196 research outputs found
Mini black holes at the LHC : discovery through di-jet suppression, mono-jet emission and a supersonic boom in the quark-gluon plasma in ALICE, ATLAS and CMS
We examine experimental signatures of TeV-mass black hole formation in heavy ion collisions at the LHC. We find that the black hole production results in a complete disappearance of all very high p_T (> 500 GeV) back-to-back correlated di-jets of total mass M > M_f ~ 1 TeV. We show that the subsequent Hawking-decay produces multiple hard mono-jets and discuss their detection. We study the possibility of cold black hole remnant (BHR) formation of mass ~ M_f and the experimental distinguishability of scenarios with BHRs and those with complete black hole decay. Finally we point out that a Heckler-Kapusta-Hawking plasma may form from the emitted mono-jets. In this context we present new simulation data of Mach shocks and of the evolution of initial conditions until the freeze-out
4-[Bis(4-fluorophenyl)methyl]piperazin-1-ium 2-hydroxybenzoate 2-hydroxybenzoic acid monosolvate
The title compound, C17H19F2N2
+·C7H5O3
−·C7H6O3, is a co-crystal from 4-[bis(4-fluorophenyl)methyl]piperazin-1-ium, salicylate anion and salicylic acid in a 1:1:1 ratio. In addition to an intramolecular O—H⋯O hydrogen bond, the crystal packing shows hydrogen bonds between the piperazinium cation and salicylate anion (N—H⋯O), as well as between the salicylic acid molecule and anion (O—H⋯O), giving rise to a three-dimensional network
Bypass of lethality with mosaic mice generated by Cre–loxP-mediated recombination
AbstractBackground The analysis of gene function based on the generation of mutant mice by homologous recombination in embryonic stem cells is limited if gene disruption results in embryonic lethality. Mosaic mice, which contain a certain proportion of mutant cells in all organs, allow lethality to be circumvented and the potential of mutant cells to contribute to different cell lineages to be analyzed. To generate mosaic animals, we used the bacteriophage P1-derived Cre–loxP recombination system, which allows gene alteration by Cre-mediated deletion of loxP-flanked gene segments.Results We generated nestin–cre transgenic mouse lines, which expressed the Cre recombinase under the control of the rat nestin promoter and its second intron enhancer. In crosses to animals carrying a loxP-flanked target gene, partial deletion of the loxP-flanked allele occurred before day 10.5 post coitum and was detectable in all adult organs examined, including germ-line cells. Using this approach, we generated mosaic mice containing cells deficient in the γ-chain of the interleukin-2 receptor (IL-2Rγ); in these animals, the IL-2Rγ-deficient cells were underrepresented in the thymus and spleen. Because mice deficient in DNA polymerase β die perinatally, we studied the effects of DNA polymerase β deficiency in mosaic animals. We found that some of the mosaic polymerase β-deficient animals were viable, but were often reduced in size and weight. The fraction of DNA polymerase β-deficient cells in mosaic embryos decreased during embryonic development, presumably because wild-type cells had a competitive advantage.Conclusions The nestin–cre transgenic mice can be used to generate mosaic animals in which target genes are mutated by Cre-mediated recombination of loxP-flanked target genes. By using mosaic animals, embryonic lethality can be bypassed and cell lineages for whose development a given target gene is critical can be identified. In the case of DNA polymerase β, deficient cells are already selected against during embryonic development, demonstrating the general importance of this protein in multiple cell types
Evidence for a Relationship between VEGF and BMI Independent of Insulin Sensitivity by Glucose Clamp Procedure in a Homogenous Group Healthy Young Men
BACKGROUND: This is the first study to experimentally explore the direct relationship between circulating VEGF levels and body mass index (BMI) as well as to unravel the role of insulin sensitivity in this context under standardized glucose clamp conditions as the methodical gold-standard. In order to control for known influencing factors such as gender, medication, and arterial hypertension, we examined a highly homogeneous group of young male subjects. Moreover, to encompass also subjects beyond the normal BMI range, low weight and obese participants were additionally included and stress hormones as a main regulator of VEGF were assessed. METHODOLOGY/PRINCIPAL FINDINGS: Under euglycemic clamp conditions, VEGF was measured in 15 normal weight (BMI 20-25 kg/m(2)), 15 low weight (BMI<20 kg/m(2)), and 15 obese (BMI>30 kg/m(2)) male subjects aged 18-30 years and the insulin sensitivity index (ISI) was calculated. Since stress axis activation promotes VEGF secretion, concentrations of ACTH, cortisol, and catecholamines were monitored. Despite of comparable ACTH (P = 0.145), cortisol (P = 0.840), and norepinephrine (P = 0.065) levels, VEGF concentrations differed significantly between BMI-groups (P = 0.008) with higher concentrations in obese subjects as compared to normal weight (P = 0.061) and low weight subjects (P = 0.002). Pearson's correlation analysis revealed a positive relationship between BMI and VEGF levels (r = 0.407; P = 0.010) but no correlation of VEGF with ISI (r = 0.224; P = 0.175). CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a positive correlation between concentrations of circulating VEGF levels and BMI in healthy male subjects under highly controlled conditions. This relationship which is apparently disconnected from insulin sensitivity may be part of some pathogenetic mechanisms underlying obesity and type 2 diabetes
Visualization of interindividual differences in spinal dynamics in the presence of intraindividual variabilities
Surface topography systems enable the capture of
spinal dynamic movement. A visualization of possible unique
movement patterns appears to be difficult due to large intraclass and small inter-class variabilities. Therefore, we investigated
a visualization approach using Siamese neural networks (SNN)
and checked, if the identification of individuals is possible based
on dynamic spinal data. The presented visualization approach
seems promising in visualizing subjects in the presence of
intraindividual variability between different gait cycles as well
as day-to-day variability. Overall, the results indicate a possible
existence of a personal spinal ‘fingerprint’. The work forms the
basis for an objective comparison of subjects and the transfer of
the method to clinical use cases
Shapiro effect in atomchip-based bosonic Josephson junctions
We analyze the emergence of Shapiro resonances in tunnel-coupled
Bose-Einstein condensates, realizing a bosonic Josephson junction. Our analysis
is based on an experimentally relevant implementation using magnetic double
well potentials on an atomchip. In this configuration the potential bias
(implementing the junction voltage) and the potential barrier (realizing the
Josephson link) are intrinsically coupled. We show that the dynamically driven
system exhibits significantly enhanced Shapiro resonances which will facilitate
experimental observation. To describe the systems response to the dynamic drive
we compare a single-mode Gross-Pitaevskii (GP) description, an improved
two-mode (TM) model and the self-consistent multi-configurational time
dependent Hartree for Bosons (MCTDHB) method. We show that in the case of
significant atom-atom interactions or strong driving, the spatial dynamics of
the involved modes have to be taken into account, and only the MCTDHB method
allows reliable predictions.Comment: 16 pages, 4 figure
Incidence of Revision Surgery After Decompression With vs Without Fusion Among Patients With Degenerative Lumbar Spinal Stenosis.
Importance
Only limited data derived from large prospective cohort studies exist on the incidence of revision surgery among patients who undergo operations for degenerative lumbar spinal stenosis (DLSS).
Objective
To assess the cumulative incidence of revision surgery after 2 types of index operations-decompression alone or decompression with fusion-among patients with DLSS.
Design, Setting, and Participants
This cohort study analyzed data from a multicenter, prospective cohort study, the Lumbar Stenosis Outcome Study, which included patients aged 50 years or older with DLSS at 8 spine surgery and rheumatology units in Switzerland between December 2010 and December 2015. The follow-up period was 3 years. Data for this study were analyzed between October and November 2021.
Exposures
All patients underwent either decompression surgery alone or decompression with fusion surgery for DLSS.
Main Outcomes and Measures
The primary outcome was the cumulative incidence of revision operations. Secondary outcomes included changes in the following patient-reported outcome measures: Spinal Stenosis Measure (SSM) symptom severity (higher scores indicate more pain) and physical function (higher scores indicate more disability) subscale scores and the EuroQol Health-Related Quality of Life 5-Dimension 3-Level questionnaire (EQ-5D-3L) summary index score (lower scores indicate worse quality of life).
Results
A total of 328 patients (165 [50.3%] men; median age, 73.0 years [IQR, 66.0-78.0 years]) were included in the analysis. Of these, 256 (78.0%) underwent decompression alone and 72 (22.0%) underwent decompression with fusion. The cumulative incidence of revisions after 3 years of follow-up was 11.3% (95% CI, 7.4%-15.1%) for the decompression alone group and 13.9% (95% CI, 5.5%-21.5%) for the fusion group (log-rank P = .60). There was no significant difference in the need for revision between the 2 groups over time (unadjusted absolute risk difference, 2.6% [95% CI, -6.3% to 11.4%]; adjusted absolute risk difference, 3.9% [95% CI, -5.2% to 17.0%]; adjusted hazard ratio, 1.40 [95% CI, 0.63-3.13]). The number of revisions was significantly associated with higher SSM symptom severity scores (β, 0.171; 95% CI, 0.047-0.295; P = .007) and lower EQ-5D-3L summary index scores (β, -0.061; 95% CI, -0.105 to -0.017; P = .007) but not with higher SSM physical function scores (β, 0.068; 95% CI, -0.036 to 0.172; P = .20). The type of index operation was not significantly associated with the corresponding outcomes.
Conclusions and Relevance
This cohort study showed no significant association between the type of index operation for DLSS-decompression alone or fusion-and the need for revision surgery or the outcomes of pain, disability, and quality of life among patients after 3 years. Number of revision operations was associated with more pain and worse quality of life
Cardioprotective Effects of Palmitoleic Acid (C16:1n7) in a Mouse Model of Catecholamine-Induced Cardiac Damage Are Mediated by PPAR Activation
Palmitoleic acid (C16:1n7) has been identified as a regulator of physiological cardiac hypertrophy. In the present study, we aimed to investigate the molecular pathways involved in C16:1n7 responses in primary murine cardiomyocytes (PCM) and a mouse model of isoproterenol (ISO)-induced cardiac damage. PCMs were stimulated with C16:1n7 or a vehicle. Afterwards, RNA sequencing was performed using an Illumina HiSeq sequencer. Confirmatory analysis was performed in PCMs and HL-1 cardiomyocytes. For an in vivo study, 129 sv mice were orally treated with a vehicle or C16:1n7 for 22 days. After 5 days of pre-treatment, the mice were injected with ISO (25 mg/kg/d s. c.) for 4 consecutive days. Cardiac phenotyping was performed using echocardiography. In total, 129 genes were differentially expressed in PCMs stimulated with C16:1n7, including Angiopoietin-like factor 4 (Angptl4) and Pyruvate Dehydrogenase Kinase 4 (Pdk4). Both Angptl4 and Pdk4 are proxisome proliferator-activated receptor α/δ (PPARα/δ) target genes. Our in vivo results indicated cardioprotective and anti-fibrotic effects of C16:1n7 application in mice. This was associated with the C16:1n7-dependent regulation of the cardiac PPAR-specific signaling pathways. In conclusion, our experiments demonstrated that C16:1n7 might have protective effects on cardiac fibrosis and inflammation. Our study may help to develop future lipid-based therapies for catecholamine-induced cardiac damage
- …