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1.
Clin Oncol (R Coll Radiol) ; 36(6): e137-e145, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38565457

RESUMO

AIMS: Sinonasal teratocarcinosarcomas (SNTCS) are rare sinonasal malignancies, the incidence of which is less than 1% of all tumors. There is limited data available on SNTCS's, often as case reports and small case series. The management of SNTCS is complicated because of its location, locally aggressive biology, difficulty in achieving complete resection, and limited data on chemotherapy in these malignancies. This audit was performed to understand the role of neoadjuvant chemotherapy (NACT) in SNTCS's, its ability to downstage the disease, achieve complete resection, and impact on long-term survival outcomes. METHODS: This was a retrospective analysis of a prospectively maintained database approved by the Institutional Ethics Committee (IEC). The baseline characteristics, the extent of tumor, Kadish stage, NACT regimen, and adverse events were extracted from the Electronic Medical Records and the patient's case file. Patients with baseline extensive/inoperable disease were referred for NACT from the multidisciplinary joint clinic followed by response assessment (RECIST v1.1). Patients underwent skull-base surgery if respectable post-completion of NACT, however, if deemed unresectable were treated with non-surgical modalities or palliative therapies. RESULTS: The data of 27 patients were evaluated from the year 2015-2022. The median age was 42 years (IQR:30-56) and 85.2% (n = 23) were males. The ECOG-PS was 0-1 in 88.8% (n = 24) patients. All 27 patients received NACT in view of extensive disease at presentation. 74.1% (n = 20) patients received Cisplatin-Etoposide and 25.9% (n = 7) received other chemotherapy regimens. The median number of chemotherapy cycles was 2(IQR:2-3). 96.3% patients (n = 26) completed the planned NACT cycles. 70.4% (n = 19) patients achieved a partial response in post-NACT imaging. 77.8% (n = 18) underwent surgery, 18.5% (n = 5) received CTRT, and 7.4% (n = 2) received definitive-RT alone. The median PFS and OS of the cohort was 19months (95%CI:12.0-25.6) and 23months (95%CI:5.94-40.06) respectively. CONCLUSION: NACT is safe, feasible, and effective with significant response rates, leading to effective downstaging, resectability and improved survival in patients with locally advanced SNTCS's.


Assuntos
Carcinossarcoma , Terapia Neoadjuvante , Neoplasias Nasais , Centros de Atenção Terciária , Humanos , Masculino , Feminino , Estudos Retrospectivos , Índia , Adulto , Pessoa de Meia-Idade , Terapia Neoadjuvante/métodos , Carcinossarcoma/tratamento farmacológico , Carcinossarcoma/terapia , Carcinossarcoma/patologia , Neoplasias dos Seios Paranasais/tratamento farmacológico , Neoplasias dos Seios Paranasais/terapia , Neoplasias dos Seios Paranasais/patologia , Teratoma/tratamento farmacológico , Teratoma/terapia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Idoso , Quimioterapia Adjuvante/métodos
2.
Cureus ; 16(2): e54816, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38405647

RESUMO

Objective Doppler velocimetry provides a sensitive, non-invasive, and safe method of surveillance of fetal hemodynamics and fetomaternal circulation. Cerebroplacental ratio (CPR) is an indicator of placental function and fetal maladaptation to placental insufficiency. Cerebroplacental ratio (CPR) is becoming a significant indicator of unfavorable pregnancy outcomes, which has implications for the assessment of fetal well-being. This study aimed to determine the cut-off value of the cerebroplacental ratio (CPR) in appropriate for gestational age (AGA) fetuses in high-risk mothers to predict adverse perinatal outcomes. We also compared the efficacy of CPR, umbilical artery pulsatility index (UmA PI), and middle cerebral artery pulsatility index (MCA PI) for predicting adverse perinatal outcomes. Design and setting This was a prospective observational study conducted at the Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India. Methods A total of 100 women with singleton high-risk pregnancies were included in this prospective observational study. Obstetric ultrasound was performed at the time of recruitment, and fetal weight and CPR were noted. Based on fetal weight, patients were divided into AGA and fetal growth restriction (FGR) groups; CPR was measured; patients were followed up fortnightly; and outcomes were noted. Main outcome The effectiveness of CPR, UmA PI, and MCA PI for predicting poor perinatal outcomes and identifying the cut-off value of CPR in appropriate for gestational age (AGA) fetuses in high-risk mothers was assessed. Result The values of MCA PI, UmA PI, and CPR were statistically significant between AGA and FGR (p-value =.023, .002 and .0001), respectively. The cut-off value for CPR-detecting adverse outcomes in AGA was 1.49. It has sensitivity, specificity, positive predictive value, and negative predictive value of 67.5%, 68%, 71.69%, and 70.21%, respectively. Conclusion Cerebroplacental ratio (CPR) reflects both circulatory insufficiency of the placenta and adaptive changes of the middle cerebral artery, indicating an important non-invasive surveillance modality.

3.
Phys Rev Lett ; 132(5): 051002, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38364164

RESUMO

We present the measurement of the cosmic ray proton spectrum from 50 TeV to 1.3 PeV using 7.81×10^{6} extensive air shower events recorded by the ground-based GRAPES-3 experiment between 1 January 2014 and 26 October 2015 with a live time of 460 day. Our measurements provide an overlap with direct observations by satellite and balloon-based experiments. The electromagnetic and muon components in the shower were measured by a dense array of plastic scintillator detectors and a tracking muon telescope, respectively. The relative composition of the proton primary from the air shower data containing all primary particles was extracted using the multiplicity distribution of muons which is a sensitive observable for mass composition. The observed proton spectrum suggests a spectral hardening at ∼166 TeV and disfavors a single power law description of the spectrum up to the Knee energy (∼3 PeV).

4.
Neurol Perspect ; 3(4)2023.
Artigo em Inglês | MEDLINE | ID: mdl-38124707

RESUMO

Background: Obstructive sleep apnea is a highly prevalent disorder, characterized by recurrent events of upper airway obstruction during sleep and associated with recurrent cycles of desaturation and re-oxygenation, sympathetic hyperactivity, and intra-thoracic pressure fluctuations, resulting in fragmentation of sleep and subsequent daytime fatigue with excessive sleepiness. Obstructive sleep apnea-induced bilateral tonic-clonic seizures are unheard of. We aimed to report 3 patients with previously undiagnosed obstructive sleep apnea who presented to the emergency department with new onset bilateral tonic-clonic seizure without any evidential neurological or metabolic cause. Methods: Patient data were obtained from medical records from the Department of Internal Medicine, IPGMER and SSKM Hospital, Kolkata, and Belle Vue Clinic, Kolkata, India. Results: Three male patients (67, 58, and 44 years old) presented with bilateral tonic-clonic seizure disorder without any underlying cause of seizures after rigorous investigations except for moderate to severe obstructive sleep apnea on polysomnography. All 2 patients were seizure-free after being treated with levetiracetam, chronic continuous positive airway pressure therapy in 2, and only continuous positive airway pressure in the other. The patients remained seizure-free on continuous positive airway pressure, even when levetiracetam was withdrawn, suggesting obstructive sleep apnea's causality in their new-onset acute seizures. Conclusion: Although further investigation is required to clarify this association, underlying obstructive sleep apnea should be ruled out in patients with a first-ever bilateral tonic-clonic seizure. Whether or not continuous positive airway pressure alone could effectively treat hypoxia and deranged cortical excitability, which may lead to seizures in cases with longstanding obstructive sleep apnea, is yet to be explored.


Introducción: La apnea obstructiva del sueño es una enfermedad con una alta prevalencia que se caracteriza por episodios recurrentes de obstrucción de las vías respiratorias altas durante el sueño, lo que conlleva ciclos repetidos de hipoxia y reoxigenación, hiperactividad simpática y fluctuaciones en la presión intratorácica. Todos estos procesos dan lugar a una fragmentación del sueño, lo que provoca fatiga diurna y somnolencia excesiva. Las crisis tónico-clónicas bilaterales inducidas por apnea obstructiva del sueño son poco conocidas. Presentamos los casos de tres pacientes con apnea obstructiva del sueño sin diagnosticar previamente que acudieron a urgencias por crisis tónico-clónicas de nueva aparición sin causa neurológica o metabólica aparente. Métodos: Los datos de nuestros pacientes se recogieron de los historiales médicos del servicio de Medicina Interna del Institute of Post-Graduate Medical Education and Research and Seth Sukhlal Karnani Memorial Hospital y de la Belle Vue Clinic, ambos en Kolkata (India). Resultados: Tres pacientes varones de 67, 58 y 44 años de edad presentaron convulsiones tónico-clónicas bilaterales sin causa identificada tras examen riguroso, exceptuando una apnea obstructiva del sueño de gravedad moderada a grave observada en la polisomnografía. Los tres pacientes recibieron tratamiento con levetiracetam durante el ingreso; al alta, se pautó tratamiento crónico con presión positiva continua de las vías respiratorias más levetiracetam en dos pacientes, y en el tercero solo presión positiva continua de las vías respiratorias. Ninguno presentó nuevas crisis tras la retirada de levetiracetam, lo que sugiere que la causa de las convulsiones era la apnea obstructiva del sueño. Conclusión: Aunque es necesario realizar más estudios para aclarar esta asociación, debemos descartar la apnea obstructiva del sueño en pacientes con crisis tónico-clónicas bilaterales de nueva aparición. Queda aún por determinar si la presión positiva continua podría tratar de forma efectiva la hipoxia y las alteraciones en la excitabilidad cortical, que podrían provocar crisis en casos de apnea obstructiva del sueño de larga evolución.

5.
Mymensingh Med J ; 32(3): 620-626, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37391949

RESUMO

Evaluation of the in vitro antibacterial activity of Chloroform extracts isolated from Henna (Lawsonia inermis) leaf against two nosocomial infection causing pathogens, gram-positive Staphylococcus aureus and gram-negative Klebsiella pneumoniae. This interventional study was carried out for the period of January 2021 to December 2021 in the Department of Pharmacology and Therapeutics in collaboration with the Department of Microbiology, Mymensingh Medical College, Bangladesh. The antibacterial activity was tested at different concentrations of Chloroform Henna leaf extracts by using disc diffusion and broth dilution method. The extract was prepared by using solvents chloroform and 0.1% Dimethyl sulfoxide (DMSO). The test microorganisms were also tested for their activity against a standard antibiotic Ciprofloxacin by broth dilution method and the result was compared with that of Chloroform extracts. Chloroform Henna Extracts (CHE) were used initially in nine different concentrations (2.5, 5, 10, 20, 50, 100, 200, 500 and 1000 mg/ml). Among different concentrations of the CHE, 100mg/ml and above concentrations showed inhibitory effect against Staphylococcus aureus and Klebsiella pneumoniae. The MIC for Staphylococcus aureus and Klebsiella pneumoniae were 100 and 200mg/ml in CHE respectively. The MIC of Ciprofloxacin was 1µg/ml against Staphylococcus aureus and 1.5µg/ml against Klebsiella pneumoniae. The MIC of Ciprofloxacin was the lowest in comparison to MICs of CHE for the test organisms. This study showed that Chloroform Henna extracts demonstrated antibacterial effects against food borne pathogens. It is clearly observed that there is definite antibacterial effect of the Chloroform extract of Henna leaves (Lawsonia inermis) against Staphylococcus aureus and Klebsiella pneumoniae.


Assuntos
Infecção Hospitalar , Lawsonia (Planta) , Infecções Estafilocócicas , Humanos , Infecção Hospitalar/tratamento farmacológico , Clorofórmio , Klebsiella pneumoniae , Staphylococcus aureus , Antibacterianos/farmacologia , Ciprofloxacina , Extratos Vegetais/farmacologia
6.
BJOG ; 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37156239

RESUMO

OBJECTIVE: To examine prevalence of novel newborn types among 541 285 live births in 23 countries from 2000 to 2021. DESIGN: Descriptive multi-country secondary data analysis. SETTING: Subnational, population-based birth cohort studies (n = 45) in 23 low- and middle-income countries (LMICs) spanning 2000-2021. POPULATION: Liveborn infants. METHODS: Subnational, population-based studies with high-quality birth outcome data from LMICs were invited to join the Vulnerable Newborn Measurement Collaboration. We defined distinct newborn types using gestational age (preterm [PT], term [T]), birthweight for gestational age using INTERGROWTH-21st standards (small for gestational age [SGA], appropriate for gestational age [AGA] or large for gestational age [LGA]), and birthweight (low birthweight, LBW [<2500 g], nonLBW) as ten types (using all three outcomes), six types (by excluding the birthweight categorisation), and four types (by collapsing the AGA and LGA categories). We defined small types as those with at least one classification of LBW, PT or SGA. We presented study characteristics, participant characteristics, data missingness, and prevalence of newborn types by region and study. RESULTS: Among 541 285 live births, 476 939 (88.1%) had non-missing and plausible values for gestational age, birthweight and sex required to construct the newborn types. The median prevalences of ten types across studies were T+AGA+nonLBW (58.0%), T+LGA+nonLBW (3.3%), T+AGA+LBW (0.5%), T+SGA+nonLBW (14.2%), T+SGA+LBW (7.1%), PT+LGA+nonLBW (1.6%), PT+LGA+LBW (0.2%), PT+AGA+nonLBW (3.7%), PT+AGA+LBW (3.6%) and PT+SGA+LBW (1.0%). The median prevalence of small types (six types, 37.6%) varied across studies and within regions and was higher in Southern Asia (52.4%) than in Sub-Saharan Africa (34.9%). CONCLUSIONS: Further investigation is needed to describe the mortality risks associated with newborn types and understand the implications of this framework for local targeting of interventions to prevent adverse pregnancy outcomes in LMICs.

7.
Nat Commun ; 14(1): 2795, 2023 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-37202402

RESUMO

Electrocyclic reactions are characterized by the concerted formation and cleavage of both σ and π bonds through a cyclic structure. This structure is known as a pericyclic transition state for thermal reactions and a pericyclic minimum in the excited state for photochemical reactions. However, the structure of the pericyclic geometry has yet to be observed experimentally. We use a combination of ultrafast electron diffraction and excited state wavepacket simulations to image structural dynamics through the pericyclic minimum of a photochemical electrocyclic ring-opening reaction in the molecule α-terpinene. The structural motion into the pericyclic minimum is dominated by rehybridization of two carbon atoms, which is required for the transformation from two to three conjugated π bonds. The σ bond dissociation largely happens after internal conversion from the pericyclic minimum to the electronic ground state. These findings may be transferrable to electrocyclic reactions in general.

8.
J Phys Condens Matter ; 35(32)2023 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-37116510

RESUMO

Reprogramming the structure of the magnonic bands during their operation is important for controlling spin waves in magnonic devices. Here, we report the tunability of the spin-wave spectra for a triangular shaped deterministic magnonic fractal, which is known as Sierpinski triangle by solving the Landau-Lifshitz-Gilbert equation using a micromagnetic simulations. The spin-wave dynamics change significantly with the variation of iteration number. A wide frequency gap is observed for a structure with an iteration number exceeding some value and a plenty of mini-frequency bandgaps at structures with high iteration number. The frequency gap could be controlled by varying the strength of the magnetic field. A sixfold symmetry in the frequency gap is observed with the variation of the azimuthal angle of the external magnetic field. The spatial distributions of the spin-wave modes allow to identify the bands surrounding the gap. The observations are important for the application of magnetic fractals as a reconfigurable aperiodic magnonic crystals.

9.
J Hazard Mater ; 454: 131496, 2023 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-37121030

RESUMO

Microplastics (MPs) have become widespread in the modern world posing a hidden threat to the global environment. However, growing accumulation and devastating impact of MPs on human health and the environment have received least attention. In the current investigation, for the first time MPs have been identified which are released from the daily usable materials like polythene bags (PB) and paper cups (PC) in response to hot and cold water exposure at different time intervals. The impact of these MPs has been assessed on the major antioxidant enzyme, bovine liver catalase (BLC). The binding of MPs caused conformational changes in BLC by decreasing the α-helical content, which results in reduction of the enzymatic activity. Kinetics study revealed nearly ∼1.4-fold compromised catalytic efficiency of catalase in response to MPs. Nevertheless, hepatic catalase activity was also significantly decreased in presence of MPs. Further, materials like glass, porcelain, stainless steel, and high-grade plastics are discovered as greener alternatives to PB and PC.


Assuntos
Microplásticos , Poluentes Químicos da Água , Humanos , Animais , Bovinos , Microplásticos/toxicidade , Plásticos , Catalase/metabolismo , Polietileno , Cinética , Antioxidantes , Água , Poluentes Químicos da Água/análise
10.
J Endocrinol Invest ; 46(9): 1865-1874, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36848018

RESUMO

PURPOSE: Bone health in primary ovarian insufficiency (POI) is under-investigated. We assessed patients with spontaneous POI for vertebral fractures (VFs) and related parameters of bone health. METHODS: 70 cases with spontaneous POI (age 32.5 ± 7.0 years) and an equal number of controls were assessed for BMD, TBS, and VFs. BMD at the lumbar-spine (L1-L4), left hip, non-dominant forearm, and TBS (iNsight software) were measured on a dual-energy X-ray absorptiometry (DXA) machine. VFs were assessed by Genant's classification. Serum FSH, LH, estradiol, T4, TSH, iPTH, serum 25(OH)D, total calcium, and inorganic phosphorus were measured. RESULTS: BMD at the lumbar-spine, hip and forearm was reduced by 11.5%, 11.4% and 9.1% in POI as compared to controls (P < 0.001). Degraded or partially degraded microarchitecture on TBS was observed in 66.7% of patients and 38.2% of controls (P = 0.001). 15.7% of the POI patients had VFs, compared to 4.3% of controls (P = 0.045). Age, duration of amenorrhea and duration of HRT use were the significant predictors of TBS (P < 0.01). Serum 25(OH)D was the significant determinant of VFs. TBS abnormalities were higher in patients with POI and VFs. BMD was not significantly different in patients with and without VFs. CONCLUSION: Thus, lumbar-spine osteoporosis, impaired TBS and VFs were present in 35.7%, 66.7% and 15.7% of patients with spontaneous POI in their early third decade. This indicates need for rigorous investigations for impaired bone health in these young patients and management with HRT, vitamin-D, and possible need for bisphosphonate therapy.


Assuntos
Fraturas por Osteoporose , Insuficiência Ovariana Primária , Fraturas da Coluna Vertebral , Feminino , Humanos , Adulto , Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Absorciometria de Fóton , Vértebras Lombares/diagnóstico por imagem
11.
Mymensingh Med J ; 32(1): 177-184, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36594318

RESUMO

To assess the role of the Glasgow Comma Score (GCS) for predicting the outcome of the patient with fever and altered sensorium was the objective of the study. This prospective observational study was conducted for six months following ethical approval. Informed consent was obtained prior enrollment. A total of 50 patients with complaints of fever for <2 weeks duration with altered sensorium with or without seizure were included in the study. GCS was calculated for all patients just after admission and before starting interventions. All patients were investigated and managed according to the hospital protocol. The outcome of the patients (living or dead within the hospital) was evaluated against the admission GCS score. The study was performed in accordance with the current Declaration of Helsinki. Of all, 42.0% (n=21) of the patients had bacterial meningitis, followed by viral encephalitis, cerebral malaria and coma vigil. Complete recovery occurred in 60.0% of cases, while recovery with disability occurred in 28.0% of cases. Death occurred in 12.0% of cases (n=6) due to cerebral malaria, viral encephalitis and bacterial meningitis (n=2 each cause). A higher number of deaths occurred in the lower GCS group (n=5 in GCS group 3-5) and this difference was statistically significant (p<0.05). Moreover, considering death as an outcome, multivariate logistic regression showed that GCS (OR 70.598, 95% CI-1.243-4009.41; p=0.039) was an independent predictor of the outcome. GCS seemed to be a predictor of the short-term outcome of the patient presenting with fever and altered sensorium in our setting. However, further exploration in larger setting with appropriate study design is recommended.


Assuntos
Encefalite Viral , Malária Cerebral , Meningites Bacterianas , Humanos , Coma/etiologia , Malária Cerebral/complicações , Febre/etiologia , Encefalite Viral/complicações , Meningites Bacterianas/complicações , Prognóstico
12.
Curr Microbiol ; 80(1): 41, 2022 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-36534266

RESUMO

Streptococcus pneumoniae (SP) infections cause morbidity and mortality among children worldwide. Hence India introduced 13-valent pneumococcal conjugate vaccine (PCV-13) in 2017 in a phased manner. The primary objective of this study was to assess the proportion of healthy children having nasopharyngeal colonization (NP) with SP. Secondary objective was to determine prevalent serotype of SP among the PCV13 vaccinated and non-vaccinated children. This cross-sectional study was conducted in 4 hospitals of Lucknow District, Northern India. Three hundred healthy children (2-59 months) were recruited between July and August 2019 from vaccination-clinics of hospitals. NP specimen was cultured using 5% sheep blood agar plate containing gentamicin. Pneumococcal isolates were identified by optochin sensitivity and bile-solubility tests. Serotyping was done using Quellung Method. Of the 300 healthy children, 56.7% (170/300) were males and 59.3% (181/300) had received at least one dose of PCV13 vaccine. The NP carriage rate of SP among healthy children was 37.7% (113/300). Vaccine serotypes were found in 33.3% (22/66) in PCV vaccinated children and 48.9% (23/47) in non-vaccinated children (p 0.09). Common vaccine serotypes that isolated were: 18C, 19A, 19F, 23F, 3, 4, 6A, 6B, 9 V. Thus more than one-third of healthy children had NP colonization with SP. Adjusting for age, there was a trend for significant reduction in vaccine serotypes in the NP with one doses versus two or more doses (ptrend = 0.04).


Assuntos
Infecções Pneumocócicas , Streptococcus pneumoniae , Masculino , Animais , Ovinos , Feminino , Sorogrupo , Estudos Transversais , Portador Sadio , Infecções Pneumocócicas/prevenção & controle , Índia
13.
J Endocrinol Invest ; 45(9): 1777-1786, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35585296

RESUMO

PURPOSE: Patients with hypoparathyroidism are at risk of vertebral fractures (VFs) despite high bone mineral density (BMD). We investigated this paradox by assessing trabecular bone score (TBS) and hip structural analysis (HSA) in non-surgical chronic hypoparathyroidism (cHypoPT) with and without VFs. METHODS: 152 cHypoPT patients (age 40.2 ± 13.4 years, M: F = 81:71) with a median follow-up of 8 (2-13) years were assessed for BMD, VFs, TBS, and HSA and compared with 152 healthy controls. VFs at T7-L4 were assessed by Genant's method. Average serum total calcium and phosphorus during follow-up were assessed. RESULTS: The lumbar spine and hip BMD were higher by 25.4 and 13.4% in cHypoPT than controls (P < 0.001). Paradoxically, VFs (30.9 vs.7.9%), including multiple (12.5 vs. 2.6%) were higher in cHypoPT (P < 0.001). Though overall average TBS (1.411 ± 0.091) was normal in cHypoPT, 25.4% of the females had subnormal TBS, more in post than pre-menopausal women (52.3 vs. 14%, P = 0.002) and as compared to males (6.1%, P = 0.001). TBS correlated with menopausal status and follow-up serum calcium-phosphorus product. For every gm/cm2 rise in BMD, TBS increase was only 0.227 in cHypoPT compared to 0.513 in controls. Frequency of VFs increased with declining TBS (P = 0.004). HSA was comparable between cHypoPT with and without VFs. 23.4% of cHypoPT with VFs had subnormal TBS. CONCLUSION: 31% of cHypoPT patients had VFs. TBS indicated degraded bone microarchitecture in 50% of the post-menopausal cHypoPT women. However, TBS has limitations to detect abnormal bone microarchitecture in cHypoPT as only one-fourth of patients with VFs showed low TBS.


Assuntos
Hipoparatireoidismo , Fraturas por Osteoporose , Fraturas da Coluna Vertebral , Absorciometria de Fóton/métodos , Adulto , Densidade Óssea , Cálcio , Osso Esponjoso/diagnóstico por imagem , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Fraturas por Osteoporose/diagnóstico , Fraturas por Osteoporose/etiologia , Fósforo , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/etiologia
14.
ISA Trans ; 125: 614-630, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33012536

RESUMO

The main objective of this paper is to improve the identification efficiency of non-linear systems using the Kalman filter (KF), which is optimised with the Artificial Electric Field (AEF) algorithm. The conventional KF suffers from the proper tuning of its parameters, which leads to a divergence problem. This issue has been solved to a great extent by the meta-heuristic AEF algorithm assisted Kalman filter (AEF-KF). This paper proposes three steps for the identification of the systems while solving the problem as mentioned above. Firstly, it converts the identification model to a measurement problem. Next, the AEF algorithm optimises the KF parameters by considering the fitness function with the KF equations. The third step is to identify the model using conventional KF algorithm with the optimised KF parameters. To evaluate the performance of the proposed method, parameter estimation error, mean squared error (MSE), fitness (FIT) percentage, statistical information and percentage improvement are considered as the performance metrics. To validate the performance of the proposed method, five distinct non-linear models are identified with the Volterra model using KF and the AEF-KF techniques under various noisy input conditions. Besides, the practical applicability of the proposed approach is also tested on two non-linear benchmark systems using experimental data sets. The obtained simulation results confirm the efficacy and robustness of the proposed identification method in terms of the convergence speed, computational time and various performance metrics as compared to KF, Kalman smoother (KS) which is optimised using different state-of-the-art evolutionary algorithms and also other existing recently reported similar types of stochastic algorithms based approaches.

16.
Science ; 374(6564): 178-182, 2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34618569

RESUMO

Conformational isomers (conformers) of molecules play a decisive role in biology and organic chemistry. However, experimental methods for investigating chemical reaction dynamics are typically not conformer-sensitive. We report on a gas-phase megaelectronvolt ultrafast electron diffraction investigation of α-phellandrene undergoing an electrocyclic ring-opening reaction. We directly imaged the evolution of a specific set of α-phellandrene conformers into the product isomer predicted by the Woodward-Hoffmann rules in real space and time. Our experimental results are in quantitative agreement with nonadiabatic quantum molecular dynamics simulations, which provide considerable detail of how conformation influences the time scale and quantum efficiency of photoinduced ring-opening reactions.

17.
Science ; 373(6556): 797-801, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34385397

RESUMO

An unconventional superconducting state was recently discovered in uranium ditelluride (UTe2), in which spin-triplet superconductivity emerges from the paramagnetic normal state of a heavy-fermion material. The coexistence of magnetic fluctuations and superconductivity, together with the crystal structure of this material, suggests that a distinctive set of symmetries, magnetic properties, and topology underlie the superconducting state. Here, we report observations of a nonzero polar Kerr effect and of two transitions in the specific heat upon entering the superconducting state, which together suggest that the superconductivity in UTe2 is characterized by a two-component order parameter that breaks time-reversal symmetry. These data place constraints on the symmetries of the order parameter and inform the discussion on the presence of topological superconductivity in UTe2.

18.
Nat Commun ; 12(1): 4981, 2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404794

RESUMO

High-harmonic generation is a cornerstone of nonlinear optics. It has been demonstrated in dielectrics, semiconductors, semi-metals, plasmas, and gases, but, until now, not in metals. Here we report high harmonics of 800-nm-wavelength light irradiating metallic titanium nitride film. Titanium nitride is a refractory metal known for its high melting temperature and large laser damage threshold. We show that it can withstand few-cycle light pulses with peak intensities as high as 13 TW/cm2, enabling high-harmonics generation up to photon energies of 11 eV. We measure the emitted vacuum ultraviolet radiation as a function of the crystal orientation with respect to the laser polarization and show that it is consistent with the anisotropic conduction band structure of titanium nitride. The generation of high harmonics from metals opens a link between solid and plasma harmonics. In addition, titanium nitride is a promising material for refractory plasmonic devices and could enable compact vacuum ultraviolet frequency combs.

19.
Mymensingh Med J ; 30(3): 808-815, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34226472

RESUMO

Healthcare professionals are the crucial and influencing source of information for vaccines and their communication among patients and communities that can accelerate successful vaccination in a country. This cross-sectional study was one of the first and foremost ones in Bangladesh to observe the basic perception and attitudes towards vaccination against COVID-19 among the healthcare workers (HCWs) - doctors, interns, nurses, ward boys, cleaners, and medical technologists of major COVID-dedicated hospitals. The cross-sectional questionnaire-based study was conducted in February 2021 among 550 HCWs to assess the perception and attitude towards vaccination against COVID-19. The study participants were targeted as the priority group for COVID-19 vaccination, working in two major COVID-dedicated hospitals, Holy Family Red Crescent Medical College Hospital (HF-center), and Sheikh Russel National Gastro-liver Institute and Hospital (SR-center) in Dhaka, Bangladesh during the pandemic. The questionnaire was structured with a three-point scale of responses from 'true', 'false', and 'do not know'. The responses were calculated on point-score as +1 for the correct response, -1 for the wrong response, and 0 for 'do not know' with an overall highest and the lowest possible score of +5 to -5. Absolute (n) and relative frequencies (%) were presented for qualitative variables, while quantitative variables were presented as mean (± standard deviation). Chi-square test was done for univariate analysis of qualitative variables and Student's t-test for quantitative variables. With the 95.27% response rate, including 204 males and 320 were female and the male: female ratio was 1: 1.56. The majority of the participants were doctors (45.8%) followed by nurses (27.9%), and MLSS (26.3%) respectively. The respondents were between 18 to 64 years of age with a mean of 36.17±10.94 years. Most of the respondents (95.99%) responded correctly about the cost-free availability of a vaccine against COVID-19 in the country, 87.40% preferred vaccination as safe and effective. Again 29.77% HCWs think the vaccine might not be safe or effective due to emergency authorization. Only 38.93% of respondents could respond correctly about the necessity of vaccines for children, 31.10% think the vaccination was not required instead of natural immunity. The positive perception and attitude of the frontline HCWs in COVID-dedicated hospitals in Bangladesh are crucial which will positively influence motivation and wide acceptance among the general population for the attainment of the nationwide vaccination program, and adopt effective strategic modification to minimize the gaps for a low-middle income country like Bangladesh with its resource constrain.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Adulto , Atitude , Bangladesh , Criança , Estudos Transversais , Feminino , Pessoal de Saúde , Hospitais , Humanos , Masculino , Pessoa de Meia-Idade , Percepção , SARS-CoV-2 , Inquéritos e Questionários , Vacinação
20.
Stud Health Technol Inform ; 280: 141-145, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34190076

RESUMO

Scoliosis is a 3D deformation of the spinal column, characterized by a lateral deviation of the spine, accompanied by axial rotation of the vertebrae. Adolescent Idiopathic Scoliosis (AIS), is the most common type, affecting children between ages 8 to 18 when bone growth is at its maximum rate. The selection of the most appropriate treatment options is based on the surgeon's experience. So, developing a clinically validated patient-specific model of the spine would aid surgeons in understanding AIS in early stages and propose an efficient method of treatment for the individual patient. This project steps include: Developing a clinically validated patient-specific Reduced Order Finite Element Model (ROFEM) of the spine, predicting AIS progression using data mining and proposing a method of treatment. First we implement FE synergistically with bio-mechanical information, image processing and data science techniques to improve predictive ability. Initial geometry of the spine will be extracted from the x-ray images from different planes and imported to FEM software to generate the spine model and perform analysis. A RO model is developed based on the detailed spinal FEM. Next, a neural network is used to predict the spinal curvature. The ability to predict the severity of AIS will have an immense impact on the treatment of AIS-affected children. Access to a predictive and patient-specific model will enable the physicians to have a better understanding of spinal curvature progression. Consequently, the physicians will be able to educate families, choose the most appropriate treatment option and asses for surgical intervention.


Assuntos
Cifose , Escoliose , Adolescente , Inteligência Artificial , Criança , Humanos , Imageamento Tridimensional , Rotação , Escoliose/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem
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