Toughening mechanisms of the elytra of the diabolical ironclad beetle.

Joining dissimilar materials such as plastics and metals in engineered structures remains a challenge1. Mechanical fastening, conventional welding and adhesive bonding are examples of techniques currently used for this purpose, but each of these methods presents its own set of problems2 such as formation of stress concentrators or degradation under environmental exposure, reducing strength and causing premature failure. In the biological tissues of numerous animal and plant species, efficient strategies have evolved to synthesize, construct and integrate composites that have exceptional mechanical properties3. One impressive example is found in the exoskeletal forewings (elytra) of the diabolical ironclad beetle, Phloeodes diabolicus. Lacking the ability to fly away from predators, this desert insect has extremely impact-resistant and crush-resistant elytra, produced by complex and graded interfaces. Here, using advanced microscopy, spectroscopy and in situ mechanical testing, we identify multiscale architectural designs within the exoskeleton of this beetle, and examine the resulting mechanical response and toughening mechanisms. We highlight a series of interdigitated sutures, the ellipsoidal geometry and laminated microstructure of which provide mechanical interlocking and toughening at critical strains, while avoiding catastrophic failure. These observations could be applied in developing tough, impact- and crush-resistant materials for joining dissimilar materials. We demonstrate this by creating interlocking sutures from biomimetic composites that show a considerable increase in toughness compared with a frequently used engineering joint.

Which surrogate insulin resistance indices best predict coronary artery disease? A machine learning approach.

BACKGROUND: Various surrogate markers of insulin resistance have been developed, capable of predicting coronary artery disease (CAD) without the need to detect serum insulin. For accurate prediction, they depend only on glucose and lipid profiles, as well as anthropometric features. However, there is still no agreement on the most suitable one for predicting CAD. METHODS: We followed a cohort of 2,000 individuals, ranging in age from 20 to 74, for a duration of 9.9 years. We utilized multivariate Cox proportional hazard models to investigate the association between TyG-index, TyG-BMI, TyG-WC, TG/HDL, plus METS-IR and the occurrence of CAD. The receiver operating curve (ROC) was employed to compare the predictive efficacy of these indices and their corresponding cutoff values for predicting CAD. We also used three distinct embedded feature selection methods: LASSO, Random Forest feature selection, and the Boruta algorithm, to evaluate and compare surrogate markers of insulin resistance in predicting CAD. In addition, we utilized the ceteris paribus profile on the Random Forest model to illustrate how the model's predictive performance is affected by variations in individual surrogate markers, while keeping all other factors consistent in a diagram. RESULTS: The TyG-index was the only surrogate marker of insulin resistance that demonstrated an association with CAD in fully adjusted model (HR: 2.54, CI: 1.34-4.81). The association was more prominent in females. Moreover, it demonstrated the highest area under the ROC curve (0.67 [0.63-0.7]) in comparison to other surrogate indices for insulin resistance. All feature selection approaches concur that the TyG-index is the most reliable surrogate insulin resistance marker for predicting CAD. Based on the Ceteris paribus profile of Random Forest the predictive ability of the TyG-index increased steadily after 9 with a positive slope, without any decline or leveling off. CONCLUSION: Due to the simplicity of assessing the TyG-index with routine biochemical assays and given that the TyG-index was the most effective surrogate insulin resistance index for predicting CAD based on our results, it seems suitable for inclusion in future CAD prevention strategies.

An optogenetic switch for the Set2 methyltransferase provides evidence for transcription-dependent and -independent dynamics of H3K36 methylation.

Histone H3 lysine 36 methylation (H3K36me) is a conserved histone modification associated with transcription and DNA repair. Although the effects of H3K36 methylation have been studied, the genome-wide dynamics of H3K36me deposition and removal are not known. We established rapid and reversible optogenetic control for Set2, the sole H3K36 methyltransferase in yeast, by fusing the enzyme with the light-activated nuclear shuttle (LANS) domain. Light activation resulted in efficient Set2-LANS nuclear localization followed by H3K36me3 deposition in vivo, with total H3K36me3 levels correlating with RNA abundance. Although genes showed disparate levels of H3K36 methylation, relative rates of H3K36me3 accumulation were largely linear and consistent across genes, suggesting that H3K36me3 deposition occurs in a directed fashion on all transcribed genes regardless of their overall transcription frequency. Removal of H3K36me3 was highly dependent on the demethylase Rph1. However, the per-gene rate of H3K36me3 loss weakly correlated with RNA abundance and followed exponential decay, suggesting H3K36 demethylases act in a global, stochastic manner. Altogether, these data provide a detailed temporal view of H3K36 methylation and demethylation that suggests transcription-dependent and -independent mechanisms for H3K36me deposition and removal, respectively.

Self-assembly of coherently dynamic, auxetic, two-dimensional protein crystals.

Two-dimensional (2D) crystalline materials possess unique structural, mechanical and electronic properties that make them highly attractive in many applications. Although there have been advances in preparing 2D materials that consist of one or a few atomic or molecular layers, bottom-up assembly of 2D crystalline materials remains a challenge and an active area of development. More challenging is the design of dynamic 2D lattices that can undergo large-scale motions without loss of crystallinity. Dynamic behaviour in porous three-dimensional (3D) crystalline solids has been exploited for stimuli-responsive functions and adaptive behaviour. As in such 3D materials, integrating flexibility and adaptiveness into crystalline 2D lattices would greatly broaden the functional scope of 2D materials. Here we report the self-assembly of unsupported, 2D protein lattices with precise spatial arrangements and patterns using a readily accessible design strategy. Three single- or double-point mutants of the C4-symmetric protein RhuA were designed to assemble via different modes of intermolecular interactions (single-disulfide, double-disulfide and metal-coordination) into crystalline 2D arrays. Owing to the flexibility of the single-disulfide interactions, the lattices of one of the variants ((C98)RhuA) are essentially defect-free and undergo substantial, but fully correlated, changes in molecular arrangement, yielding coherently dynamic 2D molecular lattices. (C98)RhuA lattices display a Poisson's ratio of -1-the lowest thermodynamically possible value for an isotropic material-making them auxetic.

Umbilical Reconstruction Techniques: A Literature Review.

BACKGROUND: There are many instances in which sacrificing the umbilicus is unavoidable. Umbilical reconstruction (umbiliconeoplasty) is an important surgical procedure to complete the abdomen's reconstruction and to give again a pleasant cosmetic appearance. OBJECTIVES: To provide a complete overview of all surgical techniques for umbiliconeoplasty described in the literature. METHODS: PubMed database was queried using 'umbilical and reconstruction', 'umbilicus and reconstruction', 'navel and reconstruction', 'umbiliconeoplasty', 'neo-omphaloplasty' or 'umbilicaneoplasty' to select the papers dealing with the reconstruction of the umbilicus. RESULTS: Sixty different techniques for the reconstruction of the missing umbilicus were described in 77 papers. Local skin flaps and the purse-string suture technique were the most frequently described techniques. The Three flaps technique, the Four flaps technique and the 2 Lateral rectangular pedicle lateral flaps technique were the most popular local flap techniques. Indications ranged from congenital pediatric defects to reconstruction during abdominoplasty. CONCLUSIONS: Several surgical techniques were described for umbilicus reconstruction. While there is not a universal algorithm for the choice of the technique, the surgeon may decide which technique to use based on other surgeons' experiences reports. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Artificial Intelligent Virtual Assistant for Plastic Surgery Patient's Frequently Asked Questions: A Pilot Study.

BACKGROUND: Artificial Intelligent Virtual Assistants (AIVA) is a segment of artificial intelligence that is rapidly developing. However, its utilization to address patients' frequently asked questions remains unexplored. METHODS: We developed an AIVA to answer questions related to 10 frequent topics asked by plastic surgery patients in our institution. Between July 27, 2018, and August 10 of 2018, we recruited subjects with administrative positions at our health care institution to chat with the virtual assistant. They asked, with their own words, 1 question for each topic and filled out a satisfaction questionnaire. Postsurvey analysis of questions and answers allowed assessment of the virtual assistant's accuracy. RESULTS: Thirty participants completed the survey. The majority was female (70%), and the mean age was 27.76 years (SD, 8.68 [19-51] years). The overall accuracy of the plastic surgery AIVA was 92.3% (277/294 questions), and participants considered the answer correct in 83.3% of the time (250/294 answers). Most of the participants considered the AIVA easy to use, answered adequately, and could be helpful for patients. However, when asked if this technology could replace a human assistant, they stayed neutral.

The Multifactorial Contribution of Publications in Plastic Surgery Journals in Microsurgery Education.

BACKGROUND: Microsurgery is one of the most complex operative skills. Recent restrictions on residents' working hours challenge residency program directors to ensure skill acquisition with scant time dedicated to microsurgery practice. We aimed to summarize the contribution of plastic surgery journals in microsurgical education. METHODS: A comprehensive literature search was performed. RESULTS: We observed an increasing number of publications on microsurgery education over the years. This could be due to the adoption of new technologies developed in the last 2 decades, the concerns about quality of resident training in the context of reduced work hours, the well-described benefit of medical simulations in other specialties, and the pressure on trainees to be proficient before operating on patients. The variety of aspects addressed in plastic surgery publications is broad: simulators, courses, skills assessment, national surveys, and technology trends. CONCLUSION: There is an upward trend in the number of publications and plastic surgery journals, demonstrating a remarkable contribution to microsurgery training.

Disparities in Access to Autologous Breast Reconstruction.

Background and objectives: This study aimed to determine if age, race, region, insurance, and comorbidities affect the type of breast reconstruction that patients receive. Materials and methods: This analysis used the Florida Inpatient Discharge Dataset from 1 January 2013 to 30 September 2017, which contains deidentified patient-level administrative data from all acute care hospitals in the state of Florida. We included female patients, diagnosed with breast cancer, who underwent mastectomy and a subsequent breast reconstruction. We performed an χ2 test and logistic regression in this analysis. Results: On the multivariable analysis, we found that age, race, patient region, insurance payer, and Elixhauser score were all variables that significantly affected the type of reconstruction that patients received. Our results show that African American (odds ratio (OR): 0.68, 95%CI: 0.58-0.78, p < 0.001) and Hispanic or Latino (OR: 0.82, 95%CI: 0.72-0.93, p = 0.003) patients have significantly lower odds of receiving implant reconstruction when compared to white patients. Patients with Medicare (OR: 1.57, 95%CI: 1.33-1.86, p < 0.001) had significantly higher odds and patients with Medicaid (OR: 0.61, 95%CI: 0.51-0.74, p < 0.001) had significantly lower odds of getting autologous reconstruction when compared to patients with commercial insurance. Conclusions: Our study demonstrated that, in the state of Florida over the past years, variables, such as race, region, insurance, and comorbidities, play an important role in choosing the reconstruction modality. More efforts are needed to eradicate disparities and give all patients, despite their race, insurance payer, or region, equal access to health care.

Chronic Tenosynovitis of the Upper Extremities Caused by Mycobacterium kansasii : A Clinical Case and Systematic Review of Literature.

Background Chronic tenosynovitis of the upper extremities caused by Mycobacterium kansasii ( M. kansasii ) is uncommon, but symptoms may overlap with other more common diseases. Late diagnosis and treatment can lead to disfiguration of structures and rupture of tendons, resulting in worse cosmetic outcomes after reconstruction. Methods We present a clinical case and literature review of M. kansasii in patients with chronic tenosynovitis of upper extremities. PubMed was queried for cases of upper extremities tenosynovitis caused by M. kansasii . The keywords " M. kansasii ," "tenosynovitis" and synonyms were used for search in different combinations. Manuscripts, with no specific data or another condition, where the infection was not located in the upper extremities, were reviews, or not in English, were excluded from the study. Results We described 23 reported cases of tenosynovitis of the upper extremity caused by M. kansasii . An immunosuppressed state was present in eight (34.8%) cases, and 12 (52.2%) patients received immunosuppressive treatment. A long-time period between the first appearance of symptoms and the definitive diagnosis was identified (median: 7 months, interquartile range: 9). The most frequent symptoms were local swelling (65.2%), pain (56.5%), mass effect (26%), and stiffness (13%). Tendon rupture was found in three (13%) patients as a complication of the disease. Moreover, seven (30.4%) patients underwent previous surgeries to try to relieve the symptoms before definitive diagnosis was achieved. Conclusion M. kansasii is an important differential causal pathogen for tenosynovitis of the upper extremities. Although rare, raising awareness about this infectious disease is imperative to avoid inadequate management and hazardous aesthetic sequelae.

Primary Hand Leiomyoma: A Systematic Review.

BACKGROUND: Primary leiomyoma is a rare cause of a mass in the hand, with few reported cases to date. To our knowledge, this constitutes the most comprehensive and up-to-date systematic review of the literature of all cases of primary hand leiomyoma. We also provide an additional case recently managed in our practice of confirmed primary vascular leiomyoma of the hand in a 44-year-old woman to add to the current body of literature. METHODS: We performed a comprehensive literature review of all articles published on primary leiomyoma of the hand. The PubMed database was used, with search terms leiomyoma hand, angioleiomyoma hand, and angiomyoma hand. Articles were selected for their accuracy in anatomic localization in the hand and confirmed pathology of leiomyoma. RESULTS: Our initial search query resulted in 216 articles. After applying the inclusion criteria, we identified 50 individual articles with 108 cases of confirmed primary leiomyoma in the hand from January 1, 1954, to July 1, 2018. Common initial clinical impressions recorded for primary hand leiomyoma included ganglion cyst, giant-cell tumor, hemangioma, and glomus tumor. Patients presenting with leiomyoma of the hand frequently describe a painful lesion, which differs from most other benign tumors of the hand at presentation. CONCLUSIONS: Leiomyoma is an important consideration when developing a differential diagnosis for primary benign masses in the hand. We hope that this comprehensive review can provide increased awareness of this tumor type.

National Analysis of Patients With External Ear Melanoma in the United States.

BACKGROUND: External ear melanoma (EEM) is a rare condition with controversies in the literature. We analyzed patients with EEM in the United States compared to other head and neck melanomas (OHNMs). METHODS: The National Cancer Database (NCDB) was used to select patients with head and neck melanoma from January 1, 2004 to December 31, 2015. Mann-Whitney and χ tests were used to estimate statistical significance, and multivariate logistic regression to identify independent associations adjusted for confounders. RESULTS: A total of 137,233 patients met the study criteria. Among them, 16,991 (12.4%) had EEM and 120,242 (87.6%) had OHNM. For patients with EEM, the mean (standard deviation) age was 66.26 (15.798) years. Most of the patients with EEM were men (85.5%), insured by Medicare (52.4%), and treated in Academic/Research Programs (47.7%) or Comprehensive Community Cancer Programs (32.3%). Most of the EEM tumors had invasive behavior (68.0%) were Stages 0 (30.3%) or I (40.3%), and were without ulceration (76.9%). Mean time to receive any treatment was 14.1 days for EEM compared with 14.6 days for OHNM (P < 0.001). We noticed a greater proportion of EEM in men (14.8%; adjusted odds ratio [aOR] 2.72 [2.605-2.852]; P < 0.001) compared to women (6.22%; reference). EEM was an independent factor for tumor Stage I (14.47%; aOR 1.61 [1.101-1.224], P < 0.001) and invasive behavior (13.86%; aOR 1.268 [1.15-1.389]; P < 0.001) compared to OHNM. CONCLUSION: EEM was associated with higher odds of invasive behavior compared to OHNM. Furthermore, men were found to have a higher likelihood to develop EEM compared to women.

Eyelid Melanoma in the United States: A National Cancer Database Analysis.

BACKGROUND: Eyelid melanoma (EM) is a rare condition that accounts for <1% of all cutaneous melanomas. In this analysis, patients diagnosed with EM in the United States were compared to those with other melanomas in the head and neck. METHODS: The National Cancer Database was used to select patients with head and neck melanoma from 2004 to 2015. RESULTS: A total of 137,233 patients met the criteria of the study. Among them, 2694 were diagnosed with EM (2%) and 134,539 in other head and neck locations (98%). Regarding the patients with EM, the mean age was 68.56 years (standard deviation 14.04). A greater number of them were treated in Academic/Research Programs (53.6%), insured by Medicare (55.7%), tumor in situ (52.2%), stage 0 (49%), and without ulceration (75.9%). The mean time to treatment commencement was 18.96 days for EM compared to 14.4 days for other melanoma in the head and neck regions (P < 0.001). There was a greater proportion of EM in female patients (odds ratio [OR] 2.371 [2.191-2.566], P < 0.001), compared to male; age greater than 80 years (OR 1.622 [1.360-1.934], P < 0.001) compared to 0 to 49 years. Moreover, EM was an independent predictor for treatment in Academic/Research Programs (OR 1.258 [1.160-1.365], P < 0.001) and diagnosis at autopsy (OR 1.414 [1.083-1.847], P = 0.011) compared to other melanoma in the head and neck region. CONCLUSION: These novel findings have the potential to guide clinical decision making in head and neck melanoma management.

Alloplastic Facial Implants: A Systematic Review and Meta-Analysis on Outcomes and Uses in Aesthetic and Reconstructive Plastic Surgery.

BACKGROUND: Alloplastic materials in facial surgery have been used successfully for various applications in the reconstructive restoration or aesthetic augmentation of the facial skeleton. The objective of this study was to conduct a comprehensive systematic review of alloplastic implant materials utilized to augment the facial skeleton stratified by anatomical distribution, indication, specific material used, and respective outcomes. METHODS: A comprehensive systematic review on alloplastic facial implant data was conducted utilizing Medline/PubMed database. Articles were stratified by (1) anatomic localization in the face, as well as (2) alloplastic material. RESULTS: A total of 17 studies (n = 2100 patients, follow-up range = 1 month-27 years) were included. Overall, mersilene mesh implants were associated with the highest risk of infection (3.38%). Methyl methacrylate implants were associated with the highest rate of hematoma (5.98%). Implants placed in the malar region (2.67%) and frontal bones (2.50%) were associated with the highest rates of infection. Implants placed in the periorbital region were associated with the highest rate of inflammation (8.0%), explantation (8.0%), and poor cosmetic outcome (17.0%). Porous implants were shown to be more likely to potentiate infection than non-porous implant types. CONCLUSIONS: Alloplastic facial implants are a reliable means of restoring facial symmetry and achieving facial skeletal augmentation with a relatively low complication profile. It is important for plastic surgeons to understand the relative risks for each type of implant to develop postoperative complications or poor long-term cosmetic results. Interestingly, porous implants were shown to be more likely to potentiate infection than non-porous implant types. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Erythroxylum in Focus: An Interdisciplinary Review of an Overlooked Genus.

The genus Erythroxylum contains species used by indigenous people of South America long before the domestication of plants. Two species, E. coca and E. novogranatense, have been utilized for thousands of years specifically for their tropane alkaloid content. While abuse of the narcotic cocaine has impacted society on many levels, these species and their wild relatives contain untapped resources for the benefit of mankind in the form of foods, pharmaceuticals, phytotherapeutic products, and other high-value plant-derived metabolites. In this review, we describe the current state of knowledge of members within the genus and the recent advances in the realm of molecular biology and biochemistry.

Postmastectomy Radiation Therapy (PMRT) before and after 2-Stage Expander-Implant Breast Reconstruction: A Systematic Review.

Background: In those undergoing treatment for breast cancer, evidence has demonstrated a significant improvement in survival, and a reduction in the risk of local recurrence in patients who undergo postmastectomy radiation therapy (PMRT). There is uncertainty about the optimal timing of PMRT, whether it should be before or after tissue expander or permanent implant placement. This study aimed to summarize the data reported in the literature on the effect of the timing of PMRT, both preceding and following 2-stage expander-implant breast reconstruction (IBR), and to statistically analyze the impact of timing on infection rates and the need for explantation. Methods: A comprehensive systematic review of the literature was conducted using the PubMed/Medline, Ovid, and Cochrane databases without timeframe limitations. Articles included in the analysis were those reporting outcomes data of PMRT in IBR published from 2009 to 2017. Chi-square statistical analysis was performed to compare infection and explantation rates between the two subgroups at p < 0.05. Results: A total of 11 studies met the inclusion criteria for this study. These studies reported outcomes data for 1565 total 2-stage expander-IBR procedures, where PMRT was used (1145 before, and 420 after, implant placement). There was a statistically significant higher likelihood of infection following pre-implant placement PMRT (21.03%, p = 0.000079), compared to PMRT after implant placement (9.69%). There was no difference in the rate of explantation between pre-implant placement PMRT (12.93%) and postimplant placement PMRT (11.43%). Conclusion: This study suggests that patients receiving PMRT before implant placement in 2-stage expander-implant based reconstruction may have a higher risk of developing an infection.

Local Pro- and Anti-Coagulation Therapy in the Plastic Surgical Patient: A Literature Review of the Evidence and Clinical Applications.

The risks of systemic anti-coagulation or its reversal are well known but accepted as necessary under certain circumstances. However, particularly in the plastic surgical patient, systemic alteration to hemostasis is often unnecessary when local therapy could provide the needed adjustments. The aim of this review was to provide a summarized overview of the clinical applications of topical anti- and pro-coagulant therapy in plastic and reconstructive surgery. While not a robust field as of yet, local tranexamic acid (TXA) has shown promise in achieving hemostasis under various circumstances, hemostats are widely used to halt bleeding, and local anticoagulants such as heparin can improve flap survival. The main challenge to the advancement of local therapy is drug delivery. However, with increasingly promising innovations underway, the field will hopefully expand to the betterment of patient care.