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We show that the wide-band gap compound semiconductors ZnO, ZnS, and CdS feature large photoplastic and photoelastic effects that are mediated by point defects. We measure the mechanical properties of ceramics and single crystals using nanoindentation, and we find that elasticity and plasticity vary strongly with moderate illumination. For instance, the elastic stiffness of ZnO can increase by greater than 40% due to blue illumination of intensity 1.4 mW/cm^{2}. Above-band-gap illumination (e.g., uv light) has the strongest effect, and the relative effect of subband gap illumination varies between samples-a clear sign of defect-mediated processes. We show giant optomechanical effects can be tuned by materials processing, and that processing dependence can be understood within a framework of point defect equilibrium. The photoplastic effect can be understood by a long-established theory of charged dislocation motion. The photoelastic effect requires a new theoretical framework which we present using density functional theory to study the effect of point defect ionization on local lattice structure and elastic tensors. Our results update the longstanding but lesser-studied field of semiconductor optomechanics, and suggest interesting applications.

Highlighted by the discovery of high-temperature superconductivity, strongly correlated oxides with highly distorted perovskite structures serve as intriguing model systems for pursuing emerging materials physics and testing technological concepts. While 3d correlated oxides with a distorted perovskite structure are not uncommon, their 4d counterparts are unfortunately rare. In this work, we report the tuning of the electrical and optical properties of a quasi-2D perovskite niobate CsBiNb2O7 via hydrogenation. It is observed that hydrogenation induces drastic changes of lattice dynamics, optical transmission, and conductance. It is suggested that changing the orbital occupancy of Nb d orbitals could trigger the on-site Coulomb interaction in the NbO6 octahedron. The observed hydrogen doping-induced electrical plasticity is implemented for simulating neural synaptic activity. Our finding sheds light on the role of hydrogen in 4d transition metal oxides and suggests a new avenue for the design and development of novel electronic phases.

We report an electrically reconfigurable metasurface platform based on optical phase change materials. Multi-cycle reversible switching is realized using conductive micro-heaters. Large-contrast spectral tuning and beam-steering are demonstrated.

The coronavirus disease 2019 (COVID-19) pandemic has had significant implications for society, with the introduction of restrictive social measures. Antibody tests provide a way of identifying patients who have been previously exposed to the virus and thus may have a degree of immunity. This is important in the development of public health policy, as local and national bodies seek to relax social restrictions in an attempt to mitigate the socioeconomic impact of the pandemic. This article explores the essential statistical concepts used to interpret the findings of diagnostic investigations, with examples illustrated using COVID-19 antibody tests.

The timing of carotid endarterectomy (CEA) for symptomatic ipsilateral carotid artery stenosis has evolved in practice over time. Key landmark trials outlined the benefit of performing CEA in the recently symptomatic carotid artery stenosis, defined as revascularisation within 6 months of the index neurological event. Further evidence and sub-analysis demonstrate that performing CEA within 2 weeks of symptoms has the maximal benefit in reducing stroke free survival and is associated with a safe perioperative complication profile. This has translated into guideline recommendations and widespread clinical practice. The case for performing urgent CEA (within 48 hours of index neurological event) over early CEA (within 2 weeks) has been put forward and studied. Data examining perioperative complications for urgent CEA are mostly derived from retrospective single series studies. A moderate balance exists in the literature for the safety and risk of urgent CEA. Although many studies present acceptable perioperative stroke and mortality rates associated with urgent CEA, evidence still exists that the perioperative complications may not be insignificant. This is particularly the case if the presenting neurology is a stroke, rather than a transient ischaemic attack (TIA) or amaurosis fugax. This should be contextualised in the practice of modern aggressive medical therapy with dual antiplatelets and statins, with evidence suggesting a reduction in recurrent ischaemic events prior to surgical intervention. Careful patient selection, presenting neurology and medical therapy is likely to be a key feature in considering urgent CEA versus early CEA.

Active metasurfaces promise reconfigurable optics with drastically improved compactness, ruggedness, manufacturability, and functionality compared to their traditional bulk counterparts. Optical phase change materials (O-PCMs) offer an appealing material solution for active metasurface devices with their large index contrast and nonvolatile switching characteristics. Here we report what we believe to be the first electrically reconfigurable nonvolatile metasurfaces based on O-PCMs. The O-PCM alloy used in the devices, Ge2Sb2Se4Te1 (GSST), uniquely combines giant non-volatile index modulation capability, broadband low optical loss, and a large reversible switching volume, enabling significantly enhanced light-matter interactions within the active O-PCM medium. Capitalizing on these favorable attributes, we demonstrated continuously tunable active metasurfaces with record half-octave spectral tuning range and large optical contrast of over 400%. We further prototyped a polarization-insensitive phase-gradient metasurface to realize dynamic optical beam steering., 12 pages, 5 figures

Amid the global COVID-19 pandemic, adaptation of healthcare systems, with strong medical leadership, has been integral to coping with the ever-changing situation. This article is based on the personal experiences of doctors in the NHS and insights into the frontline response to this situation. It reflects on leadership dilemmas and strategies implemented to overcome them, with a focus on systems thinking and adaptive leadership.

Graphical Abstract This online structured survey has demonstrated the global impact of the COVID-19 pandemic on vascular services. The majority of centres have documented marked reductions in operating and services provided to vascular patients. In the months during recovery from the resource restrictions imposed during the pandemic peaks, there will be a significant vascular disease burden awaiting surgeons. Graphical Abstract One of the most affected specialties

Inayat Hussain Khan, Azhar Ramzan BilalFaculty of Medicine, St George’s Hospital Medical School, London, UKWe read this article by Khurana et al1 with great interest. It is encouraging to see astudy which explored how adherence in patients with Type 2 Diabetes mellituscould potentially be improved.Diabetes is a condition affecting an increasing number of people and themacrovascular and microvascular changes are damaging to long term health,predisposing to vascular events such as heart attacks and strokes.2Adherence to treatment plans is essential for good glycaemic control and toprevent such complications. A study found that effective communication betweendoctors and patients is key to ensuring adherence to individual treatment plans butof course this does not always take place.3 This current study1 evaluated howtechnology can help to bridge this gap in the management of chronic conditionslike diabetes where treatment is lifelong and complex. Khurana et al1 showed thatthere is an appetite amongst patients for better use of technology to help managechronic conditions; more than 80% of the participants surveyed in this studywere interested in using electronic methods to assist them in managing theirdiabetes.Read the original article byKhurana and collegueshere.&nbsp

Azhar-Ramzan Bilal, Zishan Naeem, Zain NisarFaculty of Medicine, St George’s Hospital Medical School, London, UK Undergraduate teaching represents a significant change in education style for individuals,presenting a challenge to preclinical medical students. Based on this, we weregreatly interested in the study conducted by Parashar et al regarding the assessment oflearning styles of medical students in India in the era of digitization.1 Pertinently, theauthors identified most students possessed multimodal learning styles, with auditoryand kinesthetic being most common. As medical students within the UK, we wouldlike to offer our perspective through discussing the applicability of authors recommendationsto the contemporary medical school in the UK. View the original paper byParashar and colleagues.

AIMS: To investigate whether aneurysm shape and extent, which indicate whether a patient with ruptured abdominal aortic aneurysm (rAAA) is eligible for endovascular repair (EVAR), influence the outcome of both EVAR and open surgical repair.METHODS AND RESULTS: The influence of six morphological parameters (maximum aortic diameter, aneurysm neck diameter, length and conicality, proximal neck angle, and maximum common iliac diameter) on mortality and reinterventions within 30 days was investigated in rAAA patients randomized before morphological assessment in the Immediate Management of the Patient with Rupture: Open Versus Endovascular strategies (IMPROVE) trial. Patients with a proven diagnosis of rAAA, who underwent repair and had their admission computerized tomography scan submitted to the core laboratory, were included. Among 458 patients (364 men, mean age 76 years), who had either EVAR (n = 177) or open repair (n = 281) started, there were 155 deaths and 88 re-interventions within 30 days of randomization analysed according to a pre-specified plan. The mean maximum aortic diameter was 8.6 cm. There were no substantial correlations between the six morphological variables. Aneurysm neck length was shorter in those undergoing open repair (vs. EVAR). Aneurysm neck length (mean 23.3, SD 16.1 mm) was inversely associated with mortality for open repair and overall: adjusted OR 0.72 (95% CI 0.57, 0.92) for each 16 mm (SD) increase in length. There were no convincing associations of morphological parameters with reinterventions.CONCLUSION: Short aneurysm necks adversely influence mortality after open repair of rAAA and preclude conventional EVAR. This may help explain why observational studies, but not randomized trials, have shown an early survival benefit for EVAR.CLINICAL TRIAL REGISTRATION: ISRCTN 48334791.

Background Small bowel obstruction is a common surgical emergency, and is associated with high levels of morbidity and mortality across the world. The literature provides little information on the conservatively managed group. The aim of this study was to describe the burden of small bowel obstruction in the UK. Methods This prospective cohort study was conducted in 131 acute hospitals in the UK between January and April 2017, delivered by trainee research collaboratives. Adult patients with a diagnosis of mechanical small bowel obstruction were included. The primary outcome was in‐hospital mortality. Secondary outcomes included complications, unplanned intensive care admission and readmission within 30 days of discharge. Practice measures, including use of radiological investigations, water soluble contrast, operative and nutritional interventions, were collected. Results Of 2341 patients identified, 693 (29·6 per cent) underwent immediate surgery (within 24 h of admission), 500 (21·4 per cent) had delayed surgery after initial conservative management, and 1148 (49·0 per cent) were managed non‐operatively. The mortality rate was 6·6 per cent (6·4 per cent for non‐operative management, 6·8 per cent for immediate surgery, 6·8 per cent for delayed surgery; P = 0·911). The major complication rate was 14·4 per cent overall, affecting 19·0 per cent in the immediate surgery, 23·6 per cent in the delayed surgery and 7·7 per cent in the non‐operative management groups (P < 0·001). Cox regression found hernia or malignant aetiology and malnutrition to be associated with higher rates of death. Malignant aetiology, operative intervention, acute kidney injury and malnutrition were associated with increased risk of major complication. Conclusion Small bowel obstruction represents a significant healthcare burden. Patient‐level factors such as timing of surgery, acute kidney injury and nutritional status are factors that might be modified to improve outcomes. © 2019 The Authors. BJS Open published by John Wiley & Sons Ltd on behalf of BJS Society Ltd This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Purpose: To describe the imaging characteristics of the Nellix Endovascular Aneurysm Sealing (EVAS) System on serial computed tomography (CT) surveillance. Methods: Sixty-eight patients undergoing EVAS were enrolled in a surveillance protocol that included CT scans prior to hospital discharge and at 3, 6, and 9 months postoperatively. Images were analyzed for the presence of gas within the endobag, endoleak, and for maximum radiodensity measured in Hounsfield units (HU) within the uppermost, middle, and lowermost regions of each endobag. Results: Gas was seen within the endobags of all 68 EVAS repairs at the first postoperative CT compared with 2 (5.6%) of 36 undergoing the 3-month scan. The endobags appeared radiodense during initial imaging, and the median (interquartile range) radiodensity of the Nellix polymer decreased from 158.3 HU (149.5; 169.5) at the postoperative CT to 81.0 HU (74.0; 88.0) at 3 months, excluding 3 cases in which contrast pre-fill was utilized. Type I endoleak was seen at the periphery of the aneurysm sac or in the cleft between the endobags, with a substantially different appearance to endoleak after endovascular aneurysm repair. Conclusion: The evolution of CT appearances after EVAS was characteristic and predictable. The device endobags were initially radiodense, which may impact the detection of endoleak within 3 months of EVAS. Endoleaks after EVAS were seen in a different anatomical area to endoleaks after conventional stent-graft repair.

Highlights • Spontaneous splenic rupture should be considered in patients presenting with peritonism without preceding trauma. • Haematological and infectious causes, including Varicella Zoster, should be sought when investigating spontaneous splenic rupture. • There is limited published guidance regarding the surgical options when faced with spontaneous splenic rupture., Introduction Here we present a case of atraumatic splenic rupture secondary to varicella infection requiring emergency splenectomy. The presentation was as would be expected for epstein barr virus (EBV) related splenic injury, which is well documented in the literature. Dermatological findings however suggested varicella zoster, and viral serology subsequently confirmed the diagnosis. Presentation of case A young Romanian male presented to the emergency department with peritonism without preceding trauma. Free fluid on USS was aspirated as frank blood and cross-sectional imaging demonstrated a ruptured spleen. He underwent emergency splenectomy and recovered well. During his presentation he was noted to have an erythematous rash with different rates of evolution raising the suspicion for Varicella Zoster. This was subsequently confirmed on viral serology. Discussion A number of precedents have been identified for spontaneous splenic rupture, however Varicella Zoster has only been reported a handful of times. A number of surgical options are available for splenic rupture, and guidelines exist for traumatic splenic injury. There is limited guidance on the most effective surgical management for spontaneous splenic ruptures with haemodyamic compromise. Conclusion Atraumatic splenic rupture should be considered as an important differential in those presenting with abdominal pain and peritonism without a history of preceding trauma. Haematological and infectious diagnoses should be sought to identify causation for the splenic rupture.

ObjectiveThe aim of this study was to assess the nutritional status of patients presenting with small bowel obstruction (SBO), along with associated nutritional interventions and clinical outcomes.DesignProspective cohort study.Setting131 UK hospitals with acute surgical services.Participants2069 adult patients with a diagnosis of SBO were included in this study. The mean age was 67.0 years and 54.7% were female.Primary and secondary outcome measuresPrimary outcome was in-hospital mortality. Secondary outcomes recorded included: major complications (composite of in-hospital mortality, reoperation, unplanned intensive care admission and 30-day readmission), complications arising from surgery (anastomotic leak, wound dehiscence), infection (pneumonia, surgical site infection, intra-abdominal infection, urinary tract infection, venous catheter infection), cardiac complications, venous thromboembolism and delirium.ResultsPostoperative adhesions were the most common cause of SBO (49.1%). Early surgery (ConclusionsMalnutrition on admission is associated with worse outcomes in patients with SBO, and marked variation in management of malnutrition was observed. Future trials should focus on identifying effective and cost-effective nutritional interventions in SBO.

Introduction Rupture of an abdominal aortic aneurysm (rAAA) carries a considerable mortality rate and is often fatal. rAAA can be treated through open or endovascular surgical intervention and it is possible that more rapid access to definitive intervention might be a key aspect of improving mortality for rAAA. Diagnosis is not always straightforward with up to 42% of rAAA initially misdiagnosed, introducing potentially harmful delay. There is a need for an effective clinical decision support tool for accurate prehospital diagnosis and triage to enable transfer to an appropriate centre. Methods and analysis Prospective multicentre observational study assessing the diagnostic accuracy of a prehospital smartphone triage tool for detection of rAAA. The study will be conducted across London in conjunction with London Ambulance Service (LAS). A logistic score predicting the risk of rAAA by assessing ten key parameters was developed and retrospectively validated through logistic regression analysis of ambulance records and Hospital Episode Statistics data for 2200 patients from 2005 to 2010. The triage tool is integrated into a secure mobile app for major smartphone platforms. Key parameters collected from the app will be retrospectively matched with final hospital discharge diagnosis for each patient encounter. The primary outcome is to assess the sensitivity, specificity and positive predictive value of the rAAA triage tool logistic score in prospective use as a mob app for prehospital ambulance clinicians. Data collection started in November 2014 and the study will recruit a minimum of 1150 non-consecutive patients over a time period of 2 years. Ethics and dissemination Full ethical approval has been gained for this study. The results of this study will be disseminated in peer-reviewed publications, and international/national presentations. Trial registration number CPMS 16459; pre-results.

The chromium(III) nitrito complex trans-Cr(cyclam)(ONO)(2)(+) (1) is a very promising photochemical precursor for nitric oxide delivery to physiological targets. Here, we demonstrate that visible wavelength excitation of 1 in solutions containing thiol reductants such as the biological antioxidant glutathione (GSH) leads to permanent reaction even under anaerobic conditions, resulting in high quantum yield NO release. The nitric oxide formed under such conditions is sufficient, even at muM concentrations of 1 and using a low-intensity light source, to activate the enzyme soluble guanylyl cyclase (sGC). We also demonstrate that photolysis of 1 in the nM concentration range with a portable blue LED leads to vasorelaxation of porcine coronary arterial rings, a process also attributed to the NO activation of sGC.

UVB (Ultra-violet B) radiation is one of the major etiological factors in various dermal pathology viz. dermatitis, actinic folliculitis, solar urticaria, psoriasis and cancer among many others. UVB causes toxic manifestation in tissues by inciting inflammatory and tumor promoting events. We have designed this study to assess the anti-inflammatory and anti-tumor promotion effect of Wedelolactone (WDL) a specific IKK inhibitor. Results indicate significant restoration of anti-oxidative enzymes due to WDL treatments. We also found that WDL was effective in mitigating inflammatory markers consisting of MPO (myeloperoxidase), Mast cells trafficking, Langerhans cells suppression and COX 2 expression up regulation due to UVB exposure. We also deduce that WDL presented a promising intervention in attenuating early tumor promotion events caused by UVB exposure as indicated by the results of ODC (Ornithine Decarboxylase), Thymidine assay, Vimentin and VEGF (Vascular-endothelial growth factor) expression. This study was able to provide substantial cues for the therapeutic ability of Wedelolactone against inflammatory and tumor promoting events in murine skin depicting plausible role of NFkB pathway.

Autosomal dominant polycystic disease is a multisystem inherited condition affecting the kidneys and is an important cause of end-stage renal disease. Patients with autosomal dominant polycystic disease experience symptoms related to size and cystic nature of their kidneys, which can be difficult to manage. Traditionally, the only surgical option for management was open bilateral/unilateral native nephrectomy, which carried with it significant morbidity and mortality. Therefore, it was deemed unsafe and rarely performed. However, surgery for autosomal dominant polycystic disease has evolved rapidly with the advent of minimally invasive surgery and improved medical management of end-stage renal failure patients. Laparoscopic and hand-assisted laparoscopic techniques have been adopted and have demonstrated reduced morbidity. The timing of this intervention in relation to transplant is controversial and presents a major challenge in managing this patient population.

Advances in transplantation led to the first renal autotransplant in 1963 performed due to high ureteral injury sustained during aortic surgery. The procedure involves excision of the kidney and autologous re-implantation. Subsequently, multiple cases of renal autotransplantation have been reported in the literature for a range of indications. This reviews aims to assess the literature and experiences reported to assess the varying indications for renal autotransplant. The evidence and literature generated from experiences in this procedure are largely limited to case reports and relatively small or moderately sized case series. The main indications reported for performing autotransplant broadly includes renovascular disease, ureteral pathology and neoplastic disease. The advent of laparoscopic techniques and their implications on renal autotransplant also are discussed. Varying degrees of success are reported with this procedure with controversial issues surrounding this procedure remain, particularly in the area of neoplastic surgery. Renal autotransplant may be a useful last resort in preventing kidney loss in highly selected circumstances and when conventional methods have failed.

The use of Collaborative Filtering is becoming very popular in designing a simple yet efficient recommender system. A recommender system based on Collaborative Filtering basically predicts a user's interest in some item on the basis of the scores generated and the correlation calculated between the users. In this paper we propose a basic structure and steps of designing a recommender system that uses Collaborative Filtering (user based) along with applications of partitioning and clustering of data, thus designing a Restaurant Recommender System. The proposed system reduces the complexity and gives a clear view of the basic approach to build a recommender system from scratch.

Deterioration in renal function has been described after endovascular repair of abdominal aortic aneurysms (EVRs). The etiology is multifactorial and represents an important therapeutic target. A need exists to quantitatively summarize incidence and severity of renal dysfunction after EVR to allow better-informed attempts to preserve renal function and improve life expectancy. Here a systematic search was performed using Medline and Embase for renal function after EVR applying PRISMA statements. Univariate and multivariate random-effects meta-analyses were performed to estimate pooled postoperative changes in serum creatinine and creatinine clearance at four time points after EVR. Clinically relevant deterioration in renal function was also estimated at 1 year or more after EVR. Pooled probability of clinically relevant deterioration in renal function at 1 year or more was 18% (95% confidence interval of 14–23%, I 2 of 82.5%). Serum creatinine increased after EVR by 0.05 mg/dl at 30 days/1 month, 0.09 mg/dl at 1 month to 1 year, and 0.11 mg/dl at 1 year or more (all significant). Creatinine clearance decreased after EVR by 5.65 ml/min at 1 month–1 year and by 6.58 ml/min at 1 year or more (both significant). Thus, renal dysfunction after EVR is common and merits attention.

Experimental and density functional theory (DFT) studies are described that are focused on outlining the reactivity of the known photochemical nitric oxide precursor trans-Cr(cyclam)(ONO)(2)(+) ("CrONO", cyclam = 1,4,8,11-tetrazacycltetradecane). Studies in both aerated and deaerated aqueous media are described as are the roles of both the oxidant O(2) and a reductant such as glutathione in trapping the apparent Cr(IV) photoreaction intermediate trans-Cr(cyclam)(O)(ONO)(+). Also reported and characterized structurally is the Cr(V) product of long-term photolysis in the absence of reducing agents, the trans-dioxo species [trans-Cr(cyclam)(O)(2)](ClO(4)). Photosensitization experiments indicate that at least a significant fraction of the reaction occurs from the lowest energy doublet excited state(s). Lastly, cell culture experiments demonstrate that CrONO has little or no acute toxicity either before or after photolysis.

studies, as well as a formal meta-analysis. Primary outcomes were graft patency and wound infection. Secondary outcomes were overall wound complications, length of stay and cost-effectiveness. Results: 19 studies were reviewed, with evidence of considerable heterogeneity. Meta-analysis revealed a significantly reduced rate of primary patency in EVH (HR 1.294, 95% CI 1.027-1.630), with no significant difference with respect to wound infection (OR 0.972 95% CI 0.9311.014). Conclusions: EVH reduces primary patency rates after LEAB, but did not demonstrate a clear advantage with respect to wound complications. However the available data are heterogeneous and uncertainty is introduced by both evolution in technology and increasing technical experience. EVH should be used with caution and in the context of formal research.

To quantitatively summarize the incidence of misdiagnosis of ruptured abdominal aortic aneurysms (rAAA), the most common presenting features, and the commonest incorrect differential diagnoses.A systematic search according to PRISMA guidelines was performed using EMBASE and MEDLINE databases to identify studies reporting the initial rate of misdiagnosis of patients with rAAA. Random-effects meta-analyses were performed to estimate the rate of misdiagnosis, presenting features, and commonest differential diagnoses. A sensitivity analysis was performed for studies reporting after 1990.Nine studies comprising 1109 patients contributed to the pooled analysis, which found a 42% incidence of rAAA misdiagnosis (95% CI 29% to 55%). In studies reporting after 1990, misdiagnosis was seen in 32% (95% CI 16% to 49%). The most common erroneous differential diagnoses were ureteric colic and myocardial infarction. Abdominal pain, shock, and a pulsatile mass were presenting features in 61% (49%-72%), 46% (32%-61%), and 45% (29%-62%) of rAAAs, respectively.The rate of misdiagnosis of rAAA has remained consistent over time and is concerning. There is a need for an effective clinical decision tool to enable accurate diagnosis and triage at the scene of the emergency.