Impact of the COVID-19 Pandemic on Paediatrics Training in a Regional Victorian Hospital.

Aim: To evaluate the impact of COVID-19 on the clinical training of paediatric trainees during the pandemic at a regional hospital in Victoria, Australia. Methods: In response to a survey and feedback from paediatric trainees, a retrospective analysis was conducted to investigate the effects of the COVID-19 pandemic on medical staff attendance at onsite training in the Department of Paediatrics at a regional hospital in Victoria. The study spanned from January 2019 to December 2021. Variables collected included the number of participants attending the paediatric clinical and education meetings. A comparative analysis of attendance during the pre-COVID-19 year (2019) and the COVID-19 years (2020-2021) was conducted. Results: The total number of meetings held was 292 in 2019, which declined to 184 in 2020 and further declined to 171 in 2021, with a minimal increase in existing virtual meetings. The total attendance in paediatric clinical meetings dropped from 2190 attendees in 2019 to 1332 in 2020, and further declined to 1230 in 2021. Paediatric registrar attendance was 477 in 2019, which decreased by 29.35% to 330 in 2020 and further decreased by 38.57% to 293 in 2021. Paediatric hospital medical officer attendance showed the worst trend among paediatric trainees, with 445 attending clinical meetings in 2019 and decreasing by 50.78% to 219 in 2020 and a 52.58% decrease to 211 in 2021. Conclusion: The sudden outbreak of COVID-19 led to significant disruptions in medical education globally. This study showed a noticeable reduction in paediatric departmental clinical meetings and teaching sessions during the pandemic, as well as a significant decline in attendance by paediatric trainees and medical students. These findings confirm the experiences of paediatric trainees, who reported losing valuable teaching opportunities due to the pandemic and a demand for attention.

Performance of CBNAAT on Pleural Biopsies Obtained by Semirigid Thoracoscopy for Diagnosis of Unexplained Pleural Effusion: A Prospective Study from North India.

BACKGROUND: Exudative pleural effusions are commonly encountered in clinical practice, but in about one-fourth of cases, etiology remains elusive after initial evaluation. Medical thoracoscopy with semirigid thoracoscope is a minimally invasive procedure with high diagnostic yield for diagnosing pleural diseases, especially these undiagnosed exudative pleural effusions. In tubercular endemic areas, often, these effusions turn out to be tubercular, but the diagnosis of tubercular pleural effusion is quite challenging due to the paucibacillary nature of the disease. Although culture is the gold standard, it is time-consuming. Cartridge-based nucleic acid amplification test (CBNAAT) is a novel rapid diagnostic test for tuberculosis (TB) and has been recommended as the initial diagnostic test in patients suspected of having extrapulmonary TB (EPTB). MATERIALS AND METHODS: We conducted a prospective observational study of 50 patients with undiagnosed pleural effusion admitted to our tertiary care hospital. The primary aim of the study is to evaluate the diagnostic performance of CBNAAT on thoracoscopic guided pleural biopsy and compare it with conventional diagnostic techniques like histopathology and conventional culture. RESULTS: Of 50 undiagnosed pleural effusions, TB (50%) was the most common etiology. The overall diagnostic yield of semirigid thoracoscopy in this study was 74%. Our study showed that CBNAAT of pleural biopsies had a sensitivity of 36% only but a specificity of 100%. The sensitivity of CBNAAT was not far superior to the conventional culture. CONCLUSION: Tuberculosis (TB) is a common cause of undiagnosed pleural effusion in our set-up. CBNAAT testing of pleural biopsy, though, is a poor rule-out test for pleural TB, but it may aid in the early diagnosis of such patients.

Periorbital cellulitis as the initial presentation of acute lymphoblastic leukaemia.

A girl in early childhood with no significant medical history developed left eye periorbital oedema and erythema. She was treated with intravenous antibiotics for suspected severe periorbital cellulitis. Despite treatment, the patient's cellulitis progressed into necrotising fasciitis, and she was transferred for ophthalmology review and imaging. A CT scan and eye swab culture-confirmed Staphylococcus aureus periorbital cellulitis. Incidentally, pathology revealed significant pancytopenia suspicious of leukaemia. The patient underwent bone marrow biopsy and was diagnosed with B-cell acute lymphoblastic leukaemia (ALL). A multidisciplinary specialist assessment revealed no ocular evidence of leukaemia and no intraocular concerns. In medical literature, it is consistently found that cases of ALL initially manifesting as proptosis or eyelid oedema are invariably due to neoplastic infiltration. This case represents unique documentation where periorbital cellulitis is the initial presentation of B-cell ALL, underscoring the necessity to consider periorbital cellulitis as a possible differential diagnosis in ophthalmic manifestations of ALL.

Solvothermal synthesis of TiO2nanospheres for non-volatile memory and synaptic learning applications.

In this study, we used the one-pot solvothermal method to synthesize the TiO2nanospheres (NSs) and used them for non-volatile memory and neuromorphic computing applications. Several analytical tools were used to understand the structural, optical, morphological, and compositional characteristics of synthesized TiO2NSs. The tetragonal crystal structure of anatase TiO2was formed, according to the Rietveld refined x-ray diffraction results. The NS morphology was confirmed by field emission scanning electron microscopy and transmission electron microscopy images. X-ray photoelectron spectroscopy was probed to understand the elemental composition and electronic states of the TiO2NSs. We specifically looked at the impact of reaction time on the structural, optical, morphological, compositional, and resistive switching (RS) properties of TiO2NSs. The fabricated devices (Ag/TiO2NSs/FTO) exhibit bipolar RS behavior. The optimized RS device shows good endurance (5000 cycles) and memory retention (5000 s) properties. Moreover, fabricated devices showed double-valued charge-flux characteristics, whereas charge transport was caused by the Ohmic and space charge-limited current mechanisms. Additionally, the optimized device can mimic various synaptic characteristics including potentiation-depression, excitatory post-synaptic current, and paired-pulse facilitation.

Cancer in Kashmir Valley: Current trends, burden and pattern.

BACKGROUND: There is an overall surge of malignancies in most of the developing countries including India. Dearth of data from Kashmir prompted us to embark upon a study on burden and pattern of cancer in Kashmir over previous 5 years. METHODS: Data acquisition from January 2016 to December 2020 was accomplished from the departmental archives of a large tertiary care institute of Kashmir valley. All histologically proven malignant cases were included for the present study. Information regarding the age, gender, site of primary malignancy and histological diagnosis was obtained. RESULTS: A total of 5,392 cases of malignancies were considered for final analysis with a mean age at diagnosis of 56.73 years (SD = 15.96). Maximum number of cases were recorded in the age group of 60-69 years. Maximum number of malignancies were encountered in year 2018 with substantial drop in subsequent years. Gastrointestinal malignancies constitute more than one-third of total number of malignancies across both genders. In males, stomach was the common site of malignancy followed by lung and colorectal region whereas in females most common sites were breast, colorectal, and stomach. CONCLUSION: This study portrays close reflection of the cancer patterns within the valley in recent years which is strikingly different from rest of the country and world.

Eco-friendly MA3Bi2I9perovskite thin films based ammonia sensor.

Organic-inorganic perovskite halides (OIPH) have emerged as a wonder material with growing interest in sensors detecting various toxic gases. However, lead toxicity represents a potential obstacle, and therefore finding lead-free cost-effective compatible materials for gas sensing applications is essential. In this work, methylammonium bismuth iodide i.e. (CH3NH3)3Bi2I9(MABI) perovskite thin films-based ammonia (NH3) sensor was synthesized using an antisolvent-assisted one-step spin coating method. The MABI sensor shows a linear relationship between the responsivity and concentration of NH3with excellent reversibility, high gas responsivity, and humidity stability. The MABI thin-film sensor exhibits a maximum gas response of 24%, a short response/recovery time i.e. 0.14 s /8.15 s and good reversibility at 6 ppm of NH3. It was observed that MABI thin films based sensors have excellent ambient stability over a couple of months. This work reveals that it is feasible to design high-performance gas sensors based on environmentally-friendly Bi-based OIPH materials.

Articular 18Fluorodeoxyglucose Uptake Is Associated With Clinically Assessed Swollen Joint Count in Patients With Rheumatoid Arthritis.

OBJECTIVE: Examination and conventional radiography of joints are unable to precisely evaluate and measure disease activity in rheumatoid arthritis (RA). We quantified joint inflammation using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in people with RA to determine if PET-derived uptake variables were correlated with RA disease activity measures. METHODS: We cross-sectionally studied 34 patients with RA in a substudy of the Rheumatoid Arthritis Study of the Myocardium (RHYTHM). All patients underwent 18F-FDG-PET scanning with CT for attenuation correction and anatomic co-registration. Linear regression was used to model the associations of disease activity scores with articular FDG uptake, calculated as standardized uptake values (SUVs). Weighted joint volume SUVs (wjSUV) representing 25%, 50%, 75%, and maximum (100%) uptake (wj25SUV, wj50SUV, wj75SUV, and wjMaxSUV, respectively) were calculated as global variables of the total volume of joint inflammation in each patient. RESULTS: Calculated wj25SUV (Spearman ρ = 0.39, P = 0.04), wj50SUV (ρ = 0.39, P = 0.04), and wj75SUV (ρ = 0.37, P = 0.045) measures were significantly correlated with the number of swollen joints. Similar significant correlations were found for the Simplified Disease Activity Index but not Clinical Disease Activity or Disease Activity Score in 28 joints. No associations were found between articular FDG uptake and nonarticular RA-related variables (ie, disease duration, seropositivity, or RA treatments). CONCLUSION: Articular FDG uptake in patients with RA was significantly correlated with the number of swollen joints but not with biochemical measures of inflammation.

Predictors of Prolonged Hospital Stay in Patients with Acute Pulmonary Thromboembolism- A Hospital Based Cohort Study.

AIMS AND OBJECTIVES: Patients with pulmonary thromboembolism (PTE) are commonly admitted to hospital and generally have a prolonged hospital stay in this part of the world. We aimed to determine different clinical and laboratory parameters that are associated with prolonged hospital stay in our set-up and to analyse effectiveness of Pulmonary Embolism Severity Index (PESI) score as a predictor of prolonged hospital stay in patients with PTE. MATERIALS AND METHODS: It was a hospital based observational prospective study. Confirmed cases of PTE defined as patients with evidence of thrombus on CT pulmonary angiogram (CTPA) were included in this study. Depending on the length of hospital stay, patients were divided into two cohorts: Shorter Hospital stay (less than mean i.e., < 10 Days) and Prolonged Hospital stay (longer than mean i.e., ≥ 10 Days). Logistic regression analysis was done to identify predictors of prolonged hospital stay. RESULTS: 150 patients were included in the study with 67 patients (44.67%) having shorter hospital stay (<10 days) and 83 patients (55.33%) having prolonged hospital stay (≥10 days). On multivariate regression analysis, parameters that were found to be statistically significant were hypotension at presentation, decreased level of consciousness, pco2 < 30 mmHg, presence of S1Q3T3 pattern on electrocardiogram (ECG) and high risk PESI (class III-V). CONCLUSION: PESI class can be effectively used to predict prolonged hospital stay in patients with pulmonary embolism. Patients with hypotension at presentation, decreased level of consciousness, pco2 less than 30 mmHg, and S1Q3T3 on ECG are more likely to have prolonged hospital stay in our healthcare setup.

Clinical experience of tocilizumab treatment among a cohort of patients with COVID-19 infection from Western India.

Background: Initiation of tocilizumab (TCZ) treatment in patients with coronavirus disease 2019 (COVID-19) during the early phases of cytokine storm is crucial. This study evaluated the clinical experience of TCZ use in the treatment of patients with COVID-19. Methods: This retrospective observational study included patients (>18 years) with confirmed COVID19 treated with TCZ alone/in combination with other drugs. Data related to demographics, clinical characteristics, radiological parameters, oxygen/ventilator/vasopressor support, treatment parameters, laboratory investigations pre- and post-TCZ treatment, and clinical outcomes were retrieved from medical records. Results: Out of 95 patients (mean age, 55 years), 68.4% and 31.6% of patients had moderate and severe COVID-19 disease, respectively. The mean time to TCZ administration from symptom onset was 8.7 days. At the time of admission, the mean oxygen saturation (SpO2) was 90.4% and mean concentration of fraction of inspired oxygen (FiO2) was 80.6%. The most commonly received dose of TCZ was 400 mg (84.2%) intravenously. The mean concentration of FiO2 and SpO2 improved significantly during the treatment (P < 0.001) compared to before TCZ initiation. The change in median levels of C-reactive protein (CRP) from baseline to post-treatment (63.0 vs. 4.5 mg/dL; P < 0.001) was significant. Post TCZ treatment, 73.6% of patients improved; whereas 26.4% of patients died. Acute respiratory distress syndrome (23.2%) and elevated transaminases (12.6%) were the most commonly reported adverse events. Conclusion: Tocilizumab administration during earlier phase of cytokine storm syndrome leads to reversal of abnormal SpO2 and FiO2 concentrations to normal levels and rapid decline of elevated CRP levels in patients with COVID-19.

Phase I trial of docetaxel plus lutetium-177-labeled anti-prostate-specific membrane antigen monoclonal antibody J591 (177Lu-J591) for metastatic castration-resistant prostate cancer.

BACKGROUND: Docetaxel remains a standard of care for metatsatic castration resistant porstate cancer (mCRPC) and has radiosensitizing properties. The dose limiting toxicity (DLT) of radioimmunotherapy is myelosuppression; dose fractionation of 177Lu-J591 allows similar administered doses with less toxicity. This study (NCT00916123) was designed to determine the safety, DLT, and maximum tolerated dose of fractionated 177Lu-J591 administered concurrently with standard docetaxel. METHODS: Men with progressive mCRPC received docetaxel 75 mg/m2 every 3 weeks with escalating 2 fractionated doses of 177Lu-J591 (1.48 GBq/m2 up to max of 2.96 GBq/m2) with cycle 3. Cycle 4 of docetaxel was planned 6 weeks after cycle 3 to allow for recovery from 177Lu-J591-associated hematologic toxicity. DLT was defined as delay in docetaxel >3 weeks, prolonged myelosuppression or need for >2 platelet transfusions, febrile neutropenia, or grade ≥3 nonhematological toxicity following 177Lu-J591. PSA was assessed prior to each cycle and serial computed tomography (CT) and bone scan were performed. RESULTS: Fifteen men with progressive mCRPC received dose-escalated targeted radionuclide therapy in 4 cohorts up to the highest planned dose (2.96 GBq/m2). No DLT was seen at any dose level. Grade 4 neutropenia without fever occurred in 8 (53.5%) and thromboytopenia in 2 (13.3%), with 2 receiving prophylactic platelet transfusion. No grade ≥3 nonhematological toxicity was observed. 11 (73.3%) had >50% PSA decline, with 78.6% having favorable circulating tumor cell counts after 177Lu-J591. All patients had targeting of known sites of disease by planar 177Lu-J591 imaging. CONCLUSION: The combination of 177Lu-J591 delivered as a single fractionated cycle with docetaxel/prednisone is feasible in patients with mCRPC. Without preselection for prostate-specific membrane antigen, accurate targeting of known sites of disease and a strong preliminary efficacy signal was observed.

Screening of vitamin D and calcium concentrations in neonates of mothers at high risk of vitamin D deficiency.

OBJECTIVE: The aim of this study was to determine, retrospectively, the serum 25OHD and calcium concentrations of screened neonates of mothers at high risk of 25OHD deficiency and examine whether their measurement contributes to the management of these neonates. METHODS: Serum 25OHD and calcium concentrations from 600 samples of umbilical cord blood or venous blood collected from neonates over a 12-month period were analysed. RESULTS: There was a high prevalence of vitamin D insufficiency (27.6%, 30-50 nmol/L) and deficiency (21.3%, < 30 nmol/L) in neonates from high-risk maternal groups. There was a statistically positive but weak correlation (ρ = 0.22, P < 0.0001) between 25OHD and serum calcium. Only 7 neonates out of 569 (1.2%) had calcium concentrations in the hypocalcaemic range; however, a significant number (47.6%) were reported to be in the hypercalcaemic range. Nearly all of these were venous samples collected in first 24 h after birth. CONCLUSION: Vitamin D deficiency is prevalent in neonates of high-risk mothers but the risk of hypocalcaemia due to vitamin D deficiency at birth is low. Screening neonates entails blood testing which can cause distress to neonates and their parents, substantial imposition on staff and financial burden on the health care system. Vitamin D supplementation of these neonates from birth without routine screening appears more reasonable. Also, the data from this study suggest that the paediatric reference range for corrected calcium concentrations in neonates should be re-evaluated.

Pilot Study of [18F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET)/Magnetic Resonance Imaging (MRI) for Staging of Muscle-invasive Bladder Cancer (MIBC).

INTRODUCTION: Computed tomography (CT) has limited diagnostic accuracy for staging of muscle-invasive bladder cancer (MIBC). [18F] Fluorodeoxyglucose positron emission tomography (FDG-PET)/magnetic resonance imaging (MRI) is a novel imaging modality incorporating functional imaging with improved soft tissue characterization. This pilot study evaluated the use of preoperative FDG-PET/MRI for staging of MIBC. PATIENTS AND METHODS: Twenty-one patients with MIBC with planned radical cystectomy were enrolled. Two teams of radiologists reviewed FDG-PET/MRI scans to determine: (1) presence of primary bladder tumor; and (2) lymph node involvement and distant metastases. FDG-PET/MRI was compared with cystectomy pathology and computed tomography (CT). RESULTS: Eighteen patients were included in the final analysis, most (72.2%) of whom received neoadjuvant chemotherapy. Final pathology revealed 10 (56%) patients with muscle invasion and only 3 (17%) patients with lymph node involvement. Clustered analysis of FDG-PET/MRI radiology team reads revealed a sensitivity of 0.80 and a specificity of 0.56 for detection of the primary tumor with a sensitivity of 0 and a specificity of 1.00 for detection of lymph node involvement when compared with cystectomy pathology. CT imaging demonstrated similar rates in evaluation of the primary tumor (sensitivity, 0.91; specificity, 0.43) and lymph node involvement (sensitivity, 0; specificity, 0.93) when compared with pathology. CONCLUSIONS: This pilot single-institution experience of FDG-PET/MRI for preoperative staging of MIBC performed similar to CT for the detection of the primary tumor; however, the determination of lymph node status was limited by few patients with true pathologic lymph node involvement. Further studies are needed to evaluate the potential role for FDG-PET/MRI in the staging of MIBC.

Donor glucose-6-phosphate dehydrogenase deficiency decreases blood quality for transfusion.

BACKGROUNDGlucose-6-phosphate dehydrogenase (G6PD) deficiency decreases the ability of red blood cells (RBCs) to withstand oxidative stress. Refrigerated storage of RBCs induces oxidative stress. We hypothesized that G6PD-deficient donor RBCs would have inferior storage quality for transfusion as compared with G6PD-normal RBCs.METHODSMale volunteers were screened for G6PD deficiency; 27 control and 10 G6PD-deficient volunteers each donated 1 RBC unit. After 42 days of refrigerated storage, autologous 51-chromium 24-hour posttransfusion RBC recovery (PTR) studies were performed. Metabolomics analyses of these RBC units were also performed.RESULTSThe mean 24-hour PTR for G6PD-deficient subjects was 78.5% ± 8.4% (mean ± SD), which was significantly lower than that for G6PD-normal RBCs (85.3% ± 3.2%; P = 0.0009). None of the G6PD-normal volunteers (0/27) and 3 G6PD-deficient volunteers (3/10) had PTR results below 75%, a key FDA acceptability criterion for stored donor RBCs. As expected, fresh G6PD-deficient RBCs demonstrated defects in the oxidative phase of the pentose phosphate pathway. During refrigerated storage, G6PD-deficient RBCs demonstrated increased glycolysis, impaired glutathione homeostasis, and increased purine oxidation, as compared with G6PD-normal RBCs. In addition, there were significant correlations between PTR and specific metabolites in these pathways.CONCLUSIONBased on current FDA criteria, RBCs from G6PD-deficient donors would not meet the requirements for storage quality. Metabolomics assessment identified markers of PTR and G6PD deficiency (e.g., pyruvate/lactate ratios), along with potential compensatory pathways that could be leveraged to ameliorate the metabolic needs of G6PD-deficient RBCs.TRIAL REGISTRATIONClinicalTrials.gov NCT04081272.FUNDINGThe Harold Amos Medical Faculty Development Program, Robert Wood Johnson Foundation grant 71590, the National Blood Foundation, NIH grant UL1 TR000040, the Webb-Waring Early Career Award 2017 by the Boettcher Foundation, and National Heart, Lung, and Blood Institute grants R01HL14644 and R01HL148151.

In2O3 nanocapsules for rapid photodegradation of crystal violet dye under sunlight.

We report, a shape controlled novel synthesis of Indium oxide (In2O3) nanocapsule using biogenic reflux method. The In2O3 samples were obtained through optimization of the concentration of sodium citrate, which played a significant role to tune the size of nanocapsules. All synthesized In2O3 samples were characterized by using X-ray diffraction (XRD), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The morphological study reflects the effect of sodium citrate on the size of nanocapsules and confirms the formation of nanocapsules in the range of 50 nm. Furthermore, the photocatalytic activity of In2O3 nanocapsules based photocatalyst was carried out for the degradation of Crystal Violet (CV) dye under natural sunlight illumination. The experiment revealed that the In2O3 nanocapsule efficiently degrades 90% of CV within 180 min. This effort recommends the synthesis of In2O3 nanocapsule based photocatalyst for rapid degradation of CV under natural sunlight illumination.

A threshold-based method to predict thyroid nodules on scintigraphy scans.

Nuclear Medicine imaging is an important modality to follow up abnormalities of thyroid function tests and to uncover and characterize thyroid nodules either de novo or as previously seen on other imaging modalities, namely ultrasound. In general, the hypofunctioning 'cold' nodules pose a higher malignancy potential than hyperfunctioning 'hot' nodules, for which the risk is <1%. Hot nodules are detected by the radiologist as a region of focal increased radiotracer uptake, which appears as a density of pixels that is higher than surrounding normal thyroid parenchyma. Similarly, cold nodules show decreased density of pixels, corresponding to their decreased uptake of radiotracer, and are photopenic. Partly because Nuclear Medicine images have poor resolution, these density variations can sometimes be subtle, and a second reader computer-aided detection (CAD) scheme that can highlight hot/cold nodules has the potential to reduce false negatives by bringing the radiologists' attention to the occasional overlooked nodules. Our approach subdivides thyroid images into small regions and employs a set of pixel density cutoffs, marking regions that fulfill density criteria. Thresholding is a fundamental tool in image processing. In nuclear medicine, scroll bars to adjust standardized uptake value cutoffs are already in wide commercial use in PET/CT display systems. A similar system could be used for planar thyroid images, whereby the user varies threshold and highlights suspect regions after an initial reader survey of the images. We hypothesized that a thresholding approach would accurately detect both hot and cold thyroid nodules relative to expert readers. Analyzing 22 nodules, half of them hot and the other half cold, we found good agreement between highlighted candidate nodules and the consensus selections of two expert readers, with nonzero overlap between expert and CAD selections in all cases.

Update on Serum Glucose and Metabolic Management of Clinical Nuclear Medicine Studies: Current Status and Proposed Future Directions.

Management of a patient's blood glucose or metabolism in nuclear medicine studies has become an integral aspect of daily work primarily due to the increasing use of F-18 flurodeoxyglucose (FDG) positron emission tomography (PET). Newer tracers such as F-18 Fluciclovine and C-11 Choline, are in theory subject to metabolic shifts and changes based on patients' insulin levels, and also require attention to achieving optimum patient preparation. Metabolic derangements can also affect other studies, such as gastric emptying (GE), the results of which are dependent upon the patient's blood glucose level during the time of imaging. The growing variety of diabetic medications has increased the complexity of the instructions which need to be given to patients. Current guidelines for patient preparation were developed in the past and have only slowly evolved with the introduction of newer oral medications. In addition to older insulin formulations newer formulations with different profiles of onset, duration, and consistency of action are being used. The wide spectrum of newer drugs now in use for treating diabetes has not been accompanied by any updated consensus on how to manage these drugs for imaging studies which require blood glucose level management. In this article we review these newer diabetes medications primarily to raise awareness of the changing landscape. Our focus will be on suggestions to optimize patient preparation and management for these studies. For each scenario, our suggestions will be given as summary proposals for best patient management. Our hope is that this discussion will stimulate multicenter studies to provide data to support new practice guidelines for metabolically dependent nuclear medicine procedures.

Overcoming the Ambient Manufacturability-Scalability-Performance Bottleneck in Colloidal Quantum Dot Photovoltaics.

Colloidal quantum dot (CQD) solar cells have risen rapidly in performance; however, their low-cost fabrication under realistic ambient conditions remains elusive. This study uncovers that humid environments curtail the power conversion efficiency (PCE) of solar cells by preventing the needed oxygen doping of the hole transporter during ambient fabrication. A simple oxygen-doping step enabling ambient manufacturing irrespective of seasonal humidity variations is devised. Solar cells with PCE > 10% are printed under high humidity at industrially viable speeds. The devices use a tiny fraction of the ink typically needed and are air stable over a year. The humidity-resilient fabrication of efficient CQD solar cells breaks a long-standing compromise, which should accelerate commercialization.

Effects of High Temperature and Thermal Cycling on the Performance of Perovskite Solar Cells: Acceleration of Charge Recombination and Deterioration of Charge Extraction.

In this work, we investigated the effects of high operating temperature and thermal cycling on the photovoltaic (PV) performance of perovskite solar cells (PSCs) with a typical mesostructured (m)-TiO2-CH3NH3PbI3-xClx-spiro-OMeTAD architecture. After temperature-dependent grazing-incidence wide-angle X-ray scattering, in situ X-ray diffraction, and optical absorption experiments were carried out, the thermal durability of PSCs was tested by subjecting the devices to repetitive heating to 70 °C and cooling to room temperature (20 °C). An unexpected regenerative effect was observed after the first thermal cycle; the average power conversion efficiency (PCE) increased by approximately 10% in reference to the as-prepared device. This increase of PCE was attributed to the heating-induced improvement of the crystallinity and p doping in the hole transporter, spiro-OMeTAD, which promotes the efficient extraction of photogenerated carriers. However, further thermal cycles produced a detrimental effect on the PV performance of PSCs, with the short-circuit current and fill factor degrading faster than the open-circuit voltage. Similarly, the PV performance of PSCs degraded at high operation temperatures; both the short-circuit current and open-circuit voltage decreased with increasing temperature, but the temperature-dependent trend of the fill factor was the opposite. Our impedance spectroscopy analysis revealed a monotonous increase of the charge-transfer resistance and a concurrent decrease of the charge-recombination resistance with increasing temperature, indicating a high recombination of charge carriers. Our results revealed that both thermal cycling and high temperatures produce irreversible detrimental effects on the PSC performance because of the deteriorated interfacial photocarrier extraction. The present findings suggest that the development of robust charge transporters and proper interface engineering are critical for the deployment of perovskite PVs in harsh thermal environments.

Hybrid tandem quantum dot/organic photovoltaic cells with complementary near infrared absorption.

Monolithically integrated hybrid tandem solar cells that effectively combine solution-processed colloidal quantum dot (CQD) and organic bulk heterojunction subcells to achieve tandem performance that surpasses the individual subcell efficiencies have not been demonstrated to date. In this work, we demonstrate hybrid tandem cells with a low bandgap PbS CQD subcell harvesting the visible and near-infrared photons and a polymer:fullerene-poly (diketopyrrolopyrrole-terthiophene) (PDPP3T):[6,6]-phenyl-C60-butyric acid methyl ester (PC61BM)-top cell absorbing effectively the red and near-infrared photons of the solar spectrum in a complementary fashion. The two subcells are connected in series via an interconnecting layer (ICL) composed of a metal oxide layer, a conjugated polyelectrolyte, and an ultrathin layer of Au. The ultrathin layer of Au forms nano-islands in the ICL, reducing the series resistance, increasing the shunt resistance, and enhancing the device fill-factor. The hybrid tandems reach a power conversion efficiency (PCE) of 7.9%, significantly higher than the PCE of the corresponding individual single cells, representing one of the highest efficiencies reported to date for hybrid tandem solar cells based on CQD and polymer subcells.

Zika Virus-Associated Cognitive Impairment in Adolescent, 2016.

Incidence of neurologic manifestations associated with Zika virus infection has been increasing. In 2016, neuropsychological and cognitive changes developed in an adolescent after travel to a Zika virus-endemic area. Single-photon emission computed tomography and neuropsychological testing raised the possibility that Zika virus infection may lead to neuropsychiatric and cognitive symptoms.