This review outlines the new developments on chitosan-based bioapplications. Over the last decade, functional biomaterials research has developed new drug delivery systems and improved scaffolds for ...regenerative medicine that is currently one of the most rapidly growing fields in the life sciences. The aim is to restore or replace damaged body parts or lost organs by transplanting supportive scaffolds with appropriate cells that in combination with biomolecules generate new tissue. This is a highly interdisciplinary field that encompasses polymer synthesis and modification, cell culturing, gene therapy, stem cell research, therapeutic cloning and tissue engineering. In this regard, chitosan, as a biopolymer derived macromolecular compound, has a major involvement. Chitosan is a polyelectrolyte with reactive functional groups, gel-forming capability, high adsorption capacity and biodegradability. In addition, it is innately biocompatible and non-toxic to living tissues as well as having antibacterial, antifungal and antitumor activity. These features highlight the suitability and extensive applications that chitosan has in medicine. Micro/nanoparticles and hydrogels are widely used in the design of chitosan-based therapeuticsystems. The chemical structure and relevant biological properties of chitosan for regenerative medicine have been summarized as well as the methods for the preparation of controlled drug release devices and their applications.
► A novel polymeric flocculant has been developed based on polyacrylamide grafted carboxymethyl guar gum (CMG-g-PAM) using microwave assisted method. ► It considerably reduces the total pollutant ...content of municipal sewage wastewater. ► High colour removal capacity.
A novel polymeric flocculant based on polyacrylamide grafted carboxymethyl guar gum (CMG-g-PAM) has been synthesised by grafting polyacrylamide chains onto CMG backbone using conventional redox grafting and microwave assisted grafting methods. Under optimum grafting conditions, 82% and 96% grafting efficiencies have been observed in case of conventional and microwave assisted methods respectively. The optimum sample has been characterized using viscometry, spectroscopic analysis, elemental analysis, molecular weight and radius of gyration determination. The flocculation characteristics of grafted and ungrafted polysaccharides have been evaluated in kaolin suspension, municipal sewage wastewater and decolourization efficiency of a dye solution (methylene blue). It is evident from results that CMG-g-PAM synthesised by microwave assisted grafting method is showing best flocculation characteristics.
Interactions between midlatitude disturbances and the monsoonal circulation are significant for the Indian summer monsoon (ISM) rainfall. This paper presents examples of monsoon–midlatitude linkage ...through anticyclonic Rossby wave breaking (RWB) over West Asia during June, July and August of the years 1998–2010. RWB events over West Asia are identified by the inversion of the potential vorticity air mass at three different isentropic levels (340, 350, and 360 K) using daily NCEP–NCAR reanalysis. It is observed that RWB took place over West Asia before/during breaks in the ISM. Further, these events occur on the anticyclonic shear side of the subtropical jet, where the gradient of the zonal wind is found to be high. RWB is responsible for the southward movement of high potential vorticity air from the westerly jet, leading to the formation of a blocking high over the Arabian region. In turn, this blocking high advects and causes the descent of upper tropospheric cold and dry air towards Central India. Such an air mass with low moist static energy inhibits deep monsoonal convection and thereby leads to a dry spell. In fact, we find that RWB induced blocking over West Asia to be one of the major causes of dry spell/break episodes in ISM. Additionally, the presence of cold air over Central India reduces the north–south thermal contrast over the monsoon region thereby modifying the local Hadley circulation over the region.
Abstract A large percentage of patients subjected to general anesthesia at 65 years and older exhibit postoperative delirium (POD). Here, we test the hypothesis that inhaled anesthetics (IAs), such ...as Sevoflurane and Isoflurane, act directly on brain vascular endothelial cells (BVECs) to increase blood−brain barrier (BBB) permeability, thereby contributing to POD. Rats of young (3–5 months), middle (10–12 months) and old (17–19 months) ages were anesthetized with Sevoflurane or Isoflurane for 3 h. After exposure, some were euthanized immediately; others were allowed to recover for 24 h before sacrifice. Immunohistochemistry was employed to monitor the extent of BBB breach, and scanning electron microscopy (SEM) was used to examine changes in the luminal surfaces of BVECs. Quantitative immunohistochemistry revealed increased BBB permeability in older animals treated with Sevoflurane, but not Isoflurane. Extravasated immunoglobulin G showed selective affinity for pyramidal neurons. SEM demonstrated marked flattening of the luminal surfaces of BVECs in anesthetic-treated rats. Results suggest an aging-linked BBB compromise resulting from exposure to Sevoflurane. Changes in the luminal surface topology of BVECs indicate a direct effect on the plasma membrane, which may weaken or disrupt their BBB-associated tight junctions. Disruption of brain homeostasis due to plasma influx into the brain parenchyma and binding of plasma components (e.g., immunoglobulins) to neurons may contribute to POD. We propose that, in the elderly, exposure to some IAs can cause BBB compromise that disrupts brain homeostasis, perturbs neuronal function and thereby contributes to POD. If unresolved, this may progress to postoperative cognitive decline and later dementia.
•Characterized how long term potentiation affects extracellular lactate dynamics.•Potentiation causes enhanced acute lactate response to neuronal activity.•Potentiation causes chronic increases in ...lactate availability.•Acute and chronic changes in lactate manifest ~24 h after synaptic potentiation.
A diverse array of neurometabolic coupling mechanisms exist within the brain to ensure that sufficient metabolite availability is present to meet both acute and chronic energetic demands.
Excitatory synaptic activity, which produces the majority of the brain’s energetic demands, triggers a rapid metabolic response including a characteristic shift towards aerobic glycolysis. Herein, astrocytically derived lactate appears to serve as an important metabolite to meet the extensive metabolic needs of activated neurons. Despite a wealth of literature characterizing lactate’s role in mediating these acute metabolic needs, the extent to which lactate supports chronic energetic demands of neurons remains unclear. We hypothesized that synaptic potentiation, a ubiquitous brain phenomenon that can produce chronic alterations in synaptic activity, could necessitate persistent alterations in brain energetics. In freely-behaving rats, we induced long-term potentiation (LTP) of synapses within the dentate gyrus through high-frequency electrical stimulation (HFS) of the medial perforant pathway. Before, during, and after LTP induction, we continuously recorded extracellular lactate concentrations within the dentate gyrus to assess how changes in synaptic strength alter local glycolytic activity. Synaptic potentiation 1) altered the acute response of extracellular lactate to transient neuronal activation as evident by a larger initial dip and subsequent overshoot and 2) chronically increased local lactate availability. Although synapses were potentiated immediately following HFS, observed changes in lactate dynamics were only evident beginning ~24 h later. Once observed, however, both synaptic potentiation and altered lactate dynamics persisted for the duration of the experiment (~72 h). Persistent alterations in synaptic strength, therefore, appear to be associated with metabolic plasticity in the form of persistent augmentation of glycolytic activity.
Tuberculosis (TB) is responsible for 1.4 million deaths annually. Wide-spread misuse of anti-tubercular drugs over three decades has resulted in emergence of drug resistant TB including ...multidrug-resistant TB and extensively drug-resistant TB globally. Accurate and rapid diagnosis of drug-resistant TB is one of the paramount importance for instituting appropriate clinical management and infection control measures. The present article provides an overview of the various diagnostic options available for drug resistant TB, by searching PubMed for recent articles. Rapid phenotypic tests still requires days to weeks to obtain final results, requiring biosafety and quality control measures. For newly developed molecular methods, infrastructure, training and quality assurance should be followed. Successful control of drug resistant TB globally will depend upon strengthening TB control programs, wider access to rapid diagnosis and provision of effective treatment. Therefore, political and fund provider commitment is essential to curb the spread of drug resistant TB.
The etiopathogenesis of COVID-19 and its differential geographic spread suggest some populations are apparently 'less affected' through many host-related factors that involve angiotensin-converting ...enzyme 2 (ACE2) protein, which is also the entry receptor for SARS-CoV-2. The role of ACE2 has been well studied in COVID-19 but not in the context of malaria and COVID-19. We have previously suggested how malaria might intersect with COVID-19 through
mutation and here we evaluate the currently available data that could provide a link between the two diseases. Based on the existing global and Indian data on malaria, COVID-19 and the suggested
mutation, the association could not be examined robustly, neither accepting nor refuting the suggested hypothesis. We strongly recommend targeted evaluation of this hypothesis through carefully designed robust molecular epidemiological studies.
This work suggests a hybrid African Vultures Optimization Algorithm (AVOA) and Pattern search (hAVOA-PS) based Fuzzy PID (FPID) structure for frequency control of a nonlinear power system with ...Electric Vehicles (EVs). To illustrate the dominance of the projected hAVOA-PS algorithm, initially PI controllers are considered and results are compared with AVOA, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) methods. To further enhance the dynamic performance, PID and FPID controllers are considered. The dominance of FPID over PID and PI controllers is shown. In the next step, EVs are incorporated in the test system and a comparative analysis of hAVOA-PS based PI/PID/FPID and FPID+EV is presented. To exhibit the superiority of projected frequency control scheme in maintaining the stability of system under different disturbance conditions like load increase in area-1 only, load decrease/increase in all areas, and large load increase in all areas are considered. It is noticed that the suggested hAVOA-PS based FPID controller n presence of EV is able to maintain system stability for all the considered cases where as other compared approaches fail to maintain stability in some cases.
► Adsorption of polyacrylamide flocculants onto the iron ore tailings is established. ► Effects of pH and flocculant doses on zeta potential of the tailings were studied. ► Adsorption data was ...validated with Langmuir and Freundlich isotherm models. ► Flocculation and settling studies were carried out to optimize dewatering conditions. ► The investigation outcomes are directly applicable to dewatering practice in mineral industries.
The adsorption characteristics of polyacrylamide polymer on iron ore tailings have been studied to understand the mechanism of adsorption. Adsorptions of both the anionic and non-ionic flocculants were analyzed using Langmuir isotherm and Freundlich isotherm. It was found that in comparison to the Langmuir model the Freundlich model was a better fit to the adsorption data according to the minimum variance criterion. It was established with the support of the Langmuir model that the adsorption of anionic and non-ionic flocculants is facilitated by hydrogen bonding. The zeta potential affects the settling rate and in this case the isoelectric point of the tailings which is basically a mixture of various oxides was measured to be 4.66. The settling rate was found to increase when the pH decreased from 10 to 5. The settling rate increased with increasing flocculant dosage up to a maximum value at 80
g polymer/t solid corresponding to the maximum adsorption of polymer. However, at higher pH the clarity of supernatant liquid was very poor and flocculation was not effective for ultrafine particles at that pH.
Background: Radiosurgery seems to be a very appealing option for patients having a small petrous apex meningioma and presenting with trigeminal neuralgia, presumably because of the lower risk and ...cost involved. The aim of this study was to analyze the results of our surgical series of petrous apex meningioma presenting with trigeminal neuralgia, and to determine the efficacy of neurosurgical treatment with regard to pain control. The procedure-related complication and morbidity rates were also evaluated.
Materials and Methods: This is a retrospective study of 17 patients with a small (<3 cm) petrous apex meningioma. The included patients were refractory to medical treatment for trigeminal neuralgia and were deemed as surgical candidates. Postoperatively, the patients were assessed for pain relief according to the Barrow Neurological Institute (BNI) scale. A P value of less than 0.05 was considered significant. Magnetic resonance imaging was also performed after 6 weeks to assess the radicality of resection.
Results: In a median follow-up of approximately 2 years, the study showed that 14 of the 17 (82.4%) patients had complete pain relief, with very low morbidity and no mortality, and 100% tumor control. According to the Barrow Neurological Institute (BNI) scale for the assessment of postoperative pain relief, 52.9, 23.5, 5.9, 11.8, and 5.9% of patients had grades I, II, IIIa, IIIb, and IV in terms of their pain relief, respectively.
Conclusions: In our population of patients, surgery proved to be successful in providing symptomatic relief, with low morbidity and no mortality, and was comparable with other studies involving the minimally invasive modalities. However, these results warrant further follow-up, with recruitment of more patients, to demonstrate whether or not, surgery should be the primary choice of treatment in this subgroup of patients.
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