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Analysis of reactive astrocytes and NG2 proteoglycan in ex vivo rat models of spinal cord injury

Patar A, Dockery P, Howard L, McMahon S

J Neurosci Methods, 2019 01 01;311:418-425.
PMID: 30267723 DOI: 10.1016/j.jneumeth.2018.09.027

BACKGROUND: The use of animals to model spinal cord injury (SCI) requires extensive post-operative care and can be expensive, which makes an alternative model extremely attractive. The use ofex vivo slice cultures is an alternative way to study the pathophysiological changes that can mimic in vivo conditions and support the 3Rs (replacement, reduction and refinement) of animal use in SCI research models.
NEW METHOD: In this study the presence of reactive astrocytes and NG2 proteoglycans was investigated in two ex vivo models of SCI; stab injury and transection injury. Stereological analysis to measure immunohistochemical staining was performed on the scar and injury zones to detect astrocytes and the chondroitin sulphate proteoglycan NG2.
RESULTS: The volume fraction (Vv) of reactive astrocytes and NG2 proteoglycans increased significantly between day 3 and day 10 post injury in both ex vivo models. This data shows how ex vivo SCI models are a useful research tool allowing reduction of research cost and time involved in carrying out animal studies, as well as reducing the numbers of animals used.
COMPARISON WITH EXISTING METHOD: This is the first evidence of an ex vivo stab injury model of SCI and also the first comparison of immunohistochemical staining for injury markers within stab injured and transection injured ex vivo slice cultures.
CONCLUSIONS: The use of organotypic slice culture models provide a simple way to study the cellular consequences following SCI and they can also be used as a platform for potential therapeutics regimes for the treatment of SCI.
Biomimicking dual drug eluting twisted electrospun nanofiber yarns for post-operative wound healing

Singh P, Pandey P, Arya DK, Anjum MM, Poonguzhali S, Kumar A, et al.

Biomed Mater, 2023 Mar 27;18(3).
PMID: 36921352 DOI: 10.1088/1748-605X/acc4a1

The morbidity rate following a surgical procedure increasing rapidly in the cases associated with surgical site infections. Traditional sutures lack the ability to deliver drugs as the incorporation of the drug in their structure would hamper their mechanical properties. To prevent such infections, we developed an extracellular matrix mimicking electrospun nanofibrous yarns of poly-(D,L)-lactic acid and polyvinyl alcohol loaded with vancomycin and ferulic acid, prepared by uniaxial electrospinning technique.In-vitrocharacterization such as scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, tensile strength testing, degradation studies, and antimicrobial studies along within-vivoevaluation done with help of incision wound healing rat model and simultaneous testing of microbial load in the incised tissue. Thein-vitrostudies indicated the nanofiber yarns have size range 200-300 nm with a tensile strength of 7.54 ± 0.58 MPa. The dual drug-loaded yarn showed sustained drug release over a period of 48 h.In-vitrowater uptake and biodegradation data indicated optimum results suitable for suturing applications. Antimicrobial study showed excellent antimicrobial activity against bothS. aureus and E. coli.Results obtained fromin-vivostudy suggested excellent wound healing potential of nanofiber yarns as compared with commercial silk sutures. The histopathological studies confirmed restoring ability of nanofiber yarn to the normal skin structure. Enzyme-linked immunosorbent assay (ELISA) study revealed the downregulation of inflammatory markers i.e. TNF-alpha and IL-6, making nanofibers sutures suitable for surgical wound healing applications. Overall, the present study may conclude that the developed dual drug-loaded nanofiber yarns have excellent potential in surgical wound healing applications.
Temporal population variability in local forest communities has mixed effects on tree species richness across a latitudinal gradient

Fung T, Chisholm RA, Anderson-Teixeira K, Bourg N, Brockelman WY, Bunyavejchewin S, et al.

Ecol Lett, 2020 Jan;23(1):160-171.
PMID: 31698546 DOI: 10.1111/ele.13412

Among the local processes that determine species diversity in ecological communities, fluctuation-dependent mechanisms that are mediated by temporal variability in the abundances of species populations have received significant attention. Higher temporal variability in the abundances of species populations can increase the strength of temporal niche partitioning but can also increase the risk of species extinctions, such that the net effect on species coexistence is not clear. We quantified this temporal population variability for tree species in 21 large forest plots and found much greater variability for higher latitude plots with fewer tree species. A fitted mechanistic model showed that among the forest plots, the net effect of temporal population variability on tree species coexistence was usually negative, but sometimes positive or negligible. Therefore, our results suggest that temporal variability in the abundances of species populations has no clear negative or positive contribution to the latitudinal gradient in tree species richness.
Combination of Measurements of the Top Quark Mass from Data Collected by the ATLAS and CMS Experiments at sqrt[s]=7 and 8 TeV

Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.

Phys Rev Lett, 2024 Jun 28;132(26):261902.
PMID: 38996325 DOI: 10.1103/PhysRevLett.132.261902

A combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The datasets used correspond to an integrated luminosity of up to 5 and 20 fb^{-1} of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak t channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is m_{t}=172.52±0.14(stat)±0.30(syst) GeV, with a total uncertainty of 0.33 GeV.
Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC

Aad G, Abbott B, Abeling K, Abicht NJ, Abidi SH, Aboulhorma A, et al.

Phys Rev Lett, 2024 Jan 12;132(2):021803.
PMID: 38277607 DOI: 10.1103/PhysRevLett.132.021803

The first evidence for the Higgs boson decay to a Z boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around 140 fb^{-1} for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is 2.2±0.7 times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.