88 research outputs found
âA robust and simple catheter connector assembly for long-term self-administration experiments â
Intravenous self-administration in rats is used widely to study the reinforcing effects of drugs and serves as the gold standard for assessing their use and misuse potential. One challenge that researchers often encounter when scaling up experiments is balancing the cost, time investment to construct, and robustness of each implanted catheter. These catheters include multiple components such as surgical meshing and a variety of entry ports designed to facilitate the connection of the rat to a catheter port tethering system. Other considerations include maintaining the catheters free of blockage during the extent of the drug self-administration experiment. These large-scale studies provide ample opportunity for the catheter system to fail. The failure and replacement of commercially purchased catheters leads to ballooning expenses, and the failure of in-lab manufactured catheters requires the manufacture of reserves, also increasing costs, as these handmade products are inherently more variable. We have developed a catheter system that combines a commercially available implantable back-mounted entry connector system with inexpensive medical items such as surgical mesh, sutures, and an air-tight back flow prevention system to bolster the overall success of self-administration experiments. Method to bolster commercially available jugular catheter components for long-lasting self- administration experiments. Reduces the overall cost per unit of self-administration experiments. Easily assembled by laboratory students and staff
The Importance of Acquisition Learning on Nicotine and Varenicline Drug Substitution in a Drug-Discriminated Goal-Tracking Task
Nicotine and varenicline (ChantixÂź; the leading non-nicotine cessation pharmacotherapy) can come to control appetitive behaviors such as goal-tracking. We tested rats (N = 48) in a drug-discriminated goal-tracking (DGT) task where each rat received daily subcutaneous injections of either nicotine (0.4 mg/kg) or saline (0.9% [w/v]) interspersed across the acquisition phase (Phase 1). On saline days, sucrose was intermittently available. On nicotine days, sucrose was withheld. All rats acquired the discrimination with increased goal-tracking rates on saline days relative to nicotine days. Following acquisition, rats were separated into four groups to assess drug-substitution and discrimination reversal in Phase 2. The first group maintained the stimulus-reinforcer relation from acquisition (NICâ). The reversal group was now given access to sucrose on nicotine days (NIC+). The substitution group replaced nicotine with varenicline (1 mg/kg) while maintaining the acquisition stimulus-reinforcer relation (VARâ). The substitution and reversal group had nicotine replaced by varenicline and the stimulus-reinforcer relation reversed (VAR+). Rats in all groups learned or maintained their Phase 1 discriminations. For Phase 2, the reversal groups (+ conditions) acquired their discriminations within 10 sessions. The VARâgroup displayed a pattern of disrupted discrimination at the outset of Phase 2 but was reestablished after continued training. In substitution testing, VAR groups received nicotine and NIC groups received varenicline. The NICâand VARâgroups displayed full substitution of the test stimulus whereas the NIC+ and VAR+ groups displayed partial substitution of the test stimulus. Rats underwent nicotine extinction in Phase 3. Initial responding for each group mimicked Phase 2 training (i.e., higher responding by the reversal groups). All rats maintained similarly low levels of responding after six sessions. In conclusion, initial learning history with nicotine (i.e., + or â) influenced drug-stimulus substitution and the rate at which new learning (e.g., reversal) occurs with the varenicline and nicotine interoceptive stimuli
A Comprehensive Study to Delineate the Role of an Extracellular Vesicle-Associated MicroRNA-29a in Chronic Methamphetamine Use Disorder
Extracellular vesicles (EVs), which express a repertoire of cargo molecules (cf. proteins, microRNA, lipids, etc.), have been garnering a prominent role in the modulation of several cellular processes. Here, using both non-human primate and rodent model systems, we provide evidence that brain-derived EV (BDE) miRNA, miR-29a-3p (mir-29a), is significantly increased during chronic methamphetamine (MA) exposure. Further, miR-29a levels show significant increase both with drug-seeking and reinstatement in a rat MA self-administration model. We also show that EV-associated miR-29a is enriched in EV pool comprising of small EVs and exomeres and further plays a critical role in MA-induced inflammation and synaptodendritic damage. Furthermore, treatment with the anti-inflammatory drug ibudilast (AV411), which is known to reduce MA relapse, decreased the expression of miR-29a and subsequently attenuated inflammation and rescued synaptodendritic injury. Finally, using plasma from MUD subjects, we provide translational evidence that EV-miR29a could potentially serve as a biomarker to detect neuronal damage in humans diagnosed with MA use disorder (MUD). In summary, our work suggests that EV-associated miR-29a-3p plays a crucial role in MUD and might be used as a potential blood-based biomarker for detecting chronic inflammation and synaptic damage
A comprehensive study to delineate the role of an extracellular vesicle-associated microRNA-29a in chronic methamphetamine use disorder
Extracellular vesicles (EVs), which express a repertoire of cargo molecules (cf. proteins, microRNA, lipids, etc.), have been garnering a prominent role in the modulation of several cellular processes. Here, using both non-human primate and rodent model systems, we provide evidence that brain-derived EV (BDE) miRNA, miR- 29a-3p (mir-29a), is significantly increased during chronic methamphetamine (MA) exposure. Further, miR-29a levels show significant increase both with drug-seeking and reinstatement in a rat MA self-administration model. We also show that EVassociated miR-29a is enriched in EV pool comprising of small EVs and exomeres and further plays a critical role in MA-induced inflammation and synaptodendritic damage. Furthermore, treatment with the anti-inflammatory drug ibudilast (AV411), which is known to reduce MA relapse, decreased the expression of miR-29a and subsequently attenuated inflammation and rescued synaptodendritic injury. Finally, using plasma fromMUDsubjects, we provide translational evidence that EV-miR29a could potentially serve as a biomarker to detect neuronal damage in humans diagnosed with MA use disorder (MUD). In summary, our work suggests that EVassociated miR-29a-3p plays a crucial role in MUD and might be used as a potential blood-based biomarker for detecting chronic inflammation and synaptic damage
Charge transport in hybrid nanorod-polymer composite photovoltaic cells
ABSTRACT Charge transport in composites of inorganic nanorods and a conjugated polymer is investigated using a photovoltaic device structure. We show that t he current-voltage (I-V) curves in the dark can be modelled using the Shockley equation modified to include series and shunt resistance at low current levels, and using an improved model that incorporates both the Shockley equation and the presence of a space charge limited region at high currents. Under illumination the efficiency of photocurrent generation is found to be dependent on applied bias. Furthermore, the photocurrent-light intensity dependence was found to be sublinear. An analysis of the shunt resistance as a function of light intensity suggests that the photocurrent as well as the fill factor is diminished as a result of increased photoconductivity of the active layer at high light intensity. By studying the intensity dependence of the open circuit voltage for nanocrystals with different diameters and thus band gaps, it was inferred that Fermi-level pinning occurs at the interface between the aluminum electrode and the nanocrystal.
The Second Monocular Depth Estimation Challenge
This paper discusses the results for the second edition of the Monocular
Depth Estimation Challenge (MDEC). This edition was open to methods using any
form of supervision, including fully-supervised, self-supervised, multi-task or
proxy depth. The challenge was based around the SYNS-Patches dataset, which
features a wide diversity of environments with high-quality dense ground-truth.
This includes complex natural environments, e.g. forests or fields, which are
greatly underrepresented in current benchmarks.
The challenge received eight unique submissions that outperformed the
provided SotA baseline on any of the pointcloud- or image-based metrics. The
top supervised submission improved relative F-Score by 27.62%, while the top
self-supervised improved it by 16.61%. Supervised submissions generally
leveraged large collections of datasets to improve data diversity.
Self-supervised submissions instead updated the network architecture and
pretrained backbones. These results represent a significant progress in the
field, while highlighting avenues for future research, such as reducing
interpolation artifacts at depth boundaries, improving self-supervised indoor
performance and overall natural image accuracy.Comment: Published at CVPRW202
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers âŒ99% of the euchromatic genome and is accurate to an error rate of âŒ1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Many Labs 2: Investigating Variation in Replicability Across Samples and Settings
We conducted preregistered replications of 28 classic and contemporary published findings, with protocols that were peer reviewed in advance, to examine variation in effect magnitudes across samples and settings. Each protocol was administered to approximately half of 125 samples that comprised 15,305 participants from 36 countries and territories. Using the conventional criterion of statistical significance (p < .05), we found that 15 (54%) of the replications provided evidence of a statistically significant effect in the same direction as the original finding. With a strict significance criterion (p < .0001), 14 (50%) of the replications still provided such evidence, a reflection of the extremely highpowered design. Seven (25%) of the replications yielded effect sizes larger than the original ones, and 21 (75%) yielded effect sizes smaller than the original ones. The median comparable Cohenâs ds were 0.60 for the original findings and 0.15 for the replications. The effect sizes were small (< 0.20) in 16 of the replications (57%), and 9 effects (32%) were in the direction opposite the direction of the original effect. Across settings, the Q statistic indicated significant heterogeneity in 11 (39%) of the replication effects, and most of those were among the findings with the largest overall effect sizes; only 1 effect that was near zero in the aggregate showed significant heterogeneity according to this measure. Only 1 effect had a tau value greater than .20, an indication of moderate heterogeneity. Eight others had tau values near or slightly above .10, an indication of slight heterogeneity. Moderation tests indicated that very little heterogeneity was attributable to the order in which the tasks were performed or whether the tasks were administered in lab versus online. Exploratory comparisons revealed little heterogeneity between Western, educated, industrialized, rich, and democratic (WEIRD) cultures and less WEIRD cultures (i.e., cultures with relatively high and low WEIRDness scores, respectively). Cumulatively, variability in the observed effect sizes was attributable more to the effect being studied than to the sample or setting in which it was studied.UCR::VicerrectorĂa de InvestigaciĂłn::Unidades de InvestigaciĂłn::Ciencias Sociales::Instituto de Investigaciones PsicolĂłgicas (IIP
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60â109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
âTypicalâ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (â€â18 years: 69, 48, 23; 85%), older adults (â„â70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each Pâ<â0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
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