Analysis of gas chromatography/mass spectrometry data for catalytic lignin depolymerization using positive matrix factorization

Various catalytic technologies are being developed to efficiently convert lignin into renewable chemicals. However, due to its complexity, catalytic lignin depolymerization often generates a wide and complex distribution of product compounds. Gas chromatography/mass spectrometry (GC-MS) is a common analytical technique to profile the compounds that comprise lignin depolymerization products. GC-MS is applied not only to determine the product composition, but also to develop an understanding of the catalytic reaction pathways and of the relationships among catalyst structure, reaction conditions, and the resulting compounds generated. Although a very useful tool, the analysis of lignin depolymerization products with GC-MS is limited by the quality and scope of the available mass spectral libraries and the ability to correlate changes in GC-MS chromatograms to changes in lignin structure, catalyst structure, and other reaction conditions. In this study, the GC-MS data of the depolymerization products generated from organosolv hybrid poplar lignin using a copper-doped porous metal oxide catalyst and a methanol/dimethyl carbonate co-solvent was analyzed by applying a factor analysis technique, positive matrix factorization (PMF). Several different solutions for the PMF model were explored. A 13-factor solution sufficiently explains the chemical changes occurring to lignin depolymerization products as a function of lignin, reaction time, catalyst, and solvent. Overall, seven factors were found to represent aromatic compounds, while one factor was defined by aliphatic compounds

The role of error processing in the contextual interference effect during the training of perceptual-cognitive skills

The contextual interference (CI) effect refers to the learning benefits that occur from a random compared to blocked practice order. In this paper, the cognitive effort explanation for the CI effect was examined by investigating the role of error processing. In two experiments, a perceptual-cognitive task was used in which participants anticipated three different tennis skills across a pre-test, three practice sessions, and retention test. During practice, the skills were presented in either a random or blocked practice order. In Experiment 1, cognitive effort was examined using a probe reaction time task. In Experiment 2, cognitive effort was manipulated for two groups by inserting a cognitively demanding secondary task into the inter-trial interval. The CI effect was found in both experiments as the random groups displayed superior learning in the retention test compared to the blocked groups. Cognitive effort during practice was greater in random compared to blocked practice groups in Experiment 1. In Experiment 2, greater decrements in secondary task performance following an error were reported for the random group when compared to the blocked group. The suggestion is that not only the frequent switching of tasks in randomized orders causes increased cognitive effort and the CI effect, but it is also error processing in combination with task switching. Findings extend the cognitive effort explanation for the CI effect and propose an alternative hypothesis highlighting the role of error processing

New information on the Jurassic lepidosauromorph Marmoretta oxoniensis

The earliest known crown-group lepidosaurs are known from the Middle Triassic; however, their stem group is poorly sampled, with only a few representative fossils found. This is partly due to the small size and delicate bones of early stem-lepidosaurs (= non-lepidosaurian lepidosauromorphs), which make both preservation in the fossil record and subsequent discovery less likely. The Middle Jurassic lepidosauromorph Marmoretta oxoniensis is re-examined using high-resolution micro-computed tomography to reveal parts of the skull anatomy that were previously unknown. These include a squamosal, postorbital, more complete parietal, pterygoids, and an articulated posterior section of the mandible. Some differences between this and other Marmoretta specimens were identified as a result, such as the arrangement of palatal teeth and the shape of the parabasisphenoid. The status of Marmoretta as a stem-lepidosaur or stem-squamate has been debated. To evaluate this, we tested the phylogenetic position of Marmoretta by including our new data in an adapted phylogenetic character matrix. We recover Marmoretta as a stem-lepidosaur and sister to Fraxinisaura rozynekae. Our findings support the hypothesis that both taxa belonged to a clade of non-lepidosaurian lepidosauromorphs that co-existed with lepidosaurs into the Middle Jurassic

A reassessment of the enigmatic diapsid Paliguana whitei and the early history of Lepidosauromorpha

Lepidosaurs include lizards, snakes, amphisbaenians and the tuatara, comprising a highly speciose evolutionary radiation with widely varying anatomical traits. Their stem-lineage originated by the late middle Permian 259 million years ago, but its early fossil record is poorly documented, obscuring the origins of key anatomical and functional traits of the group. Paliguana whitei, from the Early Triassic of South Africa, is an enigmatic fossil species with the potential to provide information on this. However, its anatomy and phylogenetic affinities remain highly uncertain, and have been debated since its discovery more than 100 years ago. We present microtomographic three-dimensional imaging of the cranial anatomy of P. whitei that clarifies these uncertainties, providing strong evidence for lepidosauromorph affinities based on the structure of the temporal region and the implantation of marginal dentition. Phylogenetic analysis including these new data recovers Paliguana as the earliest known stem-lepidosaur, within a long-lived group of early diverging lepidosauromorphs that persisted to at least the Middle Jurassic. Our results provide insights into cranial evolution on the lepidosaur stem-lineage, confirming that characteristics of pleurodont dental implantation evolved early on the lepidosaur stem-lineage. By contrast, key functional traits related to hearing (quadrate conch) and feeding (streptostyly) evolved later in the lepidosaur crown-group

A July Spike in Fatal Medication Errors: A Possible Effect of New Medical Residents

residencies and acquire increased responsibility for patient care. Many have suggested that these new medical residents may produce errors and worsen patient outcomes—the so-called “July Effect; ” however, we have found no U.S. evidence documenting this effect. OBJECTIVE: Determine whether fatal medication errors spike in July

BRCA1 and BRCA2 mutations in a population-based study of male breast cancer

Background: The contribution of BRCA1 and BRCA2 to the incidence of male breast cancer (MBC) in the United Kingdom is not known, and the importance of these genes in the increased risk of female breast cancer associated with a family history of breast cancer in a male first-degree relative is unclear. Methods: We have carried out a population-based study of 94 MBC cases collected in the UK. We screened genomic DNA for mutations in BRCA1 and BRCA2 and used family history data from these cases to calculate the risk of breast cancer to female relatives of MBC cases. We also estimated the contribution of BRCA1 and BRCA2 to this risk. Results: Nineteen cases (20%) reported a first-degree relative with breast cancer, of whom seven also had an affected second-degree relative. The breast cancer risk in female first-degree relatives was 2.4 times (95% confidence interval [CI] = 1.4–4.0) the risk in the general population. No BRCA1 mutation carriers were identified and five cases were found to carry a mutation in BRCA2. Allowing for a mutation detection sensitivity frequency of 70%, the carrier frequency for BRCA2 mutations was 8% (95% CI = 3–19). All the mutation carriers had a family history of breast, ovarian, prostate or pancreatic cancer. However, BRCA2 accounted for only 15% of the excess familial risk of breast cancer in female first-degree relatives. Conclusion: These data suggest that other genes that confer an increased risk for both female and male breast cancer have yet to be found

Lack of insurance coverage and urgent care use for asthma: A retrospective cohort study

BACKGROUND: Asthma is a common chronic disease with profound impacts upon individuals and the US health care system. Inadequate health care coverage has been associated with more frequent and severe exacerbations of the disease. We examined the relationship between adequacy of health care coverage and use of emergent care of adults with asthma. METHODS: The 2001 Behavioral Risk Factor Surveillance System was the source of data on adults with current asthma. Bivariate and multiple logistic regression analysis modeled identifiable factors in predicting urgent or emergent care. RESULTS: Key variables included demographics and information on self-reported gaps in health care coverage. The primary outcome was emergency room or urgent care visits for worsening of asthma symptoms. Of 16,234 subjects nationally with current asthma, 2,195 from eight states had valid responses to a supplemental module asking about emergency room use or urgent care visits because of asthma. Thirty four percent of these individuals required such care in the previous year. Having an interruption in health care coverage in the past year was associated with an increased risk of needed urgent or emergent care (crude Odds Ratio [OR] 1.48, 95% confidence intervals [CI]1.03, 2.1). The association was not statistically significant in the adjusted multivariate model including race/ethnicity, employment status, gender, age, education and the ability to identify a primary physician (adjusted OR 1.2, 95% CI 0.8, 1.8). CONCLUSION: This study provides population-level, generalizable evidence of increased risk of exacerbations of asthma in adults and (1) their demographic characteristics, and (2) continuous adequate health care coverage

Choice of activity-intensity classification thresholds impacts upon accelerometer-assessed physical activity-health relationships in children

It is unknown whether using different published thresholds (PTs) for classifying physical activity (PA) impacts upon activity-health relationships. This study explored whether relationships between PA (sedentary [SED], light PA [LPA], moderate PA [MPA], moderate-to-vigorous PA, vigorous PA [VPA]) and health markers differed in children when classified using three different PTs

Universal access: the benefits and challenges in bringing integrated HIV care to isolated and conflict affected populations in the Republic of Congo

The Pool region of the Republic of Congo is an isolated, conflict-affected area with under-resourced and poorly functioning health care services. Despite significant AIDS-related mortality and morbidity in this area, and a national level commitment to universal HIV care, HIV has been largely neglected. In 2005 Médecins Sans Frontières decided to introduce HIV care activities. However, in this setting of high basic health care needs, limited medical resources and competing medical priorities, a vertical HIV programme was not suitable. This paper describes the process of integrating HIV care and treatment into basic health services, the clinical outcomes of 222 patients started on antiretroviral treatment (ART), and the benefits to communities and health care systems. Key lessons learned include the use of multi-skilled human resources, the step-wise implementation of HIV activities, the initial engagement of an HIV experienced staff member, the use of simplified and adapted testing, clinical and monitoring protocols and drug regimens, the introduction of more complex monitoring tools to simplify clinical management decisions and intensive staff education regarding the benefits of HIV integration. This project in a rural and remote conflict-affected setting demonstrates that integrated HIV programs can save lives and play a key role in helping to achieve universal access to ART in Africa