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1.
Mil Med ; 189(Supplement_3): 767-774, 2024 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-39160831

RESUMEN

INTRODUCTION: Advancements in information technology have facilitated information exchange practices within the Military Health System (MHS), enabling "systems of systems" approaches that broaden and coordinate the set of capabilities available to enhance patient outcomes. This is applicable for MHS modeling and simulation (M&S) applications as well. Learning from successful approaches applied in current interoperability solutions used in the military helps to ensure interoperability practices yield trusted compositions of simulations. MATERIALS AND METHODS: The use of formal methods provides the rigor necessary to unambiguously communicate these approaches across the MHS community. Here, 3 formal methods are proposed to ensure the harmonization of models and alignment of M&S data needed for simulation interoperability for MHS applications. RESULTS: To clarify considerations relevant for establishing simulation interoperability, the proposed formal methods are examined within a notional example of an injury sustained because of blast exposure. The first method applies the principles of semiotics, addressing the coding of information via syntax and semantics, to understand how to align and transform data across simulations within a composition. The second method applies the concepts of well-specified co-simulations, and the use of different techniques, tools, and algorithms to address the composition and synchronization of M&S components. The third method applies the mathematical branch of model theory to codify expert knowledge about concepts, assumptions, and constraints to ensure conceptual alignment within the simulation composition. CONCLUSIONS: Biomedical research must contend with complexity inherent to computational human body modeling, enlisting expert knowledge from multiple domains supporting the development of cross-disciplinary research tools that resolve research foci and associated differences in underlying theories, methods, and applied tools. This is closely related to the broader context of digital engineering for military systems engineering.


Asunto(s)
Medicina Militar , Humanos , Medicina Militar/métodos , Simulación por Computador/normas , Simulación por Computador/tendencias , Servicios de Salud Militares/estadística & datos numéricos , Servicios de Salud Militares/normas
2.
Mil Med ; 188(Suppl 6): 176-184, 2023 11 08.
Artículo en Inglés | MEDLINE | ID: mdl-37948248

RESUMEN

INTRODUCTION: Although existing auditory injury prevention standards benefit warfighters, the Department of Defense could do more to understand and address auditory injuries (e.g., hearing loss, tinnitus, and central processing deficits) among service members. The Blast Injury Prevention Standards Recommendation (BIPSR) Process is designed to address the needs of all the Military Services for biomedically valid Military Health System (MHS) Blast Injury Prevention Standards. MATERIALS AND METHODS: Through the BIPSR Process, stakeholders provided their intended uses and requested functionalities for an MHS Blast Injury Prevention Standard. The BIPSR Process established a broad-based, non-advocacy panel of auditory injury Subject Matter Expert (SME) Panel with members drawn from industry, academia, and government. The SME Panel selected evaluation factors, weighted priorities, and then evaluated the resulting candidate MHS Auditory Blast Injury Prevention Standards against the evaluation criteria. The SME Panel members provided rationales for their decisions, documented discussions, and used iterative rounds of feedback to promote consensus building among members. The BIPSR Process used multi-attribute utility theory to combine members' evaluations and compare the candidate standards. RESULTS: The SME Panel identified and collated information about existing auditory injury datasets to identify gaps and promote data sharing and comprehensive evaluations of standards for preventing auditory blast injury. The panel evaluated the candidate standards and developed recommendations for an MHS Blast Injury Prevention Standard. CONCLUSIONS: The BIPSR Process illuminated important characteristics, capabilities, and limitations of candidate standards and existing datasets (e.g., limited human exposure data to evaluate the validity of injury prediction) for auditory blast injury prevention. The evaluation resulted in the recommendation to use the 8-hour Equivalent Level (LAeq8hr) as the interim MHS Auditory Blast Injury Prevention Standard while the community performs additional research to fill critical knowledge gaps.


Asunto(s)
Traumatismos por Explosión , Pérdida Auditiva , Servicios de Salud Militares , Personal Militar , Acúfeno , Humanos , Traumatismos por Explosión/prevención & control , Explosiones , Acúfeno/prevención & control
3.
Mil Med ; 188(Suppl 6): 536-544, 2023 11 08.
Artículo en Inglés | MEDLINE | ID: mdl-37948275

RESUMEN

INTRODUCTION: Experiences by service members in recent conflicts and training environments illuminate concerns about the possible effects of blast overpressure (BOP) exposure on brain health. Section 734 of the National Defense Authorization Act for Fiscal Year (FY) 2018 (Public Law 115-91) requires that the Secretary of Defense conducts a longitudinal medical study on blast pressure exposure of members of the Armed Forces during combat and training, and the Assistant Secretary of Defense for Health Affairs was assigned responsibility for fulfilling requirements. The study's goal is to improve DoD's understanding of the impact of BOP exposure from weapon systems on service members' brain health and inform policy for risk mitigation, unit readiness, and health care decisions. This article focuses on the activities of the Weapon Systems Line of Inquiry (LOI) and the development of a prototype BOP Tool. MATERIALS AND METHODS: The DoD established the Section 734 Workgroup, which developed a program structure with five LOIs. The Weapon Systems LOI coordinated, collated, and analyzed information on BOP resulting from heavy weapons and blast events to inform strategies, and accounted for emerging research on health effects and performance. Ongoing research was leveraged to develop a BOP Tool as a standalone module and for integration into the Range Managers Toolkit. RESULTS: The effort identified opportunities for the DoD to improve the clarity of communications about BOP exposure, risk, and safety; establish methods to leverage emerging research; and develop a prototype BOP Tool to predict exposure loads when firing heavy weapons in training. CONCLUSIONS: It is recommended that the DoD revises requirements and policy to improve and standardize safety guidance throughout research, development, testing, and evaluation; acquisition; and training. The validated BOP Tool allows users to generate a scenario to predict BOP exposure and allows service members to modify them during planning for safer training.


Asunto(s)
Explosiones , Cuerpo Humano , Humanos , Encéfalo
4.
Indian J Gastroenterol ; 42(2): 279-285, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-37162701

RESUMEN

Pancytopenia in children with celiac disease (CeD) is postulated to be due to nutritional deficiency such as vitamin B12, folate and copper or an autoimmune process resulting in aplastic anemia with hypoplastic marrow. In the present case series, we report the profile and explore the etiology of pancytopenia among children with CeD. There are only a few case reports of pancytopenia in children with CeD. We enrolled newly diagnosed cases of CeD and pancytopenia presenting in the celiac disease clinic over three years. Detailed evaluation was carried out for the cause of pancytopenia. We followed up on the cases for compliance and response to gluten-free diet at three months, six months and 12 months. Twenty patients were eligible for inclusion. They were divided into two groups: one with aplastic anemia with hypoplastic marrow labeled as Gp CeD-AA and the other with megaloblastic/nutritional anemia labeled as Gp CeD-MA. Patients in Gp CeD-MA presented with classical symptoms of CeD as recurrent diarrhea, abdomen distension, pallor and poor weight gain. They had none or just one transfusion requirement and had an early and complete recovery from pancytopenia. Patients in Gp CeD-AA presented with atypical symptoms such as epistaxis, short stature, fever, pallor and weakness. They had a multiple blood transfusion requirement and had delayed and partial recovery from pancytopenia. Pancytopenia is not a disease in itself but is the presentation of an underlying disease. It can occur due to various coexisting disorders in children with CeD, which can be as simple as nutritional deficiencies to as complex as an autoimmune process or malignancy. CeD should be included in the differential diagnosis of aplastic anemia as CeD and aplastic anemia both have a similar pathological process involving T cell destruction of tissues.


Asunto(s)
Anemia Aplásica , Anemia Megaloblástica , Enfermedad Celíaca , Pancitopenia , Humanos , Niño , Pancitopenia/etiología , Pancitopenia/diagnóstico , Pancitopenia/patología , Anemia Aplásica/complicaciones , Anemia Aplásica/diagnóstico , Anemia Aplásica/patología , Enfermedad Celíaca/complicaciones , Enfermedad Celíaca/diagnóstico , Palidez/complicaciones , Anemia Megaloblástica/complicaciones
5.
Front Cell Neurosci ; 17: 1007062, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36814869

RESUMEN

Background: Blast induced Traumatic Brain Injury (bTBI) has become a signature casualty of military operations. Recently, military medics observed neurocognitive deficits in servicemen exposed to repeated low level blast (LLB) waves during military heavy weapons training. In spite of significant clinical and preclinical TBI research, current understanding of injury mechanisms and short- and long-term outcomes is limited. Mathematical models of bTBI biomechanics and mechanobiology of sensitive neuro-structures such as synapses may help in better understanding of injury mechanisms and in the development of improved diagnostics and neuroprotective strategies. Methods and results: In this work, we formulated a model of a single synaptic structure integrating the dynamics of the synaptic cell adhesion molecules (CAMs) with the deformation mechanics of the synaptic cleft. The model can resolve time scales ranging from milliseconds during the hyperacute phase of mechanical loading to minutes-hours acute/chronic phase of injury progression/repair. The model was used to simulate the synaptic injury responses caused by repeated blast loads. Conclusion: Our simulations demonstrated the importance of the number of exposures compared to the duration of recovery period between repeated loads on the synaptic injury responses. The paper recognizes current limitations of the model and identifies potential improvements.

6.
Pediatr Gastroenterol Hepatol Nutr ; 26(1): 50-57, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36816433

RESUMEN

Purpose: The purpose of this study was to determine the pattern of human leukocyte antigen (HLA)-DQ genotype in children diagnosed with celiac disease (CD) (biopsy proven), and to compare this with a control group; and secondarily, to correlate HLA genotypes with clinical profiles of CD. Methods: This cross-sectional comparative observational study included 26 controls and 52 patients diagnosed with CD who presented at Sir Padampat Mother and Child Health Institute, Jaipur, from May, 2017 to October, 2018. HLA DQ genotype was assessed for each patients and correlated with clinical profiles. Results: HLA DQ2/DQ8 genotypes were significantly more common in CD (present in 100.0% cases) than in controls (23.1%) in Northern India (Rajasthan). When HLA DQ2.5 and DQ8 were present together, individuals had significantly more atypical presentations and severe findings on duodenal biopsy. Similarly, patients with the HLA DQ 2.5 genotype were also predisposed to more severe endoscopic findings, while HLA DQ2.2 predisposed them to less severe biopsy findings. HLA DQ8 was significantly associated with later age at diagnosis (>5 years) and shorter stature. The highest HLA DQ relative risk (RR) for CD development was associated with HLA DQ2.5 and DQ2.2 in combination, followed by HLA DQ2.5 and DQ8 in combination, while HLA DQx.5 and HLA DQ2.2 together had the lowest risk. Conclusion: HLA DQ2/DQ8 genotypes are strongly associated with pediatric CD patients in northern India. These genotypes and their combinations may be associated with different clinical presentations of CD, and may help predict severity of CD.

7.
Appl Opt ; 62(5): 1399-1405, 2023 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-36821245

RESUMEN

B 4 C-coated thin film mirrors are used in high brilliance synchrotron and x-ray free electron laser beamlines due to their low absorption coefficient and high thermal stability. As in the case of gold, platinum, and other thin film mirrors, B 4 C-coated mirrors also are affected due to synchrotron radiation-induced carbon contaminations in beamlines. In the present study, a graphitic carbon (C) layer deposited on top of boron carbide (B x C) thin film surface is removed by five successive oxygen radio frequency (RF) plasma exposures (RF power, 10 W; O 2 flow, 30 sccm; exposure time, 10 min each). Before and after the carbon layer removal, structural and compositional properties of the B x C/C bilayer are characterized by soft x-ray reflectivity, x-ray photoelectron spectroscopy, grazing angle x-ray diffraction, and Raman spectroscopy techniques. Characterization results reveal that in the first four exposures the carbon layer thickness decreases continuously without affecting the B x C layer properties; however, in the fifth exposure, the carbon layer is completely removed along with a partial etching of the B x C layer too.

8.
ACS Omega ; 7(50): 46466-46474, 2022 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-36570223

RESUMEN

Nanocomposite zinc oxide nanorods capped with oleic acid (ZOR) with positive dielectric anisotropy liquid crystal (LC) 4'-octyl-4-biphenylcarbonitrile (8CB) filled in unaligned cells exhibit homeotropic alignment of host LC molecules. Further, systematic investigation of the textural, dielectric, and conductivity properties of nanocomposites filled in planar cells is performed with increasing concentration of nanorods. At a nanorod concentration ≤0.2 wt % in 8CB, the order parameter of nanocomposite samples is found to be increasing and ionic conductivity is found to be decreasing as compared to pure LC. Beyond 0.3 wt % concentration of nanorods in 8CB, vertical alignment (VA) of host LC is observed even in a planar aligned cell. The VA of LC molecules in ZOR nanocomposites is confirmed through attenuated total reflection-Fourier transform infrared absorption spectra studies.

9.
J Neurotrauma ; 39(21-22): 1533-1546, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35652331

RESUMEN

Blast-induced traumatic brain injury (bTBI) has been suggested to be caused by direct head exposure and by torso exposure to a shock wave (thoracic hypotheses). It is unclear, however, how torso exposure affects the brain in real time. This study applied a mild-impulse laser-induced shock wave(s) (LISW[s]) only to the brain (Group 1), lungs (Group 2), or to the brain and lungs (Group 3) in rats. Because LISWs are unaccompanied by a dynamic pressure in principle, the effects of acceleration can be excluded, allowing analysis of the pure primary mechanism (the effects of a shock wave). For all rat groups, real-time monitoring of the brain and systemic responses were conducted for up to 1 h post-exposure and motor function assessments for up to seven days post-exposure. As reported previously, brain exposure alone caused cortical spreading depolarization (CSD), followed by long-lasting hypoxemia and oligemia in the cortices (Group 1). It was found that even LISW application only to the lungs caused prolonged hypoxemia and mitochondrial dysfunction in the cortices (Group 2). Importantly, features of CSD and mitochondrial dysfunction were significantly exacerbated by combined exposure (Group 3) compared with those caused by brain exposure alone (Group 1). Motor dysfunction was observed in all exposure groups, but their time courses differed depending on the groups. Rats with brain exposure alone exhibited the most evident motor dysfunction at one day post-exposure, and after that, it did not change much for up to seven days post-exposure. Alternatively, two groups of rats with lung exposure (Group 2 and Group 3) exhibited continuously aggravated motor functions for up to seven days post-exposure, suggesting different mechanisms for motor dysfunction caused by brain exposure and that caused by lung exposure. As for the reported thoracic hypotheses, our observations seem to support the volumetric blood surge and vagovagal reflex. Overall, the results of this study indicate the importance of the torso guard to protect the brain and its function.


Asunto(s)
Traumatismos por Explosión , Animales , Ratas , Traumatismos por Explosión/complicaciones , Encéfalo , Rayos Láser , Pulmón , Hipoxia/complicaciones
10.
JMIR Infodemiology ; 2(1): e31473, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-37113803

RESUMEN

Background: Public sentiments are an important indicator of crisis response, with the need to balance exigency without adding to panic or projecting overconfidence. Given the rapid spread of the COVID-19 pandemic, governments have enacted various nationwide measures against the disease with social media platforms providing the previously unparalleled communication space for the global populations. Objective: This research aims to examine and provide a macro-level narrative of the evolution of public sentiments on social media at national levels, by comparing Twitter data from India, Singapore, South Korea, the United Kingdom, and the United States during the current pandemic. Methods: A total of 67,363,091 Twitter posts on COVID-19 from January 28, 2020, to April 28, 2021, were analyzed from the 5 countries with "wuhan," "corona," "nCov," and "covid" as search keywords. Change in sentiments ("very negative," "negative," "neutral or mixed," "positive," "very positive") were compared between countries in connection with disease milestones and public health directives. Results: Country-specific assessments show that negative sentiments were predominant across all 5 countries during the initial period of the global pandemic. However, positive sentiments encompassing hope, resilience, and support arose at differing intensities across the 5 countries, particularly in Asian countries. In the next stage of the pandemic, India, Singapore, and South Korea faced escalating waves of COVID-19 cases, resulting in negative sentiments, but positive sentiments appeared simultaneously. In contrast, although negative sentiments in the United Kingdom and the United States increased substantially after the declaration of a national public emergency, strong parallel positive sentiments were slow to surface. Conclusions: Our findings on sentiments across countries facing similar outbreak concerns suggest potential associations between government response actions both in terms of policy and communications, and public sentiment trends. Overall, a more concerted approach to government crisis communication appears to be associated with more stable and less volatile public sentiments over the evolution of the COVID-19 pandemic.

11.
Front Bioeng Biotechnol ; 9: 654677, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34277581

RESUMEN

According to the US Defense and Veterans Brain Injury Center (DVBIC) and Centers for Disease Control and Prevention (CDC), mild traumatic brain injury (mTBI) is a common form of head injury. Medical imaging data provides clinical insight into tissue damage/injury and injury severity, and helps medical diagnosis. Computational modeling and simulation can predict the biomechanical characteristics of such injury, and are useful for development of protective equipment. Integration of techniques from computational biomechanics with medical data assessment modalities (e.g., magnetic resonance imaging or MRI) has not yet been used to predict injury, support early medical diagnosis, or assess effectiveness of personal protective equipment. This paper presents a methodology to map computational simulations with clinical data for interpreting blunt impact TBI utilizing two clinically different head injury case studies. MRI modalities, such as T1, T2, diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC), were used for simulation comparisons. The two clinical cases have been reconstructed using finite element analysis to predict head biomechanics based on medical reports documented by a clinician. The findings are mapped to simulation results using image-based clinical analyses of head impact injuries, and modalities that could capture simulation results have been identified. In case 1, the MRI results showed lesions in the brain with skull indentation, while case 2 had lesions in both coup and contrecoup sides with no skull deformation. Simulation data analyses show that different biomechanical measures and thresholds are needed to explain different blunt impact injury modalities; specifically, strain rate threshold corresponds well with brain injury with skull indentation, while minimum pressure threshold corresponds well with coup-contrecoup injury; and DWI has been found to be the most appropriate modality for MRI data interpretation. As the findings from these two cases are substantiated with additional clinical studies, this methodology can be broadly applied as a tool to support injury assessment in head trauma events and to improve countermeasures (e.g., diagnostics and protective equipment design) to mitigate these injuries.

12.
Clin Cosmet Investig Dent ; 13: 77-81, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33762852

RESUMEN

BACKGROUND: Palatal rugae are asymmetric and irregular ridges on the anterior palatal region, which have proven to be useful in the field of forensic dentistry. This study aims to use morphological analysis of palatal rugae patterns to assess sex in a South Indian adult population. MATERIALS AND METHODS: This cross-sectional study was undertaken to evaluate a total of 300 maxillary dental casts (150 males and 150 females). The rugae patterns were marked by one observer and classified as per Thomas and Kotze criteria by another observer. The rugae patterns were classified based on the total number of rugae, shape, predominant direction of rugae, and unification of rugae. RESULTS: The palatal rugae in female participants showed a higher incidence of circular rugae and backward directed rugae, while male participants showed more forward-directed rugae. The logistic regression analysis showed a significant association of with circular (OR=1.48; 95% CI= 1.02-2.13), forward (OR=0.87; 95% CI= 0.78-0.97) and backward (OR=1.23; 95% CI= 1.08-1.41) palatal rugae with sex. CONCLUSION: Certain palatal rugae patterns can be used for the assessment of sex with limited accuracy.

13.
Mil Med ; 186(Suppl 1): 529-536, 2021 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-33499497

RESUMEN

INTRODUCTION: During training and combat operations, military personnel may be exposed to repetitive low-level blast while using explosives to gain entry or by firing heavy weapon systems such as recoilless weapons and high-caliber sniper rifles. This repeated exposure, even within allowable limits, has been associated with cognitive deficits similar to that of accidental and sports concussion such as delayed verbal memory, visual-spatial memory, and executive function. This article presents a novel framework for accurate calculation of the human body blast exposure in military heavy weapon training scenarios using data from the free-field and warfighter wearable pressure sensors. MATERIALS AND METHODS: The CoBi human body model generator tools were used to reconstruct multiple training scenes with different weapon systems. The CoBi Blast tools were used to develop the weapon signature and estimate blast overpressure exposure. The authors have used data from the free-field and wearable pressure sensors to evaluate the framework. RESULTS: Carl-Gustav and 0.50 caliber sniper training scenarios were used to demonstrate and validate the developed framework. These simulations can calculate spatially and temporally resolved blast loads on the whole human body and on specific organs vulnerable to blast loads, such as head, face, and lungs. CONCLUSIONS: This framework has numerous advantages including easier model setup and shorter simulation times. The framework is an important step towards developing an advanced field-applicable technology to monitor low-level blast exposure during heavy weapon military training and combat scenarios.


Asunto(s)
Traumatismos por Explosión , Personal Militar , Carrera , Conmoción Encefálica , Explosiones , Humanos
14.
Indian Pediatr ; 58(2): 123-125, 2021 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-33257599

RESUMEN

OBJECTIVE: To study the clinical and laboratory profile and to assess period for viral clearance in COVID 19 children. METHODS: We reviewed hospital records of children (<18 years) admitted from 1 April to 31 May, 2020 at a tertiary-care public hospital and identified those positive for severe acute respiratory syndrome corona virus (SARS-CoV-2) by RT-PCR of respiratory secretions. RESULTS: 81.2% of the 85 children studied were asymptomatic and 3 (8.5%) died. Severe lymphopenia (43.8%), raised C-reactive protein (93.8%), raised erythrocyte sedimentation rate (75%) and high (>500ng/mL) levels of D-dimer (37.5%) were common. Median (IQR) duration of viral shedding was 7 (5-10) days, with range of 2 to 45 days; 96.3% had viral clearance within 14 days. CONCLUSIONS: Majority of children aged <18 years with SARS-CoV-2 infection had viral clearance within 14 days.


Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Antivirales/sangre , Sedimentación Sanguínea , Proteína C-Reactiva/análisis , COVID-19/sangre , COVID-19/epidemiología , COVID-19/fisiopatología , COVID-19/terapia , Prueba de COVID-19/métodos , Prueba de COVID-19/estadística & datos numéricos , Niño , Femenino , Productos de Degradación de Fibrina-Fibrinógeno/análisis , Hospitalización/estadística & datos numéricos , Humanos , India/epidemiología , Recuento de Linfocitos/métodos , Masculino , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/fisiología , Esparcimiento de Virus
15.
J Phys Chem Lett ; 11(23): 10278-10282, 2020 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-33216558

RESUMEN

Confinement has profound effects on protein functions. Nanoscale probes for confinement or excluded volume interactions could help us understand how these interactions influence protein functions. This work reports on the increased luminescence of BSA-gold nanoclusters when confined. Confinement of the BSA-gold nanoclusters occurred within reverse micelles (RMs), where the size of the RMs determined the degree of confinement. The confinement-enhanced luminescence is reversible, i.e., the emission returns to its original value following cyclic changes in RM size. Circular dichroism measurements show an increase in alpha-helical character of the BSA-stabilized nanoclusters with confinement, which could provide a mechanism for the increase in luminescence. The alpha-helical character of the native proteins also increases with confinement, suggesting that the protein-nanocluster might sense confinement in an analogous fashion as the proteins. When the RMs approach the size of the protein, the intensity becomes independent of alpha-helical character, suggesting a different mechanism for the luminescence increase.


Asunto(s)
Oro/química , Luminiscencia , Nanopartículas del Metal/química , Albúmina Sérica Bovina/química , Animales , Bovinos
16.
J Synchrotron Radiat ; 27(Pt 6): 1633-1639, 2020 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-33147189

RESUMEN

Transition elements exhibit strong correlations and configuration interactions between core and valence excited states, which give rise to different excitations inside materials. Nickel exhibits satellite features in its emission and absorption spectra. Effects of such transitions on the optical constants of nickel have not been reported earlier and the available database of Henke et al. does not represent such fine features. In this study, the optical behaviour of ion beam sputter deposited Ni thin film near the L2,3-edge region is investigated using reflection spectroscopy techniques, and distinct signatures of various transitions are observed. The soft X-ray reflectivity measurements in the 500-1500 eV photon energy region are performed using the soft X-ray reflectivity beamline at the Indus-2 synchrotron radiation source. Kramers-Kronig analysis of the measured reflectivity data exhibit features corresponding to spin orbital splitting and satellite transitions in the real and imaginary part of the refractive index (refraction and absorption spectra). Details of fine features observed in the optical spectra are discussed. To the best of our knowledge, this is the first study reporting fine features in the measured optical spectra of Ni near its L2,3-edge region.

17.
ACS Omega ; 5(33): 20983-20990, 2020 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-32875234

RESUMEN

The ability for cells to self-synthesize metal-core nanoclusters (mcNCs) offers increased imaging and identification opportunities. To date, much work has been done illustrating the ability for human tumorigenic cell lines to synthesize mcNCs; however, this has not been illustrated for nontumorigenic cell lines. Here, we present the ability for human nontumorigenic microglial cells, which are the major immune cells in the central nervous system, to self-synthesize gold (Au) and iron (Fe) core nanoclusters, following exposures to metallic salts. We also show the ability for cells to internalize presynthesized Au and Fe mcNCs. Cellular fluorescence increased in most exposures and in a dose dependent manner in the case of Au salt. Scanning transmission electron microscopic imaging confirmed the presence of the metal within cells, while transmission electron microscopy images confirmed nanocluster structures and self-synthesis. Interestingly, self-synthesized nanoclusters were of similar size and internal structure as presynthesized mcNCs. Toxicity assessment of both salts and presynthesized NCs illustrated a lack of toxicity from Au salt and presynthesized NCs. However, Fe salt was generally more toxic and stressful to cells at similar concentrations.

18.
JMIR Public Health Surveill ; 6(2): e19447, 2020 05 22.
Artículo en Inglés | MEDLINE | ID: mdl-32412418

RESUMEN

BACKGROUND: With the World Health Organization's pandemic declaration and government-initiated actions against coronavirus disease (COVID-19), sentiments surrounding COVID-19 have evolved rapidly. OBJECTIVE: This study aimed to examine worldwide trends of four emotions-fear, anger, sadness, and joy-and the narratives underlying those emotions during the COVID-19 pandemic. METHODS: Over 20 million social media twitter posts made during the early phases of the COVID-19 outbreak from January 28 to April 9, 2020, were collected using "wuhan," "corona," "nCov," and "covid" as search keywords. RESULTS: Public emotions shifted strongly from fear to anger over the course of the pandemic, while sadness and joy also surfaced. Findings from word clouds suggest that fears around shortages of COVID-19 tests and medical supplies became increasingly widespread discussion points. Anger shifted from xenophobia at the beginning of the pandemic to discourse around the stay-at-home notices. Sadness was highlighted by the topics of losing friends and family members, while topics related to joy included words of gratitude and good health. CONCLUSIONS: Overall, global COVID-19 sentiments have shown rapid evolutions within just the span of a few weeks. Findings suggest that emotion-driven collective issues around shared public distress experiences of the COVID-19 pandemic are developing and include large-scale social isolation and the loss of human lives. The steady rise of societal concerns indicated by negative emotions needs to be monitored and controlled by complementing regular crisis communication with strategic public health communication that aims to balance public psychological wellbeing.


Asunto(s)
Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/psicología , Internacionalidad , Pandemias , Neumonía Viral/epidemiología , Neumonía Viral/psicología , Medios de Comunicación Sociales/tendencias , COVID-19 , Emociones , Humanos
19.
Metabolomics ; 16(3): 39, 2020 03 12.
Artículo en Inglés | MEDLINE | ID: mdl-32166461

RESUMEN

INTRODUCTION: Blast-induced neurotrauma (BINT) has been recognized as the common mode of traumatic brain injury amongst military and civilian personnel due to an increased insurgent activity domestically and abroad. Previous studies from this laboratory have identified three major pathological events following BINT which include blood brain barrier disruption the earliest event, followed by oxidative stress and neuroinflammation as secondary events occurring a few hours following blast. OBJECTIVES: Our recent studies have also identified an increase in oxidative stress mediated by the activation of superoxide producing enzyme NADPH oxidase (NOX) in different brain regions at varying levels with neurons displaying higher oxidative stress (NOX activation) compared to any other neural cell. Since neurons have higher energy demands in brain and are more prone to oxidative damage, this study evaluated the effect of oxidative stress on blast-blast induced changes in metabolomics profiles in different brain regions. METHODS: Animals were exposed to mild/moderate blast injury (180 kPa) and examined the metabolites of energy metabolism, amino acid metabolism as well as the profiles of plasma membrane metabolites in different brain regions at different time points (24 h, 3 day and 7 day) after blast using 1H NMR spectroscopy. Effect of apocynin, an inhibitor of superoxide producing enzyme NADPH oxidase on cerebral metabalomics profiles was also examined. RESULTS: Several metabolomic profile changes were observed in frontal cortex and hippocampus with concomitant decrease in energy metabolism. In addition, glutamate/glutamine and other amino acid metabolism as well as metabolites involved in plasma membrane integrity were also altered. Hippocampus appears metabolically more vulnerable than the frontal cortex. A post-treatment of animals with apocynin, an inhibitor of NOX activation significantly prevented the changes in metabolite profiles. CONCLUSION: Together these studies indicate that blast injury reduces both cerebral energy and neurotransmitter amino acid metabolism and that oxidative stress contributes to these processes. Thus, strategies aimed at reducing oxidative stress can have a therapeutic benefit in mitigating metabolic changes following BINT.


Asunto(s)
Traumatismos por Explosión/metabolismo , Lesiones Traumáticas del Encéfalo/metabolismo , Modelos Animales de Enfermedad , Estrés Oxidativo , Acetofenonas , Animales , Traumatismos por Explosión/patología , Lesiones Traumáticas del Encéfalo/inducido químicamente , Lesiones Traumáticas del Encéfalo/patología , Masculino , Metabolómica , Ratas , Ratas Sprague-Dawley
20.
J Synchrotron Radiat ; 26(Pt 4): 1152-1160, 2019 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-31274439

RESUMEN

Deposition of synchrotron-radiation-induced carbon contamination on beamline optics causes their performance to deteriorate, especially near the carbon K edge. The photon flux losses due to carbon contamination have spurred researchers to search for a suitable decontamination technique to restore the optical surface and retain its performance. Several in situ and ex situ refurbishing strategies for beamline optics are still under development to solve this serious issue. In this work, the carbon contamination is removed from a large (340 mm × 60 mm) Au-coated toroidal mirror surface using a capacitively coupled low-pressure RF plasma. Before and after RF plasma cleaning, the mirror was characterized by Raman spectroscopy, soft X-ray reflectivity (SXR) and atomic force microscopy (AFM) techniques. The Raman spectra of the contaminated mirror clearly show the G (1575-1590 cm-1) and D (1362-1380 cm-1) bands of graphitic carbon. The SXR curve of the contaminated mirror shows a clear dip near the critical momentum transfer of carbon, indicating the presence of carbon contamination on the mirror surface. This dip disappears after removal of the contamination layer by RF plasma exposure. A decrease in the intensities of the CO bands is also observed by optical emission spectrometry during plasma exposure. The AFM and SXR results suggest that the root-mean-square (r.m.s.) roughness of the mirror surface does not increase after plasma exposure.


Asunto(s)
Oro/química , Gases em Plasma , Ondas de Radio , Microscopía de Fuerza Atómica , Óptica y Fotónica , Espectrometría Raman/métodos , Sincrotrones
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