MESP: An efficient method to validate an ONIOM partition for the modelization of phosphine ligands commonly used in the Pauson–Khand reaction

In this study we discuss the modelization of phosphine ligands commonly used in inorganic and organometallic chemistry as for example the asymmetric Pauson–Khand reaction by means of ONIOM method. A fundamental question that arises after the decision of using QM/MM methods for a certain study is how to partition the system. Which atoms are going to be included in the QM region and which atoms are going to be included in the MM region? Chemical knowledge is most of the time the guiding line for this choice, but tests should be run in case of uncertainty. For the setting of the QM/MM border, two criteria have been employed: results from geometry optimizations of the ligand complexed to tungsten penta(tetra)carbonyl and calculations of the molecular electrostatic potential (MESP) for the ligand alone. We have shown that these two methods give similar conclusions and thus MESP can be used to validate the ONIOM partition of these systems. This later approach has the advantage of being fast and computationally inexpensive.     

Evaluation of Japanese practice guidelines for newly diagnosed childhood idiopathic thrombocytopenic purpura

Background: Practice guidelines for childhood idiopathic thrombocytopenic purpura (ITP) were proposed in 1998 and 2004 in Japan. It is important to evaluate the feasibility and validity of the guidelines because the guidelines are based not on evidence but on opinion. Methods: Records of 30 consecutive hospitalized patients aged 0–15 years (median, 3 years; 17 boys, 13 girls) were retrospectively reviewed. The feasibility and validity of the 2004 guidelines were evaluated by calculating an implementation rate, a response rate to first treatments, and a final clinical outcome. Results: Deviation from the guidelines was found in two patients. Management of the other 28 patients followed the guidelines. The implementation rate was 93.3%. Twenty‐one of the 28 eligible patients (75%) responded to the first treatment, whereas seven patients (25%) required additional treatment. In 23 patients (76.7%) platelet counts returned to normal within 6 months. Seven patients (23.3%) developed chronic conditions. All patients had no complications and achieved a platelet count >150 000/µL within 6 years. Conclusion: The 2004 Japanese guidelines are feasible and valid for the management of newly diagnosed childhood ITP patients.     

The fold of alpha-synuclein fibrils

The aggregation of proteins into amyloid fibrils is associated with several neurodegenerative diseases. In Parkinson's disease it is believed that the aggregation of alpha-synuclein (alpha-syn) from monomers by intermediates into amyloid fibrils is the toxic disease-causative mechanism. Here, we studied the structure of alpha-syn in its amyloid state by using various biophysical approaches. Quenched hydrogen/deuterium exchange NMR spectroscopy identified five beta-strands within the fibril core comprising residues 35-96 and solid-state NMR data from amyloid fibrils comprising the fibril core residues 30-110 confirmed the presence of beta-sheet secondary structure. The data suggest that beta1-strand interacts with beta2, beta2 with beta3, beta3 with beta4, and beta4 with beta5. High-resolution cryoelectron microscopy revealed the protofilament boundaries of approximately 2 x 3.5 nm. Based on the combination of these data and published structural studies, a fold of alpha-syn in the fibrils is proposed and discussed.     

76例系统性红斑狼疮患者血清自身抗体检测及意义

系统性红斑狼疮(SLE)是一种以免疫系统功能异常为特征的自身免疫性疾病,由于遗传、环境因素间复杂的相互作用,造成患者体内细胞免疫与体液免疫失衡,导致患者血清中存在一些对疾病诊断具有高度特异性的多种自身抗体.我们对76例SLE患者进行了抗核抗体(ANA)、抗ds-DNA抗体及抗ENA多肽抗体的检测,对检测结果及其临床意义进行了分析,现将结果报道如下.     

Correction: An efficient one pot ipso-nitration: structural transformation of a dipeptide by N-terminus modification

Correction for ‘An efficient one pot ipso-nitration: structural transformation of a dipeptide by N-terminus modification’ by Rajib Sarkar et al., RSC Adv., 2015, 5, 59570–59575.

The authors wish to clarify a few sentences by stating that the major product in the ipso-nitration reaction is probably the phenol 3 (Scheme 1). The ipso-nitration reaction happened in TFA, NaNO₂ and H₂SO₄, which are comparatively drastic conditions for a peptide. Initially the yield of target compound 2 was 40%. As we had a single crystal structure matching the structure of compound 2, and the structure exactly matched with the mass spectroscopy data, we did not analyze the remaining 60% of the reaction product, which was likely phenol 3. Moreover, phenol 3 has the same formula and mass as our target compound 2. We have been misled by this fact and did not analyze the reaction mixture further. The moderate yields may indeed indicate that the other product (phenol 3) could have been present which we have missed.Open in a separate windowScheme 1The schematic presentation of possible products from the ipso-nitration of peptide 1. Both products 2 and 3 have the same chemical formula and exact mass.Ref. 14 should also be updated to include more relevant literature reports of ipso-nitration (ref. 14d-h in the article, presented here as ref. 1a–e). In 1939, E. B. Starkey reported the replacement of an amine group by a nitro group through a diazotization reaction.^1a In 1947, Hodgson and co-workers reported the replacement of a diaxonium by a nitro group.^1bSingh and co-workers proposed a radical mechanism (Scheme 2) for the ipso-nitration reaction.^1e Therefore, the mechanism we originally proposed in the article may not be correct, as we are unable to rule out the possibility that the reaction occurs via a radical mechanism.Open in a separate windowScheme 2The schematic of a radical mechanism adopted from Tetrahedron Lett., 1982, 23, 5191.The authors apologise for these errors and are indebted to an RSC Advances Board member and the editorial team for the exchange of information and the discussion regarding this corrigendum.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

Functional Poly(Dimethyl Aminoethyl Methacrylate) by Combination of Radical Ring‐Opening Polymerization and Click Chemistry for Biomedical Applications

In this work, the macromolecular design and modular synthesis of degradable and biocompatible copolymers via radical polymerization and click chemistry is highlighted and the resulting systems are evaluated as gene delivery carriers. Poly(ethylene glycol) (PEG) grafted poly[2‐methylene‐1,3‐dioxepane (MDO)‐co‐propargyl acrylate (PA)‐co‐2‐(dimethyl aminoethyl methacrylate (DMAEMA)] (MPD) is synthesized using radical polymerization and azide‐alkyne click chemistry. The polymers are less cytotoxic and are able to condense plasmid DNA into nanosized particles. The low transfection efficiency of polyplexes in HepG2 cells is significantly improved by mixing Tat peptide with polyplexes.     

Cysticercosis of larynx

A rare case of cysticercosis of occurring in larynx in a 50 years male presenting with hoarseness of voice is reported.