2,595 research outputs found

    CO₂ Reduction to CO with 19% Efficiency in a Solar-Driven Gas Diffusion Electrode Flow Cell under Outdoor Solar Illumination

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    Solar-driven reduction of carbon dioxide represents a carbon-neutral pathway for the synthesis of fuels and chemicals. We report here results for solar-driven CO₂ reduction using a gas diffusion electrode (GDE) directly powered by a photovoltaic cell. A GaInP/GaInAs/Ge triple-junction photovoltaic cell was used to power a reverse-assembled gas diffusion electrode employing a Ag nanoparticle catalyst layer. The device had a solar-to-CO energy conversion efficiency of 19.1% under simulated AM 1.5G illumination at 1 Sun. The use of a reverse-assembled GDE prevented transition from a wetted to a flooded catalyst bed and allowed the device to operate stably for >150 h with no loss in efficiency. Outdoor measurements were performed under ambient solar illumination in Pasadena, California, resulting in a peak solar-to-CO efficiency of 18.7% with a CO production rate of 47 mg·cm⁻² per day and a diurnal-averaged solar-to-fuel conversion efficiency of 5.8%

    Heart failure-associated anemia: bone marrow dysfunction and response to erythropoietin

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    Heart failure (HF)-associated anemia is common and has a poor outcome. Because bone marrow (BM) dysfunction may contribute to HF-associated anemia, we first investigated mechanisms of BM dysfunction in an established model of HF, the transgenic REN2 rat, which is characterized by severe hypertrophy and ventricular dilatation and SD rats as controls. Secondly, we investigated whether stimulation of hematopoiesis with erythropoietin (EPO) could restore anemia and BM dysfunction. After sacrifice, erythropoietic precursors (BFU-E) were isolated from the BM and cultured for 10 days. BFU-E were quantified and transcript abundance of genes involved in erythropoiesis were assayed. Number of BFU-E were severely decreased in BM of REN2 rats compared to SD rats (50 ± 6.2 vs. 6.4 ± 1.7, p < 0.01). EPO treatment increased hematocrit in the SD-EPO group (after 6 weeks, 49 ± 1 vs. 58 ± 1%, p < 0.01); however, in the mildly anemic REN2 rats, there was no effect (43 ± 1 vs. 44 ± 1%). This was paralleled by a 67% decrease in BFU-E in BM of REN2 rats compared to SD (p < 0.01). EPO significantly improved BFU-E in both SD and REN2 but could not restore this to control levels in the REN2 rats. Expression of several genes involved in differentiation (LMO2), mobilization (SDF-1), and iron incorporation (transferrin receptor) of the BM were differentially expressed in REN2 rats compared to SD rats, and EPO did not normalize this. Altogether, these results suggest that BM dysfunction is an important contributor to HF-associated anemia and that EPO is not an effective agent to treat HF-associated anemia

    INTERACTIVE IMAGE PROCESSING AND MANIPULATION

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    ABSTRACT Electronic imaging informatics spans a diverse range of applications. These applications would benefit from an interpretive imaging platform, which allows dynamic manipulation and processing of electronic images. Ch is an embeddable C/C++ interpreter that provides an interpretive platform for C/C++ based scripts and programs. Combining Ch with ImageMagick provides the functionality for rapid development of user defined image manipulation and processing applications and scripts. The presented Ch ImageMagick package provides users with the ability to interpretively execute C code based on the ImageMagick C library. This article describes the integration of ImageMagick and Ch. The use of ImageMagick utilities in Ch scripts for rapid prototyping is illustrated. A Web-based example demonstrates the use of Ch and ImageMagick in C based CGI scripting to facilitate the development of Web-based applications involving image manipulation and processing

    Rosette-forming glioneuronal tumor: a pineal region case with IDH1 and IDH2 mutation analyses and literature review of 43 cases

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    Rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle is a mixed glio-neuronal neoplasm recently codified by the World Health Organization WHO Classification of Central Nervous System (CNS) Tumors (2007). To date, 43 cases have been described in the literature; most occurring in the fourth ventricle region. We report the fourth case involving the pineal region in a 16-year-old female with signs of increased intracranial pressure (ICP). A stereotactic biopsy of the mass was followed by a debulking procedure. Both specimens revealed classic RGNT histology. The patient had stable scans 7 months post-resection. The clinical, radiological and histopathologic features of the previously described 43 cases are reviewed along with our illustrative case. Mean age of patients was 30 ± 12.8 years with 1.9:1 female to male ratio. The most common presenting signs related to increased ICP and posterior fossa involvement, including: headache (62.8%), ataxia (39.5%) and vomiting and vertigo (both 16.3%). This tumor usually presents with cystic changes (54.5%) with focal enhancement (60.9%) and hydrocephalus (43.2%). Microcalcifications and satellite lesions were common radiographic observations. All reported cases had the classic biphasic pattern. Rosenthal fibers and eosinophilic granular bodies are each present in approximately two thirds of cases. Ki-67 labeling index is consistently low (mean (%): 1.8 ± 0.75 SD). The isocitrate dehydrogenase 1 or 2 mutation found in low grade diffuse gliomas is not identified in this RGNT case. Reported outcome is nearly uniformly excellent after complete or subtotal resection. A solitary report of recurrence after 10 years and the limited experience with this entity suggest that long term follow up is advisable

    Changes in body weight and cardiovascular risk factors in a Chinese population with type 2 diabetes mellitus: a longitudinal study

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    IntroductionThe primary care management of blood glucose, blood pressure, lipid profiles, and body weight is important among patients with type 2 diabetes mellitus (T2DM) to prevent disease progression. Information on how weight changes would improve or deteriorate cardiovascular (CV) risk factors is warranted for making primary care recommendations. We aimed to investigate the changes in body weight and CV risk factors and to analyse their association in a Chinese population with T2DM.MethodsWe retrieved longitudinal data between 2020 and 2021 from 1,758 adult primary care patients enrolled in a diabetic retinopathy (DR) screening programme. Linear associations of changes in body weight with CV risk factors were explored. Multivariable logistic regression analysis was performed to examine associations between different weight change categories and the worsening of CV risk factors.ResultsThe mean age of all the participants was 63.71 years, and over half of participants were females. During a one-year follow-up period, 24.7% of patients had a weight loss of ≥3%, while 22.2% of patients had a weight gain of ≥3%. Patients who had a weight loss of ≥3% were more likely to prevent the worsening of haemoglobin A1c (HbA1c) and triglycerides, while those who had a weight gain of ≥3% tended to have worsened HbA1c, lipid profiles, and blood pressure.ConclusionResults from this real-world investigation suggested the concurrent need for weight loss intervention among patients who are overweight or obese and weight gain prevention among patients whose body weight falls within the normal range in the context of community-based diabetes management

    Full characterization of vibrational coherence in a porphyrin chromophore by two-dimensional electronic spectroscopy

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    In this work we present experimental and calculated two-dimensional electronic spectra for a 5,15-bisalkynyl porphyrin chromophore. The lowest energy electronic Qy transition couples mainly to a single 380 cm–1 vibrational mode. The two-dimensional electronic spectra reveal diagonal and cross peaks which oscillate as a function of population time. We analyze both the amplitude and phase distribution of this main vibronic transition as a function of excitation and detection frequencies. Even though Feynman diagrams provide a good indication of where the amplitude of the oscillating components are located in the excitation-detection plane, other factors also affect this distribution. Specifically, the oscillation corresponding to each Feynman diagram is expected to have a phase that is a function of excitation and detection frequencies. Therefore, the overall phase of the experimentally observed oscillation will reflect this phase dependence. Another consequence is that the overall oscillation amplitude can show interference patterns resulting from overlapping contributions from neighboring Feynman diagrams. These observations are consistently reproduced through simulations based on third order perturbation theory coupled to a spectral density described by a Brownian oscillator model

    Longitudinal changes in blood pressure and fasting plasma glucose among 5,398 primary care patients with concomitant hypertension and diabetes: An observational study and implications for community-based cardiovascular prevention

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    AimsTo assess longitudinal changes in blood pressure (BP) and fasting plasma glucose (FPG) in primary care patients with concomitant hypertension and type 2 diabetes mellitus (T2DM), and to explore factors associated with patients' inability to improve BP and FPG at follow-up.MethodsWe constructed a closed cohort in the context of the national basic public health (BPH) service provision in an urbanised township in southern China. Primary care patients who had concomitant hypertension and T2DM were retrospectively followed up from 2016 to 2019. Data were retrieved electronically from the computerised BPH platform. Patient-level risk factors were explored using multivariable logistic regression analysis.ResultsWe included 5,398 patients (mean age 66 years; range 28.9 to 96.1 years). At baseline, almost half [48.3% (2,608/5,398)] of patients had uncontrolled BP or FPG. During follow-up, more than one-fourth [27.2% (1,467/5,398)] of patients had no improvement in both BP and FPG. Among all patients, we observed significant increases in systolic BP [2.31 mmHg, 95% confidence interval (CI): 2.04 to 2.59, p &lt; 0.001], diastolic BP (0.73 mmHg, 0.54 to 0.92, p &lt; 0.001), and FPG (0.12 mmol/l, 0.09 to 0.15, p &lt; 0.001) at follow-up compared to baseline. In addition to changes in body mass index [adjusted odds ratio (aOR)=1.045, 1.003 to 1.089, p = 0.037], poor adherence to lifestyle advice (aOR = 1.548, 1.356 to 1.766, p &lt; 0.001), and unwillingness to actively enrol in health-care plans managed by the family doctor team (aOR = 1.379, 1.128 to 1.685, p = 0.001) were factors associated with no improvement in BP and FPG at follow-up.ConclusionA suboptimal control of BP and FPG remains an ongoing challenge to primary care patients with concomitant hypertension and T2DM in real-world community settings. Tailored actions aiming to improve patients' adherence to healthy lifestyles, expand the delivery of team-based care, and encourage weight control should be incorporated into routine healthcare planning for community-based cardiovascular prevention

    Quantifying Inactive Lithium in Lithium Metal Batteries

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    Inactive lithium (Li) formation is the immediate cause of capacity loss and catastrophic failure of Li metal batteries. However, the chemical component and the atomic level structure of inactive Li have rarely been studied due to the lack of effective diagnosis tools to accurately differentiate and quantify Li+ in solid electrolyte interphase (SEI) components and the electrically isolated unreacted metallic Li0, which together comprise the inactive Li. Here, by introducing a new analytical method, Titration Gas Chromatography (TGC), we can accurately quantify the contribution from metallic Li0 to the total amount of inactive Li. We uncover that the Li0, rather than the electrochemically formed SEI, dominates the inactive Li and capacity loss. Using cryogenic electron microscopies to further study the microstructure and nanostructure of inactive Li, we find that the Li0 is surrounded by insulating SEI, losing the electronic conductive pathway to the bulk electrode. Coupling the measurements of the Li0 global content to observations of its local atomic structure, we reveal the formation mechanism of inactive Li in different types of electrolytes, and identify the true underlying cause of low Coulombic efficiency in Li metal deposition and stripping. We ultimately propose strategies to enable the highly efficient Li deposition and stripping to enable Li metal anode for next generation high energy batteries

    Band Edge Tailoring in Few-Layer Two-Dimensional Molybdenum Sulfide/Selenide Alloys

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    Chemical alloying is a powerful approach to tune the electronic structure of semiconductors and has led to the synthesis of ternary and quaternary two-dimensional (2D) dichalcogenide semiconductor alloys (e.g., MoSSe₂, WSSe₂, etc.). To date, most of the studies have been focused on determining the chemical composition by evaluating the optical properties, primarily via photoluminescence and reflection spectroscopy of these materials in the 2D monolayer limit. However, a comprehensive study of alloying in multilayer films with direct measurement of electronic structure, combined with first-principles theory, is required for a complete understanding of this promising class of semiconductors. We have combined first-principles density functional theory calculations with experimental characterization of MoS_(2(1-x))Se_(2x) (where x ranges from 0 to 1) alloys using X-ray photoelectron spectroscopy to evaluate the valence and conduction band edge positions in each alloy. Moreover, our observations reveal that the valence band edge energies for molybdenum sulfide/selenide alloys increase as a function of increasing selenium concentration. These experimental results agree well with the results of density functional theory calculations showing a similar trend in calculated valence band edges. Our studies suggest that alloying is an effective technique for tuning the band edges of transition-metal dichalcogenides, with implications for applications such as solar cells and photoelectrochemical devices
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