Cysteine residues 87 and 320 in the amino terminal domain of NMDA receptor GluN2A govern its homodimerization but do not influence GluN2A/GluN1 heteromeric assembly

N-Methyl-D-aspartate receptors（NMDARs） play a central role in various physiological and pathological processes in the central nervous system.And they are commonly composed of four subunits,two GluN1 subunits and two GluN2 or GluN3 subunits.The different subunit compositions make NMDARs a heterogeneous population with distinct electrophysiological and pharmacological properties and thus with different abilities to conduct neuronal activities.The subunit composition,assembly process,and final structure of assembled NMDARs have been studied for years but no consensus has been achieved.In this study,we investigated the role of the amino terminal domain（ATD） of GluN2A in regulating NMDAR assembly.The ATD of GluN2A was first expressed in heterogeneous cells and the homodimer formation was investigated by fluorescent resonance energy transfer and non-reducing SDS- PAGE electrophoresis.Each of the three cysteine residues located in the ATD was mutated into alanine,and the homodimerization of the ATD or GluN2A,as well as the heteromeric assembly of NMDARs was assessed by non-reducing SDS- PAGE electrophoresis,co-immunoprecipitation and immunocytochemistry.We found that two cysteine residues,C87 and C320,in the ATD of the GluN2A subunit were required for the formation of disulfide bonds and GluN2A ATD homodimers.Furthermore,the disruption of GluN2A ATD domain dimerization had no influence on the assembly and surface expression of NMDARs.These results suggest that the two ATD domains of GluN2A are structurally adjacent in fully-assembled NMDARs.However,unlike GluN1,the homomerization of the ATD domain of GluN2A is not required for the assembly of NMDARs,implying that GluN2A and GluN1 play unequal roles in NMDAR assembly.     

The photoelectron-imaging spectroscopic study and chemical bonding analysis of VO2−, NbO2− and TaO2−

The transition-metal di-oxides, namely VO₂⁻, NbO₂⁻ and TaO₂⁻ have been studied using photoelectron velocity map imaging (PE-VMI) in combination with theoretical calculations. The adiabatic electron affinities of VO₂⁻, NbO₂⁻ and TaO₂⁻ are confirmed to be 2.029(8), 1.901(10) and 2.415(8) eV, respectively. By combining Franck–Condon (FC) simulation with theoretical calculations, the vibrational feature related to Nb–O and Ta–O stretching modes for the ground state has been unveiled. The photoelectron angular distribution (PAD) for VO₂⁻, NbO₂⁻ and TaO₂⁻ is correlated to the photo-detachment of the highest occupied molecular orbitals (HOMOs), which primarily gets involved in s- and d-orbitals of the V, Nb and Ta atoms. A variety of theoretical calculations have been used to analyze the chemical bonding features of VO₂^−1/0, NbO₂^−1/0 and TaO₂^−1/0, which show that the strong M–O (M = V, Nb and Ta) bond is mainly characterized as ionicity.

The transition-metal di-oxides, namely VO₂⁻, NbO₂⁻ and TaO₂⁻ have been studied using photoelectron velocity map imaging (PE-VMI) in combination with theoretical calculations.     

LiFePO4-coated LiNi0.6Co0.2Mn0.2O2 for lithium-ion batteries with enhanced cycling performance at elevated temperatures and high voltages

LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) is a highly promising cathode material owing to its high capacity; however, it is characterized by inferior cycling performance and safety problems. We report a novel strategy to improve electrochemical characteristics and safety issues of NCM622 by coating it with LiFePO₄ (LFP). Although having a lower capacity, LFP is a safe and long-cycle cathode material; it is more chemically and thermally stable than NCM622 when exposed to common electrolytes. The LFP-coated NCM622 (NCM@LFP) showed similar rate performance and cycling performance at room temperature compared with the pristine NCM622 under the same conditions. However, significant differences between the NCM622 and NCM@LFP began to emerge at high temperatures. During cycling at 1C for 100 cycles at 55 °C, NCM@LFP showed much improved specific discharge capacity retentions of 92.4%, 90.9%, and 88.2% in the voltage ranges of 3–4.3 V, 3–4.4 V and 3–4.5 V, respectively. The NCM622 suffered significant discharge specific capacity decay under the same condition. In addition, as demonstrated by the delayed exothermic peak in the differential scanning calorimetry (DSC) test, NCM@LFP exhibited excellent thermal stability compared with NCM622, which is critical to battery safety.

LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) is a highly promising cathode material owing to its high capacity; however, it is characterized by inferior cycling performance and safety problems.     

Certification in Medical Physics Imaging,The Workforce and Training Models

The pathway to becoming a qualified medical physicist (QMP) in the imaging physics disciplines includes several certification organizations. Imaging QMPs play an essential role in the safe practice of the diagnostic disciplines, and their qualifications are necessary for compliance with federal bodies and professional accreditation organizations. The future demand for imaging QMPs is largely unknown, but professional organizations that represent these groups agree that efforts should be made to increase the number of matriculating trainees. The number of imaging residency programs that provide the necessary professional experience to enter the certification pathway has increased substantially in recent years. Most of these programs follow a traditional academic hospital-based training model, but guidance on program construction from the accrediting body permits flexibility. Existing training models for medical physics imaging also include consortiums of affiliate partners and private consulting service groups. In this article, the authors briefly review the certification pathways for imaging QMPs, workforce estimates, and training models.     

Hypermetabolism associated with worse prognosis of amyotrophic lateral sclerosis

Journal of Neurology - Exploration of hypermetabolism in amyotrophic lateral sclerosis (ALS) with different ethnicities is needed to understand its metabolic implications for clinical management....     

Main lymphocyte subpopulations in cerebrospinal fluid and peripheral blood in HIV-1 subtypes C and B

Journal of NeuroVirology - HIV-1 subtype C (HIV-1C) shows reduced Tat protein chemoattractant activity compared with HIV-1B. The impact of HIV-1C Tat on the chemotaxis of the main lymphocyte...