Tailoring Single-Mode Random Lasing of Tin Halide Perovskites Integrated in a Vertical Cavity.

The development of random lasing (RL) with predictable and controlled properties is an important step to make these cheap optical sources stable and reliable. However, the design of tailored RL characteristics (emission energy, threshold, number of modes) is only obtained with complex photonic structures, while the simplest optical configurations able to tune the RL are still a challenge. This work demonstrates the tuning of the RL characteristics in spin-coated and inkjet-printed tin-based perovskites integrated into a vertical cavity with low quality factor. When the cavity mode is resonant with the photoluminescence (PL) peak energy, standard vertical lasing is observed. More importantly, single mode RL operation with the lowest threshold and a quality factor as high as 1 000 (twenty times the quality factor of the resonator) is obtained if the cavity mode lies above the PL peak energy due to higher gain. These results can have important technological implications toward the development of low-cost RL sources without chaotic behavior.

Large-Area, Flexible, Lead-Free Sn-Perovskite Solar Modules.

For the first time, large-area, flexible organic-inorganic tin perovskite solar modules are fabricated by means of an industry-compatible and scalable blade-coating technique. An 8-cell interconnected mini module with dimensions of 25 cm2 (active area = 8 × 1.5 cm2) reached 5.7% power conversion efficiency under 1000 W/m2 (AM 1.5G) and 9.4% under 2000 lx (white-LED).

Synchronous colon cancer presenting as toxic megacolon in a patient with ulcerative colitis: A case report.

INTRODUCTION AND IMPORTANCE: The incidence of colorectal cancer in patients with inflammatory bowel disease is greater than the general population. Of those with inflammatory bowel disease, synchronous cancers are more common in ulcerative colitis than in Crohn's disease. It is rare for synchronous cancer to present as toxic megacolon in a patient with concomitant inflammatory bowel disease, specifically ulcerative colitis. CASE PRESENTATION: In this report, we describe the clinical presentation of a 22-year-old female, who presented with toxic megacolon ultimately requiring total abdominal colectomy with end-ileostomy and a final pathology of two synchronous colon cancers, despite normal colonoscopy one year prior. The postoperative period was unremarkable, and the patient was referred to medical oncology to pursue adjuvant treatment. CLINICAL DISCUSSION: Due to the increased incidence of colorectal cancer in patients with ulcerative colitis, screening colonoscopies are typically recommended at more frequent intervals than the general population. Toxic megacolon as the presentation for colon cancer in patients with underlying ulcerative colitis is exceedingly rare. To our knowledge, this is the first case reported of synchronous colon cancer presenting as toxic megacolon in a patient with ulcerative colitis and recent negative screening colonoscopy. CONCLUSION: Colorectal cancer should always be high in the differential diagnosis for patients with ulcerative colitis regardless of the age. The principles of oncologic resection for colorectal cancer should be followed during colonic resections in patients with ulcerative colitis, even in the acute setting.

Effects of atmospheric low-level jets on the mixing process of a large tropical reservoir.

Changes in the physical and biogeochemical properties of water columns are frequently associated with cold fronts and mesoscale convective systems due to increased cloud cover. The effects of low-level jet (LLJ) events on thermal stratification and water quality, however, remain undescribed, particularly for tropical reservoirs. Here, water temperature time series are combined with meteorological data, LIDAR observations, ERA5 reanalysis data, and hydrodynamical modeling to investigate the impact of an event of LLJ over the Furnas hydropower reservoir in Brazil. The LLJ event was characterized by dry, intense, and persistent winds (~10 m s-1) blowing for more than 12 hours over the main fetch of the reservoir. In the downwind side of the lake, the surface mixed layer depth increased by 50% during the LLJ event. The changes to the water column were produced by a combination of wind-induced upwelling, shear-driven mixing, and nocturnal convective overturning, different from the heat balance expected during passing cold fronts and mesoscale convective systems. The results suggest that both momentum and heat fluxes during LLJ events need to be accounted for in lake modelings to reproduce the vertical mixing process.

Vascular Myelopathies.

There are many vascular disorders that can affect the spinal cord, and their prevalence and etiology are highly influenced by age, sex, and risk factors. This article reviews the embryology and anatomy of the spinal cord, as well as several vascular conditions, describing their clinical and imaging presentation, emphasizing the different imaging modalities' contributions to increasing specificity and better defining the most appropriate therapy strategy for improving the patient's prognosis.

Imaging Aspects of Toxic and Metabolic Myelopathies.

Metabolic and toxic myelopathies usually occurs due to several different causes. Metabolic myelopathy usually occurs due to deficiency of a nutrient, such as vitamin B12. Toxic myelopathy occurs secondary to the exposure to an external toxic agent. Although they may have a difficult diagnosis, determination of the specific cause of myelopathy is of utmost importance, because many causes are amenable to treatment. Although they have many clinical, electrophysiologic, and neuropathologic similarities, imaging may aid in the suspicion of toxic or metabolic myelopathy. The aim of this article, is to review the imaging features of the main toxic and metabolic myelopathies.

Robotic versus laparoscopic colectomy outcomes in colon adenocarcinoma in the elderly population: a propensity-score matched analysis of the National Cancer Database.

PURPOSE: While robotic surgery is more costly and involves longer intra-operative time, it has a technical advantage over laparoscopic surgery. With our aging population, patients are being diagnosed with colon cancer at older ages. The aim of this study is to compare laparoscopic versus robotic colectomy short- and long-term outcomes in elderly patients diagnosed with colon cancer at a national level. METHODS: This retrospective cohort study was conducted using the National Cancer Database. Subjects ≥ 80-years-old who were diagnosed with stage I to III colon adenocarcinoma and underwent a robotic or laparoscopic colectomy from 2010-2018 were included. The laparoscopic group was propensity-score matched in a 3:1 ratio to the robotic group with 9343 laparoscopic and 3116 robotic cases matched. The main outcomes evaluated were 30-day mortality, 30-day readmission rate, median survival, and length of stay. RESULTS: There was no significant difference in the 30-day readmission rate (OR = 1.1, CI = 0.94-1.29, p = 0.23) or 30-day mortality rate (OR = 1.05, CI = 0.86-1.28, p = 0.63) between both groups. Robotic surgery was associated with higher overall survival (42 vs 44.7 months, p < 0.001) using a Kaplan-Meier survival curve. Robotic surgery had a statistically significant shorter length of stay (6.4 vs. 5.9 days, p < 0.001). CONCLUSION: Robotic colectomies are associated with higher median survival rates and decrease in the length of hospital stay compared to laparoscopic colectomies in the elderly population.

Does race influence the attainment of the principles of oncologic surgical resection in colon adenocarcinoma? A retrospective cohort analysis from the national cancer database.

The standard operation for colon cancer resection should follow certain principles to ensure appropriate oncologic resection, such as retrieving 12 or more nodes with the specimen and adequate surgical margins. Although these principles are well documented, there is little evidence regarding the association of race and the attainment of an adequate oncologic resection. Methods: The authors performed a retrospective cohort study of all cases of resectable colon adenocarcinoma who underwent surgical resection in the National Cancer Database between 2004 and 2018. The postoperative lymph node count and margins were grouped as 'principles of oncologic surgical resection'. A multivariate logistic regression analysis was performed to assess race and other demographic variables as independent factors influencing the attainment of the principles of oncologic resection. Results: A total of 456 746 cases were included. From this cohort, 377 344 (82.6%) achieved an adequate oncologic resection and 79 402 (17.4%) did not. On logistic regression, African American and Native American patients were less likely to attain an adequate oncologic resection. Similarly, patients with an elevated Charlson-Deyo score (2 or above), stage I cancer, and patients who underwent extended resection were less likely to achieve adequate oncologic resection. Resections performed in metropolitan areas, patients with private insurance, high-income quartiles, and patients diagnosed in more recent years were more likely to achieve adequate oncologic resection. Conclusions: There are significant racial disparities regarding the attainment of the principles of oncologic resection in colon cancer, which could be explained by unconscious biases, social discrepancies, and inadequate healthcare access. Early introduction and conscientization of unconscious biases are required in surgical training.

Colo-cutaneous fistula to the thigh secondary to acute sigmoid diverticulitis: a case report.

Acute diverticulitis is one of the most common gastrointestinal illnesses that requires hospital admission. It has a broad range of presentations from uncomplicated disease to perforation and peritonitis that require emergent surgical exploration. Abscesses are one of the most common complications. We present a case of retroperitoneal abscess with extension to the antero-lateral upper thigh that was successfully treated with open Hartman's procedure with drainage of psoas abscess and open drainage of thigh abscess.

Intracranial vessel wall magnetic resonance imaging features of infectious vasculitis.

Vasculitis is a complication of several infectious diseases affecting the central nervous system, which may result in ischemic and/or hemorrhagic stroke, transient ischemic attack, and aneurysm formation. The infectious agent may directly infect the endothelium, causing vasculitis, or indirectly affect the vessel wall through an immunological mechanism. The clinical manifestations of these complications usually overlap with those of non-infectious vascular diseases, making diagnosis challenging. Intracranial vessel wall magnetic resonance imaging (VWI) enables the evaluation of the vessel wall and the diseases that affect it, providing diagnostic data beyond luminal changes and enabling the identification of inflammatory changes in cerebral vasculitis. This technique demonstrates concentric vessel wall thickening and gadolinium enhancement, associated or not with adjacent brain parenchymal enhancement, in patients with vasculitis of any origin. It permits the detection of early alterations, even before a stenosis occurs. In this article, we review the intracranial vessel wall imaging features of infectious vasculitis of bacterial, viral, and fungal etiologies.

Metastatic pancreatic adenocarcinoma presenting as large bowel obstruction: A case report.

INTRODUCTION AND IMPORTANCE: The incidence of pancreatic cancer has gradually increased over the past decades. Metastatic pancreatic cancer to the colon is rare with only seven cases reported. Symptomatic metastasis to the colon as the initial presentation of pancreatic adenocarcinoma has only been reported in two occasions prior to this report. CASE PRESENTATION: In this report, the diagnosis and operative management of a 78-year-old male who presented with three days of obstipation and computed tomography evidence of an annular obstructing mass in the sigmoid colon in addition to a pancreatic body and lesser sac mass involving the gastric antral region. The patient underwent a laparoscopic sigmoidectomy with end colostomy. Pathology revealed metastatic adenocarcinoma of pancreatic origin. The postoperative period was unremarkable, and the patient was referred to medical oncology to pursue further treatment. CLINICAL DISCUSSION: Symptomatic metastasis to the colon as the initial presentation of pancreatic adenocarcinoma is exceedingly rare. To our knowledge, this is the 3rd case to be reported and the second that was located in the sigmoid colon. CONCLUSION: The presentation of metastatic pancreatic cancer to the colon causing a colonic obstruction is rare but should be considered in cases of atypical synchronic masses in cross-sectional imaging. When metastatic disease is suspected in the sigmoid colon, it is advisable to perform a colostomy instead of an anastomosis to avoid the potential risk of anastomotic leak that could delay the immediate need for systemic therapy.

Arterial Spin Labeling: Techniques, Clinical Applications, and Interpretation.

Arterial spin labeling (ASL) is an emerging noninvasive MRI technique for assessing cerebral perfusion. An important advantage of ASL perfusion is the lack of a requirement for an exogenous tracer. ASL uses magnetically labeled water protons from arterial blood as an endogenous diffusible tracer. For this reason, ASL is an attractive perfusion imaging modality for children and for patients with contraindications or adverse reactions to gadolinium, patients with renal failure, and those who need repeated follow-up imaging. Another advantage of ASL is the possibility of quantifying cerebral blood flow, which provides an opportunity for comparative analysis among multiple longitudinal studies, unlike other MR perfusion techniques, which are semiquantitative and yield relative perfusion parameters. Advances in MRI technology and pulse sequence design have translated ASL beyond the research arena to successful clinical implementation. However, ASL is still underused in routine clinical practice. Some disadvantages of ASL include a lower signal-to-noise ratio and a longer acquisition time than those with dynamic susceptibility contrast-enhanced MRI. Additional factors limiting the use of ASL include variations in existing techniques and pulse sequence design, the complexity of implementation and postprocessing, insufficient experience with and/or knowledge of the potential clinical applications, and the absence of interpretation guidelines. The authors review the technical and physiologic basis of ASL perfusion, as well as artifacts, pitfalls, and its current clinical applications. A practical approach for interpreting ASL findings is also suggested.

Ischemic stroke with unknown onset of symptoms: current scenario and perspectives for the future.

BACKGROUND: Stroke is a major cause of disability worldwide and a neurological emergency. Intravenous thrombolysis and mechanical thrombectomy are effective in the reperfusion of the parenchyma in distress, but the impossibility to determine the exact time of onset was an important cause of exclusion from treatment until a few years ago. OBJECTIVES: To review the clinical and radiological profile of patients with unknown-onset stroke, the imaging methods to guide the reperfusion treatment, and suggest a protocol for the therapeutic approach. METHODS: The different imaging methods were grouped according to current evidence-based treatments. RESULTS: Most studies found no difference between the clinical and imaging characteristics of patients with wake-up stroke and known-onset stroke, suggesting that the ictus, in the first group, occurs just prior to awakening. Regarding the treatment of patients with unknown-onset stroke, four main phase-three trials stand out: WAKE-UP and EXTEND for intravenous thrombolysis, and DAWN and DEFUSE-3 for mechanical thrombectomy. The length of the therapeutic window is based on the diffusion weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch, core-penumbra mismatch, and clinical core mismatch paradigms. The challenges to approach unknown-onset stroke involve extending the length of the time window, the reproducibility of real-world imaging modalities, and the discovery of new methods and therapies for this condition. CONCLUSION: The advance in the possibilities for the treatment of ischemic stroke, while guided by imaging concepts, has become evident. New studies in this field are essential and needed to structure the health care services for this new scenario.

ANTECEDENTES: O acidente vascular cerebral (AVC) é uma das principais causas de incapacidade em todo o mundo, e uma emergência neurológica. A trombólise intravenosa e a trombectomia mecânica são eficazes na reperfusão do parênquima em sofrimento, mas a impossibilidade de determinar o tempo exato de início era uma causa importante de exclusão ao tratamento até alguns anos atrás. OBJETIVOS: Revisar o perfil clínico-radiológico dos pacientes com AVC de tempo indeterminado, os métodos de imagem para guiar o tratamento de reperfusão, e sugerir um protocolo para a abordagem terapêutica. MéTODOS: Os diferentes métodos de imagem foram agrupados de acordo com os tratamentos atuais baseados em evidências. RESULTADOS: A maioria dos estudos não encontrou diferença entre as características clínicas e de imagem dos pacientes com AVC reconhecido ao despertar e AVC de tempo definido, o que sugere que o icto, no primeiro grupo, ocorre próximo ao acordar. Quanto ao tratamento do AVC de tempo indeterminado, quatro grandes estudos na fase três sobressaem: WAKE-UP e EXTEND para trombólise intravenosa, e DAWN e DEFUSE-3 para trombectomia mecânica. A ampliação da janela terapêutica fundamenta-se nos paradigmas de incompatibilidade da imagem ponderada de difusão­recuperação da inversão atenuada por fluidos (diffusion weighted imaging­fluid-attenuated inversion recovery, DWI-FLAIR, em inglês), do núcleo isquêmico e penumbra, e clínico-radiológico. Os desafios na abordagem do AVC de tempo indeterminado envolvem a ampliação da janela terapêutica, a reprodutibilidade das modalidades de imagem no mundo real, e a identificação de novos métodos e tratamentos para essa condição. CONCLUSãO: É evidente o avanço nas possibilidades de tratamento do AVC isquêmico guiado pelos conceitos de imagem. Novos estudos nesse campo são essenciais, com necessidade de estruturar os serviços de saúde para esse novo cenário.

Ischemic stroke with unknown onset of symptoms: current scenario and perspectives for the future / Acidente vascular cerebral isquêmico com tempo indeterminado de início dos sintomas: cenário atual e perspectivas para o futuro

Abstract Background Stroke is a major cause of disability worldwide and a neurological emergency. Intravenous thrombolysis and mechanical thrombectomy are effective in the reperfusion of the parenchyma in distress, but the impossibility to determine the exact time of onset was an important cause of exclusion from treatment until a few years ago. Objectives To review the clinical and radiological profile of patients with unknown-onset stroke, the imaging methods to guide the reperfusion treatment, and suggest a protocol for the therapeutic approach. Methods The different imaging methods were grouped according to current evidence-based treatments. Results Most studies found no difference between the clinical and imaging characteristics of patients with wake-up stroke and known-onset stroke, suggesting that the ictus, in the first group, occurs just prior to awakening. Regarding the treatment of patients with unknown-onset stroke, four main phase-three trials stand out: WAKE-UP and EXTEND for intravenous thrombolysis, and DAWN and DEFUSE-3 for mechanical thrombectomy. The length of the therapeutic window is based on the diffusion weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch, core-penumbra mismatch, and clinical core mismatch paradigms. The challenges to approach unknown-onset stroke involve extending the length of the time window, the reproducibility of real-world imaging modalities, and the discovery of new methods and therapies for this condition. Conclusion The advance in the possibilities for the treatment of ischemic stroke, while guided by imaging concepts, has become evident. New studies in this field are essential and needed to structure the health care services for this new scenario.

Resumo Antecedentes O acidente vascular cerebral (AVC) é uma das principais causas de incapacidade em todo o mundo, e uma emergência neurológica. A trombólise intravenosa e a trombectomia mecânica são eficazes na reperfusão do parênquima em sofrimento, mas a impossibilidade de determinar o tempo exato de início era uma causa importante de exclusão ao tratamento até alguns anos atrás. Objetivos Revisar o perfil clínico-radiológico dos pacientes com AVC de tempo indeterminado, os métodos de imagem para guiar o tratamento de reperfusão, e sugerir um protocolo para a abordagem terapêutica. Métodos Os diferentes métodos de imagem foram agrupados de acordo com os tratamentos atuais baseados em evidências. Resultados A maioria dos estudos não encontrou diferença entre as características clínicas e de imagem dos pacientes com AVC reconhecido ao despertar e AVC de tempo definido, o que sugere que o icto, no primeiro grupo, ocorre próximo ao acordar. Quanto ao tratamento do AVC de tempo indeterminado, quatro grandes estudos na fase três sobressaem: WAKE-UP e EXTEND para trombólise intravenosa, e DAWN e DEFUSE-3 para trombectomia mecânica. A ampliação da janela terapêutica fundamenta-se nos paradigmas de incompatibilidade da imagem ponderada de difusão-recuperação da inversão atenuada por fluidos (diffusion weighted imaging-fluid-attenuated inversion recovery, DWI-FLAIR, em inglês), do núcleo isquêmico e penumbra, e clínico-radiológico. Os desafios na abordagem do AVC de tempo indeterminado envolvem a ampliação da janela terapêutica, a reprodutibilidade das modalidades de imagem no mundo real, e a identificação de novos métodos e tratamentos para essa condição. Conclusão É evidente o avanço nas possibilidades de tratamento do AVC isquêmico guiado pelos conceitos de imagem. Novos estudos nesse campo são essenciais, com necessidade de estruturar os serviços de saúde para esse novo cenário.

Robotic-assisted extraction of giant gastric trichobezoar: a case report.

Trichobezoar is a rare condition, almost exclusively seen in young females with certain psychiatric disorders. Trichobezoars are usually confined within the stomach and the complications include ulceration, perforation, intussusception and obstruction for which surgery is usually required. Most of the reported cases of giant gastric trichobezoar extraction underwent an exploratory laparotomy with only a few reported cases that underwent a successful laparoscopic approach. This case report details the surgical management of the first case of a giant obstructing gastric trichobezoar extraction using robotic-assisted surgery.