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To determine the reliability of teleneuropsychological (TNP) compared to in-person assessments (IPA) in people with HIV (PWH) and without HIV (HIV−).
Participants included 80 PWH (Mage = 58.7, SDage = 11.0) and 23 HIV− (Mage = 61.9, SDage = 16.7). Participants completed two comprehensive neuropsychological IPA before one TNP during the COVID-19 pandemic (March–December 2020). The neuropsychological tests included: Hopkins Verbal Learning Test-Revised (HVLT-R Total and Delayed Recall), Controlled Oral Word Association Test (COWAT; FAS-English or PMR-Spanish), Animal Fluency, Action (Verb) Fluency, Wechsler Adult Intelligence Scale 3rd Edition (WAIS-III) Symbol Search and Letter Number Sequencing, Stroop Color and Word Test, Paced Auditory Serial Addition Test (Channel 1), and Boston Naming Test. Total raw scores and sub-scores were used in analyses. In the total sample and by HIV status, test-retest reliability and performance-level differences were evaluated between the two consecutive IPA (i.e., IPA1 and IPA2), and mean in-person scores (IPA-M), and TNP.
There were statistically significant test-retest correlations between IPA1 and IPA2 (r or ρ = .603–.883, ps < .001), and between IPA-M and TNP (r or ρ = .622–.958, ps < .001). In the total sample, significantly lower test-retest scores were found between IPA-M and TNP on the COWAT (PMR), Stroop Color and Word Test, WAIS-III Letter Number Sequencing, and HVLT-R Total Recall (ps < .05). Results were similar in PWH only.
This study demonstrates reliability of TNP in PWH and HIV−. TNP assessments are a promising way to improve access to traditional neuropsychological services and maintain ongoing clinical research studies during the COVID-19 pandemic.
Recent cannabis exposure has been associated with lower rates of neurocognitive impairment in people with HIV (PWH). Cannabis’s anti-inflammatory properties may underlie this relationship by reducing chronic neuroinflammation in PWH. This study examined relations between cannabis use and inflammatory biomarkers in cerebrospinal fluid (CSF) and plasma, and cognitive correlates of these biomarkers within a community-based sample of PWH.
263 individuals were categorized into four groups: HIV− non-cannabis users (n = 65), HIV+ non-cannabis users (n = 105), HIV+ moderate cannabis users (n = 62), and HIV+ daily cannabis users (n = 31). Differences in pro-inflammatory biomarkers (IL-6, MCP-1/CCL2, IP-10/CXCL10, sCD14, sTNFR-II, TNF-α) by study group were determined by Kruskal–Wallis tests. Multivariable linear regressions examined relationships between biomarkers and seven cognitive domains, adjusting for age, sex/gender, race, education, and current CD4 count.
HIV+ daily cannabis users showed lower MCP-1 and IP-10 levels in CSF compared to HIV+ non-cannabis users (p = .015; p = .039) and were similar to HIV− non-cannabis users. Plasma biomarkers showed no differences by cannabis use. Among PWH, lower CSF MCP-1 and lower CSF IP-10 were associated with better learning performance (all ps < .05).
Current daily cannabis use was associated with lower levels of pro-inflammatory chemokines implicated in HIV pathogenesis and these chemokines were linked to the cognitive domain of learning which is commonly impaired in PWH. Cannabinoid-related reductions of MCP-1 and IP-10, if confirmed, suggest a role for medicinal cannabis in the mitigation of persistent inflammation and cognitive impacts of HIV.
Preliminary research has suggested that wearable cameras may reduce under-reporting of energy intake (EI) in self-reported dietary assessment. The aim of the present study was to test the validity of a wearable camera-assisted 24 h dietary recall against the doubly labelled water (DLW) technique. Total energy expenditure (TEE) was assessed over 15 d using the DLW protocol among forty adults (n 20 males, age 35 (sd 17) years, BMI 27 (sd 4) kg/m2 and n 20 females, age 28 (sd 7) years, BMI 22 (sd 2) kg/m2). EI was assessed using three multiple-pass 24 h dietary recalls (MP24) on days 2–4, 8–10 and 13–15. On the days before each nutrition assessment, participants wore an automated wearable camera (SenseCam (SC)) in free-living conditions. The wearable camera images were viewed by the participants following the completion of the dietary recall, and their changes in self-reported intakes were recorded (MP24+SC). TEE and EI assessed by the MP24 and MP24+SC methods were compared. Among men, the MP24 and MP24+SC measures underestimated TEE by 17 and 9 %, respectively (P< 0·001 and P= 0·02). Among women, these measures underestimated TEE by 13 and 7 %, respectively (P< 0·001 and P= 0·004). The assistance of the wearable camera (MP24+SC) reduced the magnitude of under-reporting by 8 % for men and 6 % for women compared with the MP24 alone (P< 0·001 and P< 0·001). The increase in EI was predominantly from the addition of 265 unreported foods (often snacks) as revealed by the participants during the image review. Wearable cameras enhance the accuracy of self-report by providing passive and objective information regarding dietary intake. High-definition image sensors and increased imaging frequency may improve the accuracy further.
For the material (Pb0.95Sn0.05Te)1-x(PbS)x nanostructuring from nucleation and growth and spinodal decomposition were reported to enhance the thermoelectric figure of merit over bulk PbTe, producing ZT of 1.1 - 1.4 at 650 K for x = 0.08. Thermoelectric modules made from (Pb0.95Sn0.05Te)1-x(PbS)x materials with various hot-side metal electrodes were fabricated and tested. Short circuit current was measured on unicouples of Pb0.95Sn0.05Te – PbS 8% (n-type) legs and Ag0.9Pb9Sn9Sb0.6Te20 (p-type) legs over 10 (A) for a hot side temperature of 870K, and a cold side of 300K. Hot pressed (Pb0.95Sn0.05Te)1-x(PbS)x materials were also investigated for module fabrication. Investigations of the electrical properties of hot-pressed (Pb0.95Sn0.05Te)1-x(PbS)x materials are presented along with the latest advancements in the fabrication and characteristics of modules based on the processing of these materials.
Thermoelectric modules are of great interest for power generation applications where temperature gradients of approximately 500K exist, and hot side temperatures near 800K. The fabrication of such modules requires optimization of the material compositions, low contact resistivities, and low thermal loss.
AgPbmSbTe2+m (LAST) and Ag(Pb1-xSnx)m SbTe2+m (LASTT) compounds are among the best known materials appropriate for this temperature range. Various measurement systems have been developed and used to characterize bulk samples in the LAST and LASTT systems within this operating temperature range. From the characterized data, modeling of modules based on these materials and segmented legs using LAST(T) with Bi2Te3 have been used to identify the optimal geometry for the individual legs, and the length of the Bi2Te3 segments. We have segmented LAST(T) with Bi2Te3 and achieved contact resistivities of less than 10 μΩ•cm2.
Here we give a detailed presentation on the procedures used in the fabrication of thermoelectric generators based on LAST, LASTT, and segmented with Bi2Te3 materials. We also present the output data on these generators.
PbTe-based thermoelectric (TE) materials exhibit promising thermoelectric properties and have potential applications in waste heat recovery from sources such as truck engines and shipboard engines. TE components designed for these applications will be subject to mechanical/thermal loading and vibration as a result from in-service conditions, including mechanical vibration, mechanical and/or thermal cycling, and thermal shock.
In the current study, we present and discuss the mechanical properties of several PbTe-based compositions with different dopants and processing methods, including n-type and p-type specimens fabricated both by casting and by powder processing. Room temperature hardness and Young's modulus are studied by Vickers indentation and nanoindentation while fracture strength is obtained by biaxial flexure testing. Temperature dependent Young's modulus, shear modulus, and Poisson's ratio are studied via resonant ultrasound spectroscopy (RUS).
The binding of the methylanthraniloyl derivatives of ATP
(mant-ATP), ADP (mant-ADP), 2′deoxyATP (mant-2′deoxyATP),
and 3′deoxyATP (mant-3′deoxyATP) to the catalytic
subunit of protein kinase A was studied to gain insights
into the mechanism of nucleotide binding. The binding of the
mant nucleotides leads to a large increase in fluorescence
energy transfer at 440 nm, allowing direct measurements of
nucleotide affinity. The dissociation constant of mant-ADP
is identical to that for ADP, while that for mant-ATP is
approximately threefold higher than that for ATP. The dissociation
constant for mant-3′deoxyATP is approximately fivefold
higher than that for 3′deoxyATP while derivatization
of 2′deoxyATP does not affect affinity. The time-dependent
binding of mant-ATP, mant-2′deoxyATP, and mant-ADP,
measured using stopped-flow fluorescence spectroscopy,
is best fit to three exponentials. The fast phase is ligand
dependent, while the two slower phases are ligand independent.
The slower phases are similar but not identical in rate,
and have opposite fluorescence amplitudes. Both isomers
of mant-ATP are equivalent substrates, as judged by reversed-phase
chromatography, although the rate of phosphorylation is
approximately 20-fold lower than the natural nucleotide.
The kinetic data are consistent with a three-step binding
mechanism in which initial association of the nucleotide
derivatives produces a highly fluorescent complex. Either
one or two conformational changes can occur after the formation
of this binary species, but one of the isomerized forms
must have low fluorescence compared to the initial binary
complex. These data soundly attest to the structural plasticity
within the kinase core that may be essential for catalysis.
Overall, the mant nucleotides present a useful reporter
system for gauging these conformational changes in light
of the prevailing three-dimensional models for the enzyme.
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