Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Damage Control Orthopedics Management as Vital Procedure in Elderly Patients with Femoral Neck Fractures Complicated with Chronic Renal Failure: A Retrospective Cohort Study.

BACKGROUND:Chronic renal failure (CRF) predisposes to hip fractures in elderly patients, with high subsequent mortality. Selection and timing of the surgical procedure of such patients is a serious challenge. Many clinicians believe in earlier surgery as preferable and providing better outcomes. Damage control orthopedics (DCO) aids to adjust and optimize the overall condition of patients. METHODS:In 32 patients with femoral neck fractures complicated with CRF, we evaluated how the timing of the surgery determines the mortality rates if the DCO approach is applied. Preoperative ASA grading, POSSUM score, P-POSSUM score and DCO were carried out. Based on the assessment, timing of the surgery was ascertained. RESULTS:Of a total of 32 patients, twenty-nine patients were accepted for either early (< 48 hours; n = 18) or delayed (3-10 days; n = 10) surgery. Hip arthroplasty (total hip arthroplasty and hemiarthroplasty) was the principal surgery option. All patients survived operation and were followed up postoperatively with the average time of 30 days. Postoperative complications tended to occur at higher rates in the early vs. delayed surgery group (7/18 vs. 5/10). During follow up, a total of 3 patients died in both groups (2/18 in the early surgery and 1/10 in the delayed surgery group), mostly from multi-organ failures and acute respiratory distress syndrome. There was no significant difference in complication rates and Harris hip score between both groups. CONCLUSION:In patients with femoral neck fracture complicated with CRF, delaying the surgery for several days does not increase the incidence of postoperative adverse events

First preoperative risk assessments.

<p>First preoperative risk assessments.</p

Chest X-ray images of a 72-year old male patient with femoral neck fracture complicated with chronic renal failure.

<p>(A) Frontal projection. (B) Lateral projection.</p

Demographic and clinical characteristics of study patients.

<p>Demographic and clinical characteristics of study patients.</p

X-ray images of the right femoral neck fracture in a 72-year old male patient with chronic renal failure before and after hemiarthroplasty.

<p>(A) Preoperative imaging shows compression fractures on the femoral neck of the right hip and shortening deformity of the femoral neck. (B) Representative images taken 6 months after right femoral head arthroplasty. (C) At 24 months of follow-up, the prosthesis was in the correct position. On subsequent X-ray images, there were no further changes.</p

The Kaplan-Meier survival curves analysis in patients with or without surgical treatment.

<p>Survival curves in 32 study patients. Based on surgical risk assessment, 28 patients were selected for surgical treatment. The remaining 4 patients could not undergo the surgery and dead within 30 days. Furthermore, mortality rates in the early surgery group were equal with the delayed surgery group.</p

Preoperative risk assessments.

<p>Preoperative risk assessments.</p

Comparison of a new minimum contact locking plate and the limited contact dynamic compression plate in an osteoporotic fracture model

The purpose of this study was to investigate the biomechanical properties of a new minimum contact locking plate (MC-LP) compared with the limited contact dynamic compression plate (LC-DCP). Eighteen pairs of fresh human osteoporotic cadaver radii were equally divided into three groups. Each specimen was tested in each of the following force applications: anteroposterior (AP) four point bending, mediolateral (ML) four point bending, and torsion. A 10-mm gap osteotomy model was used to simulate a comminuted diaphyseal radial fracture. For each pair, one radius received a limited contact dynamic compression plate (LC-DCP) and the contralateral radius was fixed with a minimum contact locking plate (MC-LP). Specimens were tested in nondestructive four point bending and torsion on an electronic universal material testing system. The results indicate that the MC-LP system is significantly more stable than the LC-DCP system when tested in four point bending and torsion in an osteoporotic comminuted radial diaphyseal fracture model