Mechanistic understanding and the control of molecular self-assembly at all hierarchical levels remain grand challenges in supramolecular chemistry. Functional realization of dynamic supramolecular materials especially requires programmed assembly at higher levels of molecular organization. Herein, we report an unprecedented molecular control on the fibrous network topology of supramolecular hydrogels and their resulting macroscopic properties by biasing assembly pathways of higher-order structures. The surface-catalyzed secondary nucleation process, a well-known mechanism in amyloid fibrilization and chiral crystallization of small molecules, is introduced as a non-covalent strategy to induce physical cross-links and bundling of supramolecular fibers, which influences the microstructure of gel networks and subsequent mechanical properties of hydrogels. In addition, seed-induced instantaneous gelation is realized in the kinetically controlled self-assembled system under this study, and more importantly, the extent of secondary nucleation events and network topology is manipulated by the concentration of seeds.
A Hot-Lab is the major source of radiation exposure by medical technicians in a nuclear medicine set up. A table top bench shield is used to reduce this exposure which consists of a lead base and a lead wall in the bottom part while a viewing window is provided in the top part through the use of thick glass or leaded glass. In our laboratory, a home-made shield was used earlier which incorporated a 254mm ordinary glass window in the top and a thick lead wall at the bottom part. Recently a commercial bench shield was procured that uses a lighter lead glass window for better viewing. This lead glass gives an equivalent lead thickness of 2.2 mm. The present work was taken up to study the changes in the radiation exposure to nuclear medicine technicians due to this change in the bench shield. The effective doses received by two technicians were 0.937 mSv and 1.098 mSv respectively when they worked for two months using the old table top bench shield. This dose came down substantially to 0.292 mSv and 0.187 mSv respectively, when they used the new table top bench shield for the same period of time. Side by side, the radiation reaching the outer surfaces of the glass shield and the lead wall were measured due to a radiation source placed at 0mm, 10mm and 20mm from the respective inner surfaces. For the lead shield the dose rates were not much different between the two models, but for the glass window, the commercial one gave much reduced dose rate. Although the dosage was higher in the indigenously made device, the duty schedules of the technicians were rotated so that none received dosage greater than safe limits over a full year. DOI: http://dx.doi.org/10.3329/bjmp.v5i1.14669 Bangladesh Journal of Medical Physics Vol.5 No.1 2012 37-40
INTRODUCTION: E-cigarette or vaping product use-associated lung injury (EVALI) encompass a host of pulmonary complications including diffuse alveolar hemorrhage, lipoid pneumonia, hypersensitivity pneumonitis, and rarely, acute eosinophilic pneumonia (AEP) [1]. AEP presents as an acute febrile illness with hypoxemia, diffuse pulmonary infiltrates, and eosinophilia on bronchoalveolar lavage (BAL) without evidence of prior infection or atopic illness [2]. Presented is a young adult patient with a history of continuous vaping and extended exposure to kitchen smoke who developed acute hypoxemic respiratory failure later diagnosed as AEP.CASE PRESENTATION: An 18-year-old male with no significant past medical history presented to the emergency department with acute onset malaise, fever, non-productive cough, and shortness of breath over 12 hours. Social history revealed 3-week workplace exposure to smoke as a barbeque cook and a 5-year history of daily vaping with reported cessation 3 weeks prior. Vitals were notable for hypoxemia which was corrected with administration of 8L of oxygen via nasal cannula. Quickly after admission, he had worsening respiratory status: tachypnea, increased oxygen requirement, use of accessory muscles, and bilaterally diminished breath sounds. He was transferred to the medical intensive care unit for emergent endotracheal intubation. Laboratory testing revealed a neutrophil predominant leukocytosis of 19.3x109/L. COVID-19, rapid influenza A and B, and urine antigens for streptococcus and legionella were negative as were autoimmune serologies. A computed tomography (CT) scan of the chest revealed diffuse bilateral consolidative opacities [Figure 1] with worsening over the next 24 hours [Figure 2]. Further investigation was undertaken with bronchoscopy. A BAL was obtained, and cell count and cultures were sent. BAL cell count was remarkable for 33% eosinophilia. The diagnosis of AEP was made, and the patient was started on systemic glucocorticoids, with significant improvement within 24 hours. DISCUSSION:The modified Philit criteria is used to make the diagnosis of AEP, which the patient satisfied [3]. Although a 5year vaping history was present, no previous significant respiratory symptoms were reported. Prior studies have demonstrated a relationship between workplace smoke exposure and AEP [3]. Based on the modified Philit criteria, we suspect that the patient had acute respiratory failure from AEP as a result of chronic EVALI acutely exacerbated by workplace smoke exposure. The treatment of AEP treatment involves high-dose intravenous glucocorticoids followed by a prolonged oral steroid taper. CONCLUSIONS:Obtaining occupation history as well as smoke exposure is as important as obtaining vaping history in an otherwise healthy young patient who presents with acute hypoxemic respiratory failure with bilateral diffuse opacities on imaging.
<p><strong>Objective: </strong>Quantitative assessment of left ventricular ejection fraction (LVEF) from radionuclide cardiac imaging study has both diagnostic and prognostic value in coronary artery disease (CAD). Gated SPECT blood pool imaging (GSBPI) and gated SPECT myocardial perfusion imaging (GSMPI) are two technically comparable radionuclide methods for non-invasive measurement of LVEF. While the former is a gold standard the latter is popular as it provides a wider array of information. This study was carried out to bridge the lack in the existing body of evidence regarding assessment of agreement of between GSBPI and GSMPI for measurement of LVEF in CAD. The objective of this study is to validate the LVEF measurements from routine GSMPI as a valuable parameter for clinical decision making through assessment of agreement between GSMPI and GSBPI performed in a short interval, in same patient having CAD.</p><p><strong>Patients and Methods: </strong>A total of 28 patients (three female) was observed with a mean age of 54.5 ± 8.5 years during February to May 2012. All patients underwent GSBPI and GSMPI with a gap of three to seven days in between. LVEF measured by GSBPI performed at rest was compared with LVEF measured in rest phase of one day stress-rest GSMPI. Agreement analysis was done with Bland Altman plot.</p><p><strong>Results: </strong>Mean LVEF measurements show an apparent overall slight underestimation by GSBPI (54.8.9±25) in comparison to GSMPI (56.9±25). Bland Altman plots show that the differences between GSBPI and GSMPI for measurement of LVEF at rest in same patient fall within two SD of the mean difference. This finding remained similar while further categorization of study patients was done on basis of ranges of LVEF, end diastolic volume (EDV), end systolic volume (ESV), infarct size and regional wall motion abnormality (RWMA).</p><p><strong>Conclusions: </strong>There was overall significant agreement between GSMPI and GSBPI for measurement of LVEF in CAD in this small study. This agreement remains significant irrespective of ranges of LVEF, EDV, ESV, infarct size and RWMA.</p><p>Bangladesh J. Nuclear Med. 19(2): 128-134, July 2016</p>
Objective: A retrospective study was conducted to assess the pattern of bone density status in a large population of both sexes who attended tertiary hospital National Institute of Nuclear Medicine and Allied Sciences (NINMAS) in a specific time period. Materials and Methods Conclusion:The results of this study suggest that advancing age and menopausal condition of female and low body weight are important risk factors for the occurrence of low BMD.
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