Simple Defects Research Articles

A Comparison for Infantile Mortality of Crucial Congenital Heart Defects in Korea over a Five-Year Period.

Background: Nearly half of congenital heart defects (CHDs) related to mortality occur during infancy although advancements in treatments have increased the survival rates. This study comprehensively examined overall and surgical mortality in CHD infants with the highest mortality rates in an effort to improve our understanding of CHD epidemiology. Methods: Participants were drawn from a dataset of 1,964,691 infants born between 2014 and 2018 in Korea. Crucial CHDs are defined here as including diverse categorical defects and classical critical CHDs but excluding simple shunt defects. Overall mortality (procedural and natural mortality) and procedural mortality (interventional and surgical mortality) for infants were analyzed. Results: The performance rate for multiple procedures in infants with crucial CHDs was 16%. The overall and surgical mortalities of crucial CHDs were 8% and 7%. The mortalities of palliative procedures were relatively high. Procedural mortalities for infants were significantly decreased in the tetralogy of Fallot (TOF), atrioventricular septal defects, and total anomalous pulmonary venous return (TAPVR) compared with overall mortalities for infants. Surgical mortalities for infants involving TOF and TAPVR were significantly lower, but those for infants involving hypoplastic left heart syndrome (HLHS) were higher than those for all ages. Conclusions: Palliative procedural techniques in infants must be improved to obtain better outcomes, particularly in the palliative surgery of HLHS. The infantile procedural outcomes for TOF and TAPVR are excellent and important in order to overcome disastrous circumstances during infancy. This comprehensive study of the overall and procedural mortalities of CHDs may have laid a cornerstone for CHD epidemiology in Korean infants.

Variability in patient-reported outcomes among different congenital heart defects: a comparative analysis of 7,498 patients from 32 countries

Abstract Background Patient-reported outcomes (PROs) may not always correlate with the complexity of congenital heart defects (CHDs), as significant variation has been observed between CHDs within complexity levels. Accurate comparisons across various types of CHDs necessitate large sample sizes. Purpose The objective of this study was to compare PROs across different CHDs in a large international sample. Methods ‘Assessment of Patterns of Patient-Reported Outcomes in Adults with Congenital Heart disease – International Study II’ (APPROACH-IS II) was an international cross-sectional investigation, in which 8,415 patients from 32 countries in 6 continents were enrolled (20 high; 7 upper-middle; 4 lower-middle; and 1 low income). For the comparison across different CHDs, conditions with at least 50 patients were included in the analysis. Hence, the sample consisted of 7,498 patients (median age=33y; 53.1% women). Patients completed questionnaires to measure perceived health status (RAND-12 Health Survey; EuroQOL-5D Visual Analog Scale); depressive symptoms (Patient Health Questionnaire-8); anxiety (General Anxiety Disorder-7) and quality of life (Linear Analog Scale). Generalized linear mixed models (GLMMs) were performed with center as random effect. Results Cyanotic heart defects were associated with the lowest scores for physical functioning, mental health, self-rated health, and quality of life (see Figure). Other CHDs found to be associated with poor PRO scores encompassed unrepaired secundum atrial septal defect, Ebstein anomaly, single ventricle, and truncus arteriosus. Conversely, the most favorable scores for all PROs, except for anxiety, were observed with isolated pulmonic stenosis. Other CHDs with favorable PRO scores comprised coarctation of the aorta, isolated small ventricular septal defect, congenital aortic valve disease, and repaired ventricular septal defect. Adjusted for sociodemographic and physiological factors, GLMMs revealed significant differences across defects, using the best score for each PRO as the reference (see Figure). Conclusion Substantial variation in PROs was observed among different types of CHDs. Interestingly, some complex heart defects demonstrated relatively good PRO scores, comparable to some simple defects. On the other hand, unrepaired simple defects or those with residual lesions, were associated with worse PROs.

Anisotropy of radiation-induced defects in Yb-implanted β-Ga2O3

RE-doped β-Ga2O3 seems attractive for future high-power LEDs operating in high irradiation environments. In this work, we pay special attention to the issue of radiation-induced defect anisotropy in β-Ga2O3, which is crucial for device manufacturing. Using the RBS/c technique, we have carefully studied the structural changes caused by implantation and post-implantation annealing in two of the most commonly used crystallographic orientations of β-Ga2O3, namely the (-201) and (010). The analysis was supported by advanced computer simulations using the McChasy code. Our studies reveal a strong dependence of the structural damage induced by Yb-ion implantation on the crystal orientation, with a significantly higher level of extended defects observed in the (-201) direction than for the (010). In contrast, the concentration and behavior of simple defects seem similar for both oriented crystals, although their evolution suggests the co-existence of two different types of defects in the implanted zone with their different sensitivity to both, radiation and annealing. It has also been found that Yb ions mostly occupy the interstitial positions in β-Ga2O3 crystals that remain unchanged after annealing. The location is independent of the crystal orientations. We believe that these studies noticeably extend the knowledge of the radiation-induced defect structure, because they dispel doubts about the differences in the damage level depending on crystal orientation, and are important for further practical applications.

Quantum bit with telecom wave-length emission from a simple defect in Si

Defect-related spin-to-photon interfaces in silicon promise the realization of quantum repeaters by combining advanced semiconductor and photonics technologies. Recently, controlled creation/erasure of simple carbon interstitial defects have been successfully realised in silicon. This defect has a stable structure near room temperature and coherently emits in the wave-length where the signal loss is minimal in optical fibres used in communication technologies. Our in-depth theoretical characterization confirms the assignment of the observed emission to the neutral charge state of this defect, as arising due to the recombination of a bound exciton. We also identified a metastable triplet state that could be applied as a quantum memory. Based on the analysis of the electronic structure of the defect and its similarities to a known optically detected magnetic resonance centre in silicon, we propose that a carbon interstitial can act as a quantum bit and may realize a spin-to-photon interface in complementary metal-oxide semiconductor-compatible platforms.

8610 The Role of Adenylyl Cyclase 2 Gene-Dosage Changes in Congenital Male Genitourinary Anomalies

Abstract Disclosure: D.J. Lamb: Advisory Board Member; Self; Ro Health, Inc. Stock Owner; Self; Fellow Health, Inc. M.A. O'Neill: None. Collectively, congenital genitourinary (GU) birth defects are the most common birth defects in males, yet relatively little is known about their cause. In part, this reflects the current clinical perspective that, because most of these birth defects can be surgically repaired, there is nothing to be gained by understanding the cause. Yet our studies show that seemingly simple birth defects like hypospadias or cryptorchidism, may be associated with other more significant underappreciated defects, such as those affecting the kidney, heart, eyes or behavior. We tested the hypothesis that chromosome microdeletions and microduplications (called copy number variations, CNVs) result in gene-dosage changes that are important regulators of GU development and when haploinsufficient or duplicated normal genitourinary development is impacted causing birth defects of the upper and/or lower genitourinary tract. We successfully used this strategy to identify 15 different previously unrecognized genes that when microduplicated or microdeleted result in conditions such as cryptorchidism, hypospadias, disorders of sexual differentiation (DSD) and other anomalies. Remarkably, gene-dosage changes affected major signaling pathways and post-translational modifications in novel, previously unrecognized ways. Herein, we focused on defining the role of a candidate gene commonly microdeleted or microduplicated in patients with cryptorchidism, hypospadias and/or micropenis. Locus mapping allowed identification of adenylate cyclase 2 (ADCY2) as a candidate gene at the 5p15.31 Cri-du-Chat region in patients with male genital tract anomalies. ADCY2 CNVs were more common in non-syndromic patients with micropenis, cryptorchidism, and/or hypospadias (1.6%) than the general population (0.07%; p< 0.001). Whole exome sequence studies revealed a range of phenotypic anomalies in patients with damaging and potentially damaging ADCY2 variants in addition to the male GU anomalies, including congenital anomalies of the kidney and urinary tract. It is our hypothesis that ADCY2 duplications result in a de-sensitization of the LH receptor diminishing testosterone biosynthesis in the testis, whereas deletions diminish LH receptor signaling. ADCY2 CNVs were assessed in 100 men with spermatogenic failure who were born with cryptorchidism. The ADCY2 CNV frequency was the same as in our cohort of boys with GU anomalies, but as adults they also have hypergonadotropic hypogonadism, which we predicted if ADCY2 over-expression was impacting adult Leydig cell steroidogenesis through partial desensitization of the LH receptor. These studies identified an unrecognized cause of GU anomalies. In the future, such knowledge may lead to improved diagnosis and therapeutic approaches to ameliorate these common birth defects. Presentation: 6/2/2024

Psychosocial burden and quality of life of parents with children with univentricular hearts compared to ASD parents and parents of heart-healthy children.

Patients with univentricular hearts can only be palliated by a staged surgical procedure that carries a high morbidity and mortality risk. The aim of this study was to examine the emotional demands, psychosocial burden, and quality of life of parents with children with univentricular hearts compared to parents of children with a simple heart defect, those with no heart defect and children with chronic diseases. An anonymous questionnaire was created to interview parents about their quality of life, stressors, needs, strategies for coping with illness, and partnership satisfaction. 73 families participated in the study. Parents of children with univentricular hearts experience a significantly higher psychosocial burden, limitations in daily life, and distress in family interactions, as well as greater emotional distress compared to the other study groups. When comparing the families of children with other chronic diseases (e.g. cystic fibrosis, chronic arthritis and diabetes), these differences remained significant. The study confirms a higher psychosocial burden, restrictions in daily life and a lower quality of life of parents with children with univentricular hearts, compared to parents of children with simple heart defects and parents of heart-healthy children or those with other chronic diseases. Since this condition persists until adolescence and adulthood, the families are exposed to special challenges and stresses throughout their lives. This has yet to be adequately addressed in the management of these families.

770. CLOSURE OF OESOPHAGEAL DEFECTS USING THE VACSTENT DEVICE: INITIAL INSIGHTS FROM THE LARGEST UK CASE SERIES

Abstract Introduction Oesophageal defects are associated with poor morbidity and mortality and often require prolonged hospitalisation and artificial nutrition. Existing endoscopic treatment modalities exhibit limitations. Covered stents are associated with a migration rate of up to 50% and closure with endoscopic clips is limited to simple defects. Vacuum therapy is a well understood and established surgical therapy to promote wound healing. Endoscopic Vacuum Therapy (EVT) utilises these principles in the management of transmural oesophageal defects. The VACstent GITM (MicroTech) is a novel device which synergistically incorporates the advantages of a fully covered oesophageal stent while concurrently employing EVT. This approach seals the defect while mitigating against stent migration through the vacuum effect. Luminal patency is also maintained which helps to preserve nutritional independence. Accelerated healing and enhanced nutrition are thought to help reduce morbidity and enhance patient quality of life. Methods This single-centre prospective case series describes outcomes for patients with transmural oesophageal defects treated with the VACstent GITM device. All procedures were performed with propofol sedation and fluoroscopic guidance. The VACstent GITM was exchanged every 5-7 days until endoscopic closure. A contrast study was used to confirm closure after which oral nutrition was restarted. The primary outcome was clinical success, defined as the endoscopic and radiological evidence of defect closure. Secondary outcomes included number of stent exchanges, technical success, and the adverse event (AE) rate. Results The VACstent GITM device was used for seven patients between October 2023 and February 2024. Four patients had anastomotic leaks with three having iatrogenic perforations. The mean patient age was 60 (± 19.3) years with 57% of the patient cohort being male. The clinical success rate was 86% with a technical success rate of 100% and a median defect closure time of 13 (± 6.6) days. A median number of 1 stent exchanges was required. The median defect size was 8mm (± 6.2). There were no reported AEs. All patients were able to successfully come of artificial nutrition. Conclusion This case series illustrates the safety and efficacy of the VACstent for the treatment of a heterogenous group of oesophageal defects. To our knowledge this represents the largest series in a cohort of patients from the United Kingdom. Larger scale comparative studies incorporating a more diverse patient cohort will further clarify the potential of the VACstent device in reducing the necessity for major surgical interventions in this complex and challenging patient population. It will also help to refine future treatment algorithms for oesophageal defect management.

First-principles study of vacancy-impurity (C, N, O) interactions in vanadium

Abstract Interstitial impurities of C, N, and O typically exist in V and its alloys, which have significant effects on the structure and properties of the materials due to their strong interaction with the vacancies. In this study, the structure and energy properties of vacancy-impurity complexes in V are comprehensively investigated by first principles calculations. The effects of impurity concentration and temperature on the concentration distribution of the complexes were studied using statistical methods. The results showed that the Vac n X 2 complexes exhibit a high sequential binding energy. There is an evident mutual attraction between the vacancy and the O atom, and it has a higher affinity than the C or N atom. The simple defect complexes of Vac 1 X 1–2 have always been the most abundant type of complex defect in V. The trapping effect of vacancy on C, N, and O atom is very significant at low temperatures rather than at high temperatures. This study would broaden the understanding of vacancy-impurity interactions in vanadium and provide new insights into the influence of C, N, and O on vacancy defect concentrations.

Minimally Invasive Surgical Repair of Simple Congenital Heart Defects Using the Right Vertical Infra-Axillary Thoracotomy Approach.

To evaluate the safety and efficacy of surgical repair for patients diagnosed with simple congenital heart defects (CHD) using the minimally invasive right vertical infra-axillary minithoracotomy (RVIAT) approach. We retrospectively reviewed the clinical data of consecutive patients who underwent minimally invasive RVIAT for repair of CHD between August 2019 and August 2022. There were 382 patients who underwent 8 primary procedures and were included in this study. The median age of the patients was 16.2 (interquartile range [IQR], 7.2 to 41.9) months, and the median weight of the patients was 8.8 (IQR, 6.5 to 14) kg. The preoperative diagnoses were as follows: ventricular septal defect, atrial septal defect, partial anomalous pulmonary venous return, partial atrioventricular septal defect, cor triatriatum, complete atrioventricular septal defect, and myxoma. The mean aortic cross-clamp time, bypass time, and operation time were 45.4 ± 19.3 min, 65.6 ± 23.1 min, and 154.5 ± 29.7 min, respectively. There was no in-hospital mortality or conversion to median sternotomy. Two patients (0.5%) required early reoperation; 1 due to postoperative bleeding and 1 for permanent pacemaker implantation. Other complications included trivial residual shunts (23 of 382, 6%), pleural effusion (3 of 382, 0.8%), pneumothorax (0.8%), and wound infection (4 of 382, 1%). There were 2 late noncardiac deaths. Late reoperation was performed on 1 patient with progressive aortic valve regurgitation who required aortic valvuloplasty. RVIAT is a minimally invasive approach that can be safely performed on patients with simple CHDs. RVIAT may be a good alternative approach for median sternotomy and cardiac intervention.

Fingertip injuries: Does administration of antibiotics give benefits? A double-blind randomized controlled trial.

Adequate debridement and defect closure is an important treatment in fingertip injuries in addition to administration of antibiotic. However, administration of anitibiotics remains controversial whether it necessary for fingertip injuries that have been treated with adequate debridement and defect closure. The goal of study is to assess the differences of infection rate between subgroups with administration of antibiotics and without antibiotic in FTI treated by debridement and simple defect closure. The study design was a double-blind randomized clinical trial. Data collection was carried out at Cipto Mangunkusumo General Hospital, Jakarta and Tangerang Regency Hospital, Banten, in July 2022-February 2023. The target population of this study were adult patients with Fingertip injuries that treated by debridement and simple defect closures with antibiotics administration and without antibiotic. Infection was assessed at day-7, 14, and 21 follow-up. There were 31 FTI subjects with 41 fingers affected. The number of male subjects was 27 people and female subjects 4 people. The most affected finger was the little finger (12 fingers, 30.8%), with most type of Allen classification was type IV (18 fingers, 43.90%), most procedure performed was primary suture (24 fingers, 58.54%). 15 subjects randomized to antibiotic group and 16 subjects to no-antibiotic group. There was 1 subject of antibiotic group and 1 subject of no-antibiotic group has infection. There are no significant differences between two groups. There were no significant differences of infection rate between antibiotics administration and without antibiotic in FTI cases that treated by debridement and simple defect closures.

Topological defects in K3 sigma models

We consider the topological defect lines commuting with the spectral flow and the N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = (4, 4) superconformal symmetry in two dimensional non-linear sigma models on K3. By studying their fusion with boundary states, we derive a number of general results for the category of such defects. We argue that while for certain K3 models infinitely many simple defects, and even a continuum, can occur, at generic points in the moduli space the category is actually trivial, i.e. it is generated by the identity defect. Furthermore, we show that if a K3 model is at the attractor point for some BPS configuration of D-branes, then all topological defects have integral quantum dimension. We also conjecture that a continuum of topological defects arises if and only if the K3 model is a (possibly generalized) orbifold of a torus model. Finally, we test our general results in a couple of examples, where we provide a partial classification of the topological defects.

Ultrasound-guided mid-point transverse process to pleura block versus thoracic paravertebral block in pediatric open-heart surgery: A randomized controlled non-inferiority study

Study objectiveThe mid-point transverse process to pleura block (MTPB) is a new variant of thoracic paravertebral block (TPVB). This study aimed to compare TPVB and MTPB with respect to intraoperative attenuation of the hemodynamic stress response to surgery and postoperative analgesia in pediatric open heart surgery with midline sternotomy. DesignA single-center, randomized, controlled, double-blind, non-inferiority study. SettingTertiary care children's university hospital. PatientsWe recruited 83 children aged 2–12 years of both sexes with American Society of Anesthesiologists (ASA) physical status class II who were scheduled for elective open cardiac surgeries with midline sternotomy for the repair of simple noncyanotic congenital heart defects. InterventionsEligible participants were randomized into either the TPVB or MTPB groups at a ratio of 1:1. In the TPVB group, patients were bilaterally injected with 0.4 ml/kg of 0.25% bupivacaine in the paravertebral space at T4 and T5. In the MTPB group, patients were bilaterally injected with 0.4 ml/kg of 0.25% bupivacaine mid-transverse process and pleura just posterior to superior costotransverse ligament at the level of T4 and T5. MeasurementsThe primary outcome was the hemodynamic responses to sternotomy incision, including heart rate (HR) and invasive mean arterial pressure (MAP), recorded before and after the induction of anesthesia, after skin incision, after sternotomy, 15 min after cardiopulmonary bypass (CPB), and after the closure of the sternum. The secondary outcomes were time needed to perform the bilateral block, intraoperative fentanyl consumption, postoperative fentanyl consumption, modified objective pain score (MOPS) measured at 1, 2, 6, 12, 18, and 24 h after extubation, extubation time, intensive care unit (ICU) discharge time, and the incidence of non-surgical complications (postoperative pruritus, postoperative vomiting, pneumothorax, hematoma or local anesthetic toxicity). Main resultsThere were no significant differences in HR and MAP in the TPVB group compared with the MTPB group at the following time points: baseline, after induction, after skin incision, after sternotomy, 15 min after CPB, and after sternal closure. Intergroup comparisons of HR and MAP did not reveal significant differences between the groups. The median (IQR) time needed to perform bilateral MTPB (7[6–8] min) was significantly (p < 0.001) shorter than that of TPVB (12[10−13] min). Intraoperative fentanyl consumption and fentanyl consumption in the first postoperative 24 h after extubation were similar in the TPVB and MTPB groups (4[2–4] vs 4[2–4] and 4.66 ± 0.649 vs 4.88 ± 1.082 μg/kg), respectively. Extubation time and ICU discharge time were comparable in the TPVB and MTPB groups (2[1–3] vs 2[1–3] h and 21.2 ± 2.5 vs 20.8 ± 2.6 h), respectively. Measurements of MOPS pain scores at 1, 2, 6, 12, 18, and 24 h after extubation were similar in both groups. The incidence of nonsurgical complications was similar in both groups. ConclusionsMTPB is non-inferior to TPVB in attenuating the intraoperative hemodynamic stress response to noxious surgical stimuli and in reducing perioperative opioid consumption, extubation time, and ICU discharge time. Moreover, MTPB is technically easier than TPVB and requires less time to perform.Clinical trial registration numberThe clinical trial registration was prospectively performed at the Pan African Clinical Trials Registry (PACTR202204901612169, approval date 01/04/2022, URL https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=22602).

Defect Engineering Strategy for Superior Integration of Metal-Organic Framework and Halide Perovskite as a Fluorescence Sensing Material.

Combining halide perovskite quantum dots (QDs) and metal-organic frameworks (MOFs) material is challenging when the QDs' size is larger than the MOFs' nanopores. Here, we adopted a simple defect engineering approach to increase the size of zeolitic imidazolate framework 90 (ZIF-90)'s pores size to better load CH3NH3PbBr3 perovskite QDs. This defect structure effect can be easily achieved by adjusting the metal-to-ligand ratio throughout the ZIF-90 synthesis process. The QDs are then grown in the defective structure, resulting in a hybrid ZIF-90-perovskite (ZP) composite. The QDs in ZP composites occupied the gap of 10-18 nm defective ZIF-90 crystal and interestingly isolated the QDs with high stability in aqueous solution. We also investigated the relationship between defect engineering and fluorescence sensing, finding that the aqueous Cu2+ ion concentration was directly correlated to defective ZIF-90 and ZP composites. We also found that the role of the O-Cu coordination bonds and CH3NHCu+ species formation in the materials when they reacted with Cu2+ was responsible for this relationship. Finally, this strategy was successful in developing Cu2+ ion fluorescence sensing in water with better selectivity and sensitivity.

Application of Computed Tomography Angiography in Preoperative Diagnosis of Coarctation of Aorta and Evaluation of Aortic Dilatation in Infants.

To evaluate the occurrence of aortic dilatation and its associated predictors with coarctation of the aorta (CoA) in infants using multi-slice computed tomography (MSCT). The clinical data of 47 infantile patients with CoA diagnosed by MSCT and 28 infantile patients with simple ventricular septal defect were analyzed retrospectively. Aortic diameters were measured at six different levels, and aortic sizes were compared by z score. The coarctation site-diaphragm ratio was used to describe the degree of narrowing. Relevant clinical data were collated and analyzed. The dilation rate and z score of the ascending aorta in the severe CoA group were significantly higher than those in the mild CoA group (11 [52.38%] vs. 21 [80.77%], P=0.038 and 2.00 ± 0.48 vs. 2.36 ± 0.43, P=0.010). Pearson's correlation analysis found that the z score of the ascending aorta was negatively correlated with the coarctation site-diaphragm ratio value (r=-0.410, P=0.004). A logistic retrospective analysis found that an increased degree of coarctation was an independent predictor of aortic dilatation (adjusted odds ratio 0.002; 95% confidence interval 0.00-0.819; P=0.043). The z score of the ascending aorta in the severe CoA group was significantly higher than that in the ventricular septal defect group (P<0.05). Most infants with CoA can also have significant dilatation of the ascending aorta, and the degree of this dilatation is related to the degree of coarctation. Assessment of aortic diameter and related malformations by MSCT can predict the risk of aortic dilatation in infants with CoA.

Therapeutic effects of treat and repair strategy in pediatric patients with pulmonary arterial hypertension and simple congenital heart defects.

Surgical indications for patients with pulmonary arterial hypertension (PAH) and congenital heart defects are controversial. The treat and repair strategy has demonstrated efficacy in adult populations, but there have been no studies on pediatric patients. This study included pediatric patients with PAH and simple congenital heart defects who underwent corrective repair between 2012 and 2021. According to the preoperative treatment strategies, the patients were divided into a regular strategy group (Group 1) and a treat-and-repair strategy group (Group 2). Postoperative recovery and follow-up results were compared between the two groups. A total of 33 patients were included in this study. Group 1 consisted of 19 patients, whereas Group 2 consisted of 14 patients. The pulmonary vascular resistance index in Group 2 was higher than that in Group 1 (10.9 ± 4.1 vs. 8.2 ± 1.6 WU, p = 0.031). There were no differences in postoperative recovery between the two groups (p > 0.05). During follow-up, five patients were lost (three in Group 1 and two in Group 2). The median follow-up period was 59 months. One patient died in Group 1, and two patients died in Group 2. There was no significant difference in the survival curve (p = 0.39). At the last follow-up, another seven patients had experienced a non-low-risk condition, with a total of three non-low-risk patients in Group 1 and seven in Group 2, including one patient in each group who had a history of ICU admission. According to the ROC curve, a preoperative PVRi <8.2 WU×m2 can predict postoperative persistent low-risk state, PVRi <5.2 WU×m2 can avoid postoperative death and/or ICU administration. In pediatric patients with PAH and simple congenital heart defects, the treat and repair strategies may provide surgery opportunities, PVRi should be <8 WU×m2, and <5.2 WU×m2 is the best choice.

Native point defects in 2D transition metal dichalcogenides: A perspective bridging intrinsic physical properties and device applications

Two-dimensional (2D) transition metal dichalcogenides (TMDs) hold immense promise as ultrathin-body semiconductors for cutting-edge electronics and optoelectronics. In particular, their sustained charge mobility even at atomic-level thickness as well as their absence of surface dangling bonds, versatile band structures, and silicon-compatibility integration make them a prime candidate for device applications in both academic and industrial domains. Despite such high expectations, group-VI TMDs reportedly exhibit a range of enigmatic properties, such as substantial contact resistance, Fermi level pinning, and limited unipolar charge transport, which are all rooted in their inherent defects. In other words, intrinsic physical properties resulting from their native defects extend their influence beyond the material level. Bridging point-defect-induced material properties and their behavior at the device level, this Perspective sheds light on the significance of crystalline defects beyond a rather simple defect–property relationship. As a distinctive approach, we briefly review the well-established defect model of conventional III–V semiconductors and further apply it to the emergent defect behaviors of 2D TMDs such as their defect-induced gap states. Within the main discussion, we survey a range of behaviors caused by the most prevalent intrinsic defect, namely, vacancies, within 2D TMDs, and their implications for electronic and optoelectronic properties when employed at the device level. This review presents an in-depth summary of complexities in material properties as well as device characteristics arising from intrinsic point defects and provides a solid foundation for the cross-links among native defects and material/device properties.

Ultrafast Optical Encoder Using Photonic Crystal Ring Resonator

ABSTRACT In this paper, we design and simulate a two-dimensional photonic crystal-based high speed logical encoder for optical computing application. The encoder consists of a ring resonator, four waveguides and two reflectors arranged in a hexagonal lattice platform. The optical encoder works on the interference effect which guides the propagation of light in the desired path. The light behavior is simulated with four different logic states. The Plane Wave Expansion (PWE) method is used to analyze the band gap and Finite Difference Time Domain (FDTD) analyzes the performance characteristics of the encoder, such as bit rate, delay time, and contrast ratio. The proposed structure has a footprint area of 143.84 µm2. The small compact size structure with simple defect paths reduces the encoder delay time, which in turn increase the data bit rate. The response time of the proposed encoder is 0.119 ps and bit rate is 8.403 Tbps. The encoder is designed with very low output power in “0” logic state and high output power in “1” logic state leading to high contrast ratio of 22.57 dB. Therefore, highly efficient 4 × 2 optical encoder is suitable to build in optical integrated circuits.

Ab Initio Study on the Vibrational and Electronic Properties of Radiation-Induced Defects in Potassium Bromide

The vibrational and electronic properties of several basic radiation defects in potassium bromide are computed at the quantum mechanical level using a periodic supercell approach based on hybrid functionals, an all-electron Gaussian-type basis set, and the Crystalcomputer code. The exciton energy in alkali halides is sufficient to create lattice defects, such as F–H Frenkel defect pairs, resulting in a relatively high concentration of single defects and their complexes. Here, we consider eight defects: the electronic F+- and F-centers (bromine vacancy without and with trapped electrons) and their dimers; hole H-center (neutral bromine atom forming the dumbbell ion with a regular Br− ion.); VK-center (Br2− molecular ion consisting of a hole and two regular ions); and two complex Br3− defects, combinations of several simple defects. The local geometry and the charge- and spin-density distributions of all defects are analyzed. Every defect shows its characteristic features in Raman spectra, and their comparison with available experimental data is discussed.

Use of a collagen-elastin matrix with split-thickness skin graft for defect coverage in complex wounds.

Severe soft tissue damage with destruction of the dermis requires plastic reconstructive treatment. For multimorbid patients or patients unable to undergo major reconstructive surgery, use of dermal substitutes, such as a collagen-elastin matrix (CEM) with a split-thickness skin graft (STSG), instead of local or free flap surgery, may be a valid and easy treatment option. We aimed to investigate and compare the outcomes and rate of successful defect reconstruction using CEM plus STSG, using either a one-step approach (simultaneous CEM and STSG) or a two-step approach (CEM and negative wound pressure therapy (NPWT), with secondary STSG transplantation). A single-centre, retrospective follow-up study of patients who had received CEM was conducted. Wounds had been treated with an STSG transplantation covering a CEM (MatriDerm, MedSkin Solutions Dr. Suwelack AG, Germany). Previous attempts at wound closure with conventional methods had failed in the selected patient population, which would usually have resulted in flap surgery. Overall, 46 patients were included (mean age 60.9±20.0 years), with a total of 49 wound sites. We analysed 38 patients with wounds that did not require flap coverage; 18 patients received the one-step approach and 20 patients received the two-step approach. The mean follow-up in these patients was 22±11.5 months, and one patient was lost to follow-up. Overall, 29 (78.4%) wounds remained closed. Wounds which did not successfully heal were related to comorbidities, such as diabetes, alcohol misuse and smoking. Using the one-step approach, long-term defect coverage was achieved in 13 (76.5%) wounds and 16 (80.0%) wounds were closed using the two-step approach. However, there was no statistically significant differences between the one- or two-step approaches regarding the rate of development of a wound healing disorder. Wound closure was achieved in 38 complex wounds using CEM plus STSG, while 11 wounds needed secondary flap coverage. In the flap-free wounds, there were no statistically significant differences between the one-step versus two-step approach. Using a simple defect reconstruction algorithm, we successfully used CEM plus STSG to treat complex wounds.

A Simple and Effective Surface Defect Detection Method of Power Line Insulators for Difficult Small Objects

A Simple and Effective Surface Defect Detection Method of Power Line Insulators for Difficult Small Objects