Stability of Cesium-Based Lead Halide Perovskites under UV Radiation.

Lead halide perovskites have been extensively studied for their potential applications, including photodetectors, solar cells, and high-energy radiation detection. These applications are possible because of their unique optoelectronic properties, such as tunable band gap, high optical absorption coefficient, and unique defect self-healing properties, which result in high defect tolerance. Despite these advantages, the long-term stability remains a critical issue that could hinder commercial applications of these materials. Reports on the stability of lead halide perovskites for optoelectronic applications have normally focused on methylammonium (MA)/formamidinium (FA), with very limited information for other systems, in particular, Cs-containing perovskites. In this paper, we report the stability of thick CsPbBr3-x Cl x polycrystalline thin films (∼8 µm) with several halide Br-Cl ratios after exposure to deep UV radiation. The chemical, crystal structure, optical, and electrical properties are analyzed, and the results are used to propose a degradation mechanism. The chemical analysis on the surface and bulk of the films indicates the formation of cesium oxide after UV exposure, with no significant change in the crystalline structure. The proposed mechanism explains the formation of cesium oxides during UV exposure. The I-V characteristics of diode structures also showed significant degradation after UV exposure, primarily at lower diode rectification ratios. The mechanism proposed in this paper can contribute to developing strategies to enhance the long-term stability of inorganic lead halide perovskites under UV exposure.

Submucosal fat accumulation in Crohn's disease: evaluation with sonography.

BACKGROUND/AIMS: The study objective is to investigate the ultrasound features that allow suspecting the presence of submucosal fat deposition, called the fat halo sign (FHS), in the intestinal wall of patients with Crohn's disease. METHODS: Computed tomography (CT) examinations over a period of 10 years were reviewed for the presence of the FHS in the bowel wall. A measurement of less than -10 Hounsfield units was regarded as indicative of fat. We included only patients who had undergone ultrasound examinations 3 months before or after CT. The study cohort group comprised 68 patients. Wall and submucosal thickness were measured on longitudinal ultrasound sections. A receiver operating characteristic curve was constructed to determine the best cutoff of ultrasound submucosal wall thickness value for predicting FHS in the bowel wall determined on CT. RESULTS: The FHS was present in 22 patients (31%) on CT. There were significant differences between submucosal thickness of patients with FHS and patients without FHS (4.19 mm vs. 2.41 mm). From the receiver operating characteristic curve, a threshold value of 3.1 mm of submucosal thickness had the best sensitivity and specificity to suspect FHS (95.5% and 89.1%, respectively; area under the curve, 0.962), with an odds ratio of 172. All of 16 patients with a submucosal thickness >3.9 mm had FHS. CONCLUSIONS: FHS in patients with Crohn's disease can be suspected on ultrasound in cases with marked thickening of the submucosa layer. In these cases, the activity of the disease should be measured by other parameters such as the color Doppler.

Solid-State Neutron Detection Based on Methylammonium Lead Bromide Perovskite Single Crystals.

Perovskite-based semiconductors, such as methylammonium and cesium lead halides (MPbX3: M = CH3NH3+ or Cs+; X = I-, Br-, or Cl-), have attracted immense attention for several applications, including radiation detection, due to their excellent electronic and optical properties.1,2,3,4,5,6 In addition, the combination of perovskites with other materials enables unique device structures. For example, robust and reliable diodes result when combined with metal oxide semiconductors. This device can be used for detection of nonionizing and ionizing radiation. In this paper, we report a unique perovskite single-crystal-based neutron detector using a heterojunction diode based on single-crystal MAPbBr3 and gallium oxide (Ga2O3) thin film. The MAPbBr3/Ga2O3 diodes demonstrate a leakage current of ∼7 × 10-10 A/mm2, an on/off ratio of ∼102, an ideality factor of 1.41, and minimal hysteresis that enables alpha particle, gamma-ray, and neutron detection at a bias as low as (-5 V). Gamma discrimination is further improved by 85% by optimizing the thickness of the perovskite single crystal. The MAPbBr3/Ga2O3 diodes also demonstrate a neutron detection efficiency of ∼3.92% when combined with a 10B neutron conversion layer.

Ultrasound findings of Crohn's disease: correlation with MR enterography.

Crohn's disease is a chronic inflammatory bowel disease characterized by periods of relative inactivity alternating with acute flare-ups. Imaging techniques play a fundamental role in the diagnosis and follow-up of Crohn's disease, providing information on the extent of disease, disease activity, and the presence of extramural complications. Because of the frequent re-evaluation required by the relapsing nature of Crohn's disease and the relative young age at which most patients are diagnosed, techniques that use ionizing radiation are best avoided in monitoring this population. Thus, magnetic resonance enterography (MRE) and ultrasonography (US) are the preferable techniques. Various studies have demonstrated that US is accurate in assessing the gut. Despite some clear advantages over MRE, US has long been underused in the evaluation of intestinal disease. This review presents an overview of the main imaging findings in Crohn's disease, correlating representative US images with MRE and surgical pathology specimens. We conclude that US reliably depicts both bowel-related and mesenteric features of Crohn's disease and US findings correlate strongly with MRE findings.

Squamous cell carcinoma related with dental implants. A clinical cases report.

One third of all cases of head and neck carcinoma (CA) concern the oral mucosa. The use of dental implants (DI) for dental rehabilitation is widely extended. However, a few studies have reported some cases with neoplasic alterations, among the tissue surrounding implants. Our aim was to analyze possible alterations at the bone-implant interface in patients with oral squamous cell carcinoma (SCC), providing new evidence that could relate or discard a possible link between these factors. We used, for the first time, different techniques, including electron microscopy and histology, to analyze the implant ´s surface and the surrounding tissue from four clinical cases with neoplasic alterations surrounding DI. Histologically, ample inflammatory tissue was found in direct contact with the implant surface. Surface analysis of this tissue, revealed titanium percentages. According to our study, no oncological relation with deterioration of the implant surface was found, although DI were constantly related with peri-implantitis, a chronic trauma of the oral mucosa that could involve a neoplastic factor. Key words:Dental implants, carcinoma, peri-implantitis.

The Role of Intravenous Contrast Agent in the Sonographic Assessment of Crohn's Disease Activity: Is Contrast Agent Injection Necessary?

BACKGROUND AND AIMS: Contrast-enhanced ultrasound [CEUS] is reported to be superior to wall thickness or colour Doppler imaging [CDI] in predicting disease activity using endoscopy as the reference standard. Our aims were to determine in patients with Crohn's disease [CD] whether the evaluation of wall thickness or CDI before CEUS examination could help to decide when the injection of contrast agent is justified as a means for detecting disease activity as determined at endoscopy, without reducing the accuracy of ultrasound. METHODS: In total, 180 patients with CD underwent both colonoscopy and ultrasound, including mural thickness, CDI and CEUS evaluation, prospectively as part of clinical care. A receiver operating characteristic curve was constructed to determine the area under the curve and the best cutoff of wall thickness and ultrasound enhancement value to discriminate between endoscopically active and inactive disease. Several analyses were carried out to determine which parameter or combination of parameters best detected endoscopic activity. RESULTS: Comparative evaluation of the different analysis showed that wall thickness alone classified 76.6% of patients correctly, CDI alone 72.7%, and thickness plus CDI 72.2%. The use of CEUS significantly improved the diagnosis of active disease: CEUS alone correctly classified 164 of 180 patients [91.1%], combined analysis of CDI and CEUS 165 of 180 [91.7%], and combined analysis of thickness, CDI and CEUS 164 of 180 [91.1%], without significant differences. Patients with CDI grade 2 or 3 showed a predictive positive value of 97% to detect disease activity, similar to CEUS [100%]. CONCLUSION: CEUS is the most reliable ultrasound criterion for endoscopic disease activity. However, the use of a contrast agent is probably not justified to assess disease activity for patients with CDI grade 2/3.

Ultrasonographic Changes at 12 Weeks of Anti-TNF Drugs Predict 1-year Sonographic Response and Clinical Outcome in Crohn's Disease: A Multicenter Study.

BACKGROUND: The objective was to assess the long-term effect of biological treatment on transmural lesions of Crohn's disease evaluated with ultrasound, including contrast-enhanced ultrasound. METHODS: Fifty-one patients with active Crohn's disease were included in a prospective multicenter longitudinal study. All patients underwent a clinical assessment and sonographic examination at baseline, 12 weeks after treatment initiation, and after 1-year of treatment. Patients were clinically followed at least 2 years from inclusion until the end of the study. Ultrasonographic evaluation included bowel wall thickness, color Doppler grade, parietal enhancement, and presence of transmural complications or stenosis. Sonographic changes after treatment were classified as normalization, improvement, or lack of response. RESULTS: Improvement at 52 weeks was more frequent in patients with improvement at final of induction (12 weeks) compared with patients who did not improve (85% versus 28%; P < 0.0001). One-year sonographic evolution correlated with clinical response; 28 of the 29 (96.5%) patients with sonographic improvement at 52 weeks showed clinical remission or response. Patients without sonographic improvement at 52 weeks of treatment were more likely to have a change or intensification in medication or surgery (13/20, 65%) during the next year of follow-up than patients with improvement on the sonography (3/28, 11%). Stricturing behavior was the only sonographic feature associated to a negative predictive value of response (P = 0.0001). CONCLUSIONS: Sonographic response after 12 weeks of therapy is more pronounced and predicts 1-year sonographic response. Sonographic response at 1-year examination correlates with 1-year clinical response and is a predictor of further treatment's efficacy, 1-year or longer period of follow-up.

Usefulness of contrast-enhanced US in the diagnosis of acute gangrenous cholecystitis: A comparative study with surgical and pathological findings.

OBJECTIVE: To prospectively determine the usefulness of contrast-enhanced ultrasound (CEUS) in the diagnostic assessment of acute gangrenous cholecystitis, using histopathology as the reference method. MATERIAL & METHODS: The local institutional review board approved the study protocol, and all patients at enrollment provided a written informed consent. From December 2011 to July 2014, all patients with a clinical-sonographic diagnosis of acute cholecystitis underwent a CEUS examination. We included only patients who underwent cholecystectomies within 24-h of CEUS. Radiologists in the course of routine clinical care interpreted the US and CEUS images at the end of the examination, filling out a questionnaire. Two radiologists, blinded to the final diagnosis, independently reviewed the video CEUS sequences for the presence of defects of the gallbladder wall enhancement. Associations between the sonographic findings and histological gangrenous cholecystitis were evaluated by using univariate and multivariate logistic regression analysis. RESULTS: A total of 150 patients were analyzed. The histological diagnoses were 41 (27%) nongangrenous cholecystitis and 109 acute gangrenous cholecystitis (73%). Multivariate analysis of the predictive parameters at univariate analysis revealed that only leukocytosis, diabetes mellitus, lithiasis and defects of wall enhancement on CEUS were independent variables related to gangrenous cholecystitis. The presence of enhancement defects on CEUS enabled the diagnosis of the gangrenous form with sensitivity between 85 and 91% and specificity of 67.5-84.8%. Interobserver agreement for CEUS interpretation was good (median k value: 0.664; range, 0.655-0.680). CONCLUSION: Local or widespread absence of gallbladder wall enhancement on CEUS is associated with the presence of gangrenous acute cholecystitis.

Sigmoid stenosis caused by diverticulitis vs. carcinoma: usefulness of sonographic features for their differentiation in the emergency setting.

OBJECTIVE: To retrospectively evaluate the accuracy of ultrasound as a diagnostic method for differentiating acute diverticulitis from colon cancer in patients with sigmoid colon stenosis. MATERIALS AND METHODS: Ultrasound examinations of 91 consecutive patients with sigmoid stenosis (50 diverticulitis and 41 colon cancers) were reviewed by two trained radiologists. Sixty-five (71%) patients presented with acute abdominal symptoms. Thirteen sonographic criteria retrieved from the literature were evaluated to differentiate benign from malignant strictures. A score including all parameters which showed significant differences between benign vs. malignant was built. Sensitivity, specificity, accuracy, and positive or negative predictive values of each sonographic sign, the overall diagnosis, and sonographic score were calculated. RESULTS: Loss of the bowel wall stratification was the most reliable criteria for the diagnosis of malignancy (92% and 94% of sensitivity and specificity, respectively), and the best inter-radiologist agreement (κ = 0.848). Adjacent lymph nodes were the most specific feature (98%) for colon cancer, but its sensitivity was low. Global assessment could differentiate both diseases with high sensitivity (92-94.9%) and specificity (98-100%). Sonographic score >3 enabled differentiation of carcinoma from diverticulitis with 95% sensitivity and 92-94% specificity, with an area under the ROC curve of 0.98-0.987. There were no significant differences in the results between patients with acute and nonacute abdominal symptoms. CONCLUSION: The combination of several morphological sonographic findings using a score can differentiate most cases of diverticulitis from colon carcinoma in sigmoid strictures.

Effects of pH changes of stock normal saline solution on 5 percent red cell suspension.

The red cell suspension (RCS) is a universally used indicator system to demonstrate antigen and antibody reactions in vitro.Saline solutions that are used in its preparation are preferred to be fresh to avoid changes in pH that may affect the results. Thus,buffered saline such as phosphate-buffered saline (PBS) is the ideal diluent because its pH is maintained for a certain period. However,normal saline solution (NSS) is more commonly used because it is inexpensive and easy to make. pH changes in the saline solutions and the RCSs were monitored for 1 week. Macroscopic examination of changes in degree of redness of RCS was also observed. Red blood cell (RBC) indices of the ethylenediaminetetraacetic acid(EDT A)-anticoagulated blood used in the preparation of the RCS were measured in the performance of an automated complete blood count. Qualitative examination of the crenation of RBCs was done on the prepared blood smears and graded by three registered medical technologists. Percentage crenation was then determined using an improved Neubauer counting chamber. Three trials were performed, and results were averaged. Statistical analysis showed hat there were significant differences in the average pH of PBS and NSS and the average pH of RCS-PBS and RCS-NSS over 1 week. RBC indices measured in EDTA-anticoagulated donor blood showed no significant difference. Macroscopic examination of changes in degree of redness of the RCS showed that color darkened over 1 week but only by a small degree. Qualitative and quantitative examination of crenation of RBCs in RCS-PBS and RCS-NSS both showed no significant differences over 1 week. The experimental group (RCS-NSS) continuously showed a higher grade of crenation than the control group (RCS-PBS). Crenation of RBCs still manifests microscopically despite the lack of a significant relationship between the pH of the saline solutions and the degree and percentage of crenation. Crenation, therefore,cannot be attributed to pH alone but occurs as a result of other factors.

Nuevos lenguajes informáticos en la difusión de información sobre medicamentos / New computerized languages for information on drugs

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Consideraciones diagnósticas en la epilepsia benigna con puntas centro-temporales (rolándicas) / Diagnostic considerations in benign epilepsy with centro-temporal spikes (rolandic)

Se muestran las características electroclínicas de 10 pacientes con los criterios de la denominada epilepsia benigna con puntas centro-temporales (rolándicas). Se observan, en todos los pacientes, los ataques durante el sueño y predomina el ataque parcial motor localizado en la hemicara (60%). En el 70% de los pacientes las descargas se observan en los trazados de sueño. Se realiza una revisión de la literatura de esta entidad, se discuten los aspectos relacionados con el carácter supuestamente favorable y la respuesta terapéutica satisfactoria en estos pacientes

Consideraciones diagnósticas en la epilepsia benigna con puntas centro-temporales (rolándicas) / Diagnostic considerations in benign epilepsy with centro-temporal spikes (rolandic)

Se muestran las características electroclínicas de 10 pacientes con los criterios de la denominada epilepsia benigna con puntas centro-temporales (rolándicas). Se observan, en todos los pacientes, los ataques durante el sueño y predomina el ataque parcial motor localizado en la hemicara (60

). En el 70

de los pacientes las descargas se observan en los trazados de sueño. Se realiza una revisión de la literatura de esta entidad, se discuten los aspectos relacionados con el carácter supuestamente favorable y la respuesta terapéutica satisfactoria en estos pacientes (AU)