with 95% confidence intervals using the fixed-effect model with moderators via linear (mixed-effect) models implemented in the metafor package in R [where the observed (age in R .We developed and applied a single nucleotide polymorphism (SNP)-based approach to relate genome ancestry to genetic determinants of health in admixed Latin American populations Fig. . First, Genome sequences from four Latin American populations – Colombia, Mexico, Peru, and Puerto Rico – were compared to whole genome sequences and whole genome genotypes of global reference populations from African, European, and Native American continental population groups in order to characterize their patterns of genetic ancestry and admixture. Each Latin American population has a distinct pattern of three-way continental genetic admixture characterized by population-specific proportions of African, European and Native American ancestry Fig. . Puerto Our approach to relating genetic ancestry to determinants of health and disease in modern Latin American populations relies on the detection of SNPs that are found at anomalously high frequencies in admixed populations compared to what is expected based on their frequencies in the ancestral source populations, i.e. ancestry-enriched SNPs. We reasoned that such ancestry-enriched SNPs are likely to have an outsized effect on health and disease in modern Latin American populations, perhaps related to an initial increase in population frequency via adaptive introgression.We developed and applied a quantitative method to identify individual SNPs that are enriched in admixed Latin American populations with respect to ancestry from one of the three ancestral source populations: Africa, Europe, and the Americas. To do so, the expected frequencies for each SNP were calculated using the frequency of the given SNP in each of the three ancestral source populations conditioned upon the proportion of each ancestral source population in the Latin American population of interest. Observed SNP frequencies were compared to expected SNP frequencies to identify ancestry-enriched SNPs; the details of this approach are shown in the Materials and Methods section.2 values are shown in Fig. The distributions and median values of ancestry-specific SNP χThe genes with mapped ancestry-specific SNPs were analyzed with gene set enrichment analysis (GSEA) to look for overrepresented health- or disease-related pathways and phenotypes Fig. . This apq-values) – are provided in Additional file A number of pathways and phenotypes have significantly overrepresented ancestry-enriched SNP genes in all four populations Fig. . These iWe focused on several notable examples of health- and disease-related pathways that were found to have significantly overrepresented ancestry-enriched SNP genes in all four Latin American populations Fig. . For eacWe explored the effects of ancestry-specific SNPs on gene regulation via expression quantitative trait loci (eQTL) analysis. eQTL are individual SNPs with genotype variants that are associated with gene expression levels; associations of this kind point to a role for SNP variants in gene regulation  , 34. To Using this approach, we found a number of cases of SNPs that show overrepresented African or European ancestry in modern Latin American populations and are also associated with ancestry-specific gene regulation Fig. . A numbeLatin America has a unique genetic heritage with high levels of admixture from African, European, and Native American ancestral source populations –11. As sHere, we have tried to address this issue by relating patterns of genetic ancestry and admixture to health and disease determinants in Latin American genomes. To do so, we developed and applied a novel SNP-based approach to ancestry enrichment analysis. Our approach leverages information on the genetic ancestry of the modern Latin American populations to discover SNP variants that exist in a given population at higher frequencies than expected, i.e. ancestry-enriched SNPs. We found that specific sets of ancestry-enriched genetic variants, from each of the three ancestral source populations, have been preferentially retained in modern Latin American populations based on a variety of roles that they play in health and fitness. These findings have relevance for the development of genomic approaches to healthcare, i.e. personalized or precision medicine, in Latin America.Gene set enrichment analysis uncovered a number of immunity, metabolism, and disease-related pathways that are significantly overrepresented with respect to genes that contain ancestry-enriched SNPs Figs.  and 5. TExpression quantitative trait loci (eQTL) analysis revealed ancestry-enriched SNPs in modern Latin American populations that are associated with African- or European-specific patterns of gene regulation Fig. . This inOne important caveat with respect to the interpretation of the results that we report is that they can only be taken to apply to the four specific populations analyzed here: Colombian in Medellin, Colombia (CLM), Mexican Ancestry in Los Angeles, California (MXL), Peruvian in Lima, Peru (PEL), and Puerto Rican in Puerto Rico (PUR). Given the diversity of Latin American populations, and in particular their distinct ancestry profiles, we should expect to see distinct ancestry enrichments for different countries in the region, such as Argentina, Chile, Brazil etc. This caveat not only applies to different countries but also applies to different populations within the same country. Colombia, for instance, is an extremely diverse country with populations from different regions that show very distinct ancestry profiles . The popAdditional file 1:Table S1. Lists of all SNPs that show significant ancestry-enrichment. For each admixed Latin American population, all ancestry-enriched SNPs (q < 0.05) are given along with their meta-information, observed and expected reference and alternate allele frequencies, and significance values. The allele  and enriched ancestry  are designated for each ancestry-enriched SNP. (XLSX 177 kb)Additional file 2:Table S2. Lists of pathways that show significant enrichment of genes with mapped ancestry-enriched SNPs for each admixed Latin American population. For each KEGG pathway with significant enrichment of genes with mapped ancestry-enriched SNPs in at least one of the four populations, the overlapping genes and FDR q-values are given. (XLSX 29.6 kb)


Methods of gout flare reporting in research settings are inconsistent and poorly defined. The aim of this study was to describe patterns of gout flare and assess the concurrent validity of different methods of flare reporting in a gout clinical trial.Daily flare diary entries including self-report of flare and pain scale from a randomised controlled trial of 120 patients with gout were analysed. Detailed pain-by-time plots for each participant were inspected and analysed for different methods of flare reporting for both self-report and the classification tree (CART)-defined flare developed by Gaffo in 2012. Concurrent validity for different methods of flare reporting were analysed.Although the single gout flare had a ‘typical’ average pattern (peak on day 1 and resolution over 14 days), individual pain-by-time plots showed wide variation in pain intensity, duration and frequency of flares. Over the four-month study period, there were 84/120 (70%) participants who experienced at least one self-reported flare that was not a ‘typical’ flare. The time to first self-reported flare correlated poorly with other measures of gout activity and other methods of flare reporting. The number of days with flare (either self-reported or Gaffo-defined) and the area under the pain-by-time curve correlated most strongly with other measures of disease severity.There is wide variation in the patterns of flare over time in individuals with gout, leading to challenges for flare reporting in clinical trials. Time-dependent reporting strategies such as number of days with flare or area under the pain-by-time curve correlate well with other measures of gout disease severity and may provide a more accurate measure of flare burden.ACTRN12609000479202, registered 17/06/2009.Clinical trial number: The online version of this article (10.1186/s41927-019-0075-6) contains supplementary material, which is available to authorized users. Recurrent flares of acute inflammatory arthritis are the central clinical feature of gout . Flares There has been recent progress defining a gout flare for use in clinical research. Elements of a gout flare were identified through patient surveys . In 2012Although the presence of being in the state of flare and the time characteristics of a single flare have been defined, the optimal method of reporting flares over time is unclear. In clinical trials of urate-lowering therapy, flares are typically reported as the percentage of participants with at least one flare or mean number of flares over a specified time period , 13. In n = 120) were randomized to one of three treatment arms for 3 months: skim milk powder enriched with glycomacropeptide (GMP) and G600 milk fat extract (G600) (n = 40), or one of two control groups; skim milk powder alone (n = 40) or lactose control (n = 40). All other gout medications including urate-lowering therapy and anti-inflammatory medications  for both prophylaxis and treatment of flares were prescribed according to the discretion of the patient’s usual doctor. Participants completed flare diary entries each day with recording of pain score  and self-report of flare for the month prior to randomisation and for the further 3 months following randomisation. The number of flares defined by self-report and by the 2012 Gaffo definition using the classification tree (CART) approach (pain score > 3 and self-report) were counted and reported as outcomes in the trial [https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=83573). The study adheres to CONSORT guidelines.Flare diary entries from a randomised controlled trial of patients with gout were analysed . After ahe trial . This stIn the current analysis, time series analysis anchored on the first self-reported or Gaffo CART-defined flare was used to model the average pain-by-time characteristics of a single flare. For the first flare pain-by-time models, the flare was defined as a contiguous period of time with non-zero pain scores bounded by 2 days of zero pain scores. Six diaries had no non-zero pain score data and two diaries had no sustained pain scores of zero; data from these participants were not included in the first flare pain-by-time model analysis, but were included in all subsequent analyses.The patterns of flare over time were examined using the pain-by-time plots over the entire observation for all study participants. Cumulative probability plots were drawn to determine the variability of days with flare (adjusted for days of observation) and flare pain intensity for all study participants over the observation period. The time-course domain in the 2015 ACR/EULAR gout classification criteria was used to define the time elements of a ‘typical’ flare  between symptomatic episodes) .The association between different methods of flare reporting with other measures of disease activity over the observation period were analysed using Spearman correlations. For both self-reported flares and Gaffo CART-defined flares, the following methods of flare reporting were analysed: time to first flare adjusted for the duration of follow-up for each participant, number of flares, number of months with at least one flare, and number of days with flare. The area under the curve for the pain-by-time plot was also analysed. The measures of gout disease activity were analysed according to the area under the curve plots over the observation period, and included measures of joint inflammation (swollen joint count (/66), tender joint count (/68), and C-reactive protein), patient global assessment  and physician global assessment . All of the measures of gout activity were recorded at baseline and then monthly. The influence of baseline gout clinical characteristics were also analysed by correlation analysis. Data were analysed using SAS .The flare diary entries for the 120 study participants had a mean (SD) follow-up period of 107 (25) days. Clinical features at baseline and over the observation period are shown in Table There were 114 participants with at least one self-reported flare during the observation period. The mean (SD) number of self-reported flares over the observation period was 2.1 (2.0) and the mean number of flares fulfilling the Gaffo CART definition was 0.9 (1.0). The average pain-by-time plots for the first observed flare are shown in Fig. Although the single gout flare had an average ‘typical’ pattern according to the 2015 ACR/EULAR gout classification criteria, analysis of individual pain-by-time plots showed wide variation in the pain intensity, duration and frequency of flares. Figure Figure Correlations of different methods of flare reporting with other measures of gout activity over the observation period were analysed Table . The timIn order to understand whether methods of flares reporting were influenced by baseline clinical characteristics, we analysed the correlations between methods of reporting with number of tophi, disease duration, number of gout flares in the prior 4 months before entering the study, and use of any anti-inflammatory medication use at the baseline visit  were measured on a monthly basis, and it is possible that these measures did not capture all gout flares, particularly if they occurred between a study visit. Consistent with clinical practice, all patients had access to standard anti-inflammatory therapy for flare management, and it is possible that some methods of flare reporting were influenced by these therapies. However, other measures of disease activity such as joint counts and inflammatory markers would also be responsive to anti-inflammatory therapy. The study used the CART version of the Gaffo-defined flare, which has marginally lower accuracy than the 4-item version in a recent validation exercise 89% vs 92%) 9% vs 92%, includiMany studies have reported that the experience of a gout flare is a major concern for people with gout , 20, 21.Patterns of flare over time vary widely in individuals with gout. Time-dependent reporting strategies such as the number of days with flare or the area under the pain-by-time curve correlate well with other measures of gout disease severity and may provide a more accurate and comprehensive assessment of flare burden.Additional file 1:Table S1. Analysis of the first observed flare. (DOCX 14 kb)Additional file 2:Table S2. Spearman correlations between different methods of flare reporting. *adjusted for duration of follow-up. P < 0.01 for all analyses. (DOCX 17 kb)Additional file 3:Table S3. Correlations between methods of reporting flares and gout clinical characteristics at baseline. (DOCX 16 kb)


The growth of 3C-SiC shows technological challenges, such as high supersaturation, a silicon-rich gas phase and a high vertical temperature gradient. We have developed a transfer method creating high-quality 3C-SiC-on-SiC (100) seeding stacks, suitable for use in sublimation “sandwich” epitaxy (SE). This work presents simulation data on the change of supersaturation and the temperature gradient between source and seed for the bulk growth. A series of growth runs on increased source to seed distances was characterized by XRD and Raman spectroscopy. Results show a decrease in quality in terms of single-crystallinity with a decrease in supersaturation. Morphology analysis of as-grown material indicates an increasing protrusion dimension with increasing thickness. This effect limits the achievable maximal thickness. Additional polytype inclusions were observed, which began to occur with low supersaturation (S ≤ 0.06) and prolonged growth (increase of carbon gas-species). From the acquired data, the supersaturation of the growth-limiting gas species SiCThe main defect limiting the growth with the presented method appears to be the protrusion defect which stems from the 3C-SiC CVD seeding layer. With increasing thickness of the crystal, a linear increasing behavior was observed similar to CVD-grown material. To investigate the material properties further, defect-free seeding layers in terms of protrusions must be used in future work.Additional comparisons were done with published numbers of the supersaturation for the transition from hexagonal to cubic material. By adapting this information to the herein presented setup and simulation database a corrected value was derived. Experimental results for increased thickness of the material suggest a minimum supersaturation of 0.1 to be sufficient for the growth of cubic silicon carbide.


We hypothesized that clinical process improvement strategies can reduce frequency of motion artifacts and expiratory phase scanning in chest CT. We reviewed 826 chest CT to establish the baseline frequency. Per clinical process improvement guidelines, we brainstormed corrective measures and priority-pay-off matrix. The first intervention involved education of CT technologists, following which 795 chest CT were reviewed. For the second intervention, instructional videos on optimal breath-hold were shown to 245 adult patients just before their chest CT. Presence of motion artifacts and expiratory phase scanning was assessed. We also reviewed 311 chest CT scans belonging to a control group of patients who did not see the instructional videos. Pareto and percentage run charts were created for baseline and post-intervention data. Baseline incidence of motion artifacts and expiratory phase scanning in chest CT was 35% (292/826). There was no change in the corresponding incidence following the first intervention . Respiratory motion and expiratory phase chest CT with the second intervention decreased . Instructional videos for patients (and not education and training of CT technologists) reduce the frequency of motion artifacts and expiratory phase scanning in chest CT. Most routine chest CT examinations are performed with a breath-hold in maximal inspiration. This ensures adequate aeration of the lung parenchyma and enables a better evaluation of normal structures and abnormalities. When patients cannot do a good inspiratory breath-hold, suboptimal chest CT examinations result from respiratory motion artifacts and expiratory phase scanning3. Suboptimal breath-holding can lead to suboptimal interpretation from the point of view of lesion detection and characterization, over-diagnosis (such as for bronchiectasis and pulmonary embolism), and inability to assess stability or change in lesion size, attenuation or morphology. Repeat CT scanning in patients with suboptimal prior test increases radiation dose, contrast volume burden, and healthcare costs while delaying patient care and impairing patient perceptions of the healthcare delivery systems6. Aside from these concerns, respiratory motion artifacts and expiratory phase scanning in chest CT with or without repeat CT scanning can have a negative effect on clinical workflow in busy and large practices for both CT technologists and the interpreting radiologists.More than any other body region, chest and cardiac computed tomography (CT) are susceptible to motion artifacts from inadequate or suboptimal breath-hold, and the cardiac pulsationsThe current project stemmed from clinical concerns over the frequency of respiratory motion artifacts and expiratory phase scanning in chest CT in our quaternary healthcare institution which has 18 multi-detector-row CT (MDCT) scanners from three vendors at six different geographic locations, and over 80 full- and part-time CT technologists. The concerns occurred despite an active and instantaneous feedback system in place for communicating suboptimal CT examinations, and written and archived CT protocols and policies for chest CT scanning. To address these concerns, we applied clinical process improvement strategies to reduce the frequency of motion artifacts and expiratory phase scanning in chest CT by 50% compared to the baseline prevalence.Close to a third of the patients  in the baseline chest CT data had motion artifacts or were expiratory. Both the inpatients  and the outpatients  had respiratory motion artifacts or expiratory phase scanning on chest CT.Process map and Ishikawa fishbone diagram are illustrated in Figs The frequency of motion artifacts and expiratory phase scanning in the chest CT examinations during PDSA-1 cycle was 36% (283/795). Both the inpatients  and outpatients  had motion artifacts or expiratory phase scanning. There was no significant statistical change in the frequency of the suboptimal chest CT examinations performed over the PDSA-1 (p = 0.917).The magnitude of motion artifacts and expiratory phase scanning in patients who viewed the instructional videos during the PDSA-2 was 8.2% (20/245 patients). Both inpatients  and outpatients  experienced a reduction in motion artifacts and expiratory phase scanning during the PDSA-2. These reductions in PDSA-2 were significant compared to both baseline data and PDSA-1 (p < 0.0001). Although lower than the baseline and the PDSA-1 data, the frequency of motion artifacts and expiratory phase scanning in the control group patients  was significantly greater than those scanned following the instructional videos in the PDSA-2 (p = 0.016). The statistical process chart summarizes the baseline, PDSA-1 and PDSA-2 data  indicated that they understood the message of the instructional videos. About 88% (215/245) said that the videos helped them follow the breath-hold instructions during their chest CT. Most patients said that they had undergone a CT before  which may explain why they were not less anxious after they saw the video .7.“I hear I forget, I see I remember, I do I understand”. These words from the most famous Chinese teacher, editor, politician and philosopher Confucius (551–479 BC) may explain why the instructional videos that made the patients “see (view)” and “do (practice)” breath hold with the instructional videos in the PDSA-2 cycle helped reduce the frequency of motion- and expiration-impaired chest CT. According to the patient survey, most patients opined that the instructional video helped them follow the breath-hold instructions for chest CT. In the healthcare settings, video modelling can motivate knowledge acquisition, decrease pre-exam anxiety, and enhance self-care8. However, authors observed no change in the motion artifacts associated with the cardiovascular MRI. This finding is contradictory to our study and may have occurred due to differences in the imaging modalities  and the cause for motion artifacts (respiratory motion in our study versus cardiac pulsations and respiratory motion for cardiovascular MRI). Another study reported that instructional videos for informing patients about the advantages, risks, and alternatives to intravenous contrast media for CT are better than routine discussion for getting informed consent9. The impact of video-assisted patient education varies with presentation type; videos with real people are more effective in altering patient behavior than videos with audio and graphical representation of health information10.Though not specific to breath-holding for chest CT, use of instructional videos has been described in radiology. A recent study reported that patient’s ability to relax during cardiovascular MRI increased with addition of video-based information before their exam11. A prior publication has reported that self-instruction videos are better than traditional didactic instructions for cardiopulmonary resuscitation in healthcare providers12. In fact, the American Heart Association and the American Red Cross use an array of instructor-led and video-based teaching to facilitate learning. Similar to our study, Marini et al. improved patient knowledge, satisfaction, and compliance with an informational video on venous thromboembolism prophylaxis. Patients who watched the video gave 83% correct responses as compared to 62% in those who did not13. Another study documented enhanced stroke literacy and efficiency in identifying stroke symptoms, as well as patient satisfaction with video based education of hospitalized stroke patients14. According to Tuong et al., patient educational videos are also more effective than written materials to increase knowledge and modify health behaviors including cancer screening, heart failure self-care adherence, and HIV testing. They also offer the benefits of providing standardized content across learners, are less resource intensive than written materials or educational sessions, and are effective among viewers of low literacy levels for other medical conditions as well15. Recently, Beskind et al. have reported that an educational video on cardiopulmonary resuscitation (CPR) for high school students increased their CPR responsiveness and performance16. Educational videos have also proven worthwhile in resident learning and training in interventional breast procedures such as stereotactic core biopsy of the breast17. The benefit noted from patient educational videos in our study concurs with the abovementioned publications on instructional videos in different clinical settings.Instructional videos for patients and healthcare staff are used in other medical specialties. In the elderly patients, instructional videos improved comprehension and satisfaction with the pain clinicset al. have reported that the convenient automatic patient instructions reduce image quality and increase the proportion of repeat CT acquisitions18. They recommend personal communication with the patients to humanize the high-tech CT environment and reduce patient anxiety. However, this is not possible in our institution due to a heterogeneous, multiethnic CT technologists’ workforce (n > 80 from various backgrounds and accents). This heterogeneity may have contributed to inadequate training and/or insufficient participation of the CT technologists at our institution.While CT technologists are paramount to quality CT examinations, they may not deliver the desired results due to the demands of multi-tasking. The PDSA-1 cycle that involved retraining of our CT technologists for acquiring chest CT with a lower frequency of respiratory motion and expiratory phase scanning was unsuccessful. This could be related to the immense technologist workload which involves checking patient identification, patient positioning, centering, oral and intravenous contrast administration, establishing and checking intravenous access during contrast administration, selecting CT and contrast injection protocols, assessing adequacy of scan coverage, determining need for delayed images, reconstructing and reformatting CT images, pushing the images to the PACS, and completing the exam in the Radiology Information System. Another reason for the PDSA-1 failure might be use of automatic patient instructions for breath-hold in our institution. Bankier Chief amongst the implications of our study is the fact that patient involvement and education had a greater effect on the quality of chest CT than the CT technologists as noted from the two-fold lower incidence of motion artifacts and expiratory phase scanning amongst subjects in the PDSA-2 cycle who viewed the instructional videos compared to those scanned without video viewing and with technologist training alone. Such patient involvement can be accomplished with instructional videos which we have made available free of cost  in a busy CT practice . In smaller and less complicated practices, adequate training of the CT technologists may reduce the frequency of motion- and expiration-impaired chest CT. Although the instructional videos are available only in English, we are working on translating the video into other languages. The frequency of motion- and expiration-impaired chest CT amongst inpatients remain high since many did not or could not follow the instructional videos. For such patients, we introduced a fast, non-breath-hold scanning protocols on several MDCT scanners. However, our CT technologists did not apply these fast protocols in eligible patients who did not follow breath-hold instructions. Although our study does not have a prolonged washout phase to assess the lasting effect of the PDSA-2, the patients participating in the PDSA-2 were recruited over a period of 2 months. Although we did not compare our methods of addressing motion- and expiration-impaired chest CT with other methods of reducing their frequency, our CT technologists have used the other methods of coaching and interacting with the patients. For example, our technologists instructed the patients to follow the breath-hold instructions prior to their scanning. Patients were also provided automatic voice instructions at the time of scanning to help them with the breath-hold.In conclusion, as compared to education and training of CT technologists, patient instructional videos led to a substantial reduction in the frequency of motion artifacts and expiratory phase scanning in chest CT examinations. Clinical process improvement beyond caregiver education and training are necessary to reduce frequency of motion impaired and suboptimal expiratory phase chest CT.Per the hospital policy, the Partners Human Research Committee (PHRC) exempted this quality assessment and improvement project from the need for approval. All methods were performed in accordance with the relevant guidelines and regulations. The MDCT scanners included in our study ranged from 64-slice and 256 single-source , 128-slice and 192-slice dual-source , and 128-slice single-source . The scanners and the scan protocols for chest CT did not change over the course of the study.Baseline data included 826 consecutive chest CT examinations  performed between April 9, 2017 and May 6, 2017. These examinations belonged to both inpatients and outpatients. We reviewed the CT images and the radiology reports in the picture archiving and communication system (PACS) for presence of respiratory motion artifacts and expiratory phase imaging that limited evaluation of normal structures or abnormalities in the thorax. Chest CT examinations with motion artifacts confined to the para-cardiac regions, likely related to cardiac pulsations were deemed optimal. For each examination, we recorded the date and time of CT, patient age, gender, endotracheal intubation, location at the time of scanning (inpatient or outpatient), study indications, pertinent radiology report findings, and any mention of respiratory motion artifacts and expiratory phase scanning in the radiology reports.20. We created a Pareto chart with the QI Macros software . A detailed process map was created from physician order entry for chest CT up to the radiology report finalization . To understand the sources and the causes of motion artifacts and expiratory phase scanning in chest CT, we created an Ishikawa fishbone diagram using the Visio program.In accordance with the process improvement steps, we determined the frequency and probable causes of respiratory motion artifacts and expiratory phase scanning in the baseline chest CT examinationsNext, we conducted two brainstorming sessions under leadership of two senior chest subspecialty radiologists . In the first session, these radiologists discussed causes and strategies to mitigate respiratory motion artifacts and expiratory phase scanning with CT quality assurance manager, CT operations manager, senior imaging operations manager, and CT technologist supervisor. Discussions from the first session were brainstormed with the other radiologists in the thoracic imaging division in the second session. A priority and payoff matrix helped stratify various interventions per their ease of implementation and impact.The outcome measure was defined as the percentage of chest CT with respiratory motion artifacts or expiratory phase scanning. The balance measure was any increase in time required to complete the acquisition of chest CT because of any intervention designed to reduce the frequency of suboptimal chest CT.From the priority-payoff matrix, we decided to increase awareness about the frequency, and need for reducing suboptimal chest CT amongst the CT technologists. This was conducted as part of the PDSA-1 in three interactive didactic sessions to educate all CT technologists taking part in the three work shifts. Each session lasted for 30–45 minutes and was led by one of the two senior chest subspecialty radiologists (SD or MK). During these sessions, the radiologists discussed the incidence, cause and implications of suboptimal chest CT from respiratory motion artifacts and expiratory phase scanning. We presented the baseline data on incidence of suboptimal chest CT and demonstrated techniques for enhancing patient cooperation with breath-hold instructions.After the training sessions of the PDSA-1, we reviewed 795 consecutive chest CT examinations  performed between July 9, 2017 and August 5, 2017. A thorough review of both chest CT images and radiology reports was performed to record the above data fields described in the baseline data section.Since the PDSA-1 did not decrease the frequency of motion artifacts and expiratory phase scanning in chest CT, we implemented PDSA-2. We created three instructional videos with role players  using professional videography services. Informed consent was taken for study participation and publication of identifying information/images in an online open-access publication. These videos showed good breath-hold for chest CT and encouraged patients to practice breath-hold before their scanning. The three video clips demonstrated maximum inspiratory breath-hold for routine chest and diffuse lung disease protocols  in the PDSA-2 who viewed the instructional videos before their chest CT examinations between June 4, 2018 and July 27, 2018. We reviewed chest CT images and radiology reports of all patients and recorded similar data fields described in the preceding baseline data section. Over this timeframe, we also reviewed 311 consecutive chest CT examinations  performed in the patients who did not see the instructional videos. These 311 chest CT examinations constituted the control group to assess long-term effect of PDSA-1 and to assess the frequency of suboptimal chest CT during the same time that PDSA-2 was being conducted.Data were recorded in Microsoft Excel for statistical analyses. A percentage run-chart (p chart) displayed the trend of suboptimal chest CT at the baseline and during the PDSA-1 and PDSA-2 (QI Macros). Descriptive statistics were performed to determine the mean patient age, gender count, and frequency of motion artifacts and expiratory phase scanning in chest CT performed over the duration of the study. We used Wilcoxon rank sum test to compare patients’ frequency of suboptimal chest CT in the baseline data, PDSA-1, PDSA-2, and the control group. A p-value of less than 0.05 was considered as a significant difference.Supplementary Video 1Supplementary Video 2Supplementary Video 3


Pre-eclampsia is associated with significant changes to the cardiovascular system during pregnancy. Eccentric and concentric remodelling of the left ventricle occurs, resulting in impaired contractility and diastolic dysfunction. It is unclear whether these structural and functional changes resolve completely after delivery.The objective of the study was to determine cardiac diastolic function at delivery and one year post-partum in women with severe pre-eclampsia, and to determine possible future cardiovascular risk.This was a descriptive study performed at Steve Biko Academic Hospital, a tertiary referral hospital in Pretoria, South Africa. Ninety-six women with severe preeclampsia and 45 normotensive women with uncomplicated pregnancies were recruited during the delivery admission. Seventy-four (77.1%) women in the pre-eclamptic group were classified as a maternal near miss. Transthoracic Doppler echocardiography was performed at delivery and one year post-partum.At one year post-partum, women with pre-eclampsia had a higher diastolic blood pressure (p = 0.001) and body mass index (p = 0.02) than women in the normotensive control group. Women with early onset pre-eclampsia requiring delivery prior to 34 weeks’ gestation had an increased risk of diastolic dysfunction at one year post-partum  and this was irrespective of whether the patient had chronic hypertension or not.Women who develop early-onset pre-eclampsia requiring delivery before 34 weeks are at a significant risk of developing cardiac diastolic dysfunction one year after delivery compared to normotensive women with a history of a low-risk pregnancy. Pre-eclampsia is a pregnancy-specific disorder characterised by new-onset hypertension and proteinuria after 20 weeks’ gestation. Hypertensive disorders in pregnancy have been one of the top five causes of maternal mortality in South Africa for more than a decade.2Pregnancy is associated with significant haemodynamic and hormonal changes affecting the cardiovascular system. There is a 20% increase in cardiac output by eight weeks’ gestation.4Despite these changes, the left ventricular contractile function is maintained and any changes in cardiac geometry are rapidly reversible within three months post-partum in normotensive women.5Cardiac changes classically associated with pre-eclampsia are diastolic dysfunction and an after-load-mediated left ventricular remodelling of the maternal heart.About 20% of women with pre-term pre-eclampsia and severe disease undergo severe left ventricular hypertrophy with advanced cardiac dysfunction.11Diastolic dysfunction is described as impaired left ventricular filling and may be present in the setting of normal or abnormal systolic function. Pre-clinical diastolic dysfunction is associated with the development of future heart failure and is a predictor of all-cause mortality.13Desai et al. found that diastolic filling abnormalities were demonstrated in a significant proportion of pre-eclamptic pregnancies complicated by pulmonary oedema compared to control groups of women who were hypertensive and normotensive in pregnancy.13 The authors of this study postulated that the diastolic filling abnormalities demonstrated in the study occurred within a short time frame of severe pre-eclampsia in pregnancy or could represent pre-eclampsia superimposed on established hypertension.Whether diastolic dysfunction persists after delivery is uncertain. Identifying factors that may affect future cardiovascular risk may identify a group of women requiring increased postpartum vigilance and lifestyle modification. The aim of this study was to determine cardiac diastolic function at delivery and one year post-partum in women with severe pre-eclampsia and to further determine possible future cardiovascular risk.This was a descriptive study of women with severe pre-eclampsia, performed at Steve Biko Academic Hospital from 1 April 2013 to 30 March 2016. The Cardiology Department at Steve Biko Academic Hospital reserved echocardiographic appointments every Wednesday during the study period. Post-partum women with severe pre-eclampsia were identified on a Wednesday morning and if fit to be transported to the cardiology clinic, were informed of the study. Echocardiographic studies were performed on patients who consented to the procedure and were agreeable to follow-up studies.One hundred and six women with severe pre-eclampsia and 45 normotensive, low-risk women who served as the control group were identified and recruited shortly after delivery. Women with structural heart disease or pulmonary embolus were excluded from the study. Women diagnosed with maternal metabolic syndrome were not recruited to the control group.Echocardiograms of the maternal heart were performed between day two and seven post-delivery and follow-up scans were done after one year. Hypertensive disorders were classified according to the classification and diagnosis of the International Society for the Study of Hypertension in Pregnancy (ISSHP).14Doppler echocardiography was carried out by the Department of Cardiology at Steve Biko Academic Hospital. The following echocardiographic parameters were assessed in the evaluation of diastolic dysfunction: left ventricular ejection fraction (LVEF), mitral E-wave (E) and mitral A-wave velocities (A), E/A ratio, mitral E-velocity deceleration time (DT), lateral early diastolic (e′) velocity tissue Doppler and E/e′ ratio.The diagnosis of diastolic dysfunction was made by a clinician in the cardiac-obstetric unit. All women diagnosed with diastolic dysfunction had the following minimum positive criteria: average E/e′ > 14 and lateral e′ velocity < 10 cm/s. The American Society of Echocardiography and the European Association of Cardiovascular Imaging have described the advantages and limitations used to assess left ventricular diastolic function15 Descriptive statistics in the form of means and standard deviations in the case of continuous data, and frequencies and percentages in the case of categorical data were calculated. A p-value of < 0.05 was considered significant. Ethical approval for the study was obtained from the University of Pretoria Ethics Committee (No. 125/2013).There were 6 536 deliveries at our hospital during the recruitment phase of the study (1 April 2013 – 30 March 2015). Four hundred and sixty-three (7.1%) women presented with severe pre-eclampsia and 106 women were recruited to the study. Ten women were lost to follow up. Data were therefore recorded for 96 women with severe pre-eclampsia and 45 controls.Seventy-four (77.1%) women in the study group for whom data were available fulfilled the World Health Organisation (WHO) criteria for the classification of a maternal near miss. Of the 96 women with severe pre-eclampsia, 14 were diagnosed with chronic hypertension and four with diabetes prior to pregnancy. At one year, the mean diastolic blood pressure and mean body mass index was significantly higher among the women who had pre-sclampsia during pregnancy compared to the normotensive control group. Twenty women (20.83%) with pre-eclampsia were diagnosed with diastolic dysfunction at delivery compared with six (13.3%) of the controls (p = 0.26). Of the 20 women who were diagnosed with diastolic dysfunction at delivery, 13 (65%) had early-onset pre-eclampsia, requiring delivery prior to 34 weeks. At one year, 11 (11.46%) women with pre-eclampsia were diagnosed with diastolic dysfunction compared with three (6.67%) in the control group .Women with early-onset pre-eclampsia requiring delivery prior to 34 weeks’ gestation had an increased risk of diastolic dysfunction at one year post-partum  . DeliverLeft ventricular systolic function was normal and similar in both groups, suggesting preservation of systolic function in both pre-eclamptics and controls. There was a significant decrease in lateral e′ and a significant increase in A velocity between the pre-eclamptic and control group at one year.Heart failure is a progressive condition, which begins with risk factors for left ventricular dysfunction and progresses further to asymptomatic changes in cardiac structure and function, finally evolving into heart failure.5The American College of Cardiology has highlighted the importance of identifying asymptomatic cardiac dysfunction for early intervention and improvement of outcome.16Zanstra et al. found that 24% of women with the metabolic syndrome during pregnancy had diastolic dysfunction at six months post-partum, compared to 6.3% of women with low-risk pregnancies.The rate of diastolic dysfunction at one year in the two groups of women with early-onset pre-eclampsia (22.7%) and low-risk pregnancies (6.7%) in our study were similar to rates reported by Zanstra et al.The Olmsted study described the predictive significance of left ventricular diastolic dysfunction using multivariableadjusted analyses.This study found that early-onset pre-eclampsia was a risk factor for diastolic dysfunction, while women who developed pre-eclampsia after 34 weeks had a risk similar to that of low-risk parous women . This may be explained by the proposed differences in pathophysiology between early- and late-onset pre-eclampsia.Redman et al. have suggested that pre-eclampsia could be the result of intrinsic or extrinsic placental causes.The placentas of women with early-onset disease differ significantly from those who develop pre-eclampsia at term.30Pre-eclampsia is a known risk factor for future chronic hypertension. Hypertension and hypertensive heart disease are one of the key contributors to the burden of non-communicable cardiovascular disease in Africa. Young African women are bearing the brunt of this increasing public health problem.34Nakimuli et al., in a study of pre-eclampsia in women of African ancestry, found that African ancestry was the second strongest risk factor for pre-eclampsia after chronic hypertension.35 African ancestry was also a risk factor for earlyonset pre-eclampsia and poor obstetric outcomes such as foetal growth restriction and stillbirth.It is estimated that for every woman who dies during pregnancy or childbirth, 20 others will suffer severe morbidity.The prognosis of women with compromised cardiac function is poorer than that of men.18 Women often present with atypical symptoms, resulting in delayed presentation, delayed diagnosis and suboptimal care compared to men.40This is the first study to evaluate diastolic function in a pre-eclamptic group of predominantly African population. Although we did not look at other risk factors for cardiovascular disease in this population, the study provides valuable information in identifying a potential group of women at risk of disease at an early stage. This would provide opportunities for screening and lifestyle modification.The strength of this study is that it is one of the first to look at cardiac diastolic function in an African population where the rates of hypertension both during and outside of pregnancy were high. A possible limitation is that most patients were seen for the first time during pregnancy, with severe acute hypertension. Only 14.6% of women were known to have chronic hypertension. It is possible that some women had undiagnosed chronic hypertension – this is especially likely as the rate of chronic hypertension postpartum at one year was 54.2%. Some of the women with undiagnosed chronic hypertension may have had pre-existing diastolic dysfunction that could have been worsened by the superimposed pre-eclampsia. A further limitation is that only a select group of pre-eclamptic women were recruited to the study.Women who develop early-onset pre-eclampsia requiring delivery prior to 34 weeks’ gestation have an increased risk of cardiac diastolic dysfunction one year after delivery. Diastolic dysfunction precedes the onset of systolic dysfunction and clinical heart failure. A strategy to screen and treat women with cardiovascular risk, particularly in lower- and middle-income countries should be explored further.