237 research outputs found
On the minimal number of critical points of functions on h-cobordisms
Let (W,M,M'), dim W > 5, be a non-trivial h-cobordism (i.e., the Whitehead
torsion of (W,V) is non-zero). We prove that every smooth function f: W -->
[0,1], f(M)=0, f(M')=1 has at least 2 critical points. This estimate is sharp:
W possesses a function as above with precisely two critical points.Comment: 7 pages, Late
A study of efficacy of tranexamic acid in reduction of blood loss in primary total knee arthroplasty
Background: Tranexamic acid (TXA) has been shown to be effective in reducing blood loss during trauma and surgeries. Although there is no well-established protocol, it is now increasingly being used in joint replacement surgeries. The present study was designed to study the effect of intravenously given tranexamic acid during primary total knee replacement in reducing intraoperative blood loss and need for blood transfusion requirement, compared to a placebo.Methods: This study was designed as a parallel arm, double blind trial. 100 patients of primary osteoarthritis undergoing total knee arthroplasty under tourniquet was included in the study. The efficacy of a single preoperative bolus of TXA in the dose of 15 mg/kg on perioperative blood losses was studied against a placebo with objectives to compare the pre- and 24-hours post-operative level of haemoglobin (Hb) and haematocrit (Hct) levels and assess total volume of blood loss till 24-hours postoperatively and need for blood transfusion.Results: Out of 168 patients, who underwent TKA in our centre during the period of the study, 100 were included in the study, 50 patients were included in placebo group and 50 patients were included in TXA group. There was a statistically significant reduction in the use of transfusion (Fisher exact test; P=0.001). A total of 46 units of blood were used; 42 units transfused to participants in the placebo group and only 4 units transfused to participants in the TXA group. Conclusions: Intravenous TXA in primary arthroplasty leads to a statistically significant reduction in total blood loss and requirement for allogeneic blood transfusion with no apparent increased risk of thrombo-embolic complications
Reforms, Incentives and Banking Sector Productivity: A Case of Nepal
We model banks as profit-cum-utility maximizing firms and study, inter alia, bankers' incentives (optimal effort) and incentive driven productivity following deregulations. Our model puts to test a panel of Nepalese commercial banks which went through deep financial reforms in the recent past. We find that (i) bankers' efforts and productivity have notably improved in Nepal, (ii) bankers' efforts significantly explain the banking sector's productivity, (iii) the proportion of non-performing loans has considerably declined, and (iv) banking services have become costly, although the bank spread has moderately declined. Our approach is different from the widely used data envelopment analysis (DEA) of bank productivity, hence complements the literature. It also informs the current policy debate in Nepal where the Central Bank is seen to be geared towards regulating the financial system and micro-managing the banking institutions
A latent class model for obesity
We extend the discrete data latent class literature by explicitly defining a latent variable for class membership as a function of both observables and unobservables, thereby allowing the equations defining the class membership and observed outcomes to be correlated. The procedure is then applied to modelling observed obesity outcomes, based upon an underlying ordered probit equation
Spatially resolved spectroscopic differentiation of hydrophilic and hydrophobic domains on individual insulin amyloid fibrils
The formation of insoluble β-sheet-rich protein structures known as amyloid fibrils is associated with numerous neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease. A detailed understanding of the molecular structure of the fibril surface is of interest as the first contact with the physiological environment in vivo and plays a decisive role in biological activity and associated toxicity. Recent studies reveal that the inherent sensitivity and specificity of tip-enhanced Raman scattering (TERS) renders this technique a compelling method for fibril surface analysis at the single-particle level. Here, the reproducibility of TERS is demonstrated, indicating its relevance for detecting molecular variations. Consequently, individual fibrils are systematically investigated at nanometer spatial resolution. Spectral parameters were obtained by band-fitting, particularly focusing on the identification of the secondary structure via the amide III band and the differentiation of hydrophobic and hydrophilic domains on the surface. In addition multivariate data analysis, specifically the N-FINDR procedure, was employed to generate structure-specific maps. The ability of TERS to localize specific structural domains on fibril surfaces shows promise to the development of new fibril dissection strategies and can be generally applied to any (bio)chemical surface when structural variations at the nanometer level are of interest
Disposable versus reusable ureteroscopes. A prospective multicenter randomized comparison
Introduction: To compare reusable and disposable flexible ureteroscopes in terms of efficacy and safety for patients undergoing RIRS, with
specific reference to post-operative complications and infection rates. Materials and methods: Patients with a renal stone eligible for RIRS
were enrolled in this multicenter, randomized, clinical trial study. Patients were randomized into two groups: group A (90 patients) underwent RIRS with a reusable flexible ureteroscope and group B (90 patients) were treated with a disposable one. Results: The patients’ demographics, stones features and preoperative urine cultures were comparable between the groups. The SFRs were not significantly different (86,6% and 90,0% for group A and group B respectively, p = 0.11) and the mean cost for each procedure was comparable (2321 € in group A vs 2543 € in group B, p = 0.09). However, the days of hospitalization and of antibiotic therapy were higher in group A (p ≤ 0.05). The overall complication rate in group A was 8.8% whilst in group B it was 3.3% (p ≤ 0.05); in particular, group A exhibited a greater number of major complications (Clavien score IIIa-V). The overall postoperative infections rate was 16.6% in group A and 3.3% in group B (p ≤ 0.05). Furthermore, none of the patients in group B developed urosepsis or had a positive blood culture, while 3 patients in group A did (p < 0.05).
Conclusions: The use of disposable ureteroscopes is characterized by significantly lower post-operative complications and infection rates,
while having comparable costs and SFRs vis Ă vis reusable ureteroscopes
A comparison among PCNL, Miniperc and Ultraminiperc for lower calyceal stones between 1 and 2 cm: A prospective, comparative, multicenter and randomised study
Background: Conventional Percutaneous Lithotripsy (PCNL) has been an effective, successful and easy approach for especially > 1 cm sized calyceal stones however risks of complications and nephron loss are inevitable. Our aim is to compare the efficacy and safety of PCNL, MiniPerc (MP) and UltraMiniPerc (UMP) for lower calyceal stones between 1 and 2 cm with a multicenter prospective randomized study. Methods: Between January 2015 and June 2018, 132 consecutive patients with single lower calyceal stone were enrolled. Patients were randomized in three groups; A: PCNL; B: MP; C: UMP. 44 patients for the Group A, 47 for Group B and 41 for Group C. Exclusion criterias were the presence of coagulation impairments, age of < 18 or > 75, presence of infection or serious comorbidities. Patients were controlled with computerized tomography scan after 3 months. A negative CT or an asymptomatic patient with stone fragments < 3 mm size were the criteria to assess the stone-free status. Patient characteristics, stone free rates (SFR) s, complications and re-treatment rates were analyzed. Results: The mean stone size were 16.38, 16.82 and 15.23 mm respectively in Group A, B and C(p = 0.34). The overall SFR was significantly higher in Group A (86.3%) and B (82.9%) as compared to Group C (78%)(p < 0.05). The re-treatment rate was significantly higher in Group C (12.1%) and complication rates was higher in Group A (13.6%) as compared to others(p < 0.05). The hospitalization was significantly shorter in Group C compared to Group A (p = 0.04). Conclusions: PCNL and MP showed higher efficacy than UMP to obtain a better SFR. Auxiliary and re-treatment rates were higher in UMP. On the other hand for such this kind of stones PCNL had more complications. Overall evaluation favors MP as a better indication in stones 1-2 cm size
Holmium laser enucleation of the prostate with Virtual Basket mode: faster and better control on bleeding
Background: To compare clinical intra and early postoperative outcomes between conventional Holmium laser enucleation of the prostate (HoLEP) and Holmium laser enucleation of the prostate using the Virtual Basket tool (VB-HoLEP) to treat benign prostatic hyperplasia (BPH). Methods: This prospective randomized study enrolled consecutive patients with BPH, who were assigned to undergo either HoLEP (n = 100), or VB-HoLEP (n = 100). All patients were evaluated preoperatively and postoperatively, with particular attention to catheterization time, operative time, blood loss, irrigation volume and hospital stay. We also evaluated the patients at 3 and 6 months after surgery and assessed maximum flow rate (Qmax), postvoid residual urine volume (PVR), the International Prostate Symptom Score (IPSS) and the Quality of Life score (QOLS). Results: No significant differences in preoperative parameters between patients in each study arm were found. Compared to HoLEP, VB-HoLEP resulted in less hemoglobin decrease (2.54 vs. 1.12 g/dl, P = 0.03) and reduced operative time (57.33 ± 29.71 vs. 42.99 ± 18.51 min, P = 0.04). HoLEP and VB-HoLEP detrmined similar catheterization time (2.2 vs. 1.9 days, P = 0.45), irrigation volume (33.3 vs. 31.7 l, P = 0.69), and hospital stay (2.8 vs. 2.7 days, P = 0.21). During the 6-month follow-up no significant differences in IPSS, Qmax, PVR, and QOLS were demonstrated. Conclusions: HoLEP and VB-HoLEP are both efficient and safe procedures for relieving lower urinary tract symptoms. VB-HoLEP was statistically superior to HoLEP in blood loss and operative time. However, procedures did not differ significantly in catheterization time, hospital stay, and irrigation volume. No significant differences were demonstrated in QOLS, IPSS, Qmax and PVR throughout the 6-month follow-up. Trial Registration: Current Controlled Trials ISRCTN72879639; date of registration: June 25th, 2015. Retrospectively registred
- …