Synthesis of ligand-free CZTS nanoparticles via a facile hot injection route.

Single-phase, ligand-free Cu2ZnSnS4 (CZTS) nanoparticles that can be dispersed in polar solvents are desirable for thin film solar cell fabrication, since water can be used as the solvent for the nanoparticle ink. In this work, ligand-free nanoparticles were synthesized using a simple hot injection method and the precursor concentration in the reaction medium was tuned to control the final product. The as-synthesized nanoparticles were characterized using various techniques, and were found to have a near-stoichiometric composition and a phase-pure kesterite crystal structure. No secondary phases were detected with Raman spectroscopy or scanning transmission electron microscopy energy dispersive x-ray spectroscopy. Furthermore, high resolution transmission electron microscopy showed large-sized nanoparticles with an average diameter of 23 nm ± 11 nm. This approach avoids all organic materials and toxic solvents that otherwise could hinder grain growth and limit the deposition techniques. In addition the synthesis route presented here results in nanoparticles of a large size compared to other ligand-free CZTS nanoparticles, due to the high boiling point of the solvents selected. Large particle size in CZTS nanoparticle solar cells may lead to a promising device performance. The results obtained demonstrate the suitability of the synthesized nanoparticles for application in low cost thin film solar cells.

The CEPHEUS Pan-Asian survey: high low-density lipoprotein cholesterol goal attainment rate among hypercholesterolaemic patients undergoing lipid-lowering treatment in a Hong Kong regional centre.

OBJECTIVES. To evaluate attainment of low-density lipoprotein cholesterol goals among hypercholesterolaemic patients undergoing lipid-lowering drug treatment in Hong Kong and to identify potential determinants of treatment outcomes. DESIGN. Cross-sectional observational study. SETTING. A single site in Hong Kong, as part of the CEPHEUS Pan-Asian survey. PATIENTS. Subjects with hypercholesterolaemia aged 18 years or above, who had been on lipid-lowering drug treatment for at least 3 months with no dose adjustment for at least 6 weeks. RESULTS. A total of 561 such patients (mean age, 65.3; standard deviation, 9.7 years) were evaluated. Most had major cardiovascular risk factors; 534 (95.2%) of 561 patients had coronary heart disease and 534 (95.4%) of 560 patients had low-density lipoprotein cholesterol goals set at lower than 70 mg/dL. In all, 465 (82.9%) patients attained their respective low-density lipoprotein cholesterol goals. Among 75 patients who had coronary heart disease or equivalent risk, and multiple risk factors with a 10-year coronary heart disease risk of over 20%, 62 (82.7%) attained their respective low-density lipoprotein cholesterol goals. Significant predictors of low-density lipoprotein cholesterol goal attainment included the patient's baseline lipid profile (total cholesterol and low-density lipoprotein cholesterol levels), blood pressure, and drugs (statin/non-statin) used for treatment. CONCLUSIONS. Hypercholesterolaemic patients undergoing lipid-lowering drug treatment in the present Hong Kong study were able to achieve a very high attainment rate for the low-density lipoprotein cholesterol goal, despite the fact that most of them had major cardiovascular risk factors.

Does measurement of the anatomic axis consistently predict hip-knee-ankle angle (HKA) for knee alignment studies in osteoarthritis? Analysis of long limb radiographs from the multicenter osteoarthritis (MOST) study.

OBJECTIVE: Researchers commonly use the femoral shaft-tibial shaft angle (FS-TS) from knee radiographs to estimate the hip-knee-ankle angle (HKA) in studies examining risk factors for knee osteoarthritis (OA) incidence and progression. The objective of this study was to determine the relationship between HKA and FS-TS, depending on the method of calculating FS-TS and the direction and degree of knee deformity. METHODS: 120 full-length digital radiographs were assigned, with 30 in each of four alignment groups (0.0°-4.9°, and ≥5.0° of varus and valgus), from a large cohort of persons with and at risk of knee OA. HKA and five measures of FS-TS (using progressively shorter shaft lengths) were obtained using Horizons Analysis Software, Orthopaedic Alignment & Imaging Systems Inc. (OAISYS). The offsets between HKA and the different versions of FS-TS were calculated, with 95% confidence intervals (CIs). Pearson correlations were calculated. RESULTS: In varus limbs use of a shorter shaft length increased the offset between HKA and FS-TS from 5.1° to 7.0°. The opposite occurred with valgus limbs (from 5.0° to 3.7°). Correlations between HKA and FS-TS for the whole sample of 120 individuals were excellent (r range 1.00-0.88). However, correlations for individual alignment groups were low to moderate, especially for the shortest-shaft FS-TS (r range 0.41-0.66). CONCLUSIONS: The offsets obtained using the shorter FS-TS measurements vary depending on direction and degree of knee deformity, and therefore may not provide reliable predictions for HKA We recommend that full-length radiographs be used whenever an accurate estimation of HKA is required, although broad categories of alignment can be estimated with FS-TS.

STEM electron beam-induced current measurements of organic-inorganic perovskite solar cells.

We describe a new approach for preparing organic-inorganic perovskite solar cells for electron beam-induced current (EBIC) measurements in plan-view geometry. This method substantially reduces sample preparation artefacts, provides good electrical contact and keeps the preparation steps as close as possible to those for real devices. Our EBIC images were acquired simultaneously with annular dark-field scanning transmission electron microscopy images using a home-made highly sensitive EBIC amplifier. High-angle annular dark-field images and energy dispersive X-ray maps were recorded from the same area immediately afterwards. This allowed the EBIC contrast to be correlated with regions containing N and a deficiency of O. The EBIC contrast was also found to be similar to secondary electron contrast recorded with a scanning electron microscope. By identifying the generation and absorption electron processes, we determine that EBIC cannot be separated from the secondary electron and absorbed currents. This means that careful analysis needs to be performed before conclusions can be made on the origin of the current measured across p-n or p-i-n junctions.

Evaluation of acute bronchodilator reversibility in patients with symptoms of GOLD stage I COPD.

BACKGROUND: Patients with symptoms of GOLD stage I chronic obstructive pulmonary disease (COPD) can have significant abnormalities of ventilatory mechanics with greater exertional symptoms and exercise limitation than age-matched healthy subjects. In such patients the impact of bronchodilator therapy remains unknown and is difficult to evaluate. METHODS: The acute effects of nebulised ipratropium bromide 500 microg (IB) on resting pulmonary function and on dyspnoea and ventilatory parameters during symptom-limited constant work rate cycle exercise were measured. In a randomised double-blind crossover study, 16 patients with COPD (mean (SD) post-bronchodilator forced expiratory volume in 1 s (FEV(1)) 90 (7)% predicted, FEV(1)/forced vital capacity (FVC) 59 (7)%) with a significant smoking history (mean (SD) 44 (16) pack-years) inhaled either IB or placebo on each of two separate visits. Pulmonary function tests and cycle exercise at 80-85% of each subject's maximal work capacity were performed 2 h after dosing. RESULTS: Compared with placebo, FEV(1) increased 5 (9)% predicted, residual volume decreased 12 (20)% predicted and specific airway resistance decreased 81 (93)% predicted (all p<0.05) after IB. At a standardised time during exercise, dynamic inspiratory capacity and tidal volume significantly increased in tandem by 0.12 and 0.16 litres, respectively (each p<0.05), dyspnoea fell by 0.9 (1.8) Borg units (p = 0.07) and dyspnoea/ventilation ratios fell significantly (p<0.05). The fall in dyspnoea intensity at higher submaximal ventilations correlated with the concurrent decrease in end-expiratory lung volume (p<0.05). CONCLUSION: In patients with symptoms of GOLD stage I COPD, IB treatment is associated with modest but consistent improvements in airway function, operating lung volumes and dyspnoea intensity during exercise. These results provide a physiological rationale for a trial of bronchodilator therapy in selected patients with milder but symptomatic COPD.

Reliability of ventilatory parameters during cycle ergometry in multicentre trials in COPD.

We studied the distribution profiles and repeatability of key exercise performance parameters in the first large multicentre trials to include these measurements in chronic obstructive pulmonary disease (COPD). After a screening visit, 463 subjects with COPD (mean+/-SD forced expiratory volume in 1 s 43+/-13% predicted) completed two run-in visits before treatment randomisation. At the run-in visits, measurements were conducted at rest, at a standardised time near end-exercise (isotime) and at peak exercise during constant work rate (CWR) cycle tests at 75% of each individual's maximum work capacity. The intraclass correlation coefficient was used to evaluate the test-retest repeatability of measurements of endurance time (ET), inspiratory capacity (IC), ventilation and dyspnoea intensity (Borg scale) during exercise. IC, ventilation and dyspnoea ratings were normally distributed; ET showed rightward skew (median or = 0.87). Ventilation was repeatable over the same time-points (R > or = 0.92), as was dyspnoea intensity at isotime (R = 0.79) and at peak exercise (R = 0.81). In conclusion, key perceptual and ventilatory parameters can be reliably measured during CWR cycle exercise in multicentre clinical trials in moderate to very severe COPD.

Isolated left ventricular non-compaction: an unusual indication for heart transplantation.

We report a patient with isolated left ventricular non-compaction diagnosed by echocardiography and cardiac magnetic resonance imaging. She developed refractory congestive heart failure and subsequently underwent successful heart transplantation. This type of cardiomyopathy is thought to be caused by the arrest of normal embryogenesis of the endocardium and myocardium. The spectrum of clinical, radiological, and pathological abnormalities is discussed.

Controlled synthesis and association behavior of graft Pluronic in aqueous solutions.

Poly(vinyl pyrrolidone) (PVP) was grafted onto Pluronic F127 (PEO-PPO-PEO) to produce novel amphiphilic PVP-g-F127 graft copolymers. A controlled synthesis method was used to graft PVP onto different parts of F127. Two types of graft polymers were obtained: one has PVP grafted onto the PEO part of F127 and the other has PVP grafted onto the PPO part of F127. The association behavior of the two modified polymers was examined using differential scanning calorimetry, surface tension measurements, and dynamic light scattering.

Synthesis and characterization of CdSe nanorods using a novel microemulsion method at moderate temperature.

CdSe nanoparticles have been successfully synthesized using a novel microemulsion method at moderate temperature. It is found that with a combination of the surfactant AOT and hydrazine hydrate, it is possible to control the morphology of the nanoparticles. The hydrazine hydrate acts as both a reducing agent and a templating agent that favors the formation of a rodlike structure. The composition, morphology and optical properties of the CdSe nanoparticles were investigated using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption spectroscopy, photoluminescence (PL) spectroscopy, energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FT-IR) spectroscopy. The nucleation and growth mechanism for this system is also proposed based on a time-dependent study. This synthesis route provides a moderate temperature (100 degrees C) method for synthesizing rodlike CdSe, hence reducing the possibility of oxidation of this chalcogenide compound.

Study of mixed micelles and interaction parameters for polymeric nonionic and normal surfactants.

Surface tension (ST) measurements were carried out on various binary mixtures of the "normal" surfactants, such as nonionic surfactant, hexaethylene glycol mono-n-dodecyl ether(C12EO6), and cationic surfactant, tetradecyltrimethylammonium bromide (TTAB), and polymeric copolymer, Pluronic F127, F127(PPO)-g-PVP, and F127(PEO)-g-PVP. In all cases mixed micellar aggregates were formed and critical micellar concentrations of binary mixtures containing different mole fractions of the surfactants were measured using surface tension measurement. In the region where mixed micelles are formed, the interaction of two "normal" surfactants and three "polymeric" nonionic surfactants showed synergistic behavior and the results were analyzed using a interaction parameter, beta, which characterized the interaction in the mixed micelle and introduced by a regular solution theory. The regular solution theory can be applied to describe the interaction between TTAB and C12EO6, and graft polymeric surfactants systems. The results discussed in this paper indicated that regular solution theory has broader extent of application.

A case of takotsubo cardiomyopathy: transient left ventricular apical ballooning.

A 78-year-old woman was admitted to hospital with central chest pain and the electrocardiographic and cardiac marker changes typical of acute anterior myocardial infarction. Coronary angiography revealed normal epicardial coronary arteries, and left ventriculography showed apical akinesis as well as basal hyperkinesis. This is a case of transient left ventricular apical ballooning or takotsubo cardiomyopathy, possibly attributable to catecholamine-mediated myocardial stunning.

Expression of the MRP and MDR1 multidrug resistance genes in small cell lung cancer.

Acquired multidrug resistance is a major obstacle to a cure for small cell lung cancer (SCLC). Overexpression of the MDR1 gene occurs infrequently in multidrug-resistant SCLC cell lines. The multidrug resistance protein (MRP) can confer multidrug resistance, but its role in clinically acquired drug resistance is unknown. The purpose of this study was to measure expression of MRP and MDR1 mRNA in cell lines and clinical samples from SCLC patients and to correlate the results with drug sensitivity profiles. Twenty-three SCLC cell lines and 10 tumor samples from SCLC patients were examined. Samples expressing MRP and MDR1 were identified by reverse transcription-PCR, and levels of MRP mRNA in the cell lines were measured by quantitative reverse transcription-PCR. One of 23 cell lines (4%) expressed MDR1 mRNA, whereas MRP expression was detected in 19 of 23 cell lines (83%). There was a significant correlation between doxorubicin resistance and MRP expression levels (r = 0.422; P = 0.045). Of the 10 clinical samples, 3 expressed only MRP, 2 expressed only MDR1, and 4 expressed both drug resistance genes. In summary, MRP is frequently expressed in clinical samples and cell lines from SCLC patients, and the levels correlate with doxorubicin resistance in unselected SCLC cell lines. Expression of MDR1 can be detected in clinical samples of SCLC but is rarely found in cell lines from drug-resistant patients. These multidrug resistance proteins may contribute to the multifactorial problem of clinically acquired drug resistance in SCLC.

Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-g-poly(vinylpyrrolidone): association behavior in aqueous solution and interaction with anionic surfactants.

In this work, we aimed to study the association and interaction behavior of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) block copolymers grafted with poly(vinylpyrrolidone). Critical micellization concentrations were determined using fluorescent probes (pyrene) and critical micellization temperatures characterizing temperature-dependent transitions from monomers to multimolecular micelles were measured. The thermal responsiveness of the copolymer is not affected by the grafting. The hydrodynamic radius of the graft copolymer micelles is found to be greater than that of the original copolymer micelles. The graft copolymer is found to form anisotropic aggregates. The structure of the graft copolymer micelles is less disrupted by the anionic surfactant sodium dodecyl sulfate, compared to the ungraft copolymer.

Bilateral massive adrenal hemorrhage. Assessment of putative risk factors by the case-control method.

Case reports and case series have identified putative risk factors for the development of bilateral massive adrenal hemorrhage (BMAH) in humans. The anatomy and physiology of the adrenal gland allow development of a model to fit the pathophysiology behind these risk factors. Until now, these risk factors were not systematically tested using analytical epidemiologic studies. A case-control study was undertaken using sources of cases and controls from multiple teaching hospitals in Ontario, Canada. The results of multivariate logistic regression indicated that thrombocytopenia (odds ratio [OR] = 14.6, 95% confidence intervals [CI] = 3.0-70.1, p < 0.001), heparin exposure of any route or type beyond 3 days (4-6 days: OR = 17.0, CI = 1.9-154.6; > 6 days: OR = 33.5, CI = 4.3-262.6; p < 0.001), and sepsis (OR = 6.3, CI = 1.2-32.2, p = 0.019) were most strongly and independently associated with development of BMAH. Another weaker positive association included invasive radiologic procedure (OR = 4.4, CI = 0.9-22.1, p = 0.055). Neither major surgery or duration of hospitalization were independent risk factors. Although coronary artery disease and possibly diabetes and hypertension appeared to be markers for lower risk of BMAH, this may be a result of bias introduced by using hospital controls ("Berkson bias"), as the effect was not explained by a protective effect of vasoactive medications. Thus, a picture of the high-risk patient should include a patient who has been treated with heparin (any route or type) beyond 3 days and has had thrombocytopenia (not necessarily induced by heparin) during the course of an illness. If the setting includes unexplained abdominal, chest, or back pain; fever; confusion; hypotension or shock; abrupt anemia; or electrolyte disorders, clinicians should not hesitate to cover empirically with lifesaving glucocorticoids while awaiting results of confirmatory tests.

Evaluation of the use of visual analogue scale in Chinese patients.

The linear analogue score can be used in Chinese patients with relative accuracy provided it has been well explained. The error from employing a vertical presentation is significantly less than that from a horizontal one. The choice of upward or downward orientation is a matter of convenience. Younger patients and those with higher intelligence are quicker to understand the concept and can make better judgement in placing a mark where they wish it to be. A linear analogue scale seems to be a suitable method to record and study pain in a Chinese population.

Continuous calcium chloride infusion for massive nifedipine overdose.

A 37-year-old woman presented with persistent hypotension and noncardiogenic pulmonary edema after massive nifedipine overdose. Judicious use of continuous and prolonged high-dose IV calcium infusion was administered to provide sustained increases in serum ionic calcium level (approximately 2 mmol/L) and was able to improve the hemodynamic status without any major adverse reaction.

A randomised cross-over trial comparing low-dose metoclopramide and chlorpromazine with high-dose metoclopramide in Chinese patients with advanced cancer receiving cisplatinum and 5-fluorouracil.

Nineteen Chinese patients receiving chemotherapy for advanced cancer were studied for chemotherapy-induced acute nausea and vomiting. The chemotherapy consisted of cisplatinum 100 mg/m2 i.v. infusion over 4 h on day 1 and 5-fluorouracil (5-FU) 1000 mg/m2 120-h continuous infusion from day 2 to day 6, repeated every 3 weeks. At the first course of chemotherapy the patients were randomized to receive either low-dose metoclopramide and chlorpromazine or high-dose metoclopramide, and then crossed over for the second course. In the high-dose metoclopramide group there was a suggestion of an earlier onset of emesis, with slightly more frequent retching and vomiting and less food consumed. However, the duration of emesis was shorter in the high-dose group. These differences were not statistically significant. There were no major side effects. Mild salutary drowsiness was noticed in patients receiving low-dose metoclopramide and chlorpromazine. This trial suggests that, in the dosage, route and schedule described, high-dose metoclopramide is no more effective than low-dose metoclopramide together with chlorpromazine in preventing cisplatinum-induced nausea and vomiting. The low-dose scheme is more economic and suitable for patients with advanced cancer.

Prognostic index in prediction of mortality from infective endocarditis.

Out of 176 patients with infective endocarditis complicating rheumatic (120) and congenital heart disease (38), mortality occurred in 35 patients (19.9%). Presence of leukocytosis, heart failure, major embolisation and isolation of certain organisms including Staphylococci, beta-haemolytic Streptococci, Pseudomonas and Klebsiella were ominous with higher mortality rates compared with those when they were absent (P less than 0.02). Stepwise logistic multiple regression was then applied and the four most important independent variables were identified. A prognostic index for the prediction of mortality for infective endocarditis was then constructed by the summation of the regression coefficients. By applying this index, patients with infective endocarditis could be divided into subgroups with increasing proportional mortality from 5.8 to 83.3%. It provides an objective assessment of the risk patients with infective endocarditis, and a more reliable evaluation of benefit of any new treatment regimen, including cardiac surgery, during the acute stage.

The significance of proteinuria in pre-eclampsia; proteinuria associated with low birth weight only in pre-eclampsia.

To examine the significance of proteinuria in pre-eclampsia, we studied 87 nulliparous patients in whom pre-eclampsia was diagnosed clinically and whose blood pressure and urine findings returned to normal after delivery. There was no difference in the gestation at diagnosis, highest systolic and diastolic blood pressures before treatment/delivery, or the number given antenatal hypotensive therapy between patients with proteinuria (group A, n = 46) and without proteinuria (group B, n = 41). Group A patients had higher plasma urea concentration (p less than 0.02), but similar creatinine and urate concentrations to group B patients. Group A patients had a higher rate of induction of labour (p less than 0.04) and Caesarean section before labour (p less than 0.04), and the mean gestation at delivery as well as the birth weight were less (p less than 0.03 and p less than 0.004, respectively). The results suggest that proteinuria in pre-eclampsia is associated with more severe fetal involvement and growth retardation only, but not with an increased severity of the maternal condition such as hypertension and a higher plasma urate concentration.