Publications by authors named "Himanshu Shekhar"

Iron oxide nanoparticles (IONPs) have been extensively explored in biomedicine, bio-sensing, hyperthermia, and drug/gene delivery, attributed to their versatile and tunable properties. However, owing to its numerous applications, the functionalization of IONPs with appropriate materials is in demand. To achieve optimal functionalization of IONPs, polydopamine (PDA) was utilized due to its ability to provide a superior functionalized surface, near-infrared light absorption, and adhesive nature to customize desired functionalized IONPs.

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Plastic pollution has become a major environmental concern, and various plastic polymers are used daily. A study was conducted to examine the toxic effects of polyethylene terephthalate (PET) nanoplastics (NPLs) on Drosophila melanogaster. We have successfully synthesized PET NPLs and characterized using DLS, Zeta potential, TEM, HRTEM, SAED, XRD, FTIR, and Raman spectroscopy to gain crucial insights into the structure and properties.

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The planned relocation of communities away from areas of climate-related risk has emerged as a critical strategy to adapt to the impacts of climate change. Empirical examples from around the world show, however, that such relocations often lead to poor outcomes for affected communities. To address this challenge, and contribute to developing guidelines for just and sustainable relocation processes, this paper calls attention to three fundamental tensions in planned relocation processes: (1) conceptualizations of risk and habitability; (2) community consultation and ownership; and (3) siloed policy frameworks and funding mechanisms.

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Sonodynamic therapy (SDT) is a promising alternative to photodynamic therapy for achieving site-specific cytotoxic therapy. Porphyrin derivative molecules have been reported extensively in photodynamic therapy. We have previously shown that the glycosylation of porphyrin-based sonosensitizers can enhance their cellular uptake.

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Background: Tension in the spinal cord is a trademark of tethered cord syndrome. Unfortunately, existing tests cannot quantify tension across the bulk of the cord, making the diagnostic evaluation of stretch ambiguous. A potential non-destructive metric for spinal cord tension is ultrasound-derived shear wave velocity (SWV).

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Hermite-scan (H-scan) imaging is a tissue characterization technique based on the analysis of raw ultrasound radio frequency (RF) echoes. It matches the RF echoes to Gaussian-weighted Hermite polynomials of various orders to extract information related to scatterer diameter. It provides a color map of large and small scatterers in the red and blue H-scan image channels, respectively.

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Background:  Between individual patients with lumbar disk prolapse (LDP), the natural course of disease is significantly variable. Spontaneous resolution is reported to occur in up to 70% of cases. However, we currently cannot predict for whom and when this will occur.

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Aims: Patients with cauda equina syndrome (CES) require emergency imaging and surgical decompression. The severity and type of symptoms may influence the timing of imaging and surgery, and help predict the patient's prognosis. Categories of CES attempt to group patients for management and prognostication purposes.

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Histotripsy is a focused ultrasound therapy that ablates tissue via bubble cloud activity. Real-time ultrasound image guidance is used to ensure safe and effective treatment. Plane-wave imaging enables tracking of histotripsy bubble clouds at a high frame rate but lacks adequate contrast.

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Distal rod migration remains uncommon and has been reported in a variety of anatomical locations, including the retroperitoneal region, the knee, and the pelvis. It is postulated that spinal fixation without fusion might allow the mechanical system some vulnerability to motion effects of the spine. Bilateral distal rod migration is rarer still.

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Introduction: Irritable Bowel Disease is a functional Gastro-intestinal disorder that is characterised by chronic abdominal pain, and altered bowel habit unexplained by the organic cause.[1] Probiotics are live micro organisms that are intended to extend health benefits when consumed generally by improving gut microbiota.[2] The role of probiotics continues to be controversial in IBS.

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Limited work has been reported on the acoustic and physical characterization of protein-shelled UCAs. This study characterized bovine serum albumin (BSA)-shelled microbubbles filled with perfluorobutane gas, along with SonoVue, a clinically approved contrast agent. Broadband attenuation spectroscopy was performed at room (23 ± 0.

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Background: Today's food industry is extensive and complicated, encompassing anything from subsistence agriculture to multinational food corporations. The mobility of food and food elements in food systems has a major impact on biodiversity preservation and the overall sustainability of our fragile global ecosystem. Identifying the human and livestock consumption patterns across regions and territories will optimize the dietary standards of the habitually undernourished and the expanding population without substantially increasing the amount of land under cultivation.

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Background: The morphology of distal femur and proximal tibia varies between different ethnicities, and it can affect the tunnel dimensions and positions while doing ACL reconstruction which may affect the clinical outcome. There is limited data on the clinical outcome and CT based tunnel placement evaluation in femur and tibia of Indian nonathletic population.

Methods: Thirty non-athletic patients with mean age of 25.

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Background: The setup errors during supine-CSI (sCSI) using single or dual immobilisation (SM, DM) subsets from two institutions were reviewed to determine if DM consistently decreased the required planning target volumes (PTV) margins and to identify the optimal image guidance environments.

Materials And Methods: Ours and a sister institutional cohort, each with a subset of SM or DM sCSI and daily 3-dimensional online image verification sets, were reviewed for the cranial and spinal regions translational shifts. Using descriptive statistics, scatter plots and independent sample Mann-Whitney test we compared shifts in each direction for two subsets in each cohort deriving PTV margins (Van Herk: VH, Strooms: St recipes) for the cranial and spinal regions.

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Microbubbles are tiny gas-filled bubbles that have a variety of applications in ultrasound imaging and therapeutic drug delivery. Microbubbles can be synthesized using a number of techniques including sonication, amalgamation, and saline shaking. These approaches can produce highly concentrated microbubble suspensions but offer minimal control over the size and polydispersity of the microbubbles.

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Background: Traumatic atlanto-occipital dislocation is an unstable injury of the craniocervical junction. For pediatric patients, surgical arthrodesis of the occipitocervical junction is the recommended management. While having a high success rate for stabilization, the fusion comes with obvious morbidity of limitation in cervical spine flexion, extension, and rotation.

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Fiber Bragg gratings (FBGs) are a potential alternative to piezoelectric ultrasound sensors for applications that demand high sensitivity and immunity to electromagnetic interference (EMI). However, limited data exist on the quantitative performance characterization of FBG sensors in the MHz frequency range relevant to biomedical ultrasound. In this work, we evaluated an FBG to detect MHz-frequency ultrasound and tested the feasibility of measuring passive cavitation signals nucleated using a commercial contrast agent (SonoVue).

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COVID-19 initially spread among prominent global cities and soon to the urban centers of countries across the globe. While cities are the hotbeds of activities, they also seem highly exposed to global risks including the pandemic. Using the case of COVID-19 and the World Risk Index framework, this paper examines if the leading cities from the global south are inherently vulnerable and exposed to global risks and can they exacerbate the overall risk of their respective nations.

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Background: Empyema thoracis is defined as the presence of pus in the pleural cavity and carries significant morbidity and mortality. This study aimed to explore the demographic and clinico-radiological characteristics of patients with empyema thoracis.

Material And Methods: The present study was conducted in a tertiary care teaching hospital in North India.

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Histotripsy is a focused ultrasound therapy for tissue ablation via the generation of bubble clouds. These effects can be achieved noninvasively, making sensitive and specific bubble imaging essential for histotripsy guidance. Plane-wave ultrasound imaging can track bubble clouds with an excellent temporal resolution, but there is a significant reduction in echoes when deep-seated organs are targeted.

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Multidrug-resistant bacteria have emerged in both community and hospital settings, partly due to the misuse of antibiotics. The inventory of viable antibiotics is rapidly declining, and efforts toward discovering newer antibiotics are not yielding the desired outcomes. Therefore, alternate antibacterial therapies based on physical mechanisms such as light and ultrasound are being explored.

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Objectives: To evaluate the long-term outcomes of intrascleral haptic fixation of posterior chamber intraocular lens (PCIOL) with fibrin glue in children.

Methods: This is a retrospective case study conducted in a tertiary eye institute in North India. A total of 118 eyes of 82 children who underwent glued intrascleral haptic fixation of PCIOLs were retrospectively analyzed.

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The role of ultrasound in medicine and biological sciences is expanding rapidly beyond its use in conventional diagnostic imaging. Numerous studies have reported the effects of ultrasound on cellular and tissue physiology. Advances in instrumentation and electronics have enabled successful applications of therapeutic ultrasound.

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