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result(s) for
"Sen, Souvik"
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Stress Path Analysis for Characterization of In Situ Stress State and Effect of Reservoir Depletion on Present-Day Stress Magnitudes: Reservoir Geomechanical Modeling in the Gulf of Suez Rift Basin, Egypt
2021
A reservoir geomechanical modeling has been attempted in the hydrocarbon-bearing Miocene formations in the offshore Badri field, Gulf of Suez, Egypt. Pore pressure established from the direct downhole measurements indicated sub-hydrostatic condition in the depleted mid-Miocene Hammam Faraun and Kareem reservoirs. Vertical stress (
S
v
) estimated using bulk density data yielded an average of 0.98 PSI/feet (22.17 MPa/km) gradient. Magnitudes of minimum (
S
hmin
) and maximum (
S
hmax
) horizontal stresses were deduced from the poro-elastic model. Relative stress magnitudes (
S
v
≥
S
hmax
>
S
hmin
) reflect a normal faulting tectonic stress in the Badri field. Pore pressure and stress perturbations (ΔPP and Δ
S
h
) in the depleted reservoirs investigated from actual measurements recognized ‘stress path’ values of 0.54 and 0.59 against the Hammam Faraun and Kareem Formations, respectively. These stress path values are far away from the normal faulting limit (0.68), indicating induced normal faulting or fault reactivation to be unlikely at the present depletion rate.
Journal Article
Pioglitazone after Ischemic Stroke or Transient Ischemic Attack
by
Kleindorfer, Dawn
,
Inzucchi, Silvio E
,
Berger, Leo
in
Aged
,
Bone surgery
,
Brain Ischemia - drug therapy
2016
In this trial in nondiabetic patients with insulin resistance and a recent ischemic stroke or transient ischemic attack, pioglitazone was associated with a lower risk of stroke and MI than was placebo but with a higher risk of weight gain, edema, and bone fracture.
Ischemic stroke and transient ischemic attack (TIA) affect more than 14 million persons worldwide annually.
1
,
2
Affected patients are at increased risk for future cardiovascular events,
3
,
4
and prevention of these adverse outcomes is a major goal in their care.
Treatment of insulin resistance represents a potential new preventive strategy that could be added to standard care after ischemic stroke or TIA.
5
Insulin resistance is nearly universal in patients with type 2 diabetes but is also present in more than 50% of patients without diabetes who have had an ischemic stroke or a TIA.
6
The presence of insulin resistance increases . . .
Journal Article
Geomechanical and Petrophysical Assessment of the Lower Turonian Tight Carbonates, Southeastern Constantine Basin, Algeria: Implications for Unconventional Reservoir Development and Fracture Reactivation Potential
by
Sen, Souvik
,
Radwan, Ahmed E.
,
Baouche, Rafik
in
Analysis
,
Environmental aspects
,
fracture reactivation
2022
In this study, we assessed the unconventional reservoir characteristics of the Lower Turonian carbonates from the southeastern Constantine Basin. We integrated petrography, petrophysical, and rock-mechanical assessments to infer formation properties and unconventional reservoir development strategies. The studied fossiliferous argillaceous limestones are rich in planktonic foraminifera, deposited in a calm and low energy depositional condition, i.e., deep marine basinal environment. Routine core analysis exhibits very poor porosity (mostly < 5%) and permeability (<0.1 mD), implying the dominance of nano and microporosity. Micritization and calcite cementation are inferred as the major reservoir quality-destroying diagenetic factors. Based on the wireline log-based elastic properties, the upper part of the studied interval exhibits higher brittleness (BI > 0.48) and fracability (FI > 0.5) indices compared to the lower interval. Borehole breakouts indicate ~N-S SHmax orientation and a normal to strike-slip transitional stress state has been constrained based on a geomechanical assessment. We analyzed safe wellbore trajectory and minimum mud weight requirements to ensure stability in the deviated and horizontal wells required for field development. At the present stress state, none of the fracture orientations are critically stressed. We inferred the fracture reactivation potential during hydraulic stimulation required to bring the tight Turonian limestones into production. Additional pore pressure build-up required to reactivate optimally oriented natural fractures has also been inferred to ensure success of hydraulic fracturing.
Journal Article
Safety and efficacy of multipotent adult progenitor cells in acute ischaemic stroke (MASTERS): a randomised, double-blind, placebo-controlled, phase 2 trial
by
Uchino, Ken
,
Wechsler, Lawrence R
,
Sila, Cathy A
in
Adherent cells
,
Adult
,
Adult Stem Cells - transplantation
2017
Multipotent adult progenitor cells are a bone marrow-derived, allogeneic, cell therapy product that modulates the immune system, and represents a promising therapy for acute stroke. We aimed to identify the highest, well-tolerated, and safest single dose of multipotent adult progenitor cells, and if they were efficacious as a treatment for stroke recovery.
We did a phase 2, randomised, double-blind, placebo-controlled, dose-escalation trial of intravenous multipotent adult progenitor cells in 33 centres in the UK and the USA. We used a computer-generated randomisation sequence and interactive voice and web response system to assign patients aged 18–83 years with moderately severe acute ischaemic stroke and a National Institutes of Health Stroke Scale (NIHSS) score of 8–20 to treatment with intravenous multipotent adult progenitor cells (400 million or 1200 million cells) or placebo between 24 h and 48 h after symptom onset. Patients were ineligible if there was a change in NIHSS of four or more points during at least a 6 h period between screening and randomisation, had brainstem or lacunar infarct, a substantial comorbid disease, an inability to undergo an MRI scan, or had a history of splenectomy. In group 1, patients were enrolled and randomly assigned in a 3:1 ratio to receive 400 million cells or placebo and assessed for safety through 7 days. In group 2, patients were randomly assigned in a 3:1 ratio to receive 1200 million cells or placebo and assessed for safety through the first 7 days. In group 3, patients were enrolled, randomly assigned, and stratified by baseline NIHSS score to receive 1200 million cells or placebo in a 1:1 ratio within 24–48 h. Patients, investigators, and clinicians were masked to treatment assignment. The primary safety outcome was dose-limiting toxicity effects. The primary efficacy endpoint was global stroke recovery, which combines dichotomised results from the modified Rankin scale, change in NIHSS score from baseline, and Barthel index at day 90. Analysis was by intention to treat (ITT) including all patients in groups 2 and 3 who received the investigational agent or placebo. This study is registered with ClinicalTrials.gov, number NCT01436487.
The study was done between Oct 24, 2011, and Dec 7, 2015. After safety assessments in eight patients in group 1, 129 patients were randomly assigned (67 to receive multipotent adult progenitor cells and 62 to receive placebo) in groups 2 and 3 (1200 million cells). The ITT populations consisted of 65 patients who received multipotent adult progenitor cells and 61 patients who received placebo. There were no dose-limiting toxicity events in either group. There were no infusional or allergic reactions and no difference in treatment-emergent adverse events between the groups (64 [99%] of 65 patients in the multipotent adult progenitor cell group vs 59 [97%] of 61 in the placebo group). There was no difference between the multipotent adult progenitor cell group and placebo groups in global stroke recovery at day 90 (odds ratio 1·08 [95% CI 0·55–2·09], p=0·83).
Administration of multipotent adult progenitor cells was safe and well tolerated in patients with acute ischaemic stroke. Although no significant improvement was observed at 90 days in neurological outcomes with multipotent adult progenitor cells treatment, further clinical trials evaluating the efficacy of the intervention in an earlier time window after stroke (<36 h) are planned.
Athersys Inc.
Journal Article
Weaving a new web: gregarious parasitism in Idris Förster (Hymenoptera: Scelionidae) attacking spider eggs
by
Sen, Souvik
,
Rajmohana, K.
,
Dinesh, K. P.
in
Adaptability
,
Animals
,
Biology and Life Sciences
2025
The present study, conducted in West Bengal, India, explored the unique ‘multi-chambered’ appearance of certain spider eggs, leading to the discovery of gregarious parasitism in the idiobiont endoparasitoid Idris Förster (Hymenoptera: Scelionidae). Little is known about the roles of parasitoid Hymenoptera in regulating spider populations. Phylogenetic analysis based on the mitochondrial cytochrome c oxidase I marker identified five distinct species of Idris . These five gregarious species, identified in association with various spider hosts across multiple locations during a two-year study, offer new insights into host-parasitoid interactions and their adaptability in different host systems. Additionally, six novel host associations between egg parasitoids and five spider species from two families are documented. Under the family Scelionidae, Idris is the second genus, after Telenomus Haliday, adapting to gregarious development. Our findings emphasize the existence of diverse trophic interactions and life strategies in nature that are yet to be documented.
Journal Article
Geomechanical attributes of the Cenozoic sediments of ODP leg 161, western Mediterranean Sea and its implications as geological proxy
2021
This work characterizes the rock-mechanical properties and in-situ stress magnitudes of the Cenozoic sedimentary succession encountered in the ODP Leg 161 holes of the western Mediterranean Sea. This study attempts to infer the link between the variation of the rock-mechanical parameters within the Pliocene–Pleistocene stratigraphy with mineralogy and depositional environment. Wireline logs and bulk mineralogical compositions of five scientific holes drilled in the Central Tyrrhenian Basin (974C), South Balearic margin (975C) and Alboran Basin areas (976B, 977A and 979A) were evaluated. Study infers that a lower sedimentation rate in the greater water depths of the Central Tyrrhenian Basin resulted in increased inter-grain bonding and thus higher rock strengths in the Hole 974C sediments when compared to the other drilling sites. Estimated Young’s modulus and elastic property-based brittleness index gradually increase with depth within the lower part of the Pliocene–Pleistocene formation as carbonate % increases in response to the depositional environment shifting from Pleistocene hemipelagic environment to pelagic condition in Pliocene. Our results indicate that the rock strength and elastic brittleness properties can be utilized as confident geological proxies for depositional environments in the western Mediterranean sea region. Density-derived porosity shows an overall normal sediment compaction trend yielding hydrostatic pore pressure. Interpreted vertical stress (13.68–17.45 MPa/km) and minimum horizontal stress (12.19–14.56 MPa/km) gradients infer a normal to strike-slip tectonic regime. Due to the unavailability of calibration data, we inferred the upper bound of maximum horizontal stress (SH) gradient, ranging between 13.88 and 18.47 MPa/km. E-Quality wellbore breakouts interpreted from the acoustic image logs in Miocene Basement (Hole 976B) suggested NW–SE to N-S SH azimuth western Alboran Basin, parallel to the African and Eurasian plate movement direction.
Journal Article
Periodontal Disease, Atrial Fibrillation and Stroke
by
Gottesman, Rebecca F.
,
Soliman, Elsayed Z.
,
Redd, Kolby
in
Alcohol use
,
Arteriosclerosis
,
Atherosclerosis
2021
We recently described the association between periodontal disease (PD) and stroke risk.
The purpose of this study was to test the association between PD, dental care utilization and incident atrial fibrillation (AF), as well as AF as a mediator to PD- stroke association.
In dental cohort of the Atherosclerosis Risk in Communities Study (ARIC), participants without prior AF underwent full-mouth periodontal measurements. PD was defined on an ordinal scale as healthy (referent), mild, moderate and severe. In ARIC main cohort, participants were classified as regular or episodic dental care users. These patients were followed for AF, over 17 years. Cox proportional hazards models adjusted for AF risk factors were used to study relationships between PD severity, dental care utilization and AF. Mediation analysis was used to test if AF mediated the PD- stroke association.
In dental ARIC cohort, 5,958 were assessed without prior AF, 754 were found to have AF. Severe PD was associated with AF on both univariable (crude HR, 1.54; 95% CI, 1.26-1.87) and multivariable (adjusted HR, 1.31, 95% CI, 1.06-1.62) analyses. Mediation analysis suggested AF mediates the association between PD and stroke. In the main ARIC cohort, 9,666 participants without prior AF were assessed for dental care use, 1558 were found to have AF. Compared with episodic users, regular users had a lower risk for AF on univariable (crude HR, 0.82, 95% CI, 0.74-0.90) and multivariable (adjusted HR, 0.88, 95% CI, 0.78-0.99) analyses.
PD is associated with AF. The association may explain the PD-stroke risk. Regular users had a lower risk of incident AF compared with episodic users.
[Display omitted]
Journal Article
In Situ Stress Determination Based on Acoustic Image Logs and Borehole Measurements in the In-Adaoui and Bourarhat Hydrocarbon Fields, Eastern Algeria
2023
The study of in situ stress from image logs is a key factor for understanding regional stresses and the exploitation of hydrocarbon resources. This work presents a comprehensive geomechanical analysis of two eastern Algerian hydrocarbon fields to infer the magnitudes of principal stress components and stress field orientation. Acoustic image logs and borehole measurements were used in this research to aid our understanding of regional stress and field development. The studied In-Adaoui and Bourarhat fields encompass a combined thickness of 3050 m of Paleozoic and Mesozoic stratigraphy, with the primary reservoir facies in the Ordovician interval. The Ordovician sandstone reservoir interval indicates an average Poisson’s ratio (v) of 0.3, 100–150 MPa UCS, and 27–52 GPa Young’s modulus (E). Direct formation pressure measurements indicate that the sandstone reservoir is in a hydrostatic pore pressure regime. Density-derived vertical stress had a 1.1 PSI/feet gradient. Minimum horizontal stress modeled from both Poisson’s ratio and an effective stress ratio-based approach yielded an average 0.82 PSI/feet gradient, as validated with the leak-off test data. Drilling-induced tensile fractures (DITF) and compressive failures, i.e., breakouts (BO), were identified from acoustic image logs. On the basis of the DITF criterion, the maximum horizontal stress gradient was found to be 1.57–1.71 PSI/feet, while the BO width-derived gradient was 1.27–1.37 PSI/feet. Relative stress magnitudes indicate a strike-slip stress regime. A mean SHMax orientation of N130°E (NW-SE) was interpreted from the wellbore failures, classified as B-quality stress indicators following the World Stress Map (WSM) ranking scheme. The inferred stress magnitude and orientation were in agreement with the regional trend of the western Mediterranean region and provide a basis for field development and hydraulic fracturing in the low-permeable reservoir. On the basis of the geomechanical assessments, drilling and reservoir development strategies are discussed, and optimization opportunities are identified.
Journal Article
Protocol for Escitalopram and Language Intervention for Subacute Aphasia (ELISA): A randomized, double blind, placebo-controlled trial
by
Bonilha, Leonardo
,
Sen, Souvik
,
Stockbridge, Melissa D.
in
Antidepressants
,
Aphasia
,
Aphasia - drug therapy
2021
In this forthcoming multicenter, prospective, randomized, double-blind placebo-controlled trial, we will investigate the augmentative effects of a selective serotonin reuptake inhibitor, escitalopram, on language therapy in individuals with post-stroke aphasia. We hypothesize that, when combined with language therapy, daily escitalopram will result in greater improvement than placebo in an untrained picture naming task (Philadelphia Naming Test short form) administered one week after the end of language therapy. We also will examine whether escitalopram’s effect on language is independent of its effect on depression, varies with lesion location, or is associated with increased functional connectivity within the left hemisphere. Finally, we will examine whether individuals with BDNF met alleles show reduced response to treatment and reduced changes in connectivity. We expect to enroll 88 participants over four years. Participants are given escitalopram or placebo within one week of their stroke for 90 days and receive fifteen 45-minute computer-delivered sessions of language treatment beginning 60 days from the start of drug therapy. Patients then complete a comprehensive assessment of language at one, five, and twenty weeks after the last language therapy session. ELISA is the first randomized, controlled trial evaluating the effect of a selective serotonin reuptake inhibitor on the improvement of language in people with aphasia undergoing language treatment during the acute to subacute post-stroke period. Trial registration : The trial is registered with ClinicalTrials.gov NCT03843463 .
Journal Article
Sequence Stratigraphic Model of Middle Permian Barakar Formation from a Marginal Gondwana Basin, India
2018
Gondwana deposits are extensively found across the continents. Here we study the Middle Permian Barakar Formation from the marginal Gondwana Basin, eastern India, being deposited in a normal fault setting. Availability of extensive cores as well as geophysical log suites (gamma-resistivity-density from drilled wells) from the study area helped us achieving high resolution interpretation. Core study identifies fluvial sedimentary architectures, which were correlated with the geophysical logs and modeled field-wide to understand vertical and horizontal facies disposition. The facies analysis has been used to establish a sequence stratigraphic model of the cyclic Barakar deposition. Four major fining upward depositional sequences were identified, each sequence comprises of low accommodation system tract (LAST) at base and high accommodation system tract (HAST) at top. LAST is characterized by vertically stacked, multistory amalgamated channel sandstone dominated facies, while floodplain dominated facies characterizes HAST, reflecting a gradual shift from braided to meandering depositional system from bottom to top of each cycle. Study reveals depocenter to be in the western part, supported by eastward thinning of sediment packets, all being deposited in a half-graben setting.
Journal Article