595 research outputs found
Tectonic Implications of Stratigraphy Architecture in Distal Part of Foreland Basin, Southwestern Taiwan
Polythiophenes comprising conjugated pendantstoward long-term air-stable inverted polymer solar cellswith high open circuit voltages
A series of polythiophenes (PTs) functionalized with bulky conjugated side chains comprising tert-butylsubstituted carbazole (tCz) as an electron donor pendant and bisbenzothiazolylvinyl (DBT) as anelectron acceptor pendant were synthesized via Stille copolymerization for polymer solar cell (PSC)applications. We use the descriptors PTtCz, PT(tCz)0.9(DBT)0.1, PT(tCz)0.64(DBT)0.36, PT(tCz)0.45(DBT)0.55,and PTDBT to identify each of these conjugated polymers, with the names denoting the compositionsof the bulky pendants. The tunable energy levels of the PTs were accomplished by incorporating bothtCz as a donor pendant and DBT as an acceptor pendant, while retaining the low-lying HOMO levels( 5.26 to 5.39 eV). Furthermore, lower bandgaps were observed for the DBT-derived PTs because ofstronger donor–p–acceptor characteristics and more efficient intramolecular charge transfer.Conventional PSCs were fabricated by spin-coating the blend of each PT and the fullerene derivative(PC71BM). The conventional PSC devices exhibited high open circuit voltages (Voc) of around 0.79–0.91 V. The power conversion efficiency (PCE) of the PSCs based on PTtCz : PC71BM (w/w ¼ 1 : 2.5)reached 2.48% with a Voc of 0.91 V, short circuit current (Jsc) of 6.58 (mA cm 2) and fill factor (FF) of41% under the illumination of AM1.5, 100 mW cm 2. Furthermore, a PTtCz/PC71BM-based inverted PSCwith ZnOx and MoO3 as an electron extraction layer and a hole extraction layer respectively was capableof retaining ca. 80% of its original efficiency after storage under ambient conditions (withoutencapsulation) for 1032 h, according to the ISOS-D-1 shelf protocol. The highly durable inverted PSCaccompanied by a large Voc value was achieved for the PT-type polymers
catena-Poly[silver(I)-μ-acridine-9-carboxylato-κ3 N:O,O′]
In the title coordination polymer, [Ag(C14H8NO2)]n, the AgI cation is coordinated by two O atoms and one N atom from two symmetry-related acridine-9-carboxylate ligands in a distorted trigonal-planar geometry. The metal atoms are connected by the ligands to form chains running parallel to the b axis. π–π stacking interactions [centroid-to-centroid distances 3.757 (2)–3.820 (2) Å] and weak Ag⋯O interactions further link the chains to form a layer network parallel to the ab plane. The AgI cation is disordered over two positions, with refined site-occupancy factors of 0.73 (3):0.27 (3)
Combined effect of Cu- and ZnO- NPs on antibiotic resistance genes in an estuarine water
Most studies of whether and how nanoparticles (NPs) affect antibiotic resistance genes (ARGs) focus on testing single NPs type. In this study, we determined the combined effect of Cu- and ZnO- NPs in the water samples collected from the Yangtze River Estuary and found the effect differs greatly from that produced by individual NPs. The results showed that the Cu- and ZnO- NPs co-exposure resulted in an enrichment of ARGs, whereas individual Cu- and ZnO- NPs exposure decreased the abundance of ARGs. Furthermore, the co-exposure of Cu- and ZnO- NPs induced obvious changes in the microbial communities compared to the control communities. Redundancy analysis suggested that the microbial community contributed the most (43.5%) to the ARG profiles, followed by dissolved metal ions (25.7%), MRGs, (19.4%), and MGEs (4.4%). Network analysis found several potential hosts (such as Mycobacterium and Escherichia coli) and implied the extent of the risk of ARG transmission into various environmental niches by these common microbes
Novel polythiophene derivatives functionalized withconjugated side-chain pendants comprisingtriphenylamine/carbazole moieties for photovoltaic cellapplications†
We synthesized a series of polythiophenes (PTs) featuring 2-ethylhexyl-substituted terthiophene (T) orquaterthiophene (BT) as the conjugated unit in the polymer backbone with pendant conjugated tertbutyl-substituted triphenylamine (tTPA)- or carbazole (tCz)-containing moieties as side chains, namelyPTtTPA, PBTtTPA, PTtCz and PBTtCz. Incorporating T and BT moieties into the polymer backbone andattaching tTPA or tCz units promoted efficient conjugation within the extended conjugated frameworksof the polymers, resulting in lower band-gap energies and red-shifting of the maximal UV-Visabsorption wavelength. The higher electron-donating ability of tTPA resulted in broader absorptionbands and lower band-gap energies of PTtTPA and PBTtTPA as compared with PTtCz and PBTtCz.Incorporation of the T and BT moieties into the polymer backbone enhanced the compatibility of PTand the fullerene derivative by reducing the side-chain density of PT, thus providing sufficient freevolume for efficient incorporation of [6,6]phenyl-C61-butyric acid methyl ester (PC61BM) into thepolymer chains. Polymer solar cells (PSCs) were fabricated by spin-coating a blend of each PT with thefullerene derivative (PC61BM) as a composite film-type photoactive layer; PBTtTPA/PC61BM-based PSCsshowed superior photovoltaic (PV) performance to PTtTPA/PC61BM-based PSCs in terms of conjugationand absorption band broadness. However, PBTtCz/PC61BM-based PSCs showed inferior PV performanceto PTtCz/PC61BM-based PSCs. The lower HOMO level led to a higher open-circuit voltage (Voc; 0.74 V)and larger photo-energy conversion efficiency (h; 2.77%) of PTtCz/PC61BM-based PSCs
Prevalence and risk factors for diabetic retinopathy in a high-risk Chinese population
BACKGROUND: Lifestyle plays an important role in the development of diabetic retinopathy. The lifestyle in Guangzhou is different from other cities in China as the Cantonese prefer eating rice porridge, but not spicy foods. The objectives of this study were to investigate the prevalence and determinants of diabetic retinopathy in a high-risk population of Guangzhou. METHODS: Subjects (619 totals) aged over 45 years old, without known diabetes were recruited from five randomly selected Guangzhou communities in 2009–2010. All participants were invited to complete the Finnish Diabetes Risk Score (FINDRISC) questionnaire. Subjects with FINDRISC score ≥ 9 were included in the study, and underwent an investigation of demographic data, a standardized physical examination, ocular fundus examination, and laboratory analyses. The minimum criterion for diagnosis of diabetic retinopathy was the presence of at least one microaneurysm. RESULTS: Of 619 subjects, 208 eligible subjects (122 women) with FINDRISC score ≥ 9 were included in the study. The mean age was 69.2 ± 8.5 years. Diabetic retinopathy was detected in 31 subjects, and the prevalence of diabetic retinopathy in subjects with high risk for diabetes was 14.9%. In binary logistic regression analysis, risk factors associated with diabetic retinopathy were history of impaired glucose regulation [odds ratio (OR), 7.194; 95% confidence interval (CI): 1.083, 47.810], higher hemoglobin A1c (HbA1c; OR, 2.912; 95% CI: 1.009, 8.402), higher two-hour postprandial plasma glucose level (OR, 1.014; 95% CI: 1.003, 1.025), and presence of microalbuminuria (OR, 5.387; 95% CI: 1.255, 23.129). CONCLUSIONS: Diabetic retinopathy was prevalent in a high-risk Chinese population from Guangzhou. Histories of impaired glucose regulation and microalbuminuria were strong risk factors for diabetic retinopathy
Duration of untreated bipolar disorder: A multicenter study
Little is known about the demographic and clinical differences between short and long duration of untreated bipolar disorder (DUB) in Chinese patients. This study examined the demographic and clinical features of short (≤2 years) and long DUB (\u3e2 years) in China. A consecutively recruited sample of 555 patients with bipolar disorder (BD) was examined in 7 psychiatric hospitals and general hospital psychiatric units across China. Patients’ demographic and clinical characteristics were collected using a standardized protocol and data collection procedure. The mean DUB was 3.2 ± 6.0 years; long DUB accounted for 31.0% of the sample. Multivariate analyses revealed that longer duration of illness, diagnosis of BD type II, and earlier misdiagnosis of BD for major depressive disorder or schizophrenia were independently associated with long DUB. The mean DUB in Chinese BD patients was shorter than the reported figures from Western countries. The long-term impact of DUB on the outcome of BD is warranted
Prognosticators and Risk Grouping in Patients with Lung Metastasis from Nasopharyngeal Carcinoma: A more accurate and appropriate assessment of prognosis
<p>Abstract</p> <p>Background</p> <p>Lung metastases arising from nasopharyngeal carcinomas (NPC) have a relatively favourable prognosis. The purpose of this study was to identify the prognostic factors and to establish a risk grouping in patients with lung metastases from NPC.</p> <p>Methods</p> <p>A total of 198 patients who developed lung metastases from NPC after primary therapy were retrospectively recruited from January 1982 to December 2000. Univariate and multivariate analyses of clinical variables were performed using Cox proportional hazards regression models. Actuarial survival rates were plotted against time using the Kaplan-Meier method, and log-rank testing was used to compare the differences between the curves.</p> <p>Results</p> <p>The median overall survival (OS) period and the lung metastasis survival (LMS) period were 51.5 and 20.9 months, respectively. After univariate and multivariate analyses of the clinical variables, age, T classification, N classification, site of metastases, secondary metastases and disease-free interval (DFI) correlated with OS, whereas age, VCA-IgA titre, number of metastases and secondary metastases were related to LMS. The prognoses of the low- (score 0-1), intermediate- (score 2-3) and high-risk (score 4-8) subsets based on these factors were significantly different. The 3-, 5- and 10-year survival rates of the low-, intermediate- and high-risk subsets, respectively (P < 0.001) were as follows: 77.3%, 60% and 59%; 52.3%, 30% and 27.8%; and 20.5%, 7% and 0%.</p> <p>Conclusions</p> <p>In this study, clinical variables provided prognostic indicators of survival in NPC patients with lung metastases. Risk subsets would help in a more accurate assessment of a patient's prognosis in the clinical setting and could facilitate the establishment of patient-tailored medical strategies and supports.</p
- …