Chulalongkorn University

About: Chulalongkorn University is a education organization based out in Bangkok, Thailand. It is known for research contribution in the topics: Population & Catalysis. The organization has 20156 authors who have published 34324 publications receiving 647815 citations. The organization is also known as: Chula & CU.

Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC

Abstract: The performance is presented of the reconstruction and identification algorithms for electrons and photons with the CMS experiment at the LHC. The reported results are based on proton-proton collision data collected at a center-of-mass energy of 13 TeV and recorded in 2016-2018, corresponding to an integrated luminosity of 136 fb$^{-1}$. Results obtained from lead-lead collision data collected at $\sqrt{s_\mathrm{NN}}=$ 5.02 TeV are also presented. Innovative techniques are used to reconstruct the electron and photon signals in the detector and to optimize the energy resolution. Events with electrons and photons in the final state are used to measure the energy resolution and energy scale uncertainty in the recorded events. The measured energy resolution for electrons produced in Z boson decays in proton-proton collision data ranges from 2 to 5%, depending on electron pseudorapidity and energy loss through bremsstrahlung in the detector material. The energy scale in the same range of energies is measured with an uncertainty smaller than 0.1 (0.3)% in the barrel (endcap) region in proton-proton collisions and better than 1 (3)% in the barrel (endcap) region in heavy ion collisions. The timing resolution for electrons from Z boson decays with the full 2016-2018 proton-proton collision data set is measured to be 200 ps.

NAFLD fibrosis score: A prognostic predictor for mortality and liver complications among NAFLD patients

Abstract: AIM: To study whether the severity of liver fibrosis estimated by the nonalcoholic fatty liver disease (NAFLD) fibrosis score can predict all-cause mortality, cardiac complications, and/or liver complications of patients with NAFLD over long-term follow-up. METHODS: A cohort of well-characterized patients with NAFLD diagnosed during the period of 1980-2000 was identified through the Rochester Epidemiology Project. The NAFLD fibrosis score (NFS) was used to separate NAFLD patients with and without advanced liver fibrosis. We used the NFS score to classify the probability of fibrosis as -1.5 to 0.67 for high probability. Primary endpoints included all-cause death and cardiovascular- and/or liver-related mortality. From the 479 patients with NAFLD assessed, 302 patients (63%) greater than 18 years old were included. All patients were followed, and medical charts were reviewed until August 31, 2009 or the date when the first primary endpoint occurred. By using a standardized case record form, we recorded a detailed history and physical examination and the use of statins and metformin during the follow-up period. RESULTS: A total of 302/479 (63%) NAFLD patients (mean age: 47 ± 13 year) were included with a follow-up period of 12.0 ± 3.9 year. A low probability of advanced fibrosis (NFS -1.5) was found in 121 patients (40%). At the end of the follow-up period, 55 patients (18%) developed primary endpoints. A total of 39 patients (13%) died during the follow-up. The leading causes of death were non-hepatic malignancy (n = 13/39; 33.3%), coronary heart disease (CHD) (n = 8/39; 20.5%), and liver-related mortality (n = 5/39; 12.8%). Thirty patients had new-onset CHD, whereas 8 of 30 patients (27%) died from CHD-related causes during the follow-up. In a multivariate analysis, a higher NFS at baseline and the presence of new-onset CHD were significantly predictive of death (OR = 2.6 and 9.2, respectively; P < 0.0001). Our study showed a significant, graded relationship between the NFS, as classified into 3 subgroups (low, intermediate and high probability of liver fibrosis), and the occurrence of primary endpoints. The use of metformin or simvastatin for at least 3 mo during the follow-up was associated with fewer deaths in patients with NAFLD (OR = 0.2 and 0.03, respectively; P < 0.05). Additionally, the rate of annual NFS change in patients with an intermediate or high probability of advanced liver fibrosis was significantly lower than those patients with a low probability of advanced liver fibrosis (0.06 vs 0.09, P = 0.004). The annual NFS change in patients who died was significantly higher than those in patients who survived (0.14 vs 0.07, P = 0.03). At the end of the follow-up, we classified the patients into 3 subgroups according to the progression pattern of liver fibrosis by comparing the NFS at baseline to the NFS at the end of the follow-up period. Most patients were in the stable-fibrosis (60%) and progressive-fibrosis (37%) groups, whereas only 3% were in the regressive fibrosis. CONCLUSION: A higher NAFLD fibrosis score at baseline and a new onset of CHD were significantly predictive of death in patients with NAFLD.

Toughening of polybenzoxazine by alloying with urethane prepolymer and flexible epoxy : A comparative study

Abstract: The toughness of polybenzoxazine can effectively be improved by alloying with isophorone diisocyanate (IPDI)-based urethane prepolymers (PU) or with flexible epoxy (EPO732). The experimental results, i.e., flexural testing and dynamic mechanical analysis, reveal that the toughness of the alloys of the rigid polybenzoxazine and the PU or the EPO732 systematically increases with the amount of either toughener, due to the addition of more flexible molecular segments in the polymer hybrids. The curing temperature of the benzoxazine resin (bisphenol A-aniline type [BA-a]) at about 225°C shifts to a higher value when the fraction of BA-a in either alloy decreases. Interestingly, the enhancement in the glass transition temperature (Tg) of BA-a/PU alloys is clearly observed, i.e., Tg of the BA-a/PU alloys are significantly higher (Tg beyond 200°C) than those of the parent resins, i.e., 165°C for BA-a and −70°C for PU. However, this characteristic is not observed in the BA-a/EPO732 alloy systems. The enhanced Tg of the BA-a/PU alloy at a 70/30 mass ratio is found to be 220°C, while that of BA-a/EPO732 at the same mass ratio is observed to be only 95°C, which further decreases as the content of epoxy fraction increases. Furthermore, the degradation temperature based on 5% weight loss in the thermogravimetric analyzer (TGA) thermograms of the BA-a/PU alloys is found to improve with the presence of the PU, though the opposite trend is observed in the BA-a/EPO732 systems. The char yield of both alloy systems is steadily enhanced with the increased benzoxazine content because the char yield of the polybenzoxazine is inherently higher than that of the two tougheners. Therefore, the polybenzoxazine alloys with the IPDI-based urethane prepolymer, e.g., the 70/30 BA-a/PU, are a promising system for a tough, high thermal stability polymeric network, suitable for both bulk and composite matrix applications. POLYM. ENG. SCI. 45:288–296, 2005. © 2005 Society of Plastics Engineers.