Temperature-dependent performance of amorphous silicon photovoltaic/thermal systems in the long term operation

The influences of temperature on the performance of amorphous silicon (a-Si) solar cells and photovoltaic (PV) systems are extensively studied in the literature. The benefit from thermal annealing effect at a higher temperature than ambient has been demonstrated, which makes a-Si cells a promising material for photovoltaic/thermal (PV/T) system. However, the temperature-dependent performance of a-Si PV/T system in the long term operation has rarely been reported. The temperature effect will be more complicated than that on a single cell or PV system. Particularly, the exergetic efficiency and mechanical behavior of the PV/T system at different temperatures are unknown. To fill the above knowledge gap, two identical a-Si PV/T systems are developed. One operates at a water inlet temperature of 60 °C with an a-Si cell temperature of up to 70 °C. The other operates at an inlet temperature of 30 °C. Long-term outdoor tests from December 2017 to June 2019 have been conducted. Results indicate that the difference in the electrical efficiency between the two systems is 0.47% in the initial stage, and it gradually narrows to only 0.13% over time. The overall exergy efficiency at 60 °C generally exceeds that at 30 °C, which proves the superiority of the a-Si PV/T operating at medium temperature. Besides, the long-term operation at 60 °C has not led to a lower level of reliability

Feasibility of an innovative amorphous silicon photovoltaic/thermal system for medium temperature applications

Medium temperature photovoltaic/thermal (PV/T) systems have immense potential in the applications of absorption cooling, thermoelectric generation, and organic Rankine cycle power generation, etc. Amorphous silicon (a-Si) cells are promising in such applications regarding the low temperature coefficient, thermal annealing effect, thin film and avoidance of large thermal stress and breakdown at fluctuating temperatures. However, experimental study on the a-Si PV/T system is rarely reported. So far the feasibility of medium temperature PV/T systems using a-Si cells has not been demonstrated. In this study, the design and construction of an innovative a-Si PV/T system of stainless steel substrate are presented. Long-term outdoor performance of the system operating at medium temperature has been monitored in the past 15 months. The average electrical efficiency was 5.65%, 5.41% and 5.30% at the initial, intermediate and final phases of the long-test test, accompanied with a daily average thermal efficiency from about 21% to 31% in the non-heating season. The thermal and electrical performance of the system at 60 °C, 70 °C and 80 °C are also analyzed and compared. Moreover, a distributed parameter model with experimental validation is developed for an inside view of the heat transfer and power generation and to predict the system performance in various conditions. Technically, medium temperature operation has not resulted in interruption or observable deformation of the a-Si PV/T system during the period. The technical and thermodynamic feasibility of the a-Si PV/T system at medium operating temperature is demonstrated by the experimental and simulation results

Characterizing Kirkwood-Dirac nonclassicality and uncertainty diagram based on discrete Fourier transform

In this paper, we investigate the Kirkwood-Dirac nonclassicality and uncertainty diagram based on discrete Fourier transform (DFT) in a $d$ dimensional system. The uncertainty diagram of complete incompatibility bases $\mathcal {A},\mathcal {B}$ are characterized by De Bi\`{e}vre [arXiv: 2207.07451]. We show that for the uncertainty diagram of the DFT matrix which is a transition matrix from basis $\mathcal {A}$ to basis $\mathcal {B}$, there is no ``hole" in the region of the $(n_{\mathcal {A}}, n_{\mathcal {B}})$-plane above and on the line $n_{\mathcal {A}}+n_{\mathcal {B}}\geq d+1$, whether the bases $\mathcal {A},\mathcal {B}$ are not complete incompatible bases or not. Then we present that the KD nonclassicality of a state based on the DFT matrix can be completely characterized by using the support uncertainty relation $n_{\mathcal {A}}(\psi)n_{\mathcal {B}}(\psi)\geq d$, where $n_{\mathcal {A}}(\psi)$ and $n_{\mathcal {B}}(\psi)$ count the number of nonvanishing coefficients in the basis $\mathcal {A}$ and $\mathcal {B}$ representations, respectively. That is, a state $|\psi\rangle$ is KD nonclassical if and only if $n_{\mathcal {A}}(\psi)n_{\mathcal {B}}(\psi)> d$, whenever $d$ is prime or not. That gives a positive answer to the conjecture in [Phys. Rev. Lett. \textbf{127}, 190404 (2021)]

Prevalence, predictors, and management for balloon uncrossable or undilatable lesions in patients undergoing percutaneous coronary intervention with in-stent restenosis chronic total occlusion

BackgroundPercutaneous coronary intervention for in-stent restenosis (ISR) chronic total occlusion (CTO) has been a great challenge. There are occasions when the balloon is uncrossable or undilatable (BUs) even though the guidewire has passed, leading to failure of the procedure. Few studies have focused on the incidence, predictors, and management of BUs during ISR-CTO intervention.MethodsPatients with ISR-CTO were recruited consecutively between January 2017 and January 2022 and divided into two groups based on the presence of BUs. The clinical data of the two groups (BUs group and non-BUs group) were retrospectively analyzed and compared to explore the predictors and clinical management strategies of BUs.ResultsA total of 218 patients with ISR-CTO were included in this study, 23.9% (52/218) of whom had BUs. The percentage of ostial stents, stent length, CTO length, the presence of proximal cap ambiguity, moderate to severe calcification, moderate to severe tortuosity, and J-CTO score were higher in the BUs group than in the non-BUs group (p < 0.05). The technical success rate and the procedural success rate were lower in the BUs group than in the non-BUs group (p < 0.05). Multivariable logistic regression analysis showed that ostial stents (OR: 2.011, 95% CI: 1.112–3.921, p = 0.031), the presence of moderate to severe calcification (OR: 3.383, 95% CI: 1.628–5.921, p = 0.024) and moderate to severe tortuosity (OR: 4.816, 95% CI: 2.038–7.772, p = 0.033) were independent predictors of BUs.ConclusionThe initial rate of BUs in ISR-CTO was 23.9%. Ostial stents, presence of moderate to severe calcification, and moderate to severe tortuosity were independent predictors of BUs

Association of soluble suppression of tumorigenicity 2 protein with new-onset atrial fibrillation in patients with acute ST-segment elevation myocardial infarction undergoing primary PCI

BackgroundPrevious studies have indicated that the soluble suppression of tumorigenicity 2 protein (sST2) is associated with new-onset atrial fibrillation (NOAF) in patients diagnosed with coronary artery disease (CAD). However, the predictive value of sST2 in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) has not been well studied.MethodsA total of 580 patients with STEMI undergoing primary PCI were consecutively recruited between January 2021 and January 2023. These patients were then categorized into two groups: the NOAF group and the no NOAF groups based on the presence of NOAF during admission. The concentration of sST2 in blood samples was measured in all patients. The clinical data from the two groups were prospectively analyzed to investigate the predictive factors of NOAF in patients with STEMI undergoing primary PCI.ResultsA total of 41 (7.1%) patients developed NOAF. The presence of NOAF has been found to be associated with various factors, including age, diabetes mellitus, hypertension, the left atrial (LA) diameter, N-terminal pro-brain natriuretic peptide, C-reactive protein (CRP), sST2, a Killip class of ≥2, and a final TIMI flow grade of <3. After including multiple factors, it was observed that LA diameter, CRP, sST2, a Killip class of ≥2, and a final TIMI flow grade of <3 remained significant risk factors for developing NOAF. The receiver operating characteristic (ROC) curve showed the following findings: (1) when the LA diameter exceeded 38.5 mm, the sensitivity and specificity values were observed to be 67.2% and 68.2%, respectively, and the area under the ROC curve (AUC) was 0.683 [95% confidence interval (CI): 0.545–0.732; p = 0.003]; (2) when the CRP level exceeded 8.59, the sensitivity and specificity values were observed to be 68.6% and 69.2%, respectively, and the AUC was 0.713 (95% CI: 0.621–0.778; p < 0.001); and (3) when the sST2 value exceeded 53.3, the sensitivity and specificity values were 79.2% and 68.7%, respectively, and the AUC was 0.799 (95% CI: 0.675–0.865; p < 0.001).ConclusionsST2 has been identified as an independent predictor of NOAF in patients with STEMI undergoing PCI

Fat fraction quantification of lumbar spine: comparison of T1-weighted two-point Dixon and single-voxel magnetic resonance spectroscopy in diagnosis of multiple myeloma

PURPOSEWe aimed to investigate the value of T1-weighted two-point Dixon technique and single-voxel magnetic resonance spectroscopy (MRS) in diagnosis of multiple myeloma (MM) through quantifying fat content of vertebral marrow.METHODSA total of 30 MM patients and 30 healthy volunteers underwent T1-weighted two-point Dixon and single-voxel MRS imaging. The fat fraction map (FFM) was reconstructed from the Dixon images using the equation FFM = Lip/In, where Lip represents fat maps and In represents in-phase images. The fat fraction (FF) of MRS was calculated by using the integral area of Lip peak divided by the sum of integral area of Lip peak and water peak.RESULTSFF values measured by the Dixon technique and MRS were significantly decreased in MM patients (45.99%±3.39% and 47.63%±4.38%) compared with healthy controls (64.43%±0.96% and 76.22%±1.91%) (P < 0.001 with both methods). FF values measured by Dixon technique were significantly positively correlated to those measured by MRS in MM (r = 0.837, P < 0.001) and healthy control group (r = 0.735, P < 0.001), respectively. There was no significant difference between area under the curve (AUC) obtained by the Dixon technique (0.878±0.047; range, 0.785 to 0.971; optimal cutoff, 56.35 for healthy controls vs. MM) and MRS (0.883±0.047; range, 0.791 to 0.974; optimal cutoff, 61.00 for healthy controls vs. MM). The ability of Dixon technique to differentiate MM group from healthy controls was equivalent to single-voxel MRS.CONCLUSIONRegarding detection of fat contents in vertebral bone, T1-weighted two-point Dixon technique exhibited equivalent performance to single-voxel MRS in the diagnosis of multiple myeloma. Moreover, two-point Dixon is a more convenient and stable technique for assessing bone marrow changes in MM patients than single-voxel MRS

Higher Serum Uric Acid Is Associated with Higher Bone Mineral Density in Chinese Men with Type 2 Diabetes Mellitus

Accumulating evidence suggests that oxidative stress is associated with osteoporosis. Serum uric acid (UA) is a strong endogenous antioxidant. Therefore, we investigated the relationship between the serum UA and BMD in Chinese men with T2DM. In this cross-sectional study of 621 men with T2DM, BMDs at lumbar spine (L2–4), femoral neck (FN), and total hip (TH) were measured by dual-energy X-ray absorptiometry (DXA). Serum levels of UA, calcium (Ca), 25-OH vitamin D3 (vitD3), parathyroid hormone (PTH), and creatinine (Cr) were also tested. Data analyses revealed that serum UA levels were positively associated with BMD at all sites (p<0.05) in men with T2DM after adjusting for multiple confounders. The serum UA levels were positively correlated with body weight (r=0.322), body mass index (BMI) (r=0.331), Ca (r=0.179), and Cr (r=0.239) (p<0.001) and were also positively associated with the concentrations of PTH (r=0.10, p<0.05). When compared with those in the lowest tertile of UA levels, men with T2DM in the highest tertile had a lower prevalence of osteoporosis or osteopenia (adjusted odds ratio 0.54, 95% confidence interval [CI] 0.31–0.95). These data suggest that higher serum levels of UA are associated with higher BMDs and lower risks of osteoporosis in Chinese men with T2DM

A functional nuclear localization sequence in the C-terminal domain of SHP-1

The Src homology 2 domain-containing protein tyrosine phosphatases SHP-1 and SHP-2 play an important role in many intracellular signaling pathways. Both SHP-1 and SHP-2 have been shown to interact with a diverse range of cytosolic and membrane-bound signaling proteins. Generally, SHP-1 and SHP-2 perform opposing roles in signaling processes; SHP-1 acts as a negative regulator of transduction in hemopoietic cells, whereas SHP-2 acts as a positive regulator. Intriguingly, SHP-1 has been proposed to play a positive regulating role in non-hemopoietic cells, although the mechanisms for this are not understood. Here we show that green fluorescent protein-tagged SHP-1 is unexpectedly localized within the nucleus of transfected HEK293 cells. In contrast, the highly related SHP-2 protein is more abundant within the cytoplasm of transfected cells. In accordance with this, endogenous SHP-1 is localized within the nucleus of several other nonhemopoietic cell types, whereas SHP-2 is distributed throughout the cytoplasm. In contrast, SHP-1 is confined to the cytoplasm of hemopoietic cells, with very little nuclear SHP-1 evident. Using chimeric SHP proteins and mutagenesis studies, the nuclear localization signal of SHP-1 was identified within the C-terminal domain of SHP-1 and found to consist of a short cluster of basic amino acids (KRK), Although the KRK motif resembles half of a bipartite nuclear localization signal, it appears to function independently and is absolutely required for nuclear import. Our findings show that SHP-1 and SHP-2 are distinctly localized within nonhemopoietic cells, with the localization of SHP-1 differing dramatically between nonhemopoietic and hemopoietic cell lineages. This implies that SHP-1 nuclear import is a tightly regulated process and indicates that SHP-1 may possess novel nuclear targets