Medical X-ray imaging procedures require digital flat detectors operating at low doses to reduce radiation health risks. Solution-processed organic-inorganic hybrid perovskites have characteristics ...that make them good candidates for the photoconductive layer of such sensitive detectors. However, such detectors have not yet been built on thin-film transistor arrays because it has been difficult to prepare thick perovskite films (more than a few hundred micrometres) over large areas (a detector is typically 50 centimetres by 50 centimetres). We report here an all-solution-based (in contrast to conventional vacuum processing) synthetic route to producing printable polycrystalline perovskites with sharply faceted large grains having morphologies and optoelectronic properties comparable to those of single crystals. High sensitivities of up to 11 microcoulombs per air KERMA of milligray per square centimetre (μC mGy
cm
) are achieved under irradiation with a 100-kilovolt bremsstrahlung source, which are at least one order of magnitude higher than the sensitivities achieved with currently used amorphous selenium or thallium-doped cesium iodide detectors. We demonstrate X-ray imaging in a conventional thin-film transistor substrate by embedding an 830-micrometre-thick perovskite film and an additional two interlayers of polymer/perovskite composites to provide conformal interfaces between perovskite films and electrodes that control dark currents and temporal charge carrier transportation. Such an all-solution-based perovskite detector could enable low-dose X-ray imaging, and could also be used in photoconductive devices for radiation imaging, sensing and energy harvesting.
This paper proposes a coarse-fine dual-loop architecture for the digital low drop-out (LDO) regulators with fast transient response and more than 200-mA load capacity. In the proposed scheme, the ...output voltage is coregulated by two loops, namely, the coarse loop and the fine loop. The coarse loop adopts a fast current-mirror flash analog to digital converter and supplies high output current to enhance the transient performance, while the fine loop delivers low output current and helps reduce the voltage ripples and improve the regulation accuracies. Besides, a digital controller is implemented to prevent contentions between the two loops. Fabricated in a 28-nm Samsung CMOS process, the proposed digital LDO achieves maximum load up to 200 mA when the input and the output voltages are 1.1 and 0.9 V, respectively, with a chip area of 0.021 mm 2 . The measured output voltage drop of around 120 mV is observed for a load step of 180 mA.
Organic–inorganic halide perovskite is believed to be a potential candidate for high efficiency solar cells because power conversion efficiency (PCE) was certified to be more than 22%. Nevertheless, ...mismatch of PCE due to current density (J)–voltage (V) hysteresis in perovskite solar cells is an obstacle to overcome. There has been much lively debate on the origin of J–V hysteresis; however, effective methodology to solve the hysteric problem has not been developed. Here we report a universal approach for hysteresis-free perovskite solar cells via defect engineering. A severe hysteresis observed from the normal mesoscopic structure employing TiO2 and spiro-MeOTAD is almost removed or does not exist upon doping the pure perovskites, CH3NH3PbI3 and HC(NH2)2PbI3, and the mixed cation/anion perovskites, FA0.85MA0.15PbI2.55Br0.45 and FA0.85MA0.1Cs0.05PbI2.7Br0.3, with potassium iodide. Substantial reductions in low-frequency capacitance and bulk trap density are measured from the KI-doped perovskite, which is indicative of trap-hysteresis correlation. A series of experiments with alkali metal iodides of LiI, NaI, KI, RbI and CsI reveals that potassium ion is the right element for hysteresis-free perovskite. Theoretical studies suggest that the atomistic origin of the hysteresis of perovskite solar cells is not the migration of iodide vacancy but results from the formation of iodide Frenkel defect. Potassium ion is able to prevent the formation of Frenkel defect since K+ energetically prefers the interstitial site. A complete removal of hysteresis is more pronounced at mixed perovskite system as compared to pure perovskites, which is explained by lower formation energy of K interstitial (−0.65 V for CH3NH3PbI3 vs −1.17 V for mixed perovskite). The developed KI doping methodology is universally adapted for hysteresis-free perovskite regardless of perovskite composition and device structure.
Summary Background Compared with open resection, laparoscopic resection of rectal cancers is associated with improved short-term outcomes, but high-level evidence showing similar long-term outcomes ...is scarce. We aimed to compare survival outcomes of laparoscopic surgery with open surgery for patients with mid-rectal or low-rectal cancer. Methods The Comparison of Open versus laparoscopic surgery for mid or low REctal cancer After Neoadjuvant chemoradiotherapy (COREAN) trial was an open-label, non-inferiority, randomised controlled trial done between April 4, 2006, and Aug 26, 2009, at three centres in Korea. Patients (aged 18–80 years) with cT3N0–2M0 mid-rectal or low-rectal cancer who had received preoperative chemoradiotherapy were randomly assigned (1:1) to receive either open or laparoscopic surgery. Randomisation was stratified by sex and preoperative chemotherapy regimen. Investigators were masked to the randomisation sequence; patients and clinicians were not masked to the treatment assignments. The primary endpoint was 3 year disease-free survival, with a non-inferiority margin of 15%. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov , number NCT00470951. Findings We randomly assigned 340 patients to receive either open surgery (n=170) or laparoscopic surgery (n=170). 3 year disease-free survival was 72·5% (95% CI 65·0–78·6) for the open surgery group and 79·2% (72·3–84·6) for the laparoscopic surgery group, with a difference that was lower than the prespecified non-inferiority margin (–6·7%, 95% CI −15·8 to 2·4; p<0·0001). 25 (15%) patients died in the open group and 20 (12%) died in the laparoscopic group. No deaths were treatment related. Interpretation Our results show that laparoscopic resection for locally advanced rectal cancer after preoperative chemoradiotherapy provides similar outcomes for disease-free survival as open resection, thus justifying its use. Funding National Cancer Center, South Korea.
Human breast milk (HBM) is essential for the infant's growth and development right after birth and is an irreplaceable source of nutrition for early human survival. Various infant formulas have many ...similarities to HBM in many components, but there is no perfect substitute for HBM. Recently, various breast milk components and their roles have been studied according to the development of various analysis techniques. As is already well known, HBM contains about 87-88% water, and 124 g/L solid components as macronutrients, including about 7% (60-70 g/L) carbohydrates, 1% (8-10 g/L) protein, and 3.8% (35-40 g/L) fat. The composition may vary depending on the environmental factors, including maternal diet. Colostrum is low in fat but high in protein and relatively rich in immune-protective components. Although HBM contains enough vitamins to ensure normal growth of the infant, vitamins D and K may be insufficient, and the infant may require their supplementation. Growth factors in HBM also serve as various bioactive proteins and peptides on the intestinal tract, vasculature, nervous system, and endocrine system. In the past, HBM of a healthy mother was thought to be sterile. However, several subsequent studies have confirmed the presence of rich and diverse microbial communities in HBM. Some studies suggested that the genera Staphylococcus and Streptococcus may be universally predominant in HBM, but the origin of microbiota still remains controversial. Lastly, milk is the one of most abundant body fluid of microRNAs, which are known to play a role in various functions, such as immunoprotection and developmental programming, through delivering from HBM and absorption by intestinal epithelial cells. In conclusion, HBM is the most important source of nutrition for infants and includes microbiomes and miRNAs for growth, development, and immunity.
An upscalable perovskite film deposition method combining raster ultrasonic spray coating and chemical vapor deposition is reported. This method overcomes the coating size limitation of the existing ...stationary spray, single‐pass spray, and spin‐coating methods. In contrast with the spin‐coating method (>90% Pb waste), negligible Pb waste during PbI2 deposition makes this method more environmentally friendly. Outstanding film uniformity across the entire area of 5 cm × 5 cm is confirmed by both large‐area compatible characterization methods (electroluminescence and scattered light imaging) and local characterization methods (atomic force microscopy, scanning electron microscopy, photoluminescence mapping, UV–vis, and X‐ray diffraction measurements on multiple sample locations), resulting in low solar cell performance decrease upon increasing device area. With the FAPb(I0.85Br0.15)3 (FA = formamidinium) perovskite layer deposited by this method, champion solar modules show a power conversion efficiency of 14.7% on an active area of 12.0 cm2 and an outstanding shelf stability (only 3.6% relative power conversion efficiency decay after 3600 h aging). Under continuous operation (1 sun light illumination, maximum power point condition, dry N2 atmosphere with <5% relative humidity, no encapsulation), the devices show high light‐soaking stability corresponding to an average T80 lifetime of 535 h on the small‐area solar cells and 388 h on the solar module.
A negligible‐Pb‐waste and upscalable perovskite film processing method combining raster ultrasonic spray coating and chemical vapor deposition is developed. Perovskite solar module shows a power conversion efficiency of 14.7% on 12 cm2 active area, much lower substrate size dependence than the spin‐coating method, and outstanding operational stability near the maximum power point under 1 sun illumination (T80 lifetime of 388 h).
While the seroprevalence of SARS-CoV-2 in healthy people does not differ significantly among age groups, those aged 65 years or older exhibit strikingly higher COVID-19 mortality compared to younger ...individuals. To further understand differing COVID-19 manifestations in patients of different ages, three age groups of ferrets are infected with SARS-CoV-2. Although SARS-CoV-2 is isolated from all ferrets regardless of age, aged ferrets (≥3 years old) show higher viral loads, longer nasal virus shedding, and more severe lung inflammatory cell infiltration, and clinical symptoms compared to juvenile (≤6 months) and young adult (1-2 years) groups. Furthermore, direct contact ferrets co-housed with the virus-infected aged group shed more virus than direct-contact ferrets co-housed with virus-infected juvenile or young adult ferrets. Transcriptome analysis of aged ferret lungs reveals strong enrichment of gene sets related to type I interferon, activated T cells, and M1 macrophage responses, mimicking the gene expression profile of severe COVID-19 patients. Thus, SARS-CoV-2-infected aged ferrets highly recapitulate COVID-19 patients with severe symptoms and are useful for understanding age-associated infection, transmission, and pathogenesis of SARS-CoV-2.
A perovskite solar cell based on ZnO nanorods was prepared, and its photovoltaic performance was investigated. ZnO nanorods were grown on the ZnO seed layer from solution, and their diameters and ...lengths were controlled by precursor concentration and growth time. CH3NH3PbI3 perovskite infiltrated ZnO nanorods showed a power conversion efficiency of 11.13% with short-circuit current density J sc of 20.08 mA/cm2, open-circuit voltage V oc of 991 mV and fill factor of 0.56. Square spectral feature of external quantum efficiency (EQE) was observed, where EQE exceeded 80% in almost the entire wavelength range from 400 to 750 nm, and the integrated current density of 20.03 mA/cm2 calculated from EQE data was in good agreement with the observed J sc. Compared to the perfect spectral response of ZnO nanorods, a perovskite solar cell based on TiO2 nanorods exhibited an integrated current density (16 mA/cm2) much lower than the measured J sc (20.9 mA/cm2). In addition, time-limited photocurrent response under 530 and 700 nm monochromatic beams at 10 Hz showed that device signal amplitude, associated with charge collection, was rapidly saturated for the ZnO nanorod-based device whereas charge collection was not fully detected for the TiO2 nanorod-based device because of slow collection rate. The current results suggest that ZnO nanorod is an effective charge collection system in CH3NH3PbI3 based perovskite solar cells.
Human breast milk (HBM) is not only an indispensable source of nutrients for early human growth and development, supplying components that support infant growth and development, but also contains ...various essential immunologic components with anti-infectious activities and critical roles in the formation of immunity. It is also known that HBM contains its own unique microbiome, including beneficial, commensal, and potentially probiotic bacteria, that can contribute to infant gut colonization. In addition, HBM-derived extracellular vesicles, exosomes, and microRNA are attracting increasing interest for their potential to transfer to the infant and their role in infant development. In this article, we examine some of the various constituents in HBM and review the evidence supporting their associated health effects and their potential applications in human health.
Summary Background The safety and short-term efficacy of laparoscopic surgery for rectal cancer after preoperative chemoradiotherapy has not been demonstrated. The aim of the randomised Comparison of ...Open versus laparoscopic surgery for mid and low REctal cancer After Neoadjuvant chemoradiotherapy (COREAN) trial was to compare open surgery with laparoscopic surgery for mid or low rectal cancer after neoadjuvant chemoradiotherapy. Methods Between April 4, 2006, and Aug 26, 2009, patients with cT3N0–2 mid or low rectal cancer without distant metastasis after preoperative chemoradiotherapy were enrolled at three tertiary-referral hospitals. Patients were randomised 1:1 to receive either open surgery (n=170) or laparoscopic surgery (n=170), stratified according to sex and preoperative chemotherapy regimen. Short-term outcomes assessed were involvement of the circumferential resection margin, macroscopic quality of the total mesorectal excision specimen, number of harvested lymph nodes, recovery of bowel function, perioperative morbidity, postoperative pain, and quality of life. Analyses were based on the intention-to-treat population. Patients continue to be followed up for the primary outcome (3-year disease-free survival). This study is registered with ClinicalTrials.gov , number NCT00470951. Findings Two patients (1·2%) in the laparoscopic group were converted to open surgery, but were included in the laparoscopic group for analyses. Estimated blood loss was less in the laparoscopic group than in the open group (median 217·5 mL 150·0–400·0 in the open group vs 200·0 mL 100·0–300·0 in the laparoscopic group, p=0·006), although surgery time was longer in the laparoscopic group (mean 244·9 min SD 75·4 vs 197·0 min 62·9, p<0·0001). Involvement of the circumferential resection margin, macroscopic quality of the total mesorectal excision specimen, number of harvested lymph nodes, and perioperative morbidity did not differ between the two groups. The laparoscopic surgery group showed earlier recovery of bowel function than the open surgery group (time to pass first flatus, median 38·5 h 23·0–53·0 vs 60·0 h 43·0–73·0, p<0·0001; time to resume a normal diet, 85·0 h 66·0–95·0 vs 93·0 h 86·0–121·0, p<0·0001; time to first defecation, 96·5 h 70·0–125·0 vs 123 h 94·0–156·0, p<0·0001). The total amount of morphine used was less in the laparoscopic group than in the open group (median 107·2 mg 80·0–150·0 vs 156·9 mg 117·0–185·2, p<0·0001). 3 months after proctectomy or ileostomy takedown, the laparoscopic group showed better physical functioning score than the open group (0·501 n=122 vs −4·970 n=128, p=0·0073), less fatigue (−5·659 n=122 vs 0·098 n=129, p=0·0206), and fewer micturition (−2·583 n=122 vs 4·725 n=129, p=0·0002), gastrointestinal (−0·400 n=122 vs 4·331 n=129, p=0·0102), and defecation problems (0·535 n=103 vs 5·327 n=99, p=0·0184) in repeated measures analysis of covariance, adjusted for baseline values. Interpretation Laparoscopic surgery after preoperative chemoradiotherapy for mid or low rectal cancer is safe and has short-term benefits compared with open surgery; the quality of oncological resection was equivalent. Funding The National Cancer Center, South Korea.
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