232 research outputs found
Feasibility of Using Saltcedar as a Filler in Injection-Molded Polyethylene Composites
Saltcedar (Tamarix ramosissima) was investigated for use as a filler in wood-plastic composites (WPCs). The mineral content, water-soluble extractive content, and thermal stability of saltcedar flour were compared with those of a commercial pine wood flour. The wood flours were compounded with plastic, and the viscosities of the composite melts containing the two species were compared. Injection-molded composites produced from the compounded material were evaluated for mechanical performance and weatherability. Saltcedar flour had more minerals and water-soluble extractives than pine flour, which resulted in lower thermal stability, but also lower melt viscosity when compounded with high-density polyethylene. Injection-molded WPCs made from unextracted saltcedar performed similarly to those made from pine in accelerated weathering tests, but their mechanical properties were generally lower. The flexural modulus of elasticity increased when extracted wood flour was used, especially for the saltcedar composites. However, color stability and flexural strength changed little. Producing WPCs from these composites is possible, although economically feasible applications that use the advantageous properties of these species and that can tolerate or address the less desirable ones need to be identified and demonstrated
Waste-Wood-Derived Fillers for Plastics
Filled thermoplastic composites are stiffer, stronger, and more dimensionally stable than their unfilled counterparts. Such thermoplastics are usually provided to the end-user as a precompounded, pelletized feedstock. Typical reinforcing fillers are inorganic materials like talc or fiberglass, but materials derived from waste wood, such as wood flour and recycled paper fiber, are also effective as fillers. The goal of this project was to generate commercial interest in using waste-wood–paper-derived fillers (WPFs) to reinforce thermoplastics. The research strategy was twofold: developmental research and outreach. Specific objectives were (1) to improve wastepaper fiber preparation, feeding, and compounding methods, and optimize composite performance, and (2) to communicate to end-product manufacturers the advantages of WPF thermoplastics.
The research was led and supported by the Forest Products Laboratory (FPL), with input from a consortium of 15 fiber suppliers and plastics manufacturers. Additional funding was provided by the Wisconsin Department of Natural Resources. Equipment was leased and installed at FPL. Eight general purpose formulations were developed—they included extrusion and injection molding grades of both polyethylene and polypropylene, reinforced with WPFs. An information packet containing performance data, appropriate processing conditions, sample pellets, sample parts, and a questionnaire was sent to nearly 500 commercial
plastics manufacturers in Wisconsin, Illinois, and Michigan. In response to requests for in-house trials, FPL researchers conducted nearly 18 site visits. The researchers ensured proper handling of the material, provided consultation, and gathered information about processing and performance. The trials went very well, and parts were successfully manufactured at all facilities. Products included automobile trim components and housings, vacuum cleaner parts, paint brush handles, bicycle parts, cosmetic cases, and other household items. Great interest has been shown in the use of WPF thermoplastics; one consortium member is establishing a 4 million kg/yr (9 million lb/yr) facility. Total market demand is conservatively expected to exceed 45 million kg/yr (100 million lb/yr)
Limiting the Persistence of a Chromosome Break Diminishes Its Mutagenic Potential
To characterize the repair pathways of chromosome double-strand breaks (DSBs), one approach involves monitoring the repair of site-specific DSBs generated by rare-cutting endonucleases, such as I-SceI. Using this method, we first describe the roles of Ercc1, Msh2, Nbs1, Xrcc4, and Brca1 in a set of distinct repair events. Subsequently, we considered that the outcome of such assays could be influenced by the persistent nature of I-SceI-induced DSBs, in that end-joining (EJ) products that restore the I-SceI site are prone to repeated cutting. To address this aspect of repair, we modified I-SceI-induced DSBs by co-expressing I-SceI with a non-processive 3′ exonuclease, Trex2, which we predicted would cause partial degradation of I-SceI 3′ overhangs. We find that Trex2 expression facilitates the formation of I-SceI-resistant EJ products, which reduces the potential for repeated cutting by I-SceI and, hence, limits the persistence of I-SceI-induced DSBs. Using this approach, we find that Trex2 expression causes a significant reduction in the frequency of repair pathways that result in substantial deletion mutations: EJ between distal ends of two tandem DSBs, single-strand annealing, and alternative-NHEJ. In contrast, Trex2 expression does not inhibit homology-directed repair. These results indicate that limiting the persistence of a DSB causes a reduction in the frequency of repair pathways that lead to significant genetic loss. Furthermore, we find that individual genetic factors play distinct roles during repair of non-cohesive DSB ends that are generated via co-expression of I-SceI with Trex2
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Resilience to AD pathology in Top Cognitive Performers
Successful cognitive aging is often thought to result from resistance to the accumulation of pathology, resilience to the effects of pathological accumulation, or some combination of the two. While evidence for resilience has been found in typical aging populations, the oldest-old provide us with a unique window into the role of pathological accumulation in impacting cognition. Here, we aimed to assess group differences in measures of amyloid and tau across older age groups using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI age: 60-89) and The 90+ Study (age: 90-101). Additionally, using the ADNI dataset, we performed exploratory analyses of regional cingulate AV-45 SUVRs to assess if amyloid load in particular areas was associated with Top Cognitive Performance (TCP). Consistent with the literature, results showed no group differences in amyloid SUVRs both regionally and in the whole cortex. For tau with AV-1451, we also observed no differences in Braak composite SUVRs. Interestingly, these relationships persisted in the oldest-old. This indicates that Top Cognitive Performance throughout aging does not reflect resistance to amyloid and tau burden, but that other mechanisms may be associated with protection against amyloid and tau related neurodegeneration
A Journey to the West: The Ancient Dispersal of Rice Out of East Asia.
Funder: Max Planck Institute for the Science of Human HistoryRice is one of the most culturally valued and widely grown crops in the world today, and extensive research over the past decade has clarified much of the narrative of its domestication and early spread across East and South Asia. However, the timing and routes of its dispersal into West Asia and Europe, through which rice eventually became an important ingredient in global cuisines, has remained less clear. In this article, we discuss the piecemeal, but growing, archaeobotanical data for rice in West Asia. We also integrate written sources, linguistic data, and ethnohistoric analogies, in order to better understand the adoption of rice outside its regions of origin. The human-mediated westward spread of rice proceeded gradually, while its social standing and culinary uses repeatedly changing over time and place. Rice was present in West Asia and Europe by the tail end of the first millennium BC, but did not become a significant crop in West Asia until the past few centuries. Complementary historical, linguistic, and archaeobotanical data illustrate two separate and roughly contemporaneous routes of westward dispersal, one along the South Asian coast and the other through Silk Road trade. By better understanding the adoption of this water-demanding crop in the arid regions of West Asia, we explore an important chapter in human adaptation and agricultural decision making
Alternative-NHEJ Is a Mechanistically Distinct Pathway of Mammalian Chromosome Break Repair
Characterizing the functional overlap and mutagenic potential of different pathways of chromosomal double-strand break (DSB) repair is important to understand how mutations arise during cancer development and treatment. To this end, we have compared the role of individual factors in three different pathways of mammalian DSB repair: alternative-nonhomologous end joining (alt-NHEJ), single-strand annealing (SSA), and homology directed repair (HDR/GC). Considering early steps of repair, we found that the DSB end-processing factors KU and CtIP affect all three pathways similarly, in that repair is suppressed by KU and promoted by CtIP. In contrast, both KU and CtIP appear dispensable for the absolute level of total-NHEJ between two tandem I-SceI–induced DSBs. During later steps of repair, we find that while the annealing and processing factors RAD52 and ERCC1 are important to promote SSA, both HDR/GC and alt-NHEJ are significantly less dependent upon these factors. As well, while disruption of RAD51 causes a decrease in HDR/GC and an increase in SSA, inhibition of this factor did not affect alt-NHEJ. These results suggest that the regulation of DSB end-processing via KU/CtIP is a common step during alt-NHEJ, SSA, and HDR/GC. However, at later steps of repair, alt-NHEJ is a mechanistically distinct pathway of DSB repair, and thus may play a unique role in mutagenesis during cancer development and therapy
De novo intrachromosomal gene conversion from OPN1MW to OPN1LW in the male germline results in Blue Cone Monochromacy
X-linked cone dysfunction disorders such as Blue Cone Monochromacy and
X-linked Cone Dystrophy are characterized by complete loss (of) or reduced L-
and M- cone function due to defects in the OPN1LW/OPN1MW gene cluster. Here we
investigated 24 affected males from 16 families with either a structurally
intact gene cluster or at least one intact single (hybrid) gene but harbouring
rare combinations of common SNPs in exon 3 in single or multiple OPN1LW and
OPN1MW gene copies. We assessed twelve different OPN1LW/MW exon 3 haplotypes
by semi-quantitative minigene splicing assay. Nine haplotypes resulted in
aberrant splicing of ≥20% of transcripts including the known pathogenic
haplotypes (i.e. ‘LIAVA’, ‘LVAVA’) with absent or minute amounts of correctly
spliced transcripts, respectively. De novo formation of the ‘LIAVA’ haplotype
derived from an ancestral less deleterious ‘LIAVS’ haplotype was observed in
one family with strikingly different phenotypes among affected family members.
We could establish intrachromosomal gene conversion in the male germline as
underlying mechanism. Gene conversion in the OPN1LW/OPN1MW genes has been
postulated, however, we are first to demonstrate a de novo gene conversion
within the lineage of a pedigree
COOL-LAMPS. VI. Lens Model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens
We present a strong lensing analysis of COOL J1241+2219, the brightest known gravitationally lensed galaxy at z ≥ 5, based on new multiband Hubble Space Telescope (HST) imaging data. The lensed galaxy has a redshift of z = 5.043, placing it shortly after the end of the “Epoch of Reionization,” and an AB magnitude z AB = 20.47 mag (Khullar et al.). As such, it serves as a touchstone for future research of that epoch. The high spatial resolution of HST reveals internal structure in the giant arc, from which we identify 15 constraints and construct a robust lens model. We use the lens model to extract the cluster mass and lensing magnification. We find that the mass enclosed within the Einstein radius of the z = 1.001 cluster lens is M(<5.″77)=1.079−0.007+0.023×1013M☉ , significantly lower than other known strong lensing clusters at its redshift. The average magnification of the giant arc is 〈μ arc〉 = 76−20+40 , a factor of 2.4−0.7+1.4 greater than previously estimated from ground-based data; the flux-weighted average magnification is 〈μ arc〉 = 92−31+37 . We update the current measurements of the stellar mass and star formation rate (SFR) of the source for the revised magnification to log(M⋆/M⊙)= 9.7 ± 0.3 and SFR = 10.3−4.4+7.0 M ⊙ yr−1, respectively. The powerful lensing magnification acting upon COOL J1241+2219 resolves the source and enables future studies of the properties of its star formation on a clump-by-clump basis. The lensing analysis presented here will support upcoming multiwavelength characterization with HST and JWST data of the stellar mass assembly and physical properties of this high-redshift lensed galaxy
COOL-LAMPS VI: Lens model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens
We present a strong lensing analysis of COOL J1241+2219, the brightest known
gravitationally lensed galaxy at , based on new multi-band Hubble
Space Telescope (HST) imaging data. The lensed galaxy has a redshift of
z=5.043, placing it shortly after the end of the Epoch of Reionization, and an
AB magnitude z_AB=20.47 mag (Khullar et al. 2021). As such, it serves as a
touchstone for future research of that epoch. The high spatial resolution of
HST reveals internal structure in the giant arc, from which we identify 15
constraints and construct a robust lens model. We use the lens model to extract
cluster mass and lensing magnification. We find that the mass enclosed within
the Einstein radius of the z=1.001 cluster lens is
M(<5.77'')=, significantly lower than other known
strong lensing clusters at its redshift. The average magnification of the giant
arc is , a factor of greater
than previously estimated from ground-based data; the flux-weighted average
magnification is We update the current
measurements of the stellar mass and star formation rate (SFR) of the source
for the revised magnification, and yr. The powerful lensing
magnification acting upon COOL J1241+2219 resolves the source and enables
future studies of the properties of its star formation on a clump-by-clump
basis. The lensing analysis presented here will support upcoming
multiwavelength characterization with HST and JWST data of the stellar mass
assembly and physical properties of this high-redshift lensed galaxy.Comment: Submitted to Ap
Challenge Accepted! a Critical Reflection on How to Perform a Health Survey Among University Students—An Example of the Healthy Campus Mainz Project
Background: Universities represent an important setting of everyday life for health promotion. The Healthy Campus Mainz project aims to develop an evidence-based and comprehensive student health management program covering physical, mental, and social health promotion. Hence, an initial health survey was performed in order to identify the students' health concerns and resources. Up until now, it remains unclear which topics to choose in a health survey among university students and which strategies can be recommended to receive an acceptable response rate or representative student sample within a university setting. The present paper contributes to the call for the present research topic “Public Health Promotion in University Students” by describing methods for health assessment. Therefore, the current paper aims to give an empirical example on how to perform a health survey among university students, focusing on (1) choosing topics for the survey and (2) methodological considerations of how to reach the target population.Methods: An online questionnaire including around 270 items was developed covering a comprehensive set of health topics. Participants were recruited via the university email. Mixed channels for survey promotion, such as lecture visits and social media, were used, accompanied by different monetary and non-monetary incentives. Descriptive analyses were performed to describe the sample.Results: A total of 5,006 participants (out of 31,213 registered students) viewed the first page of the questionnaire; of whom, 4,714 continued further. After a manual data cleaning according to the predefined criteria, the final sample was 4,351, demonstrating a response rate of 13.9%. Students from different study disciplines participated. However, some study disciplines showed a low participation rate, hence, making the results not free from some bias.Discussion: This survey is exceptional as it integrates a great variety of health aspects. The incentive strategy demonstrated promising results. Future research should try to improve target-group-specific recruitment strategies for the traditionally underrepresented groups, such as males and specific study disciplines. This would not only include advancing marketing strategies, but also refining the incentive strategy
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