The mechanism of the amine-catalysed isomerizationof dialkyl maleate: A computational study

DFT at B3LYP/6-31G (d,p) level calculation results for the amine-catalysed isomerization of dimethyl maleate revealed that the mechanism proceeds via foursteps: (1) a concerted proton transfer from one amine molecule to another which subsequently enhances the addition of the adduct thus formed to the C-C double bond to yield INT1. (2) Abstraction of a proton from the -carbon of INT1 by a second amine molecule to give intermediate INT2. (3) Rotation about the C-C single bond followed by proton abstraction by an amine molecule to yield unstable INT3, and (4) an elimination of an amine molecule to yield the trans isomer, dimethyl fumarate. Furthermore, it was found that step 1 is the rate limiting step. However, the activation energy difference between steps 1 and 2 was significantly low and its value depends on the amine catalyst used. The activation energy was found to be lower in water when compared to that calculated in the gas phase. In addition, linear correlation was found between the amine-catalysed isomerization experimental rate and the pKa of the amine catalyst on one hand and the enthalpic and free activation energies on the other hand. The calculations also confirmed that the reaction is first order in dimethyl maleate, second order in the amine catalyst and overall third order. This study disproves three of the four different intermediates that were previously suggested to explain the amine catalysed isomerization of dialkyl maleates. The study verifies the intermediate suggested by Rappopor

Design Optimization of 3D Steel Frameworks Under Constraints of Natural Frequencies of Vibration

Steel multistorey 3D frames are commonly used in business and residential buildings, industrial sheds, warehouses, etc. The design optimization of tall steel buildings is usually governed by horizontal loadings, such as, wind load, as well as its dynamic behavior, for which the structure must have the stiffness and stability in accordance with the safety criteria established by codes. This chapter deals with sizing structural optimization problems, concerning weight minimization of 3D steel frames, considering natural frequencies of vibration as well as allowable displacements as the constraints of the optimization problem. The discrete design variables are to be chosen from commercial profiles tables. A differential evolution (DE) is the search algorithm adopted coupled to an adaptive penalty method (APM) to handle the constraints. Three different 3D frames are optimized, presenting very interesting results

Necessity and concerns about lipid-lowering medical treatments and risk factors for non-adherence: A cross-sectional study in Palestine

Aims: Strong evidence indicates that drugs reduce blood lipids and improve cardiovascular end-points, leading to their wide usage. However, the success of these drugs can be affected by poor patient's adherence to prescribed medication. This study aimed to evaluate medication adherence in patients with dyslipidaemia in association with patient beliefs about medicines. Methods: The study was conducted from January 2019 to July 2019 at the middle governmental primary healthcare clinics in Ramallah and Bethlehem cities, and used a cross-sectional design. Adherence was determined using the 4-item Morisky medication adherence scale, while beliefs were determined using the Beliefs about Medicines Questionnaire. Results: Of 220 patients, 185 agreed to participate in the study, resulting in a response rate of 84.1%. Of the participants, 106 (57.3%) were men, and almost half (88, 46.5%) were ≥56 years. Medication non-adherence was high (47.6%), but a majority (65.5%) reported believing their treatment to be necessary for their continued good health. Accordingly, the mean necessity score (17.3, SD 3.7) significantly outweighed (P < .001) the mean concerns score (14.0, SD 3.5). Multivariate regression demonstrated four variables to be significantly correlated with non-adherence: illiterate (OR = 2.52; CI: 0.9-4.3; P = .03), polypharmacy (OR = 3.18; CI: 1.9-5.7; P = .007), having comorbidity (OR = 3.10; CI: 2.2-4.6; P = .005) and having concerns about side effects (OR = 2.89; CI: 1.1-4.6, P = .04). Conclusion: Non-adherence among patients taking lipid-lowering agents was high despite most holding positive beliefs regarding medication necessity. This may be due to concern also being high. Physicians should identify and target high-risk patients and individualise their treatment plans in order to achieve adequate control of dyslipidaemia.We thank all workers at health clinics at Ramallah and Bethlehem who helped in finishing this study and also we thank the participants who willingly accepted to share for the purpose of this study

L-Ornithine-L-Aspartate and Intermittent Renal Replacement Therapy in Fulminant Hepatitis A

Hepatitis A is a common viral infection worldwide that is transmitted via the fecal-oral route. Since the introduction of an efficient vaccine, the incidence of infection has decreased but the number of cases has risen due to widespread community outbreaks among unimmunized individuals. Classic symptoms include fever, malaise, dark urine, and jaundice, and are more common in older children and adults. People are often most infectious 14 days prior to and 7 days following the onset of jaundice. We will discuss the case of a young male patient, diagnosed with acute hepatitis A, leading to fulminant hepatitis refractory to conventional therapy and the development of subsequent kidney injury. The medical treatment through the course of hospitalization was challenging and included the use of L-ornithine-L-aspartate and prolonged intermittent hemodialysis, leading to a remarkable outcome. Hepatitis A is usually self-limited and vaccine-preventable; supportive care is often sufficient for treatment, and chronic infection or chronic liver disease rarely develops. However, fulminant hepatitis, although rare, can be very challenging to manage as in the case of our patient

The synthetic bacterial lipopeptide Pam3CSK4 modulates respiratory syncytial virus infection independent of TLR activation

Respiratory syncytial virus (RSV) is an important cause of acute respiratory disease in infants, immunocompromised subjects and the elderly. However, it is unclear why most primary RSV infections are associated with relatively mild symptoms, whereas some result in severe lower respiratory tract infections and bronchiolitis. Since RSV hospitalization has been associated with respiratory bacterial co-infections, we have tested if bacterial Toll-like receptor (TLR) agonists influence RSVA2- GFP infection in human primary cells or cell lines. The synthetic bacterial lipopeptide Pam3-Cys-Ser-Lys4 (Pam3CSK4), the prototype ligand for the heterodimeric TLR1/TLR2 complex, enhanced RSV infection in primary epithelial, myeloid and lymphoid cells. Surprisingly, enhancement was optimal when lipopeptides and virus were added simultaneously, whereas addition of Pam3CSK4 immediately after infection had no effect. We have identified two structurally related lipopeptides without TLR-signaling capacity that also modulate RSV infection, whereas Pam3CSK4-reminiscent TLR1/2 agonists did not, and conclude that modulation of infection is independent of TLR activation. A similar TLR-independent enhancement of infection could also be demonstrated for wild-type RSV strains, and for HIV-1, measles virus and human metapneumovirus. We show that the effect of Pam3CSK4 is primarily mediated by enhanced binding of RSV to its target cells. The Npalmitoylated cystein

Reassessing China’s Higher Education Development: A Focus on Academic Culture

During the past three and a half decades, China has been progressing in higher education in a surprisingly dramatic manner, evidenced especially by scientific publications and sheer numbers of graduates. Such a fact has national, regional and global implications. China’s higher education development and its future directions are now placed highly on the research agendas of many from various parts of the world. Unlike the general acknowledgment of China’s achievements, assessment of the future development of China’s higher education is wide open to question. To some, Chinese universities are on a trajectory to become “world-class” and China’s high-fliers challenge Western supremacy. To others, China’s notion of “world-class” status has been largely imitative. Pumping resources into universities will only lead to diminishing returns as Chinese culture and practices will act as a brake to the pursuit of academic excellence. An increasing deal of attention has been paid to where China will be located in a global higher education landscape and in what shape. Based on the author’s long-standing professional observation and recent empirical studies, this article assesses China’s higher education development, with a particular focus on the challenges brought forward by academic culture. It interrogates China’s pride of the idea that Chinese universities are not willing to assume that Western models define excellence, and asks how far Chinese universities could move within their current development model.postprin

Breakdown of the Giant Spin Model in the Magnetic Relaxation of the Mn6 Nanomagnets

We study the spin dynamics in two variants of the high-anisotropy Mn-6 nanomagnet by inelastic neutron scattering, magnetic resonance spectroscopy and magnetometry. We show that a giant-spin picture is completely inadequate for these systems and that excited S multiplets play a key role in determining the effective energy barrier for the magnetization reversal. Moreover, we demonstrate the occurrence of tunneling processes involving pair of states having different total spin