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1.
Phys Rev E ; 109(5): L052301, 2024 May.
Article de Anglais | MEDLINE | ID: mdl-38907508

RÉSUMÉ

Phase transitions are crucial in shaping the collective dynamics of a broad spectrum of natural systems across disciplines. Here, we report two distinct heterogeneous nucleation facilitating single step and multistep phase transitions to global synchronization in a finite-size adaptive network due to the trade off between time scale adaptation and coupling strength disparities. Specifically, small intracluster nucleations coalesce either at the population interface or within the populations resulting in the two distinct phase transitions depending on the degree of the disparities. We find that the coupling strength disparity largely controls the nature of phase transition in the phase diagram irrespective of the adaptation disparity. We provide a mesoscopic description for the cluster dynamics using the collective coordinates approach that brilliantly captures the multicluster dynamics among the populations leading to distinct phase transitions. Further, we also deduce the upper bound for the coupling strength for the existence of two intraclusters explicitly in terms of adaptation and coupling strength disparities. These insights may have implications across domains ranging from neurological disorders to segregation dynamics in social networks.

2.
Phys Rev E ; 109(4-1): 044212, 2024 Apr.
Article de Anglais | MEDLINE | ID: mdl-38755849

RÉSUMÉ

Swarmalators are oscillators that can swarm as well as sync via a dynamic balance between their spatial proximity and phase similarity. Swarmalator models employed so far in the literature comprise only one-dimensional phase variables to represent the intrinsic dynamics of the natural collectives. Nevertheless, the latter can indeed be represented more realistically by high-dimensional phase variables. For instance, the alignment of velocity vectors in a school of fish or a flock of birds can be more realistically set up in three-dimensional space, while the alignment of opinion formation in population dynamics could be multidimensional, in general. We present a generalized D-dimensional swarmalator model, which more accurately captures self-organizing behaviors of a plethora of real-world collectives by self-adaptation of high-dimensional spatial and phase variables. For a more sensible visualization and interpretation of the results, we restrict our simulations to three-dimensional spatial and phase variables. Our model provides a framework for modeling complicated processes such as flocking, schooling of fish, cell sorting during embryonic development, residential segregation, and opinion dynamics in social groups. We demonstrate its versatility by capturing the maneuvers of a school of fish, qualitatively and quantitatively, by a suitable extension of the original model to incorporate appropriate features besides a gallery of its intrinsic self-organizations for various interactions. We expect the proposed high-dimensional swarmalator model to be potentially useful in describing swarming systems and programmable and reconfigurable collectives in a wide range of disciplines, including the physics of active matter, developmental biology, sociology, and engineering.

3.
Chaos ; 34(2)2024 Feb 01.
Article de Anglais | MEDLINE | ID: mdl-38363957

RÉSUMÉ

We investigate the effect of the fraction of pairwise and higher-order interactions on the emergent dynamics of the two populations of globally coupled Kuramoto oscillators with phase-lag parameters. We find that the stable chimera exists between saddle-node and Hopf bifurcations, while the breathing chimera lives between Hopf and homoclinic bifurcations in the two-parameter phase diagrams. The higher-order interaction facilitates the onset of the bifurcation transitions at a much lower disparity between the inter- and intra-population coupling strengths. Furthermore, the higher-order interaction facilitates the spread of breathing chimera in a large region of the parameter space while suppressing the spread of the stable chimera. A low degree of heterogeneity among the phase-lag parameters promotes the spread of both stable chimera and breathing chimera to a large region of the parameter space for a large fraction of the higher-order coupling. In contrast, a large degree of heterogeneity is found to decrease the spread of both chimera states for a large fraction of the higher-order coupling. A global synchronized state is observed above a critical value of heterogeneity among the phase-lag parameters. We have deduced the low-dimensional evolution equations for the macroscopic order parameters using the Ott-Antonsen Ansatz. We have also deduced the analytical saddle-node and Hopf bifurcation curves from the evolution equations for the macroscopic order parameters and found them to match with the bifurcation curves obtained using the software XPPAUT and with the simulation results.

4.
PLOS Digit Health ; 2(10): e0000233, 2023 Oct.
Article de Anglais | MEDLINE | ID: mdl-37889905

RÉSUMÉ

During the COVID-19 pandemic, the use of mobile phone data for monitoring human mobility patterns has become increasingly common, both to study the impact of travel restrictions on population movement and epidemiological modeling. Despite the importance of these data, the use of location information to guide public policy can raise issues of privacy and ethical use. Studies have shown that simple aggregation does not protect the privacy of an individual, and there are no universal standards for aggregation that guarantee anonymity. Newer methods, such as differential privacy, can provide statistically verifiable protection against identifiability but have been largely untested as inputs for compartment models used in infectious disease epidemiology. Our study examines the application of differential privacy as an anonymisation tool in epidemiological models, studying the impact of adding quantifiable statistical noise to mobile phone-based location data on the bias of ten common epidemiological metrics. We find that many epidemiological metrics are preserved and remain close to their non-private values when the true noise state is less than 20, in a count transition matrix, which corresponds to a privacy-less parameter ϵ = 0.05 per release. We show that differential privacy offers a robust approach to preserving individual privacy in mobility data while providing useful population-level insights for public health. Importantly, we have built a modular software pipeline to facilitate the replication and expansion of our framework.

5.
Am J Public Health ; 113(5): 555-558, 2023 05.
Article de Anglais | MEDLINE | ID: mdl-36862972

RÉSUMÉ

Objectives. To assess wildfire risks to California inpatient health care facilities in 2022. Methods. Locations of inpatient facilities and associated inpatient bed capacities were mapped in relation to California Department of Forestry and Fire Protection fire threat zones (FTZs), which combine expected fire frequency with potential fire behavior. We computed the distances of each facility to the nearest high, very high, and extreme FTZs. Results. Half (107 290 beds) of California's total inpatient capacity is within 0.87 miles of a high FTZ and 95% (203 665 beds) is within 3.7 miles of a high FTZ. Half of the total inpatient capacity is within 3.3 miles of a very high FTZ and 15.5 miles of an extreme FTZ. Conclusions. Wildfires threaten a large number of inpatient health care facilities in California. In many counties, all health care facilities may be at risk. Public Health Implications. Wildfires in California are rapid-onset disasters with short preimpact phases. Policies should address facility-level preparedness including smoke mitigation, sheltering measures, evacuation procedures, and resource allocation. Regional evacuation needs, including access to emergency medical services and patient transportation, must also be considered. (Am J Public Health. 2023;113(5):555-558. https://doi.org/10.2105/AJPH.2023.307236).


Sujet(s)
Incendies , Feux de friches , Humains , Patients hospitalisés , Californie , Transport sanitaire
6.
J Orthop Case Rep ; 12(2): 93-96, 2022 Feb.
Article de Anglais | MEDLINE | ID: mdl-36199727

RÉSUMÉ

Introduction: Distal tibial physeal fractures and talus fractures are rare injuries in children and adolescents. Even rare is a combination of these two fractures. Axial compression is an accepted mechanism of injury in talus fractures with position of foot at the point of impact determining the extended patterns. A concomitant medial malleolus fracture suggests a supinated foot at the time of impact. Case Presentation: We report a case of a 13-year-old girl child who sustained a Type IV Salter-Harris injury of distal tibial physis along with a displaced vertical (sagittal) type fracture of the talus body. The uniqueness in our case was that the talar body fracture was a vertical type and that too displaced in the same line along with medial malleolus fragment. Open reduction of both the fractures was done through anteromedial approach followed by minimal fixation with K-wires. Good results were observed at 1 year following the surgery. Conclusion: Injuries of this nature are very uncommon and even more unusual in pediatric age group. This case report emphasizes the importance of having a high suspicion of uncommon fracture patterns in pediatric age group. Early and prompt diagnosis should be made using CT/MRI as a lot of these injuries may go unnoticed on plain radiographs.

7.
J Hand Surg Am ; 47(6): 585.e1-585.e10, 2022 06.
Article de Anglais | MEDLINE | ID: mdl-34420837

RÉSUMÉ

PURPOSE: We sought to assess clinical, radiological, and functional outcomes following treatment of extra-articular malunions of the distal radius using a multiplanar z-corrective osteotomy. METHODS: Fifteen patients with extra-articular distal radius malunions (13 dorsal and 2 volar) underwent z-corrective osteotomy and volar plate fixation without bone grafting. Correction and maintenance of each deformity was evaluated in terms of various radiographic indices (radial height; volar and radial tilt); osteotomy union; pain (visual analog scale); grip strength; range of motion; Disabilities of the Arm, Shoulder, and Hand scores; and Mayo wrist scores. RESULTS: The mean follow-up was 16.4 months. The mean radial height was corrected from -1.3 mm to 4.9 mm. The mean ulnar variance improved from 4.3 mm to -0.4 mm. The sagittal radial tilt and radial inclination were restored from a mean of -17.9° (dorsal) to 3.3° (volar) and from 12.0° to 17.2°, respectively. The Disabilities of the Arm, Shoulder, and Hand and Mayo wrist scores improved from means of 36 and 56 preoperatively to 24.8 and 73.3, respectively, at 6 months and further to 20.6 and 77.6, respectively, at the last follow-up. There were no nonunions or tendon-related problems. The mean pain score decreased from 4.1 preoperatively to 1.0 at 6 months and 0.8 at the last follow-up. The mean grip strength improved from 5.6 kg preoperatively to 15.6 kg at 6 months and 19.7 kg at the last follow-up. There was a statistically significant improvement in range of motion at the wrist. CONCLUSIONS: The z-osteotomy provides correction of deformity in all 3 planes, along with restoration of radial height. It also maintains a broad area of bone contact between the 2 osteotomized bone fragments, facilitating bony union and eliminating the need for bone grafting. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.


Sujet(s)
Cals vicieux , Fractures du radius , Plaques orthopédiques , Études de suivi , Cals vicieux/imagerie diagnostique , Cals vicieux/chirurgie , Humains , Ostéotomie , Douleur , Radiographie , Radius/chirurgie , Fractures du radius/imagerie diagnostique , Fractures du radius/chirurgie , Amplitude articulaire , Résultat thérapeutique
8.
Int J Burns Trauma ; 11(3): 207-219, 2021.
Article de Anglais | MEDLINE | ID: mdl-34336387

RÉSUMÉ

BACKGROUND: Optimum treatment of pathological fractures following benign bone tumours in paediatric population is controversial. The usual difficulties encountered while dealing such cases is to establish a correct pre-operative diagnosis and to choose between conservative vs operative management. The aim of the work is to highlight the difficult aspects of diagnosis and management of pathological fractures following benign bone tumours in paediatric population. METHODS: All paediatric patients (<18 years) with pathological fractures following benign bone tumours were included. Pathological fractures due to infection, metabolic bone diseases and malignant bone tumours were excluded. Initial pre-operative diagnosis was based on clinico-radiological characteristics of the tumour and FNAC/needle biopsy, while final diagnosis was confirmed with post-operative histology. Primary outcome measure was determination of any disparity between pre-operative diagnosis and final post-operative histological diagnosis and the need of a separate open biopsy procedure for establishing the exact nature of lesion. Secondary outcome measures were determination of complications following surgery, functional grade and any recurrence at latest follow-up at 3 years. RESULTS: Out of 13 patients enrolled for the study, twelve patients met the inclusion criteria. Female to male quotient was 3:1, with average age of 12.17 years. We were able to make correct pre-operative diagnosis in 10 patients (83.3%) with systematic clinico-radiological analysis and carefully performed FNAC/needle biopsy. Disparity between pre-operative and final post-operative diagnosis was seen in two patients. In one of these two patients, initial pre-operative diagnosis was fibrous dysplasia, which turned out to be ossifying fibroma on final post-operative biopsy. While the other patient required an open biopsy to establish the nature of underlying pathology, as the pre-op histological evaluation revealed equivocal nature of bone lesion. Secondary outcome measures showed superficial infection in one, coxa vara in one, limb length discrepancy in 2 and fibular graft donor site morbidity in two. None of the patient had developed recurrence. All patients had complete healing of the fracture and lesion. CONCLUSION: A thorough clinico-radiological analysis and carefully performed FNAC/needle biopsy can establish a correct pre-operative diagnosis in majority of patients with benign bone tumours complicated by pathological fracture. This approach will avoid preventable delay in the definitive treatment of such patients, and also preclude the need of a separate operation prior to definitive management. In sight of the findings of our study along with existing literature we propose for definitive treatment in straight-forward cases and pre-treatment biopsy in cases with inconclusive FNAC/needle biopsy results and lesions with suspicion of malignancy. Proper diagnostic evaluation and differentiation of benign pathological fractures from malignant counterparts followed by extended curettage or excision of lesion and biological reconstruction with or without osteosynthesis represents a feasible approach for managing such fractures.

9.
Futur J Pharm Sci ; 7(1): 106, 2021.
Article de Anglais | MEDLINE | ID: mdl-34056014

RÉSUMÉ

BACKGROUND: A large number of studies have recently reported that, because of their significant biological and pharmacological properties, heterocyclic compounds and their derivatives have attracted a strong interest in medicinal chemistry. The triazole nucleus is one of the most important heterocycles which has a feature of natural products as well as medicinal agents. Heterocyclic nitrogen is abundantly present in most medicinal compounds. The derivatization of triazole ring is based on the phenomenon of bio-isosteres in which substituted the oxygen atom of oxadiazole nucleus with nitrogen triazole analogue. MAIN TEXT: This review focuses on recent synthetic procedure of triazole moiety, which comprises of various pharmacological activities such as antimicrobial, anticonvulsant, anti-inflammatory, analgesic, antitubercular, anthelmintic, antioxidant, antimalarial, antiviral, etc.. CONCLUSION: This review highlights the current status of triazole compounds as different multi-target pharmacological activities. From the literature survey, triazole is the most widely used compound in different potential activities.

10.
J Hand Surg Am ; 46(3): 249.e1-249.e5, 2021 03.
Article de Anglais | MEDLINE | ID: mdl-32527520

RÉSUMÉ

Giant cell tumor (GCT) is a benign but locally aggressive neoplasm generally located in the epiphysis and metaphysis of the long bones. Its occurrence in the bones of the hand is rare. Giant cell tumors occurring in the hand account for only 2% of all the GCTs reported. The epimetaphyseal region of short long bones is a common site of GCTs in the hand; however, a phalangeal GCT originating in the distal phalanx is extremely rare. We present the clinical, radiological and histopathological findings of a case of GCT of the distal phalanx of the left ring finger presenting with a fungating mass and treated with en bloc resection by disarticulation of the distal interphalangeal joint.


Sujet(s)
Tumeurs osseuses , Phalanges de la main , Tumeur osseuse à cellules géantes , Tumeurs osseuses/imagerie diagnostique , Tumeurs osseuses/chirurgie , Phalanges de la main/imagerie diagnostique , Phalanges de la main/chirurgie , Tumeur osseuse à cellules géantes/imagerie diagnostique , Tumeur osseuse à cellules géantes/chirurgie , Humains
12.
J Adv Pharm Technol Res ; 2(1): 51-5, 2011 Jan.
Article de Anglais | MEDLINE | ID: mdl-22171293

RÉSUMÉ

The present study involves preparation and evaluation of floating microballoons with metformin as model drug for prolongation of gastric residence time. The microballoons were prepared by the solvent evaporation method using polymers hydroxypropylmethyl cellulose and ethyl cellulose. The shape and surface morphology of prepared microballoons were characterized by optical and scanning electron microscopy, respectively. In vitro drug release studies were performed and drug release kinetics was evaluated using the linear regression method. Effects of stirring rate during preparation, polymer concentration, solvent composition and dissolution medium on the size of microballoons, and drug release were also observed. The prepared microballoons exhibited prolonged drug release (8 hours) and remained buoyant for >10 hours. The mean particle size increased and the drug release rate decreased at higher polymer concentration. No significant effect of the stirring rate during preparation on drug release was observed. In vitro studies demonstrated diffusion-controlled drug release from the microballoons.

13.
J Adv Pharm Technol Res ; 1(1): 56-67, 2010 Jan.
Article de Anglais | MEDLINE | ID: mdl-22247832

RÉSUMÉ

Microballoons floatable on JPXIII No.1 solution were developed as a dosage form capable of floating in the stomach. Microballoons were prepared by the emulsion solvent diffusion method using enteric acrylic and other polymers with drug in a mixture of dichloromethane and ethanol. It was found that preparation temperature determined the formation of cavity inside the microsphere and the surface smoothness, determining the floatability and the drug release rate of the microballoons. The correlation between the buoyancy of microballoons and their physical properties, e.g. apparent density and roundness of microballoons were elucidated. The drug loading efficiency of microballoons was also determined. The optimum loading amount of metformin in the microballoons was found to impart ideal floatable properties to the microballoons. By fitting the data into zero order, first order and Highuchi model it was concluded that the release followed zero order release.

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