Perovskite-organic tandem solar cells with indium oxide interconnect.

Multijunction solar cells can overcome the fundamental efficiency limits of single-junction devices. The bandgap tunability of metal halide perovskite solar cells renders them attractive for multijunction architectures1. Combinations with silicon and copper indium gallium selenide (CIGS), as well as all-perovskite tandem cells, have been reported2-5. Meanwhile, narrow-gap non-fullerene acceptors have unlocked skyrocketing efficiencies for organic solar cells6,7. Organic and perovskite semiconductors are an attractive combination, sharing similar processing technologies. Currently, perovskite-organic tandems show subpar efficiencies and are limited by the low open-circuit voltage (Voc) of wide-gap perovskite cells8 and losses introduced by the interconnect between the subcells9,10. Here we demonstrate perovskite-organic tandem cells with an efficiency of 24.0 per cent (certified 23.1 per cent) and a high Voc of 2.15 volts. Optimized charge extraction layers afford perovskite subcells with an outstanding combination of high Voc and fill factor. The organic subcells provide a high external quantum efficiency in the near-infrared and, in contrast to paradigmatic concerns about limited photostability of non-fullerene cells11, show an outstanding operational stability if excitons are predominantly generated on the non-fullerene acceptor, which is the case in our tandems. The subcells are connected by an ultrathin (approximately 1.5 nanometres) metal-like indium oxide layer with unprecedented low optical/electrical losses. This work sets a milestone for perovskite-organic tandems, which outperform the best p-i-n perovskite single junctions12 and are on a par with perovskite-CIGS and all-perovskite multijunctions13.

Diagnostic yield and cost analysis of electrocardiographic screening in Swiss paediatric athletes.

OBJECTIVES: Athletes performing sports on high level are at increased risk for sudden cardiac death. This includes paediatric athletes, even though data on screening strategies in this age group remain scarce. This study aimed to assess electrocardiogram interpretation criteria in paediatric athletes and to evaluate the cost of screening. METHODS: National, multicentre, retrospective, observational study on 891 athletes of paediatric age (<18 years) evaluated by history, physical examination and 12-lead electrocardiogram. The primary outcome measure was abnormal electrocardiogram findings according to the International Recommendations for Electrographic Interpretation in Athletes. The secondary outcome measure was cost of screening. RESULTS: 19 athletes (2.1%) presented abnormal electrocardiogram findings requiring further investigations, mainly abnormal T-wave inversion. These 19 athletes were predominantly males, performing endurance sports with a mean volume of 10 weekly hours for a mean duration of 6 years of training. Further investigations did not identify any relevant pathology. All athletes were cleared for competition with regular follow-up. Total costs of the screening were 108,860 USD (122 USD per athlete). CONCLUSIONS: Our study using the International Recommendations for Electrographic Interpretation in Athletes identified a low count of abnormal findings in paediatric athletes, yet raising substantially the cost of screening. Hence, the utility of electrocardiogram-inclusive screening of paediatric athletes remains to be elucidated by longitudinal data.

[A Rarely Differential Diagnosis of Exertional Dyspnea]. / Seltene Differenzialdiagnose einer Belastungsdyspnoe.

The determination of exercise-induced dyspnea is an important multifaceted task for a differential diagnosis of the pulmonologist. We are reporting the case of a 70-year old female patient at the time of the first presentation with a tumor filling almost the entire left hemithorax. Histologically a solitary pleural fibroma could be diagnosed.

In situ Near-Ambient Pressure X-ray Photoelectron Spectroscopy Reveals the Influence of Photon Flux and Water on the Stability of Halide Perovskite.

For several years, scientists have been trying to understand the mechanisms that reduce the long-term stability of perovskite solar cells. In this work, we examined the effect of water and photon flux on the stability of CH3 NH3 PbI3 perovskite films and solar cells using in situ near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), field emission scanning electron microscopy (FESEM), and current density-voltage (J-V) characterization. The used amount of water vapor (up to 1 mbar) had a negligible impact on the perovskite film. The higher the photon flux, the more prominent were the changes in the NAP-XPS and FESEM data; also, a faster decline in power conversion efficiency (PCE) and a more substantial hysteresis in the J-V characteristics were observed. Based on our results, it can be concluded that the PCE decrease originates from the creation of Frenkel pair defects in the perovskite film under illumination. The stronger the illumination, the higher the number of Frenkel defects, leading to a faster PCE decline and more substantial hysteresis in the J-V sweeps.

Identification and tracking of problematic host cell proteins removed by a synthetic, highly functionalized nonwoven media in downstream bioprocessing of monoclonal antibodies.

The repertoire of complex proteins produced by the host cell during monoclonal antibody (mAb) production has generated a bottleneck in downstream bioprocessing. Low ppm levels of host cell proteins (HCPs) must be achieved at the downstream purification process stage to generate an end product suitable for use in humans. The increased demand for mAb drug products globally has driven research to focus on affordability of mAb production platforms. This has fuelled advancements in manufacturing R&D to deliver higher product titres with better economics without sacrificing product quality. This study highlights the beneficial effects of inclusion of the Emphaze™ AEX Hybrid Purifier, compared to a conventional clarification process, for removal problematic HCPs during downstream bioprocessing of mAbs. Advanced proteomic methods were used to track and identify known 'problematic' HCPs through a multi-cycle Protein A purification process. Removal of histone proteins was observed, along with an average total HCP reduction of 38-fold and an average reduction of 2.3 log in HCDNA concentration. Chromatographic clarification using the Emphaze™ AEX Hybrid Purifier in conjunction with Protein A chromatography resulted in the removal of problematic HCPs including 78 kD glucose-regulated protein, nidogen-1, heat shock proteins, actin, serine protease HTRA1 and matrix metalloproteinase-19. It is shown herein that the Emphaze™ AEX Hybrid Purifier, which is readily incorporated into a mAb purification process during the clarification stage, has the potential to increase Protein A resin lifetime and potentially reduce the number of subsequent polishing chromatographic steps needed to remove HCPs that have a tendency to co-purify with mAb products.

Skin type differences in solar-simulated radiation-induced oxidative stress.

BACKGROUND: Human skin protects the body from external damage, pathogens and oxidative stress factors such as ultraviolet (UV) radiation. Excessive exposure to UV radiation can lead to increased production of free radicals and hence to skin damage such as inflammation, premature skin ageing and skin cancer. Besides UV, the visible and near infrared (NIR) regions are also a source of radical production. Half of all free radicals are induced by the visible + NIR region of the solar spectrum in people with skin types I-III, but data on the effects in people with skin types IV-VI are missing. OBJECTIVES: This in vivo pilot study addressed the distribution of radical production in skin types IV and V during irradiation in the UV, visible and NIR spectral regions, comparing the first results with those of skin type II. METHODS: The measurements were performed in vivo using L-band electron paramagnetic resonance spectroscopy and the spin probe PCA. RESULTS: In skin types IV-V most radicals were induced in the visible + NIR region, followed by the NIR and UV regions of the sun spectrum. Significantly (P ≤ 0·05) more radicals were induced in skin types IV-V than in type II during NIR irradiation, whereas skin types IV-V exhibited significantly less UV-induced radicals (P ≤ 0·01) than skin type II. CONCLUSIONS: All spectral regions (UV, visible and NIR) cause free radical formation in skin types II and IV-V. After 4 min of solar-simulated exposure (UV-NIR), the radical formation in skin types IV-V is 60% of that in skin type II. Therefore people with darker skin types also need solar protection.

Inter-observer agreement in athletes ECG interpretation using the recent international recommendations for ECG interpretation in athletes among observers with different levels of expertise.

INTRODUCTION: International criteria for the interpretation of the athlete's electrocardiogram (ECG) have been proposed. We aimed to evaluate the inter-observer agreement among observers with different levels of expertise. METHODS: Consecutive ECGs of Swiss elite athletes (≥14 years), recorded during routine pre-participation screening between 2013 and 2016 at the Swiss Federal Institute of Sports were analysed. A medical student (A), a cardiology fellow (B) and an electrophysiologist (C) interpreted the ECG's independently according to the most recent criteria. The frequencies and percentages for each observer were calculated. An inter-observer reliability analysis using Cohen Kappa (κ) statistics was used to determine consistency among observers. RESULTS: A total of 287 ECGs (64.1% males) were analysed. Mean age of the athletes was 20.4±4.9 years. The prevalence of abnormal ECG findings was 1.4%. Both, normal and borderline findings in athletes showed moderate to good agreement between all observers. κ scores for abnormal findings resulted in excellent agreement (κ 0.855 in observer A vs C and B vs C to κ 1.000 in observer A vs B). Overall agreement ranged from moderate (κ 0.539; 0.419-0.685 95% CI) between observer B vs C to good agreement (κ 0.720; 0.681-0.821 95% CI) between observer A vs B. CONCLUSIONS: Our cohort of elite athletes had a low prevalence of abnormal ECGs. Agreement in abnormal ECG findings with the use of the recently published International recommendations for ECG interpretation in athletes among observers with different levels of expertise was excellent. ECG interpretation resulted in moderate to good overall agreement.

Transport Signatures of Quasiparticle Poisoning in a Majorana Island.

We investigate effects of quasiparticle poisoning in a Majorana island with strong tunnel coupling to normal-metal leads. In addition to the main Coulomb blockade diamonds, "shadow" diamonds appear, shifted by 1e in gate voltage, consistent with transport through an excited (poisoned) state of the island. Comparison to a simple model yields an estimate of parity lifetime for the strongly coupled island (∼1 µs) and sets a bound for a weakly coupled island (>10 µs). Fluctuations in the gate-voltage spacing of Coulomb peaks at high field, reflecting Majorana hybridization, are enhanced by the reduced lever arm at strong coupling. When converted from gate voltage to energy units, fluctuations are consistent with previous measurements.

[New aspects in the development of sunscreening agents]. / Neue Aspekte bei der Entwicklung von Sonnenschutzmitteln.

Sunlight is indispensable for life. Skin aging is determined not only by genetic factors but also by the influence of solar radiation which in all its spectral regions induces free radicals in the human skin. Below a critical concentration, free radicals are important for signaling processes in the human body. Exceeding a critical threshold value (FRTV), however, free radicals lead to cellular damage which, in turn, can induce skin aging, immunosuppression and even skin cancer. Recently it could be shown that 50% of the free radicals induced in the human skin by solar radiation were caused by the visible and infrared spectral regions. Taking into consideration that people who use sunscreen stay considerably longer in the sun than unprotected people, their skin could be exposed to free radical formation in the visible and infrared spectral regions, which far exceeds the critical threshold. Filter substances like those used in sunscreens for skin protection in the ultraviolet region are not available for the visible and infrared spectral regions. Using the natural protection mechanisms of the human skin as examples, however, the protective effect of sunscreens can be considerably enhanced by the addition of scattering and reflective pigments, such as titanium dioxide, as well as of antioxidants which neutralize the free radicals. Currently the focus of sunscreen development is shifting from mere UV protection to protection covering the entire solar spectrum.

Normal, superconducting and topological regimes of hybrid double quantum dots.

Epitaxial semiconductor-superconductor hybrid materials are an excellent basis for studying mesoscopic and topological superconductivity, as the semiconductor inherits a hard superconducting gap while retaining tunable carrier density. Here, we investigate double-quantum-dot structures made from InAs nanowires with a patterned epitaxial Al two-facet shell that proximitizes two gate-defined segments along the nanowire. We follow the evolution of mesoscopic superconductivity and charging energy in this system as a function of magnetic field and voltage-tuned barriers. Interdot coupling is varied from strong to weak using side gates, and the ground state is varied between normal, superconducting and topological regimes by applying a magnetic field. We identify the topological transition by tracking the spacing between successive co-tunnelling peaks as a function of axial magnetic field and show that the individual dots host weakly hybridized Majorana modes.

Plasmakristall-4: New complex (dusty) plasma laboratory on board the International Space Station.

New complex-plasma facility, Plasmakristall-4 (PK-4), has been recently commissioned on board the International Space Station. In complex plasmas, the subsystem of µm-sized microparticles immersed in low-pressure weakly ionized gas-discharge plasmas becomes strongly coupled due to the high (103-104 e) electric charge on the microparticle surface. The microparticle subsystem of complex plasmas is available for the observation at the kinetic level, which makes complex plasmas appropriate for particle-resolved modeling of classical condensed matter phenomena. The main purpose of PK-4 is the investigation of flowing complex plasmas. To generate plasma, PK-4 makes use of a classical dc discharge in a glass tube, whose polarity can be switched with the frequency of the order of 100 Hz. This frequency is high enough not to be felt by the relatively heavy microparticles. The duty cycle of the polarity switching can be also varied allowing to vary the drift velocity of the microparticles and (when necessary) to trap them. The facility is equipped with two videocameras and illumination laser for the microparticle imaging, kaleidoscopic plasma glow observation system and minispectrometer for plasma diagnostics and various microparticle manipulation devices (e.g., powerful manipulation laser). Scientific experiments are programmed in the form of scripts written with the help of specially developed C scripting language libraries. PK-4 is mainly operated from the ground (control center CADMOS in Toulouse, France) with the support of the space station crew. Data recorded during the experiments are later on delivered to the ground on the removable hard disk drives and distributed to participating scientists for the detailed analysis.

Hot super-Earths stripped by their host stars.

Simulations predict that hot super-Earth sized exoplanets can have their envelopes stripped by photoevaporation, which would present itself as a lack of these exoplanets. However, this absence in the exoplanet population has escaped a firm detection. Here we demonstrate, using asteroseismology on a sample of exoplanets and exoplanet candidates observed during the Kepler mission that, while there is an abundance of super-Earth sized exoplanets with low incident fluxes, none are found with high incident fluxes. We do not find any exoplanets with radii between 2.2 and 3.8 Earth radii with incident flux above 650 times the incident flux on Earth. This gap in the population of exoplanets is explained by evaporation of volatile elements and thus supports the predictions. The confirmation of a hot-super-Earth desert caused by evaporation will add an important constraint on simulations of planetary systems, since they must be able to reproduce the dearth of close-in super-Earths.

Exponential protection of zero modes in Majorana islands.

Majorana zero modes are quasiparticle excitations in condensed matter systems that have been proposed as building blocks of fault-tolerant quantum computers. They are expected to exhibit non-Abelian particle statistics, in contrast to the usual statistics of fermions and bosons, enabling quantum operations to be performed by braiding isolated modes around one another. Quantum braiding operations are topologically protected insofar as these modes are pinned near zero energy, with the departure from zero expected to be exponentially small as the modes become spatially separated. Following theoretical proposals, several experiments have identified signatures of Majorana modes in nanowires with proximity-induced superconductivity and atomic chains, with small amounts of mode splitting potentially explained by hybridization of Majorana modes. Here, we use Coulomb-blockade spectroscopy in an InAs nanowire segment with epitaxial aluminium, which forms a proximity-induced superconducting Coulomb island (a 'Majorana island') that is isolated from normal-metal leads by tunnel barriers, to measure the splitting of near-zero-energy Majorana modes. We observe exponential suppression of energy splitting with increasing wire length. For short devices of a few hundred nanometres, sub-gap state energies oscillate as the magnetic field is varied, as is expected for hybridized Majorana modes. Splitting decreases by a factor of about ten for each half a micrometre of increased wire length. For devices longer than about one micrometre, transport in strong magnetic fields occurs through a zero-energy state that is energetically isolated from a continuum, yielding uniformly spaced Coulomb-blockade conductance peaks, consistent with teleportation via Majorana modes. Our results help to explain the trivial-to-topological transition in finite systems and to quantify the scaling of topological protection with end-mode separation.

Towards Realistic Implementations of a Majorana Surface Code.

Surface codes have emerged as promising candidates for quantum information processing. Building on the previous idea to realize the physical qubits of such systems in terms of Majorana bound states supported by topological semiconductor nanowires, we show that the basic code operations, namely projective stabilizer measurements and qubit manipulations, can be implemented by conventional tunnel conductance probes and charge pumping via single-electron transistors, respectively. The simplicity of the access scheme suggests that a functional code might be in close experimental reach.

Efficacy and safety of deferasirox in non-thalassemic patients with elevated ferritin levels after allogeneic hematopoietic stem cell transplantation.

Elevated serum ferritin contributes to treatment-related morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). The multicenter DE02 trial assessed the safety, efficacy and impact of deferasirox on iron homeostasis after allogeneic HSCT. Deferasirox was administered at a starting dose of 10 mg/kg per day to 76 recipients of allogeneic HSCT, with subsequent dose adjustments based on efficacy and safety. Deferasirox was initiated at a median of 168 days after HSCT, with 84% of patients still on immunosuppression. Baseline serum ferritin declined from 2045 to 957 ng/mL. Deferasirox induced a negative iron balance in 84% of patients. Hemoglobin increased in the first 3 months, and trough serum cyclosporine levels were stable. Median exposure was 330 days, with a median compliance rate of >80%. The most common investigator-reported drug-related adverse events (AEs) were increased blood creatinine (26.5%), nausea (9.0%) and abdominal discomfort (8.3%). Fifty-four (71.1%) patients experienced drug-related AEs, which occasionally resulted in discontinuation (gastrointestinal (n=6), skin (n=3), elevated transaminases (n=1) and creatinine (n=1)). The incidence of AEs appeared to be dose related, with 7.5 mg/kg per day being the best-tolerated dose. Low-dose deferasirox is an effective chelation therapy after allogeneic HSCT, with a manageable safety profile, even in patients receiving cyclosporine.

In vitro fermentation of prebiotic carbohydrates by intestinal microbiota in the presence of Lactobacillus amylovorus DSM 16998.

The aim of this study was to evaluate the assimilation of the prebiotics fructooligosaccharides (FOS), galactooligosaccharides (GOS), and Konjac glucomannan oligosaccharides (KGMO) by three human (H1, H2 and H3) and pig (P1, P2 and P3) faecal microbiotas in the presence of the potentially probiotic strain Lactobacillus amylovorus DSM 16698, using an in vitro batch fermentation model. Total bacteria and L. amylovorus populations were quantified using qPCR and biochemical features (pH, production of short chain fatty acids (SCFA), lactate, ammonia, and carbohydrate assimilation) were determined. L. amylovorus did not have a competitive advantage under in vitro conditions, reflected by its reduced relative abundance during fermentation despite the carbohydrate sources added. Pig microbiota sustained more stable probiotic counts. Intermittently produced lactate was possibly assimilated by the microbiota and converted to other SCFA as the carbohydrates were assimilated, with H3 probably having a methanogenic metabolism with high lactate and acetate consumption except in the presence of FOS, which assimilation resulted in the highest total SCFA for this volunteer. Addition of FOS also resulted in lower pH and ammonia, which might have been used as nitrogen source by pig microbiota. KGMO needed longer fermentation periods to be completely assimilated by both human and porcine faecal microbiotas. Overall, our results reinforce the notion that care must be taken when generalising the effects claimed for a given probiotic or potentially probiotic strain, including the combination with different prebiotic substrates, since they may vary considerably among individuals, which is important when studying potentially pro- and prebiotic combinations for application as functional foods and feed ingredients.

Injury to the Cerebellum in Term Asphyxiated Newborns Treated with Hypothermia.

BACKGROUND AND PURPOSE: Until now, most studies of brain injury related to term neonatal encephalopathy have focused on the cerebrum and ignored the cerebellum. We sought to evaluate whether cerebellar injury occurs in term asphyxiated neonates. MATERIALS AND METHODS: Asphyxiated neonates treated with hypothermia were enrolled prospectively. Severity of brain injury in the cerebrum was scored on each MR imaging obtained during the first month of life; cerebellar injury was recorded when mentioned in the imaging or autopsy report. In addition, for some of the neonates, the ADC and fractional anisotropy were measured in 4 regions of interest in the cerebellum. RESULTS: One hundred seventy-two asphyxiated neonates met the criteria for hypothermia. Cerebellar injury was visible only on conventional imaging of 4% of the neonates for whom brain imaging was available, but it was reported in the autopsy report of 72% of the neonates who died. In addition, 41 of the asphyxiated neonates had a total of 84 ADC and fractional anisotropy maps. Neonates with brain injury described only in the cerebrum demonstrated ADC and fractional anisotropy changes similar to those of the neonates with brain injury in the cerebrum and cerebellum--increased ADC around day 10 of life and decreased fractional anisotropy on day 2-3 of life, around day 10 of life, and around 1 month of age. CONCLUSIONS: The cerebellum may be injured in term neonates after birth asphyxia. These cerebellar injuries are only rarely visible on conventional imaging, but advanced neuroimaging techniques may help to identify them.

Is waist circumference per body mass index rising differentially across the United States, England, China and Mexico?

BACKGROUND/OBJECTIVES: Little is known about whether waist circumference (WC) has increased disproportionately relative to body mass index (BMI) around the world. SUBJECTS/METHODS: Data came from the US National Health and Nutrition Examination Survey (1988-1994 and 2007-2010), Health Survey for England (1992-1993 and 2008-2009); the Mexican Nutrition Survey (1999) and the Mexican National Health and Nutrition Survey (NHNS 2012); and the China Health and Nutrition Survey (1993 and 2011). Country- and sex-stratified (for the United States, also race-/ethnicity-stratified) multivariable linear regressions were used to estimate mean difference in WC over time relative to BMI at specified overweight and obesity cutoff points, adjusting for age and survey year. RESULTS: Although mean WC and BMI shifted upward over time in all age-sex subpopulations in all four countries, trends in overweight prevalence were less consistent. However, WC relative to BMI increased at varying magnitudes across all countries and subpopulations, except US Black men. The magnitude of increase was largest for women in the youngest age group (20-29 years), particularly for women in Mexico (+6.6 cm, P<0.0001) and China (+4.6 cm, P<0.0001) (holding BMI constant at 25 kg/m(2)). For men, the increase was primarily evident among Chinese men (+4.8 cm, P<0.0001). CONCLUSIONS: WC has increased disproportionately over time relative to overall body mass across the United States, England, Mexico and China, particularly among young women, with the largest increases occurring in the middle-income countries of Mexico and China. These patterns are potentially a cause for concern especially for countries undergoing rapid economic and nutritional transitions.

Epitaxy of semiconductor-superconductor nanowires.

Controlling the properties of semiconductor/metal interfaces is a powerful method for designing functionality and improving the performance of electrical devices. Recently semiconductor/superconductor hybrids have appeared as an important example where the atomic scale uniformity of the interface plays a key role in determining the quality of the induced superconducting gap. Here we present epitaxial growth of semiconductor-metal core-shell nanowires by molecular beam epitaxy, a method that provides a conceptually new route to controlled electrical contacting of nanostructures and the design of devices for specialized applications such as topological and gate-controlled superconducting electronics. Our materials of choice, InAs/Al grown with epitaxially matched single-plane interfaces, and alternative semiconductor/metal combinations allowing epitaxial interface matching in nanowires are discussed. We formulate the grain growth kinetics of the metal phase in general terms of continuum parameters and bicrystal symmetries. The method realizes the ultimate limit of uniform interfaces and seems to solve the soft-gap problem in superconducting hybrid structures.