Publications by authors named "Arpan Sinha"

Using the Lebwohl-Lasher interaction for reciprocal local alignment, we present a comprehensive phase diagram for a dry, apolar, active nematic system using its stochastic off-lattice dynamics. The nematic-isotropic transition in this system is first-order and occurs alongside a fluctuation-dominated phase separation. Our phase diagram identifies three distinct regions based on activity and orientational noise relative to alignment strength: a homogeneous isotropic phase, a nematic phase with giant density fluctuations, and a coexistence region.

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Active nematics undergo spontaneous symmetry breaking and show phase separation instability. Within the prevailing notion that macroscopic properties depend only on symmetries and conservation laws, different microscopic models are used out of convenience. Here, we test this notion carefully by analyzing three different microscopic models of apolar active nematics.

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Hereditary thrombotic thrombocytopenic purpura (hTTP), also known as Upshaw-Schulman syndrome, is a rare genetic disorder caused by mutations in the ADAMTS13 gene that leads to decreased or absent production of the plasma von Willebrand factor (VWF)-cleaving metalloprotease ADAMTS13. The result is circulating ultra-large multimers of VWF that can cause microthrombi, intravascular occlusion and organ damage, especially at times of turbulent circulation. Patients with hTTP may have many overt or clinically silent manifestations, and a high index of suspicion is required for diagnosis.

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Background: Peripheral venous access in patients with sickle cell disease (SCD) can become difficult over time due to frequent access and scarring. Infusion ports provide reliable central venous access. Deep venous thrombosis (DVT) and infections are complications associated with SCD and infusion ports.

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D-2-hydroxyglutaric aciduria (D-2-HGA) is a rare metabolic disorder characterized by developmental delay, hypotonia, and bi-allelic mutations in D-2-hydroxyglutarate dehydrogenase or a single gain-of-function mutation in isocitrate dehydrogenase 2 Metaphyseal chondromatosis with D-2-hydroxyglutaric aciduria (MC-HGA) is a type of D-2-HGA that has been previously reported in ten patients (OMIM 614875), three of whom had somatic mosaicism for R132 variants in isocitrate dehydrogenase 1 (). We describe a 3-year-old boy with MC-HGA who subsequently developed acute myeloid leukemia (AML) and was found to have an R132C mutation in a leukemic bone marrow sample. Further testing revealed presence of somatic mosaicism for R132C variant, suggesting an association of in inducing myeloid leukemogenesis.

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Despite advancements in the diagnosis and treatment of acute lymphoblastic leukemia (ALL), a need for improved strategies to decrease morbidity and improve cure rates in relapsed/refractory ALL still exists. Such approaches include the identification and implementation of novel targeted combination regimens, and more precise upfront patient risk stratification to guide therapy. New curative strategies rely on an understanding of the pathobiology that derives from systematically dissecting each cancer's genetic and molecular landscape.

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Background: Vascular complications such as pulmonary hypertension (PH) occur at an increased rate following splenectomy in patients with various hemolytic blood disorders including thalassemia. The goal of this retrospective cross-sectional analysis was to assess the independent association of splenectomy with an elevated tricuspid regurgitation velocity (TRV) in people with homozygous sickle cell disease (HbSS). TRV is a noninvasive screening test for PH and a surrogate marker of prognosis in sickle cell disease (SCD).

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Hematopoietic stem cells (HSCs) have extensive regenerative capacity to replace all blood cell types, an ability that is harnessed in the clinic for bone marrow transplantation. Finding appropriate donors remains a major limitation to more extensive usage of HSC-based therapies. Derivation of patient-specific HSCs from pluripotent stem cells offers great promise to remedy this problem if scientists could crack the code on how to make robust, transplantable HSCs in a dish.

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Background: Hydroxyurea (HU) induces dose-dependent increased fetal hemoglobin (HbF) for sickle cell disease (SCD). Large deviation from historical personal best (PBest) HbF, a clinic-based version of maximum dose, may identify a subset with suboptimal HU adherence over time.

Procedure: Retrospective clinical data from youth ages 10-18 years prescribed HU at two centers were extracted from medical records at three time points: pre-HU initiation, PBest and a recent assessment.

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Cases of pregnancy-associated severe aplastic anemia (SAA) have been reported in the literature with historically high rates of mortality. We report the case of a 17-year-old female diagnosed with SAA at 26 weeks of gestation. She experienced intrauterine fetal demise and did not achieve hematologic remission after delivery.

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