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41.
Several classes of immunomodulators are used for treating relapsing-remitting multiple sclerosis (RRMS). Most of these disease-modifying therapies, except teriflunomide, carry the risk of progressive multifocal leukoencephalopathy (PML), a severely debilitating, often fatal virus-induced demyelinating disease. Because teriflunomide has been shown to have antiviral activity against DNA viruses, we investigated whether treatment of cells with teriflunomide inhibits infection and spread of JC polyomavirus (JCPyV), the causative agent of PML. Treatment of choroid plexus epithelial cells and astrocytes with teriflunomide reduced JCPyV infection and spread. We also used droplet digital PCR to quantify JCPyV DNA associated with extracellular vesicles isolated from RRMS patients. We detected JCPyV DNA in all patients with confirmed PML diagnosis (n = 2), and in six natalizumab-treated (n = 12), two teriflunomide-treated (n = 7), and two nonimmunomodulated (n = 2) patients. Of the 21 patients, 12 (57%) had detectable JCPyV in either plasma or serum. CSF was uniformly negative for JCPyV. Isolation of extracellular vesicles did not increase the level of detection of JCPyV DNA versus bulk unprocessed biofluid. Overall, our study demonstrated an effect of teriflunomide inhibiting JCPyV infection and spread in glial and choroid plexus epithelial cells. Larger studies using patient samples are needed to correlate these in vitro findings with patient data.  相似文献   
42.
Premature browning is a condition wherein ground beef exhibits a well‐done appearance before reaching the USDA recommended internal cooked meat temperature of 71.1 °C; however, the mechanism is unclear. The objectives of this study were: (1) to determine the effects of packaging and temperature on metmyoglobin reducing activity (MRA) of cooked ground beef patties and (2) to assess the effects of temperature and pH on thermal stability of NADH‐dependent reductase, lactate dehydrogenase (LDH), and oxymyoglobin (OxyMb) in‐vitro. Beef patties (lean: fat = 85:15) were packaged in high‐oxygen modified atmosphere (HiOX‐MAP) or vacuum (VP) and cooked to either 65 or 71 °C. Internal meat color and MRA of both raw and cooked patties were determined. Purified NADH‐dependent reductase and LDH were used to determine the effects of pH and temperature on enzyme activity. MRA of cooked patties was temperature and packaging dependent (P < 0.05). Vacuum packaged patties cooked to 71 °C had greater (P < 0.05) MRA than HiOX‐MAP counterparts. Thermal stability of OxyMb, NADH‐dependent reductase, and LDH were different and pH‐dependent. LDH was able to generate NADH at 84 °C; whereas NADH‐dependent reductase was least stable to heat. The results suggest that patties have MRA at cooking temperatures, which can influence cooked meat color.  相似文献   
43.
Emotional and motivational dysfunction is fundamental to schizophrenia, and yet, the nature and scope of associated deficits are not well understood. This study assessed the integrity of emotional responding from the perspective of its underlying motivational systems during different phases of schizophrenia. Evaluative, somatic, and autonomic responses were measured during viewing of pictures categorized by emotional content, including threat, mutilation, contamination, illness, pollution, mild erotica, families, food, and nature. Participants were 13 patients at ultra high risk or prodromal for psychosis, 40 first-episode schizophrenia patients, 37 chronic schizophrenia patients, and 74 healthy comparison subjects. Irrespective of phase of illness, schizophrenia patients showed a robust and normal pattern of response across multiple systems, with differential engagement of the defensive and appetitive systems as a function of the motivational significance assigned to specific emotional contexts. Although the integrity of core motivational states also appeared to be intact in prodromal patients, a less consistent pattern of response was observed. As continuing efforts are made to identify emotional and motivational abnormalities in schizophrenia, identified deficits will likely be independent of a fundamental dysfunction in basic emotion and motivation response systems and involve integration with higher order processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
44.
Using commitment theory, the present study explored longitudinal associations between physical aggression and various aspects of commitment and relationship stability. Participants (N = 1,278) were unmarried adults between the ages of 18 and 35 who were in a heterosexual romantic relationship at the time of the initial assessment. Of these, 51.6% reported never experiencing physical aggression in their current relationship, 12.8% reported experiencing physical aggression in the past, but not in the last year, and 35.6% reported experiencing physical aggression in the last year. As hypothesized, those who had experienced aggression in the last year were more likely to have broken up 1 year later. They also generally reported lower levels of dedication and higher levels of constraint commitment compared with those with no history of physical aggression. Among those who had experienced aggression in the last year, constraints and other commitment-related variables explained more about who broke up over time than did relationship adjustment alone, indicating the importance of measuring commitment constructs in future research about which aggressive couples are most likely to end their relationships. Clinical implications of these results are discussed, particularly in regard to preventive relationship education programs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
45.
Large river systems create challenges when sampling zooplankton. The dynamics of large rivers, spatial heterogeneity of biota, and behaviours of zooplankton can all contribute to large variation in estimation. The gear utilized for zooplankton collections may also be a factor, and there is not a well‐studied gear, nor industry standard, for collection in riverine systems. The lack of consistent sampling methods makes it difficult to compare zooplankton within and across systems. A standard method for zooplankton collection would be valuable for comparison among studies. To optimize zooplankton assessment in large river habitats, we tested how community estimations varied between four common zooplankton sampling devices across three river habitat types. We tested four gears: the Schindler–Patalas trap, integrated tube sampler, powered water pump, and horizontal tow net. Each device was used to collect samples in thalweg, channel border, and backwater river habitats within Pool 8 of the Upper Mississippi River in June, July, and August of 2017. Our results support that there are qualitative and quantitative differences in zooplankton estimates among gear in different habitats. The powered pump most often yielded highest abundances of total and individual zooplankton taxa allowing for more reliable community comparisons. With some modification, the pump is recommended as the most appropriate sampling gear when performing quantitative studies of zooplankton composition and abundance in large river habitats.  相似文献   
46.
On February 27 to 28, 2018, the Produce Safety Alliance convened a national water summit in Covington, KY to discuss the requirements of the United States Food and Drug Administration's (FDA) Food Safety Modernization Act Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption (Produce Safety Rule [PSR]). The goals of the meeting were to better understand the challenges growers face in implementing the requirements in Subpart E–Agricultural Water and work collaboratively to develop practical solutions to meet fruit and vegetable production needs while protecting public health. To meet these goals, the summit engaged a diverse group of stakeholders including growers, researchers, extension educators, produce industry members, and regulatory personnel. Key outcomes included defining implementation barriers due to diversity in water sources, distribution systems, commodity types, climates, farm size, and production activities. There was an articulated need for science‐based solutions, such as the use of agricultural water system assessments and sharing of federal, state, and regional water quality data, to ensure qualitative and quantitative standards reduce microbial risks. These identified challenges and needs resulted in significant debate about whether reopening the PSR–Subpart E for modification or attempting to address concerns through guidance would provide the best mechanism for alleviating concerns. In addition, training, outreach, and technical assistance were identified as vital priorities once the concerns are formally addressed by FDA. The water summit highlighted the critical need for transparency of FDA's progress on reevaluating the Subpart E requirements to help guide growers’ decisions regarding the use of agricultural water.  相似文献   
47.
There is a positive relationship between student participation in computer-supported collaborative learning (CSCL) environments and improved complex problem-solving strategies, increased learning gains, higher engagement in the thinking of their peers, and an enthusiastic disposition toward groupwork. However, student participation varies from group to group, even in contexts where students and teachers have had extensive training in working together. In this study, we use positioning theory and interaction analysis to conceptualize and investigate relationships between student interactions across two partner pairs working with technology in an all-female cryptography summer camp and their negotiated positions of power and status. The analysis resulted in uneven participation patterns, unequal status orderings, and an imbalance of power in both comparison cases. We found a reflexive relationship between partner interactions around shared technology resources and negotiated positions of power and status, which leads us to conclude that interactions around technology function as an important indicator of negotiated positionings of power and status in CSCL settings, and vice-versa. With that said, we found qualitative differences in the ways emergent status problems impacted each team’s productivity with the cryptography challenge, which has important implications for future research on CSCL settings and classroom practice.  相似文献   
48.
Occurrence of a new generation of disinfection byproducts   总被引:19,自引:0,他引:19  
A survey of disinfection byproduct (DBP) occurrence in the United States was conducted at 12 drinking water treatment plants. In addition to currently regulated DBPs, more than 50 DBPs that rated a high priority for potential toxicity were studied. These priority DBPs included iodinated trihalomethanes (THMs), other halomethanes, a nonregulated haloacid, haloacetonitriles, haloketones, halonitromethanes, haloaldehydes, halogenated furanones, haloamides, and nonhalogenated carbonyls. The purpose of this study was to obtain quantitative occurrence information for new DBPs (beyond those currently regulated and/or studied) for prioritizing future health effects studies. An effort was made to select plants treating water that was high in total organic carbon and/or bromide to enable the detection of priority DBPs that contained bromine and/or iodine. THMs and haloacetic acids (HAAs) represented the two major classes of halogenated DBPs formed on a weight basis. Haloacetaldehydes represented the third major class formed in many of the waters. In addition to obtaining quantitative occurrence data, important new information was discovered or confirmed at full-scale plants on the formation and control of DBPs with alternative disinfectants to chlorine. Although the use of alternative disinfectants (ozone, chlorine dioxide, and chloramines) minimized the formation of the four regulated THMs, trihalogenated HAAs, and total organic halogen (TOX), several priority DBPs were formed at higher levels with the alternative disinfectants as compared with chlorine. For example, the highest levels of iodinated THMs-which are not part of the four regulated THMs-were found at a plant that used chloramination with no prechlorination. The highest concentration of dichloroacetaldehyde was at a plant that used chloramines and ozone; however, this disinfection scheme reduced the formation of trichloroacetaldehyde. Preozonation was found to increase the formation of trihalonitromethanes. In addition to the chlorinated furanones that have been measured previously, brominated furanones-which have seldom been analyzed-were detected, especially in high-bromide waters. The presence of bromide resulted in a shift to the formation of other bromine-containing DBPs not normally measured (e.g., brominated ketones, acetaldehydes, nitromethanes, acetamides). Collectively, -30 and 39% of the TOX and total organic bromine, respectively, were accounted for (on a median basis) bythe sum of the measured halogenated DBPs. In addition, 28 new, previously unidentified DBPs were detected.These included brominated and iodinated haloacids, a brominated ketone, and chlorinated and iodinated aldehydes.  相似文献   
49.
The last several decades have seen decreases in SO(4)(2-) deposition across the northeastern United States. As a result, SO(4)(2-) concentrations in lakes and streams have also decreased and many surface water bodies have become less acidic. During the same time period, there has been a concurrent increase in dissolved organic carbon (DOC) concentrations in many lakes and streams. We used fluorescence spectroscopy to characterize the dissolved organic matter (DOM) quality of archived samples from nine acid-sensitive lakes in Maine collected between 1993 and 2009, and determined that increased DOM contributions to lakes were primarily derived from litter and soil. All five lakes with increasing DOC trends demonstrated significant decreasing (i.e., more terrestrial) trends in fluorescence index (FI) and significant positive correlations between SO(4)(2-) and FI. This study used the chemical signature of terrestrial DOM to support the hypothesis that increased DOC concentrations in lakes and streams are driven by declining acid deposition and increased solubility of soil organic matter across a large area of the landscape.  相似文献   
50.
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