Steric Hindrance as a Mechanistic Probe for Olefin Reactivity: Variability of the Hydrogenic Canopy over the Isomeric Adamantylideneadamantane/Sesquihomoadamantene Pair (A Combined Experimental and Theoretical Study)

Access to each CC face of adamantylideneadamantane (AA) and sesquihomoadamantene (SA) is hindered by the hydrogenic canopy consisting of four β-hydrogens; otherwise, these olefins have quite normal environments. X-ray crystallography and density functional (DFT) calculations show a 0.5 Å larger annular opening in the protective cover of AA than that in SA. This contributes to the remarkable differences in reactivity toward various reagents, not only by limiting access to the olefin site in SA but also by inhibiting reactions which force these hydrogens closer together. Thus, AA is subject to typical olefin-addition reactions with bromine, sulfuryl chloride, m-chloroperbenzoic acid, dioxygen, and so forth, albeit sometimes at attenuated rates. On the other hand, SA is singularly unreactive under identical reaction conditions, except for the notable exceptions that include Brønsted (protonic) acids, a nitrosonium cation, and dichlorine. The exceptions are characterized as three sterically limited (electrophilic) reagents whose unique reactivity patterns are shown to be strongly influenced by steric access to the CC center. As such, the different degrees of steric encumbrance in the isomeric donors AA and SA shed considerable light on the diverse nature of olefinic reactions. In particular, they evoke mechanistic features in electrophilic addition versus electron transfer, which are otherwise not readily discernible with other less hindered olefinic donors. Transient structures of the olefinic-reaction intermediates such as the protonated carbocations AA−H+ and SA−H+ as well as the cation radicals AA•+ and SA•+ are probed by the combination of X-ray crystallographic analyses and density functional theoretical computations

Functional and radiological comparison of transforaminal lumbar interbody fusion method with interbody fusion device versus stand-alone bone graft in lumbar canal stenosis or degenerative lumbar instability

Background: Spinal stability is the vertebral ability to maintain their relationship and limit their relative displacements during physiologic postures and loads.Methods: Hospital based prospective randomized comparative study design between 2 groups included patients of both sex attending SMS hospital Jaipur, from April 2018 to June 2019 or till sample size was achieved, with due permission from institutional ethical committee and review board and after taking written informed consent from patients.Results: Inter group comparison of VAS score showed same results in both groups which showed statistically non-significant results. VAS score showed significantly reduction in both group A and B till the study period. Inter group comparison of ODI score showed same results in both groups which showed statistically non-significant results. ODI score showed significantly reduction in both group A and B till the study period. Inter group comparison of fusion rate score showed same results in both groups which showed statistically non-significant results. Fusion rate score showed significantly increased in both group A and B till the study period and at the 12 month it was 100% fusion rate.Conclusions: In the current series, the TLIF procedure with local bone graft alone improved anterior vertebral translation, disc height, and lumbar lordosis. A proper surgical technique with adequate discectomy and facetectomy would contribute greatly to the improvement of the radiological parameters; however, this improvement was not maintained at the latest follow up.

Charge Delocalization in Self-Assembled Mixed-Valence Aromatic Cation Radicals

The spontaneous assembly of aromatic cation radicals (D+•) with their neutral counterpart (D) affords dimer cation radicals (D2+•). The intermolecular dimeric cation radicals are readily characterized by the appearance of an intervalence charge-resonance transition in the NIR region of their electronic spectra and by ESR spectroscopy. The X-ray crystal structure analysis and DFT calculations of a representative dimer cation radical (i.e., the octamethylbiphenylene dimer cation radical) have established that a hole (or single positive charge) is completely delocalized over both aromatic moieties. The energetics and the geometrical considerations for the formation of dimer cation radicals is deliberated with the aid of a series of cyclophane-like bichromophoric donors with drastically varied interplanar angles between the cofacially arranged aryl moieties. X-ray crystallography of a number of mixed-valence cation radicals derived from monochromophoric benzenoid donors established that they generally assemble in 1D stacks in the solid state. However, the use of polychromophoric intervalence cation radicals, where a single charge is effectively delocalized among all of the chromophores, can lead to higher-order assemblies with potential applications in long-range charge transport. As a proof of concept, we show that a single charge in the cation radical of a triptycene derivative is evenly distributed on all three benzenoid rings and this triptycene cation radical forms a 2D electronically coupled assembly, as established by X-ray crystallography

Diagnosis and management of malignant peripheral nerve sheath tumors: Current practice and future perspectives

One of the most common malignancies affecting adults with the neurofibromatosis type 1 (NF1) cancer predisposition syndrome is the malignant peripheral nerve sheath tumor (MPNST), a highly aggressive sarcoma that typically develops from benign plexiform neurofibromas. Approximately 8-13% of individuals with NF1 will develop MPNST during young adulthood. There are few therapeutic options, and the vast majority of people with these cancers will die within 5 years of diagnosis. Despite efforts to understand the pathogenesis of these aggressive tumors, the overall prognosis remains dismal. This manuscript will review the current understanding of the cellular and molecular progression of MPNST, diagnostic workup of patients with these tumors, current treatment paradigms, and investigational treatment options. Additionally, we highlight novel areas of preclinical research, which may lead to future clinical trials. In summary, MPNST remains a diagnostic and therapeutic challenge, and future work is needed to develop novel and rational combinational therapy for these tumors

Spawning and larval rearing technique for tropical clown fish Amphiprion sebae under captive condition

Research on breeding and larval rearing of marine ornamental fishes are in its fancy . For the first time in India, successful breedi!19 and larval rearing of Tropical clown fish Amphiprion sebae was accomplished at Regional Centre of Central Marine Fisheries Research Institute, Mandapam Camp. Adult pairs of clown fishes along with sea anemones collected from the in-shore waters of Gulf of Mannar were maintained in one tonne glass aquarium fitted with bio-filters

The Ayurveda Education in India: How Well Are the Graduates Exposed to Basic Clinical Skills?

“Ayurveda” is an ancient system of healthcare that is native to India. At present, in India, there are more than 240 colleges that offer a graduate-level degree (Bachelor of Ayurvedic Medicine and Surgery—BAMS) in Ayurveda. Even though the Central Council of Indian Medicine, the governing body that monitors the matters related to Ayurveda education, has imposed various educational norms and regulations, the standard of education has been a cause of concern in recent years. The mushrooming of substandard Ayurvedic colleges is the most important factor that is being held responsible for this kind of erosion in the standards. The present study is a mailed survey, which was carried out to evaluate the “Extent of exposure to basic clinical skills during BAMS course” as perceived by the sample groups of students and teachers drawn from 32 Ayurvedic educational institutions spread all over India. A methodically validated questionnaire was used as the tool in the study, to which 1022 participants responded. The study indicates that there are some serious flaws in the existing system of the graduate-level Ayurveda education. Since the Ayurvedic graduates play an important role in the primary healthcare delivery system of the country, governing bodies are required to take necessary steps to ensure the adequate exposure of the students to basic clinical skills. Along with the strict implementation of all the regulatory norms during the process of recognition of the colleges, introducing some changes in the policy model may also be required to tackle the situation