Crystalline silicon comprises 90% of the global photovoltaics (PV) market and has sustained a nearly 30% cumulative annual growth rate, yet comprises less than 2% of electricity capacity. To sustain ...this growth trajectory, continued cost and capital expenditure (capex) reductions are needed. Thinning the silicon wafer well below the industry-standard 160 μm, in principle reduces both manufacturing cost and capex, and accelerates economically-sustainable expansion of PV manufacturing. In this analysis piece, we explore two questions surrounding adoption of thin silicon wafers: (a) What are the market benefits of thin wafers? (b) What are the technological challenges to adopt thin wafers? In this analysis, we re-evaluate the benefits and challenges of thin Si for current and future PV modules using a comprehensive technoeconomic framework that couples device simulation, bottom-up cost modeling, and a sustainable cash-flow growth model. When adopting an advanced technology concept that features sufficiently good surface passivation, the comparable efficiencies are achievable for both 50 μm wafers and 160 μm ones. We then quantify the economic benefits for thin Si wafers in terms of poly-Si-to-module manufacturing capex, module cost, and levelized cost of electricity (LCOE) for utility PV systems. Particularly, LCOE favors thinner wafers for all investigated device architectures, and can potentially be reduced by more than 5% from the value of 160 μm wafers. With further improvements in module efficiency, an advanced device concept with 50 μm wafers could potentially reduce manufacturing capex by 48%, module cost by 28%, and LCOE by 24%. Furthermore, we apply a sustainable growth model to investigate PV deployment scenarios in 2030. It is found that the state-of-the-art industry concept could not achieve the climate targets even with very aggressive financial scenarios, therefore the capex reduction benefit of thin wafers is advantageous to facilitate faster PV adoption. Lastly, we discuss the remaining technological challenges and areas for innovation to enable high-yield manufacturing of high-efficiency PV modules with thin Si wafers.
This technoeconomic analysis revisits the concept of thin silicon wafer for its potential cost benefits and technological challenges.
Abstract
Based on our dedicated Swift monitoring program, MOMO, OJ 287 is one of the best-monitored blazars in the X-ray–UV–optical regime. Here, we report results from our accompanying, dense, ...multifrequency (1.4–44 GHz) radio monitoring of OJ 287 between 2015 and 2022 covering a broad range of activity states. Fermi
γ
-ray observations were added. We characterize the radio flux and spectral variability in detail, including discrete correlation function and other variability analyses, and discuss its connection with the multiwavelength emission. Deep fades of the radio and optical–UV fluxes are found to occur every 1–2 yr. Further, it is shown that a precursor flare of thermal bremsstrahlung predicted by one of the binary supermassive black hole (SMBH) models of OJ 287 was absent. We then focus on the nature of the extraordinary, nonthermal, 2016/2017 outburst that we initially discovered with Swift. We interpret it as the latest of the famous optical double-peaked outbursts of OJ 287, favoring binary scenarios that do not require a highly precessing secondary SMBH.
Background
Esophageal perforations and extensive anastomotic leaks after esophageal resection or gastrectomy are surgical emergencies with high mortality rates. In recent years, the use of ...self-expanding metallic stents (SEMS) has emerged as a promising treatment alternative for bridging and sealing the damage. This study aimed to evaluate the role of covered SEMS for the management of esophageal perforations and anastomotic leaks.
Methods
All esophageal stent placement procedures (174 procedures for 157 patients) at the authors’ unit between January 1999 and April 2008 were assessed by a retrospective chart review. Of the 157 patients, 10 (6.4%) were treated with SEMS for sealing of an iatrogenic esophageal perforation (
n
= 4), a spontaneous esophageal rupture in Boerhaave’s syndrome (
n
= 4), or an anastomotic leakage (
n
= 2).
Results
The median time from perforation or anastomotic leak to stent insertion was 13 days (range, 2 h to 48 days). The esophageal leak was totally sealed for 8 (80%) of 10 patients. The overall mortality rate was 50% (
n
= 5), and three (30%) of the five deaths were related to the perforation (
n
= 2) or leakage (
n
= 1). In both of the perforation cases, the diagnosis and treatment were substantially delayed. One patient with an anastomotic leak after gastrectomy died of the complication despite successful operative and SEMS treatment. Two of the deaths were unrelated to the perforation. In both cases, the cause of death was a disseminated malignant disease.
Conclusions
Traumatic perforations and anastomotic leaks can be treated effectively with covered SEMS together with adequate drainage of the thoracic cavity even in cases of severely ill patients with inveterate esophageal perforations and leaks.
Industrial Czochralski silicon (Cz-Si) photovoltaic (PV) efficiencies have routinely reached >20% with the passivated emitter rear cell (PERC) design. Nanostructuring silicon (black-Si) by ...dry-etching decreases surface reflectance, allows diamond saw wafering, enhances metal gettering, and may prevent power conversion efficiency degradation under light exposure. Black-Si allows a potential for >20% PERC cells using cheaper multicrystalline silicon (mc-Si) materials, although dry-etching is widely considered too expensive for industrial application. This study analyzes this economic potential by comparing costs of standard texturized Cz-Si and black mc-Si PERC cells. Manufacturing sequences are divided into steps, and costs per unit power are individually calculated for all different steps. Baseline costs for each step are calculated and a sensitivity analysis run for a theoretical 1 GW/year manufacturing plant, combining data from literature and industry. The results show an increase in the overall cell processing costs between 15.8% and 25.1% due to the combination of black-Si etching and passivation by double-sided atomic layer deposition. Despite this increase, the cost per unit power of the overall PERC cell drops by 10.8%. This is a significant cost saving and thus energy policies are reviewed to overcome challenges to accelerating deployment of black mc-Si PERC across the PV industry.
ABSTRACT
We report results from our ongoing project MOMO (Multiwavelength Observations and Modelling of OJ 287). In this latest publication of a sequence, we combine our Swift UVOT–XRT and Effelsberg ...radio data (2.6–44 GHz) between 2019 and 2022.04 with public SMA data and gamma-ray data from the Fermi satellite. The observational epoch covers OJ 287 in a high state of activity from radio to X-rays. The epoch also covers two major events predicted by the binary supermassive black hole (SMBH) model of OJ 287. Spectral and timing analyses clearly establish: a new UV–optical minimum state in 2021 December at an epoch where the secondary SMBH is predicted to cross the disc surrounding the primary SMBH; an overall low level of gamma-ray activity in comparison to pre-2017 epochs; the presence of a remarkable, long-lasting UV–optical flare event of intermediate amplitude in 2020–2021; a high level of activity in the radio band with multiple flares; and particularly a bright, ongoing radio flare peaking in 2021 November that may be associated with a gamma-ray flare, the strongest in 6 yr. Several explanations for the UV–optical minimum state are explored, including the possibility that a secondary SMBH launches a temporary jet, but the observations are best explained by variability associated with the main jet.
Background and study aims
The majority of recent large series on endoscopic retrograde cholangiopancreatography (ERCP) complications have been multicenter studies reflecting varying degrees of ...experience and ERCP volume; major ERCP complications are associated with low case volume. The aim of this study was to report and analyze the frequency of severe and fatal complications associated with ERCP at a single specialized surgical high-volume referral center (Turku University Central Hospital).
Methods
All scheduled ERCP procedures (
n
= 2788) at our unit between January 1997 and December 2005 were included and the procedure-related severe and fatal complications were assessed by retrospective chart review. Complications were classified as severe or fatal according to standardized guidelines.
Results
The number of ERCP procedures performed was 2555, of which 71% were therapeutic and 29% were diagnostic. Seventeen (0.8%) severe complications were identified in 16 patients, of whom 15 underwent a therapeutic endoscopic procedure. Of the 17 severe complications, perforation constituted five cases (0.2%), pancreatitis occurred in five patients (0.2%), bleeding in five cases (0.2%), and two patients suffered from purulent cholangitis (0.1%). Procedure-related mortality was 0.08% (
n
= 3).
Conclusions
In our study the rate of severe or fatal complications of ERCP is low in experienced hands at a high-volume center, comparing favorably to corresponding complication rates of multicenter series, which further supports the importance of centralizing ERCP procedures in high-volume advanced centers.
Cellular mRNAs are exported from the nucleus as fully spliced RNAs. Proofreading mechanisms eliminate unprocessed and irregular pre-mRNAs to control the quality of gene expression. Retroviruses need ...to export partially spliced and unspliced full-length RNAs to the cytoplasm where they serve as templates for protein synthesis and/or as encapsidated RNA in progeny viruses. Genetically complex retroviruses such as HIV-1 use Rev-equivalent proteins to export intron-retaining RNA from the nucleus using the cellular CRM1-driven nuclear export machinery. By contrast, genetically simpler retroviruses such as murine leukaemia virus (MLV) recruit the NXF1 RNA export machinery. In this study, we reveal for the first time that MLV hijacks both NXF1 and CRM1-dependent pathways to achieve optimal replication capacity. The CRM1-pathway marks the MLV full-length RNA (FL RNA) for packaging, while NXF1-driven nuclear export is coupled to translation. Thus, the cytoplasmic function of the viral RNA is determined early in the nucleus. Depending on the nature of ribonucleoprotein complex formed on FL RNA cargo in the nucleus, the FL RNA will be addressed to the translation machinery sites or to the virus-assembly sites at the plasma membrane.
The adult bone marrow, situated within the bone cavity, comprises three distinct stem cell populations: hematopoietic stem cells (HSCs), mesenchymal stromal/stem cells (MSCs) and endothelial ...progenitor/stem cells (EPCs). HSCs are a well-characterized population of self-renewing cells that give rise to all blood cells. The definition of MSCs is more complex due to the limited understanding of MSC properties. In general, MSCs are considered multipotent stromal cells that are able to differentiate into various cell types, including osteoblasts, chondrocytes and adipocytes. Compared to HSCs and MSCs, EPCs are a newly discovered population of stem/progenitor cells with the capacity to differentiate into endothelial cells, the cells forming the inner lining of a blood vessel.
Although functionally different, HSCs, MSCs and EPCs, like stem cells in general, share the ability to self-renew and differentiate into one or more cell types. The homeostasis inside the bone marrow and within the entire body is sustained by an intricate network of growth factors and transcription factors that orchestrate the proliferation and differentiation of these multipotent stem/progenitor cells. Increasing evidence indicates that microRNAs (miRNAs), small non-coding RNAs, are among the key players of this concert. This review summarizes the current insights into miRNA-mediated regulation of bone marrow stem/progenitor cell maintenance and differentiation. Furthermore, the potential contribution of miRNAs in bone marrow stem cell niches is discussed.
► MicroRNAs regulate the self-renewal and differentiation of bone marrow stem cells. ► Bone marrow stem cells reside in stem cell niches. ► MicroRNAs may be involved in the regulation of niche function.
To describe the epidemiology and clinical spectrum of reactive arthritis (ReA) following culture-confirmed infection with bacterial enteric pathogens in a population-based study in the USA.
We ...conducted telephone interviews of persons age>1 year with culture confirmed Campylobacter, Escherichia coli O157, Salmonella, Shigella and Yersinia infections reported to FoodNet (http://www.cdc.gov/FoodNet/) in Minnesota, USA and Oregon, USA between 2002 and 2004.
with new onset joint pain, joint swelling, back pain, heel pain and morning stiffness lasting >or=3 days within 8 weeks of culture (possible ReA) were invited to complete a detailed questionnaire and physical examination.
A total of 6379 culture-confirmed infections were reported; 70% completed screening interviews. Of these, 575 (13%) developed possible ReA; incidence was highest following Campylobacter (2.1/100,000) and Salmonella (1.4/100,000) infections. Risk was greater for females (relative risk (RR) 1.5, 95% CI, 1.3 to 1.7), adults (RR 2.5, 95% CI, 2.0 to 3.1) and subjects with severe acute illness (eg, fever, chills, headache, persistent diarrhoea). Risk was not associated with antibiotic use or human leukocyte antigen (HLA)-B27. A total of 54 (66%) of 82 subjects examined had confirmed ReA. Enthesitis was the most frequent finding; arthritis was less common. The estimated incidence of ReA following culture-confirmed Campylobacter, E coli O157, Salmonella, Shigella and Yersinia infections in Oregon was 0.6-3.1 cases/100,000.
This is the first population-based study of ReA following infections due to bacterial enteric pathogens in the USA. These data will help determine the burden of illness due to these pathogens and inform clinicians about potential sequelae of these infections.
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