Optimized intermolecular potential for nitriles based on Anisotropic United Atoms model

An extension of the Anisotropic United Atoms intermolecular potential model is proposed for nitriles. The electrostatic part of the intermolecular potential is calculated using atomic charges obtained by a simple Mulliken population analysis. The repulsion-dispersion interaction parameters for methyl and methylene groups are taken from transferable AUA4 literature parameters [Ungerer et al., J. Chem. Phys., 2000, 112, 5499]. Non-bonding Lennard-Jones intermolecular potential parameters are regressed for the carbon and nitrogen atoms of the nitrile group (–C≡N) from experimental vapor-liquid equilibrium data of acetonitrile. Gibbs Ensemble Monte Carlo simulations and experimental data agreement is very good for acetonitrile, and better than previous molecular potential proposed by Hloucha et al. [J. Chem. Phys., 2000, 113, 5401]. The transferability of the resulting potential is then successfully tested, without any further readjustment, to predict vapor-liquid phase equilibrium of propionitrile and n-butyronitrile

Optimization of an Electron Transport Layer to Enhance the Power Conversion Efficiency of Flexible Inverted Organic Solar Cells

The photovoltaic (PV) performance of flexible inverted organic solar cells (IOSCs) with an active layer consisting of a blend of poly(3-hexylthiophene) and [6, 6]-phenyl C61-butlyric acid methyl ester was investigated by varying the thicknesses of ZnO seed layers and introducing ZnO nanorods (NRs). A ZnO seed layer or ZnO NRs grown on the seed layer were used as an electron transport layer and pathway to optimize PV performance. ZnO seed layers were deposited using spin coating at 3,000 rpm for 30 s onto indium tin oxide (ITO)-coated polyethersulphone (PES) substrates. The ZnO NRs were grown using an aqueous solution method at a low temperature (90°C). The optimized device with ZnO NRs exhibited a threefold increase in PV performance compared with that of a device consisting of a ZnO seed layer without ZnO NRs. Flexible IOSCs fabricated using ZnO NRs with improved PV performance may pave the way for the development of PV devices with larger interface areas for effective exciton dissociation and continuous carrier transport paths

Can an hour or two of sun protection education keep the sunburn away? Evaluation of the Environmental Protection Agency's Sunwise School Program

BACKGROUND: Melanoma incidence is rising at a rate faster than any other preventable cancer in the United States. Childhood exposure to ultraviolet (UV) light increases risk for skin cancer as an adult, thus starting positive sun protection habits early may be key to reducing the incidence of this disease. METHODS: The Environmental Protection Agency's SunWise School Program, a national environmental and health education program for sun safety of children in primary and secondary schools (grades K-8), was evaluated with surveys administered to participating students and faculty. RESULTS: Pretests (n = 5,625) and posttests (n = 5,028) were completed by students in 102 schools in 42 states. Significant improvement was noted for the three knowledge variables. Intentions to play in the shade increased from 68% to 75%(p < 0.001) with more modest changes in intentions to use sunscreen. Attitudes regarding healthiness of a tan also decreased significantly. CONCLUSIONS: Brief, standardized sun protection education can be efficiently interwoven into existing school curricula, and result in improvements in knowledge and positive intentions for sun protection

Efficient Construction of an Inverted Minimal H1 Promoter Driven siRNA Expression Cassette: Facilitation of Promoter and siRNA Sequence Exchange

RNA interference (RNAi), mediated by small interfering RNA (siRNA), is an effective method used to silence gene expression at the post-transcriptional level. Upon introduction into target cells, siRNAs incorporate into the RNA-induced silencing complex (RISC). The antisense strand of the siRNA duplex then "guides" the RISC to the homologous mRNA, leading to target degradation and gene silencing. In recent years, various vector-based siRNA expression systems have been developed which utilize opposing polymerase III promoters to independently drive expression of the sense and antisense strands of the siRNA duplex from the same template.We show here the use of a ligase chain reaction (LCR) to develop a new vector system called pInv-H1 in which a DNA sequence encoding a specific siRNA is placed between two inverted minimal human H1 promoters (approximately 100 bp each). Expression of functional siRNAs from this construct has led to efficient silencing of both reporter and endogenous genes. Furthermore, the inverted H1 promoter-siRNA expression cassette was used to generate a retrovirus vector capable of transducing and silencing expression of the targeted protein by>80% in target cells.The unique design of this construct allows for the efficient exchange of siRNA sequences by the directional cloning of short oligonucleotides via asymmetric restriction sites. This provides a convenient way to test the functionality of different siRNA sequences. Delivery of the siRNA cassette by retroviral transduction suggests that a single copy of the siRNA expression cassette efficiently knocks down gene expression at the protein level. We note that this vector system can potentially be used to generate a random siRNA library. The flexibility of the ligase chain reaction suggests that additional control elements can easily be introduced into this siRNA expression cassette

Quality of Data Entry Using Single Entry, Double Entry and Automated Forms Processing–An Example Based on a Study of Patient-Reported Outcomes

Background: The clinical and scientific usage of patient-reported outcome measures is increasing in the health services. Often paper forms are used. Manual double entry of data is defined as the definitive gold standard for transferring data to an electronic format, but the process is laborious. Automated forms processing may be an alternative, but further validation is warranted. Methods: 200 patients were randomly selected from a cohort of 5777 patients who had previously answered two different questionnaires. The questionnaires were scanned using an automated forms processing technique, as well as processed by single and double manual data entry, using the EpiData Entry data entry program. The main outcome measure was the proportion of correctly entered numbers at question, form and study level. Results: Manual double-key data entry (error proportion per 1000 fields = 0.046 (95 % CI: 0.001–0.258)) performed better than single-key data entry (error proportion per 1000 fields = 0.370 (95 % CI: 0.160–0.729), (p = 0.020)). There was no statistical difference between Optical Mark Recognition (error proportion per 1000 fields = 0.046 (95 % CI: 0.001–0.258)) and double-key data entry (p = 1.000). With the Intelligent Character Recognition method, there was no statistical difference compared to single-key data entry (error proportion per 1000 fields = 6.734 (95 % CI: 0.817–24.113), (p = 0.656)), as well as double-key data entry (error proportion per 1000 fields = 3.367 (95 % CI: 0.085–18.616)), (p = 0.319))

Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers

We present a review of the interplay between the evolution of circumstellar disks and the formation of planets, both from the perspective of theoretical models and dedicated observations. Based on this, we identify and discuss fundamental questions concerning the formation and evolution of circumstellar disks and planets which can be addressed in the near future with optical and infrared long-baseline interferometers. Furthermore, the importance of complementary observations with long-baseline (sub)millimeter interferometers and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics Review"; The final publication is available at http://www.springerlink.co

"Single nucleotide polymorphisms of the OPG/RANKL system genes in primary hyperparathyroidism and their relationship with bone mineral density"

<p>Abstract</p> <p>Background</p> <p>Primary hyperparathyroidism (PHPT) affects mainly cortical bone. It is thought that parathyroid hormone (PTH) indirectly regulates the activity of osteoclasts by means of the osteoprotegerin/ligand of the receptor activator of nuclear factor-κβ (OPG/RANKL) system. Several studies have confirmed that <it>OPG </it>(osteoprotegerin) and <it>RANKL </it>(ligand of the receptor activator of nuclear factor-κβ) loci are determinants of bone mineral density (BMD) in the general population. The aim of this study is to analyze the relationship between fractures and BMD and the rs3102735 (163 A/G), rs3134070 (245 T/G) and rs2073618 (1181 G/C) SNPs of the <it>OPG </it>and the rs2277438 SNP of the <it>RANKL</it>, in patients with sporadic PHPT.</p> <p>Methods</p> <p>We enrolled 298 Caucasian patients with PHPT and 328 healthy volunteers in a cross-sectional study. We analyzed anthropometric data, history of fractures or renal lithiasis, biochemical determinants including markers for bone remodelling, BMD measurements in the lumbar spine, total hip, femoral neck and distal radius, and genotyping for the SNPs to be studied.</p> <p>Results</p> <p>Regarding the age of diagnosis, BMI, menopause status, frequency of fractures or renal lithiasis, we found no differences between genotypes in any of the SNPs studied in the PHPT group. Significant lower BMD in the distal radius with similar PTH levels was found in the minor allele homozygotes (GG) compared to heterozygotes and major allele homozygotes in both <it>OPG </it>rs3102735 (163 A/G) and <it>OPG </it>rs3134070 (245 T/G) SNPs in those with PHPT compared to control subjects. We found no differences between genotypes of the <it>OPG </it>rs2073618 (1181 G/C) SNP with regard to BMD in the PHPT subjects. In the evaluation of rs2277438 SNP of the <it>RANKL </it>in PHPT patients, we found a non significant trend towards lower BMD in the 1/3 distal radius and at total hip in the minor allele homocygotes (GG) genotype group versus heterocygotes and major allele homocygotes (AA).</p> <p>Conclusions</p> <p>Our study provides the first evaluation of the relationship between SNPs of the <it>OPG/RANK </it>system and sporadic PHPT. Subjects with PHPT and minor homocygote genotype (GG) for the <it>OPG </it>rs3102735 (163 A/G) and <it>OPG </it>rs3134070 (245 T/G) SNPs have lower BMD in the distal radius, and this association does not appear to be mediated by differences in PTH serum levels.</p

Screening for low bone mass with quantitative ultrasonography in a community without dual-energy X-ray absorptiometry: population-based survey

BACKGROUND: Dual-energy x-ray absorptiometry (DXA) is the criterion standard to identify low bone mineral density (BMD), but access to axial DXA may be limited or cost prohibitive. We screened for low bone mass with quantitative ultrasonography (QUS) in a community without DXA, analyzed its reliability and obtained reference values and estimated the prevalence of low QUS values. METHODS: We enrolled 6493 residents of Kinmen, Taiwan, and a reference group (96 men and 70 women aged 20–29 years) for this cross-sectional, community-based study. All participants completed a questionnaire and underwent ultrasonographic measurements. Reliability and validity of QUS measurements were evaluated. Broadband ultrasound attenuation (BUA) values were obtained and statistically analyzed by age, sex and weight. Annual loss of BUA was determined. Trends in the prevalence of QUS scores were evaluated. RESULTS: Two QUS were used and had a correlation coefficient of 0.90 (p < 0.001). Calcaneal BUA was significantly correlated with BMD in the femoral neck (r = 0.67, p < 0.001) and BMD of the total lumbar spine (r = 0.59, p < 0.001). BUAs in the reference group were 92.72 ± 13.36 and 87.90 ± 10.68 dB/MHz for men and women, respectively. Estimated annual losses of calcaneal BUA were 0.83% per year for women, 0.27% per year for men, and 0.51% per year for the total population. The prevalence of severely low QUS values (T-score = -2.5) tended to increase with aging in both sexes (p < 0.001). Across age strata, moderately low QUS values (-2.5 < T-score < -1.0) were 31.6–41.0% in men and 23.7–38.1% in women; a significant trend with age was observed in men (p < 0.001). CONCLUSION: Age-related decreases in calcaneal ultrasonometry, which reflected the prevalence of low bone mass, were more obvious in women than in men