Bifurcation sequence of two-dimensional Taylor-Green vortex via vortex interactions: Evolution of energy spectrum

The vorticity dynamics of the two-dimensional (2D) Taylor-Green vortex (TGV) problem is investigated in its multi-cellular configuration by solving the incompressible Navier-Stokes equation for long time intervals using a pseudo-spectral method. This helps follow the vorticity dynamics of periodic free shear layer flows by solving an extremely accurate algorithm to explain vortex interactions that lead to vortex stripping (forward cascade), merger, and reconnection (inverse cascade) during various stages of evolution of periodic arrangements of a large number of TGV vortical cells. This latter aspect has been adopted so as not to be affected by the periodicity constraints of a single periodic cell and the various imposed symmetries that attenuate disturbance growth. The analytic solution of the TGV provides the initial condition and the spatially accurate Fourier spectral method enables one to track the first instability of the initial doubly periodic vortices. Despite a plethora of studies following the primary instability to relate it with transition to turbulence and the subsequent decay of turbulence in the literature, the topic of bifurcation sequence for periodic TGV is rare, and that is one of the main aims of the present research. Instead of restricting one's attention on a single periodic TGV cell, here it is purposely reported for multiple cells of the TGV in both directions, without invoking any asymmetries extraneously. For such an ensemble, one can study various vortical interactions giving rise to atypical energy spectra, a topic that has also been seldom addressed to distinguish between successive instabilities that can upon a conjecture, lead to transition and subsequent relaminarization, versus the bifurcation sequences leading from one equilibrium state to subsequent ones. The present study shows the dominance of the latter for 2D TGV at post-critical Reynolds number

Clinico-pathological profile of diagnosed patients of lung cancer with its relation to smoking habit and educational status in a medical college of paschim medinipore west Bengal, india- A Tribal area prospective

Background: Lung cancer is one of the commonest and most lethal cancer throughout the world. Tobacco smoking continues to be the leading cause of lung cancer worldwide. An increase incidence of lung cancer has been observed in India.Objective: The aim of this study was to find out the demographic and clinico-pathological profile of diagnosed lung cancer patients and its relation to smoking habit and educational status in tribal area of paschim Medinipore West Bengal, India. Materials and Methods: We performed a retrospective analysis of histopathologically proven cases of lung cancer admitted in our hospital from June 2011 to June 2014. Results: Out of 160 patients, male 140 and female 20, 88.75% were smoker and only 15% are ≤40 years of age. Smoking is the major risk factor for lung cancer .The most frequent symptom was cough (73.75%) followed by chest pain (58.75%). The most common radiological presentation was mass lesion (66.25%).Squamous cell carcinoma was most common histopathological type followed by adenocarcinoma (51% & 31%). Poor people of tribal area who are less educated were mostly the victim of the disease. Conclusion: It was found that squamous cell carcinoma was the most frequent histopathological type. Adenocarcinoma was predominates type below 40 years and squamous cell carcinoma was more common in age group above 40 years. Smokings still remain the major risk factor. Most of cancer patients were less educated and were not aware about ill effect of smoking

Ultrasound-Responsive Nanodroplet-Based Targeted Therapy via Conversion to Microbubbles

Ultrasound-based therapy is appealing as it can be used via a wireless approach at remote parts of the body including the brain. Microbubbles are commonly used in such therapy due to their highly sound-responsive property. However, the larger size of microbubbles limits selective targeting in vitro/in vivo. Here, we report the design of nanodroplets of 70–130 nm in size that can be easily converted to microbubbles via ultrasound exposure. The advantage of this approach is that smaller nanodroplets can be used for cell/subcellular targeting, and next, they can be used for therapy by converting to microbubbles. More specifically, folate/dopamine-terminated perfluorohexane nanodroplets are designed that are loaded with a molecular drug. These nanodroplets are used for selective cell targeting, followed by ultrasound-induced microbubble conversion that is associated with drug release and intracellular reactive oxygen species generation. This approach has been used for selective cell therapy applications. The designed nanodroplet and approach can be used for the enhanced therapeutic performance of existing drugs

Chapter 10 - Polymeric nanomaterials in neuroscience

The advent of neurological disorders has taken place at an alarming rate over the past few decades. The primary challenge for the treatment and diagnosis of these neuropathies is to cross the blood–brain barrier (BBB). Nanomaterials are preferred over conventional treatments because of their nanometer range, which can interact at the molecular level with lesser adverse effects. Hence, nanomaterials can be beneficial in neuroscience because of their ability to cross BBB and compatibility for the neuronal tissues. Here, we are focusing on the neurological applications of carbon nanotubes, magnetic nanoparticles (NPs), dendrimers, nanospheres, gold NPs, liposomes, and utmost quantum dots. We have also summarized the utility and mechanism of all these NPs in the field of neuroscience, along with their prospects and approaches to avoid their substantial toxicity

Migraine and Ischemic Stroke: Deciphering the Bidirectional Pathway

Migraine and stroke are common, disabling neurological conditions with several theories being proposed to explain this bidirectional relationship. Migraine is considered as a benign neurological disorder, but research has revealed a connection between migraine and stroke, predominantly those having migraine with aura (MA). Among migraineurs, females with MA are more susceptible to ischemic stroke and may have a migrainous infarction. Migrainous infarction mostly occurs in the posterior circulation of young women. Although there are several theories about the potential relationship between MA and stroke, the precise pathological process of migrainous infarction is not clear. It is assumed that cortical spreading depression (CSD) might be one of the essential factors for migrainous infarction. Other factors that may contribute to migrainous infarction may be genetic, hormonal fluctuation, hypercoagulation, and right to left cardiac shunts. Antimigraine drugs, such as ergot alkaloids and triptans, are widely used in migraine care. Still, they have been found to cause severe vasoconstriction, which may result in the development of ischemia. It is reported that patients with stroke develop migraines during the recovery phase. Both experimental and clinical data suggest that cerebral microembolism can act as a potential trigger for MA. Further studies are warranted for the treatment of migraine, which may lead to a decline in migraine-related stroke. In this present article, we have outlined various potential pathways that link migraine and stroke

The Role of Inflammasomes in Atherosclerosis and Stroke Pathogenesis

Inflammation is a devastating outcome of cerebrovascular diseases (CVD), namely stroke and atherosclerosis. Numerous studies over the decade have shown that inflammasomes play a role in mediating inflammatory reactions post cellular injury occurring after a stroke or a rupture of an atherosclerotic plaque. In view of this, targeting these inflammatory pathways using different pharmacological therapies may improve outcomes in patients with CVD. Here, we review the mechanisms by which inflammasomes drive the pathogenesis of stroke and atherosclerosis. Also, discussed here are the possible treatment strategies available for inhibiting inflammasomes or their up-stream/down-stream mediators

Cerebro‐renal interaction and stroke

Stroke is an event causing a disturbance in cerebral function leading to death and disability worldwide. Both acute kidney injury and chronic kidney disease (CKD) are associated with an increased risk of stroke and cerebrovascular events. The underlying mechanistic approach between impaired renal function and stroke is limitedly explored and has attracted researchers to learn more for developing therapeutic intervention. Common risk factors such as hypertension, hyperphosphatemia, atrial fibrillation, arteriosclerosis, hyperhomocysteinemia, blood‐brain barrier disruption, inflammation, etc. are observed in the general population, but are high in renal failure patients. Also, risk factors like bone mineral metabolism, uremic toxins, and anemia, along with the process of dialysis in CKD patients, eventually increases the risk of stroke. Therefore, early detection of risks associated with stroke in CKD is imperative, which may decrease the mortality associated with it. This review highlights mechanisms by which kidney dysfunction can lead to cerebrovascular events and increase the risk of stroke in renal impairment. Figure representing the various steps that lead towards stroke following kidney dysfunction

Post-stroke depression: Chaos to exposition

•Post Stroke Depression (PSD) is a major neuropsychological outcome of stroke.•Symptoms materialize within months of stroke, progressing to a long-term ailment.•Identification of PSD biomarkers can help revolutionize treatment for PSD. Cerebral ischemia contributes to significant disabilities worldwide, impairing cognitive function and motor coordination in affected individuals. Stroke has severe neuropsychological outcomes, the major one being a stroke. Stroke survivors begin to show symptoms of depression within a few months of the incidence that overtime progresses to become a long-term ailment. As the pathophysiology for the progression of the disease is multifactorial and complex, it limits the understanding of the disease mechanism completely. Meta-analyses and randomized clinical trials have shown that intervening early with tricyclic antidepressants and selective serotonin receptor inhibitors can be effective. However, these pharmacotherapies possess several limitations that have given rise to newer approaches such as brain stimulation, psychotherapy and rehabilitation therapy, which in today's time are gaining attention for their beneficial results in post-stroke depression (PSD). The present review highlights numerous factors like lesion location, inflammatory mediators and genetic abnormalities that play a crucial role in the development of depression in stroke patients. Further, we have also discussed various mechanisms involved in post-stroke depression (PSD) and strategies for early detection and diagnosis using biomarkers that may revolutionize treatment for the affected population. Towards the end, along with the preclinical scenario, we have also discussed the various treatment approaches like pharmacotherapy, traditional medicines, psychotherapy, electrical stimulation and microRNAs being utilized for effectively managing PSD

Acidic pH-Triggered Release of Doxorubicin from Ligand-Decorated Polymeric Micelles Potentiates Efficacy against Cancer Cells

Current chemotherapeutic strategies against various intractable cancers are futile due to inefficient delivery, poor bioavailability, and inadequate accumulation of anticancer drugs in the diseased site with toxicity caused to the healthy neighboring cells. Drug delivery systems aiming to deliver effective therapeutic concentrations to the site of action have emerged as a promising approach to address the above-mentioned issues. Thus, as several receptors have been identified as being overexpressed on cancer cells including folate receptor (FR), where up to 100–300 times higher overexpression is shown in cancer cells compared to healthy cells, approximately 1–10 million receptor copies per cancer cell can be targeted by a folic acid (FA) ligand. Herein, we developed FA-decorated and doxorubicin-conjugated polymeric micelles of 30 nm size. The hydrophilic block comprises poly(ethylene glycol) units, and the hydrophobic block contains aspartic acid. Decoration of FA on the micelle surface induces ligand–receptor interaction, resulting in enhanced internalization into the cancer cell and inside the endolysosomal compartment. Under acidic pH, the micelle structure is disrupted and the hydrazone bond is cleaved, which covalently binds the doxorubicin with the hydrophobic backbone of the polymer and release the drug. We observed that the cellular uptake and nuclear colocalization of the targeted micelle are 2–4 fold higher than the control micelle at various incubation times in FR-overexpressed various cancer cell lines (KB, HeLa, and C6). These results indicate significant prospects for anticancer therapy as an effective and translational treatment strategy