Mechanistic Investigation of a Silylation-Based Kinetic Resolution Using Linear Free Energy Relationships and Its Application to Substrate Expansion and Polymer Supported Kinetic Resolutions

This dissertation represents our preliminary mechanistic investigations on the silylation-based kinetic resolution of secondary alcohols, and how we use that knowledge for further expansion of this methodology. Chapter 2 describes how we came up with a preliminary mechanism of our silylation-based methodology using a linear free energy relationship and a rate study. In this chapter, several para substituted triphenylsilyl chlorides were prepared that varied electronically and sterically in order to understand the substituent effects on the rate and the selectivity of the reaction. Selectivity factors and initial rates were experimentally determined for the kinetic resolution reactions with the newly designed silyl chlorides. Linear free energy relationships were found to correlate both selectivity factors and initial rates. Chapter 3 covers our 29Si NMR studies in order to understand if a complex is forming between the catalyst (-)-tetramisole and Ph3SiCl. A variety of different techniques were used including 1H NMR titrations, 29Si NMR experiments, and 1H-29Si gHSQC 2D experiments. Finally, three different mechanisms were proposed for future study. Chapter 4 discusses our efforts to apply the silylation-based methodology developed by the Wiskur lab to allylic alcohols, homoallylic alcohols, and 2-arylcyclohexanols. No enantiodiscrimination was obtained with allylic alcohols and homoallylic alcohols while a moderate level of selectivity was achieved with 2-arylcyclohexanols. Employing Ph3SiCl substituted in the para position with an isopropyl group in the kinetic resolution reaction of 2-arylcyclohexanol resulted in a doubling of the selectivity factor. The synthesis of various substrates and employing them in our kinetic resolution is discussed. Chapter 5 describes the use of a polymer supported triphenylsilyl chloride in our kinetic resolution reaction. Different molecular weight polymers containing triphenylsilyl chloride were prepared and tested in the kinetic resolution of 4-chromanol. Similar selectivity factors were reported in all cases. Reaction optimization along with future work for this project is discussed. Finally, Chapter 6 explores our attempt toward the development of a kinetic resolution of amines by transforming them into imines and employing them in an asymmetric aza-Diels-Alder reaction. Various chiral Lewis acids were attempted to achieve selectivity in the aza-Diels-Alder reaction

STRATEGI BERBAGI CATATAN KECIL DALAM IMPLEMENTASI PBL BERORIENTASI WEB UNTUK MENINGKATKAN LITERASI INFORMASI DAN HASIL BELAJAR SISWA PADA KONSEP VIRUS

Penelitian ini dilakukan bertujuan untuk mengetahui strategi berbagi catatan kecil dalam implementasi PBL berorientasi web untuk meningkatkan literasi informasi dan hasil belajar siswa pada konsep virus. Populasi pada penelitian ini adalah siswa kelas X MIA SMA Negeri 1 Ciampel Karawang. Teknik pengambilan sampel dilakukan secara purposive sampling, sehingga didapat kelas X MIA 1. Metode penelitian yang digunakan adalah Pra-Eksperimental Designs dengan desain One Group Pretest and Posttest Design. Instrumen yang digunakan adalah tes penguasaan konsep berupa 15 butir soal pilihan ganda, dan instrumen non-tes berupa penilaian sikap, penilaian psikomotor, dan angket literasi informasi siswa. Hasil perhitungan menunjukkan bahwa skor rata-rata pretest 43,67 dan posttest 80,53, skor rata-rata penilaian sikap 79,86 atau mencapai kriteria baik, dan skor rata-rata penilaian psikomotor 83,80 atau mencapai kriteria sangat baik, serta skor rata-rata penilaian kemampuan literasi informasi sebesar 93,75 atau mencapai kriteria sangat baik. Analisis data menggunakan uji N-Gain diperoleh nilai 0,67 atau mencapai kriteria sedang. Penelitian strategi berbagi catatan kecil dalam implementasi PBL berorientasi web menunjukkan adanya peningkatan hasil belajar dan kemampuan literasi siswa pada konsep virus. Kata Kunci: Strategi Berbagi Catatan Kecil, PBL, Berorientasi Web, Literasi Informasi, Hasil Belajar, Virus

The cascading failure of check dam systems during the 28 July 2022 Emamzadeh Davood flood in Iran

On July 18, 2022, an unexpected rainfall and flash flood struck the Emamzadeh Davood village in northwestern Tehran, the capital city of Iran, claiming the life of at least 23 people. In this brief communication, we report results from a recent investigation carried out by field surveys and remote sensing data, highlighting the role of anthropogenic factors and catastrophic failures in a series of check dams in intensifying the impacts of the 2022 Emamzadeh Davood event

Pancreas Transplant: Brief Review Of The Journey, Current Evidence And Future Prospects.

Pancreas transplantation has emerged as a ground breaking medical intervention for individuals suffering from diabetes mellitus, offering a potential resolution to the root cause of the disease. This review seeks to explore the realm of pancreas transplantation in greater depth. It encompasses the historical progression, nuanced surgical methodologies, intricate immune suppression protocols, resultant clinical effects, and the encouraging trajectories that offer promise in propelling this field forward. This article also entails the current scenario of pancreas transplant in India as well as the latest upgradation in techniques and modalities of pancreas transplant

Gender Differences in Response to Experimental Pain among Medical Students from a Western State of India

Background: Pain is one of the most common reasons for patients to seek medical attention and it causes considerable human suffering. Pain is a complex perception that differs enormously among individual patients. Gender plays an important role in how pain is experienced, coped with and treated. Even young healthy individuals often differ in how they perceive and cope with pain. This study was done to investigate gender differences in response to experimental pain among medical students from a western state in India. Methods: A total of 150 medical students (86 males and 64 females) participated in this interventional study. The Cold Pressor Test was used to exert experimental pain. To study the response, cardiovascular measures (radial pulse, systolic blood pressure and diastolic blood pressure) and pain sensitivity parameters (pain threshold, pain tolerance and pain rating) were assessed. Results: No significant difference was found in cardiovascular response to experimental pain between both the genders (p>0.05). Pain threshold and pain tolerance were found to be significantly higher in males whereas pain rating was found to be significantly higher in females (p<0.01). Pulse reactivity showed a negative relationship with pain threshold and pain tolerance whereas a positive relationship with pain rating, however no statistically significant relation was found between these measures. Conclusion: Females display greater pain sensitivity than males. Different pain perception might account for gender difference in pulse reactivity

TEICOPLANIN RESISTANCE IN GRAM-POSITIVE BACTERIAL ISOLATE: AN EMERGING THREAT

Objectives: Development of antimicrobial resistance in microorganism isolated from blood stream infection constitutes a major concern about their treatment. Teicoplanin is a glycopeptide antibiotic used in the treatment of infection caused by Gram-positive bacteria. This study was planned to determine Teicoplanin resistance in the Central India and recommend policy changes for prevention of the future resistance to the higher antibiotics. Methods: A total of 1855 septicemia suspected blood samples were studied. The blood culture samples were processed and identified in the microbiology laboratory according to the Clinical and Laboratory Standards Institute guidelines. Antibiotic susceptibility test was done using Kirby B disk diffusion method. Results: About 39.5% of blood culture samples showed positive growth for organism. We observed high teicoplanin resistance (29.5%) among Gram-positive isolates, predominantly (53%) in the Enterococcus species. Conclusion: Teicoplanin resistance has emerged tremendously in the present study. Hence, attention is required about this serious issue otherwise very limited choice of antibiotics will be available for treating infections in the future

Quality of life model in multiple sclerosis: personality, mood disturbance, catastrophizing and disease severity

Objective: The aim of current study was to investigate the interaction between factors such as personality, catastrophizing, mood disturbance and disease severity, which may affect the quality of life in patients with multiple sclerosis. The result of this study can identify the factors that have an impact on quality of life among these patients and hopefully it may lead to improve the services provided for these patients. Design: One hundred and thirteen participants with multiple sclerosis completed the following questionnaires: Type D Personality (DS-14), Hospital Anxiety and Depression (HADS), Illness Perception (Brief-IPQ) and Quality of Life (SF-36). The Expanded Disability Statue Scale (EDSS) assessed disease severity. Main Outcome Measures: Data was analyzed in structural equation modeling. Results: Type D personality was associated with quality of life and the relationship was mediated by disease severity, catastrophizing and mood status. Conclusion: Results showed a significant relationship between Type D personality and QOL. However, when the variables were added to the model, the relationship ceased to exist. These results suggest that personality traits are indirectly associated with QOL, mediated by another variable. Quality of Life Model in Multiple Sclerosis: Personality, Mood Disturbance, Catastrophizing and Disease Severity

A late Pleistocene long pollen record from Lake Urmia, NW Iran

A palynological study based on two 100-m long cores from Lake Urmia in northwestern Iran provides a vegetation record spanning 200 ka, the longest pollen record for the continental interior of the Near East. During both penultimate and last glaciations, a steppe of Artemisia and Poaceae dominated the upland vegetation with a high proportion of Chenopodiaceae in both upland and lowland saline ecosystems. While Juniperus and deciduous Quercus trees were extremely rare and restricted to some refugia, Hippophaë rhamnoides constituted an important phanerophyte, particularly during the upper last glacial sediments. A pronounced expansion in Ephedra shrub-steppe occurred at the end of the penultimate late-glacial period but was followed by extreme aridity that favoured an Artemisia steppe. Very high lake levels, registered by both pollen and sedimentary markers, occurred during the middle of the last glaciation and upper part of the penultimate glaciation. The late-glacial to early Holocene transition is represented by a succession of Hippophaë, Ephedra, Betula, Pistacia and finally Juniperus and Quercus. The last interglacial period (Eemian), slightly warmer and moister than the Holocene, was followed by two interstadial phases similar in pattern to those recorded in the marine isotope record and southern European pollen sequences

Modern pollen rain–vegetation relationships along a forest–steppe transect in the Golestan National Park, NE Iran

Pollen rain-vegetation relationships were studied over a forest-steppe transect in Golestan National Park, NE Iran. The surface pollen percentages were compared to the vegetation composition of the respective vegetation types in 18 sampling points using both descriptive and numerical approaches. Hyrcanian lowland forests are characterized by pollen assemblages dominated by Quercus, Carpinus betulus and low frequencies of Zelkova carpinifolia. Both Parrotia persica and Zelkova carpinifolia show a very low pollen representation in modern surface samples, an under-representation that should be taken into account in the interpretation of past vegetation records. Transitional communities between the forest and steppe including Acer monspessulanum subsp. turcomanicum, Crataegus and Paliurus scrubs, Juniperus excelsa woodlands and shrub-steppe patches are more difficult to distinguish in pollen assemblages, however, they are characterized by higher values of the dominant shrub species. The transitional vegetation communities at the immediate vicinity of the forest show also a substantial amount of grass pollen. Many insect-pollinated taxa are strongly under-represented in the pollen rain including most of the rosaceous trees and shrubs, Rhamnus, Paliurus, Acer and Berberis. Artemisia steppes are characterized by very high values of Artemisia pollen and the near absence of tree pollen

A study on perception of medical students regarding implementation of elective module in India

As suggested by the National Medical Commission (NMC) of India recently, the elective module was implemented in our medical college for MBBS admission batch 2019. Since, this was the first of its kind implementation in our institute and across the country, we planned this study to know the perception of medical students regarding the implementation of elective module. We conducted a cross-sectional survey among MBBS students of 2019 batch. A pre-validated questionnaire was prepared by the Medical Education Unit (MEU) members of our institute using online Google form and was circulated to all via WhatsApp group and email. A total of 63 responses from medical students were included for data analysis. Majority students said that objectives of the elective module were largely met and the faculty members were very helpful and responsive, and that they actively participated in the electives. Majority of them agreed that it was a very good academic activity, the time duration was appropriate, and it provided an opportunity to show creativity and for teamwork. Most students rated the overall experience of electives as "good" and above, however they were worried about getting faculty signatures in the logbooks