Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

The Chemistry and Applications of Metal-Organic Frameworks

1. INTRODUCTION Among the classes of highly porous materials, metalÀorganic frameworks (MOFs) are unparalleled in their degree of tunability and structural diversity as well as their range of chemical and physical properties. MOFs are extended crystalline structures wherein metal cations or clusters of cations (\" nodes \") are connected by multitopic organic \" strut \" or \" linker \" ions or molecules. The variety of metal ions, organic linkers, and structural motifs affords an essentially infinite number of possible combinations. 1 Furthermore, the possibility for postsynthetic modification adds an additional dimension to the synthetic variability. 2 Coupled with the growing library of experimentally determined structures, the potential to computationally predict, with good accuracy, affinities of guests for host frameworks points to the prospect of routinely predesigning frameworks to deliver desired properties. 3,4 MOFs are often compared to zeolites for their large internal surface areas, extensive porosity, and high degree of crystallinity. Correspondingly, MOFs and zeolites have been utilized for many of the same applications

Metal–Organic Framework Materials as Chemical Sensors

As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

Metal–organic frameworks (MOFs) are a unique class of crystalline solids comprised of metal cations (or metal clusters) and organic ligands that have shown promise for a wide variety of applications Over the past 15 years, research and development of these materials have become one of the most intensely and extensively pursued areas A very interesting and well-investigated topic is their optical emission properties and related applications Several reviews have provided a comprehensive overview covering many aspects of the subject up to 2011 This review intends to provide an update of work published since then and focuses on the photoluminescence (PL) properties of MOFs and their possible utility in chemical and biological sensing and detection The spectrum of this review includes the origin of luminescence in MOFs, the advantages of luminescent MOF (LMOF) based sensors, general strategies in designing sensory materials, and examples of various applications in sensing and detection

Luminescent metal–organic frameworks for chemical sensing and explosive detection

Cytomegalovirus (CMV) and BK polyomavirus (BKPyV) infections after kidney transplant have become increasingly prevalent. Based on previous studies, the mammalian target of rapamycin (mTOR) inhibitors seem like attractive alternatives with antiviral activity. The objective of this systematic review and meta‐analysis was to investigate the incidence of CMV and BKPyV infections in kidney transplantation recipients receiving mTOR inhibitors. This meta‐analysis included three comparisons of immunosuppressant regimens commonly used after kidney transplantation: Comparison 1: mTOR inhibitors versus calcineurin inhibitors (CNI); Comparison 2: mTOR inhibitors versus antimetabolites (AM); and Comparison 3: mTOR inhibitors plus a reduced‐dose of CNI versus AM plus a standard‐dose of CNI. The group containing mTOR inhibitors was the study group and the remaining one was the control group. The incidence of CMV or BKPyV infection defined by positive culture, serology, or polymerase chain reaction testing was the primary outcome. A total of 61 studies involving 13,609 patients were included. As compared with the control group, a significantly decreased risk of CMV and BKPyV infections favoring the mTOR inhibitors‐based group was shown in comparisons 1, 2, and 3 (p < 0.05). Compared with the control group in all three comparisons, mTOR inhibitors made no difference in regard to death and graft loss (p > 0.05). Compared with CNI, the incidence of biopsy‐proven acute rejection (BPAR) and anemia was higher with mTOR inhibitors (p < 0.05). In comparisons 2 and 3, the risk of new‐onset diabetes mellitus (NODM) was higher with mTOR inhibitors (p < 0.05). Early introduction of mTOR inhibitors reduced more CMV infections in comparisons 1 and 2 (p < 0.05). The mTOR inhibitor‐based regimen is an attractive alternative with lower risk of CMV and BKPyV infections in kidney transplant recipients. The combination regimen is more appropriate and acceptable than the mTOR‐inhibitor monotherapy‐based regimen. Early introduction of mTOR inhibitors is recommended, although it is worth noting that attention should be paid to wound healing when mTOR inhibitors are introduced early.

The incidence of cytomegalovirus and BK polyomavirus infections in kidney transplant patients receiving mTOR inhibitors: A systematic review and meta‐analysis

Background Intussusception is a frequent abdominal emergency in the pediatric population when the proximal bowel invaginates into the distal bowel. However, catheter-induced intussusception has not previously been described in pediatric renal transplant recipients, and the risk factors need to be investigated. Case Description We report 2 cases of post-transplant intussusception which were caused by abdominal catheters. Case 1 experienced ileocolonic intussusception 3 months after renal transplantation and presented with intermittent abdominal pain; the intussusception was successfully managed using air enema. However, this child experienced a total of 3 episodes of intussusception within 4 days, which discontinued only after removal of the peritoneal dialysis catheter. No further intussusception recurrence was observed and the patient’s intermittent pain disappeared during the follow-up. Case 2 developed ileocolonic intussusception 2 days after renal transplantation and presented currant jelly stools. The intussusception was completely irreducible until the intraperitoneal drainage catheter was eliminated; the patient discharged normal feces during the following days. A search in the databases of PubMed, Web of Science, and Embase yielded 8 similar cases. Our 2 cases had a younger age at disease onset than those retrieved in the search, and abdominal catheter was revealed as a lead point. Possible leading points of the 8 previously reported cases included post-transplant lymphoproliferative disorder (PTLD), acute appendicitis, tuberculosis, lymphocele, and firm adhesions. We noted that our cases were managed successfully with nonoperative treatment, whereas the 8 reported cases underwent surgical intervention. All of the 10 cases of intussusception occurred after renal transplantation and showed that intussusception had been induced by a lead point. Conclusions Our 2 cases implied that abdominal catheter could be a lead point to induce intussusception, especially in pediatric recipients with abdominal disorder. This experience may be applicable to other surgeries involving indwelling abdominal catheters in children. Health practitioners should consider this pathologic lead point and avoid serious consequences when intussusception occurs.

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Abdominal catheter-induced intussusception following renal transplantation in two pediatric recipients: 2 cases report and literature review

Wuzhi tablets are a dose‐sparing agent for tacrolimus (TAC) in China and increase the bioavailability of TAC. The current study aimed to evaluate the pharmacokinetic interaction magnitude of Wuzhi and TAC and explore the potential determinants of this interaction.

Cheng Wang

Papers

The incidence of cytomegalovirus and BK polyomavirus infections in kidney transplant patients receiving mTOR inhibitors: A systematic review and meta‐analysis

Abdominal catheter-induced intussusception following renal transplantation in two pediatric recipients: 2 cases report and literature review

Prediction of tacrolimus and Wuzhi tablet pharmacokinetic interaction magnitude in renal transplant recipients

Anti-disturbance Position Sensorless Control of PMSM Based on Improved Sliding Mode Observer with Suppressed Chattering and No Phase Delay

Why can poorly conductive Bi@UiO-MOF catalyze CO2 electroreduction?