Factor structure of the CES-D and measurement invariance across gender for low-income Puerto Ricans in a probability sample.

Objective: The authors of this study aimed to evaluate 2-factor structures for the Center for Epidemiologic Studies Depression Scale (CES-D) reported in the literature to determine which one proves to be a better fit with the data on low-income Puerto Ricans living on the island. Method: The sample consisted of 3,504 civilian noninstitutionalized Puerto Ricans, ranging in age from 18 to 64 who were living in low-income areas of Puerto Rico. A confirmatory factor analysis (CFA) was implemented, and model fit was assessed with the Tucker–Lewis Index (TLI), the comparative fit index (CFI), and the root-mean-square error of approximation (RMSEA). Results: The CFA results obtained for the Radloff (1977) and Guarnaccia, Angel, and Worobey (1989) models show that neither model obtained adequate fit indexes. Exploratory factor analysis revealed that the 2-factor structure not only obtained better fit indexes (TLI = .948, CFI = .955, RMSEA = .048) but also reflected a better conceptual organization of the factors (basically divided into 2 components: Negative Affect and Positive Affect). When we assessed the model fit by gender, the model consistently fit the data for the female subsample but not for the male one. Conclusions: Results confirm the need to address the issues related to measurement equivalence for specific cultural and language gaps in assessment of depressive symptoms. Lack of factor invariance across gender also raises the question of the appropriateness of this measure for the male subsample and the need for further research in the manifestation of depression in this group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in rumen bacterial and archaeal communities over the transition period in primiparous Holstein dairy cows

In the present study, we hypothesized that the rumen bacterial and archaeal communities would change significantly over the transition period of dairy cows, mainly as an adaptation to the classical use of low-grain prepartum and high-grain postpartum diets. Bacterial 16S rRNA gene amplicon sequencing of rumen samples from 10 primiparous Holstein dairy cows revealed no changes over the transition period in relative abundance of genera such as Ruminococcus, Butyrivibrio, Clostridium, Coprococcus, and Pseudobutyrivibrio. However, other dominant genus-level taxa, such as Prevotella, unclassified Ruminococcaceae, and unclassified Succinivibrionaceae, showed distinct changes in relative abundance from the prepartum to the postpartum period. Overall, we observed individual fluctuation patterns over the transition period for a range of bacterial taxa that, in some cases, were correlated with observed changes in the rumen short-chain fatty acids profile. Combined results from clone library and terminal-restriction fragment length polymorphism (T-RFLP) analyses, targeting the methyl-coenzyme M reductase α-subunit (mcrA) gene, revealed a methanogenic archaeal community dominated by the Methanobacteriales and Methanomassiliicoccales orders, particularly the genera Methanobrevibacter, Methanosphaera, and Methanomassiliicoccus. As observed for the bacterial community, the T-RFLP patterns showed significant shifts in methanogenic community composition over the transition period. Together, the composition of the rumen bacterial and archaeal communities exhibited changes in response to particularly the dietary changes of dairy cows over the transition period.     

Synthesis of Carbonated Vernonia Oil

The research objective was to determine whether naturally occurring epoxy functional vernonia oil would result in lower viscosity compounds after converting the virgin oil into the cyclic carbonate using supercritical carbon dioxide as the reactant. The cyclic carbonate was produced using relatively mild conditions as described in the paper. Carbonated vernonia oil retains the characteristic low viscosity of vernonia oil, and offers potential as a valuable, biobased intermediate for synthesizing low viscosity resins.     

Short-term forecasting of crude petroleum and natural gas production

This paper details the Box-Jenkins approach to forecasting time series and applies it to short-term natural gas marketed production and crude petroleum production in the United States. After establishing the efficacy of the approach for forecasting the two series of interest, monthly forecasts for 1978 are made. The results indicate that natural gas production in 1978 will increase by 2·8 per cent over the 1977 level while crude petroleum production will fall by 4·0 per cent.     

Docking onto chromatin via the Saccharomyces cerevisiae Rad9 Tudor domain

An integrated cellular response to DNA damage is essential for the maintenance of genome integrity. Recently, post-translational modifications to histone proteins have been implicated in DNA damage responses involving the Rad9 family of checkpoint proteins. In budding yeast, methylation of histone H3 on lysine 79 (H3-K79me) has been shown to be required for efficient checkpoint signalling and Rad9 localization on chromatin. Here, we have used a rad9 Tudor mutant allele and cells mutated for Dot1, the H3-K79 methylase, to analyse the epistatic relationship between RAD9 and DOT1 genes regarding the DNA damage resistance and checkpoint activation pathways. Our results show that RAD9 is epistatic to DOT1 and suggest that it acts downstream of the Dot1 methylase in the damage resistance and checkpoint response. We have also found that the Tudor domain of Rad9 is necessary for in vitro binding to H3-K79me as well as Rad9 focal accumulation in response to DNA damage in vivo. In summary, our study demonstrates that the interaction between Rad9, via its Tudor domain, and methylated H3-K79 is required at two different steps of the DNA damage response, an early step corresponding to checkpoint activation, and a late step corresponding to DNA repair. The study further shows that the function of this interaction is cell cycle-regulated; the role in checkpoint activation is restricted to the G(1) phase and its role in DNA repair is restricted to G(2).     

Rapid Detection and Quantification of Triacylglycerol by HPLC–ELSD in Chlamydomonas reinhardtii and Chlorella Strains

Triacylglycerol (TAG) analysis and quantification are commonly performed by first obtaining a purified TAG fraction from a total neutral lipid extract using thin-layer chromatography (TLC), and then analyzing the fatty acid composition of the purified TAG fraction by gas chromatography (GC). This process is time-consuming, labor intensive and is not suitable for analysis of small sample sizes or large numbers. A rapid and efficient method for monitoring oil accumulation in algae using high performance liquid chromatography for separation of all lipid classes combined with detection by evaporative light scattering (HPLC–ELSD) was developed and compared to the conventional TLC/GC method. TAG accumulation in two Chlamydomonas reinhardtii (21 gr and CC503) and three Chlorella strains (UTEX 1230, CS01 and UTEX 2229) grown under conditions of nitrogen depletion was measured. The TAG levels were found to be 3–6 % DW (Chlamydomonas strains) and 7–12 % DW (Chlorella strains) respectively by both HPLC–ELSD and TLC/GC methods. HPLC–ELSD resolved the major lipid classes such as carotenoids, TAG, diacylglycerol (DAG), free fatty acids, phospholipids, and galactolipids in a 15-min run. Quantitation of TAG content was based on comparison to calibration curves of trihexadecanoin (16:0 TAG) and trioctadecadienoin (18:2 TAG) and showed linearity from 0.2 to 10 μg. Algal TAG levels >0.5 μg/g DW were detectable by this method. Furthermore TAG content in Chlorella kessleri UTEX 2229 could be detected. TAG as well as DAG and TAG content were estimated at 1.6 % DW by HPLC–ELSD, while it was undetectable by TLC/GC method.     

Intraphase Microstructure–Understanding the Impact on Organic Solar Cell Performance

A comprehensive study of the effect of intraphase microstructure on organic photovoltaic (OPV) device performance is undertaken. Utilizing a bilayer device architecture, a small molecule donor (TIPS‐DBC) is deposited by both spin‐coating and by thermal evaporation in vacuum. The devices are then completed by thermal evaporation of C₆₀, an exciton blocking layer and the cathode. This bilayer approach enables a direct comparison of device performance for donor layers in which the same material exhibits subtle differences in microstructure. The electrical performance is shown to differ considerably for the two devices. The bulk and interfacial properties of the donor layers are compared by examination with photoelectron spectroscopy in air (PESA), optical absorption spectroscopy, charge extraction of photo‐generated charge carriers by linearly increasing voltage (photo‐CELIV), time‐resolved photoluminescence measurements, X‐ray reflectometry (XR), and analysis of dark current behavior. The observed differences in device performance are shown to be influenced by changes to energy levels and charge transport properties resulting from differences in the microstructure of the donor layers. Importantly, this work demonstrates that in addition to the donor/acceptor microstructure, the intraphase microstructure can influence critical parameters and can therefore have a significant impact on OPV performance.     

Preparation,characterization, and mechanical properties of poly(ε‐caprolactone)/polylactic acid blend composites

Mechanical properties of poly(ε‐caprolactone) (PCL) and polylactic acid (PLA) blend reinforced with Dura and Tenera palm press fibers were studied. Dicumyl peroxide (DCP) was used as compatibilizer in the blend composites. Fourier transforms infrared spectrophotometer (FTIR) and field emission scanning electron microscope (FESEM) was used to study the effect of treatment on the fibers and fiber/matrix adhesion respectively. The uncompatibilized blend composites exhibited higher Young's modulus than the compatibilized blend composites. Impact strength of compatibilized blend composites of Tenera fibers (FM) increased by 161% at 10 wt% fiber load more than the uncompatibilized blend composites at same fiber load. The Dura fibers (FN) enhanced impact strength by 133% at 10 wt% fiber load. Tensile strength increased by 40% for compatibilized FM blend composites. In conclusion, it was observed that DCP incorporation resulted in good interfacial adhesion as revealed by the FESEM micrographs and evidenced in the improved mechanical properties. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Transient Behavior of Inclusion Chemistry,Shape, and Structure in Fe-Al-Ti-O Melts: Effect of Titanium/Aluminum Ratio

Metallurgical and Materials Transactions B - During ladle processing of interstitial-free (IF) steel melts, it is possible for transient titanium-containing oxides to be formed if the local...