Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Nat Commun ; 14(1): 2107, 2023 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-37055427

RESUMO

Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km s-1 and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona.

3.
Indian J Clin Biochem ; 37(4): 449-457, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36262786

RESUMO

Rule-out of acute myocardial infarction (AMI) in patients presenting with acute chest pain at the emergency department (ED) is a major challenge across the globe. Patients presenting very early with chest pain may provide a diagnostic challenge even when using a cardiac necrosis specific biomarker, high sensitivity troponin (hs-Tn) as they are elevated at 3-6 h after the symptom onset. Copeptin is a marker of acute hemodynamic stress which is released within few minutes of the occurrence of MI and is elevated immediately at the presentation of patients with AMI. This indicates a complementary pathophysiology and kinetics of these two biomarkers. Hence, we evaluated whether or not a protocol with combined testing of copeptin and hs-TnI at admission in patients presenting with chest pain within 6 h in low to intermediate risk and suspected ACS leads to an earlier diagnosis of AMI and thereby, aids to prevent a higher proportion of major adverse cardiac events than the current standard protocol followed in ED. A total of 148 patients as per the inclusion criterion were recruited for the study. The dual biomarker copeptin and hs-TnI allows a rule-out of AMI at presentation with a sensitivity of 100% and NPV of 99.8%. Hence, the use of dual biomarker in conjunction with clinical assessment may obviate the need for a prolonged stay in the ED and retesting hs-TnI after 2 h (for delta check) in more than two-thirds of the patients. The inclusion of these tests could have an impact on the economic burden of the ED without jeopardizing the outcome for the patient.

4.
Lett Appl Microbiol ; 74(4): 519-535, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34919753

RESUMO

Plant growth-promoting bacteria (PGPB) expressing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity are widely acknowledged to have a role in mitigation of abiotic stress caused by extreme environmental conditions. Consequently, several studies have focused on the isolation of ACC deaminase positive PGPBs. However, the application of such strains in drought-prone arid regions has remained grossly under-exploited. In order to be used in arid agroecosystems, PGPBs need to have the dual capability: to express ACC deaminase and to have the ability to tolerate increased temperature and salt concentration. Conspicuously, to date, very few studies have reported about isolation and characterization of PGPBs with this kind of dual capability. Here we report the isolation of bacterial strains from rhizosphere(s) of Cyamopsis tetragonoloba, a commercial crop from arid regions of Rajasthan, India, and their characterization for ACC deaminase activity and thermohalotolerance. Isolates found positive for desired traits were subsequently assessed for plant growth promotion under simulated drought conditions. Our finding showed that although the bacterial diversity within the rhizosphere of C. tetragonoloba grown in the arid region is quite poor, multiple isolates are ACC deaminase positive. Four isolates were found to be ACC deaminase positive, thermohalotolerant, and successfully enhanced drought tolerance. These isolates were identified as strains belonging to genera Pseudomonas, Enterobacter, and Stenotrophomonas based on 16S rRNA sequence homology.


Assuntos
Cyamopsis , Rizosfera , Carbono-Carbono Liases/genética , Cyamopsis/genética , Secas , Enterobacter/genética , Índia , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genética , Microbiologia do Solo
5.
3 Biotech ; 11(9): 395, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34422536

RESUMO

Amaranth (Amaranthus spp.) belonging to Amaranthaceae, is known as "the crop of the future" because of its incredible nutritional quality. Amaranthus spp. (> 70) have a huge diversity in terms of their plant morphology, production and nutritional quality; however, these species are not well characterized at molecular level due to unavailability of robust and reproducible molecular markers, which is essential for crop improvement programs. In the present study, 13,051 genome-wide microsatellite motifs were identified and subsequently utilized for marker development using A. hypochondriacus (L.) genome (JPXE01.1). Out of those, 1538 motifs were found with flanking sequences suitable for primer designing. Among designed primers, 225 were utilized for validation of which 119 (52.89%) primers were amplified. Cross-species transferability and evolutionary relatedness among ten species of Amaranthus (A. hypochondriacus, A. caudatus, A. retroflexus, A. cruentus, A. tricolor, A. lividus, A. hybridus, A. viridis, A. edulis, and A. dubius) were also studied using 45 microsatellite motifs. The maximum (86.67%) and minimum (28.89%) cross-species transferability were observed in A. caudatus and A. dubius, respectively, that indicated high variability present across the Amaranthus spp. Total 97 alleles were detected among 10 species of Amaranthus. The averages of major allele frequency, gene diversity, heterozygosity and PIC were 0.733, 0.347, 0.06, and 0.291, respectively. Nei's genetic dissimilarity coefficients ranged from 0.0625 (between A. tricolor and A. hybridus) to 0.7918 (between A. viridis and A. lividus). The phylogenetic tree grouped ten species into three major clusters. Genome-wide development of microsatellite markers and their transferability revealed relationships among amaranth species which ultimately can be useful for species identification, DNA fingerprinting, and QTLs/gene(s) identification. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02930-5.

6.
Br J Neurosurg ; 31(4): 497-498, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26761183

RESUMO

Malignant transformation of intracranial epidermoid cysts to squamous cell carcinoma is a rare occurrence and only a small number have been reported to date. MRI recurrence in combination with neurological decline should prompt surgery to exclude malignant transformation. Herein, we describe our experience of such a case and contribute to the evolving series within the literature.


Assuntos
Carcinoma de Células Escamosas/patologia , Doenças Cerebelares/patologia , Ângulo Cerebelopontino/patologia , Cisto Epidérmico/patologia , Transformação Celular Neoplásica/patologia , Fossa Craniana Posterior , Cisto Epidérmico/cirurgia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Neuralgia do Trigêmeo/etiologia
7.
Saudi J Anaesth ; 10(3): 347-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27375396

RESUMO

Osteoid osteoma (OO) is a benign bone tumor, with a male-female ratio of approximately 2:1 and mainly affecting long bones. Ten percent of the lesions occur in the spine, mostly within the posterior elements. Treatment options for OO include surgical excision and percutaneous imaging-guided radiofrequency ablation (RFA). Lesions within the spine have an inherent risk of thermal damage to the vital structure because of proximity to the neural elements. We report a novel use of the epidural catheter for air injection for the neuroprotection of nerves close to the OO of the spine. A 12-year-old and 30 kg male child with an OO of the L3 vertebra was taken up for RFA. His preoperative examinations were within normal limits. The OO was very close to the L3 nerve root. Under general anesthesia, lumbar epidural catheter was placed in the L3-L4 space under imaging guidance. Ten ml of aliquots of air was injected under imaging guidance to avoid injury to the neural structures due to RFA. The air created a gap between neural elements and the tumor and served as an insulating material thereby protecting the neural elements from damage due to the RFA. Postoperatively, the patient did not develop any neurological deficit.

8.
Sci Rep ; 6: 20235, 2016 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-26819064

RESUMO

Here we present the first direct comparison of cosmogenic (10)Be and chemical species in the period of 38-45.5 kyr BP spanning the Laschamp geomagnetic excursion from the EPICA-Dome C ice core. A principal component analysis (PCA) allowed to group different components as a function of the main sources, transport and deposition processes affecting the atmospheric aerosol at Dome C. Moreover, a wavelet analysis highlighted the high coherence and in-phase relationship between (10)Be and nitrate at this time. The evident preferential association of (10)Be with nitrate rather than with other chemical species was ascribed to the presence of a distinct source, here labelled as "cosmogenic". Both the PCA and wavelet analyses ruled out a significant role of calcium in driving the (10)Be and nitrate relationship, which is particularly relevant for a plateau site such as Dome C, especially in the glacial period during which the Laschamp excursion took place. The evidence that the nitrate record from the EDC ice core is able to capture the Laschamp event hints toward the possibility of using this marker for studying galactic cosmic ray flux variations and thus also major geomagnetic field excursions at pluri-centennial-millennial time scales, thus opening up new perspectives in paleoclimatic studies.

9.
Br J Neurosurg ; 30(4): 464-6, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26742681

RESUMO

The use of expensive, sophisticated, intraoperative ultrasound systems is established in cranial neurosurgery and less so in the realms of intradural spine. For units yet to acquire such costly devices, we demonstrate our experience of the readily available, anaesthetist's SonoSite™ probe in intradural spinal surgery.


Assuntos
Neurocirurgia , Procedimentos Neurocirúrgicos/instrumentação , Neoplasias da Medula Espinal/cirurgia , Coluna Vertebral/cirurgia , Anestesia , Humanos , Microcirurgia/instrumentação , Ultrassonografia/instrumentação
11.
Anaesth Intensive Care ; 41(1): 51-6, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23362890

RESUMO

This randomised, double-blind study was designed to compare the duration of analgesia and adverse effects following intrathecal administration of dexmedetomidine or clonidine, both with bupivacaine, in trauma patients. Ninety adult trauma patients of American Society of Anesthesiologists physical status I-II, scheduled for lower limb surgery under subarachnoid block, were randomly allocated to one of three groups. All groups received hyperbaric bupivacaine 0.5% 3 ml, to which was added saline 0.5 ml (Group B): clonidine 50 µg (Group C) or dexmedetomidine 5 µg (Group D). The onset and duration of sensory and motor blockade, severity of postoperative pain, time to first rescue analgesia and total analgesic requirement for 24 hours were noted. There was no significant difference in the onset time of the block but the duration of sensory and motor blockade was prolonged in Groups C and D, compared with Group B. The time to analgesia was significantly prolonged in Group D (824±244 minutes) compared with Group C (678±178 minutes; P=0.01), the latter being longer than Group B (406±119 minutes; P=0.0001). Postoperative pain scores were lower in Groups C and D compared with group b. The requirement for rescue analgesia during the first 24 postoperative hours was significantly less in Groups C and D as compared to Group B (P=0.0001), but comparable between Groups C and D (P=0.203). In conclusion, dexmedetomidine 5 µg added to intrathecal bupivacaine 15 mg produces longer postoperative analgesia than clonidine 50 µg among trauma patients undergoing lower limb surgery.


Assuntos
Bupivacaína/farmacologia , Clonidina/farmacologia , Dexmedetomidina/farmacologia , Dor Pós-Operatória/prevenção & controle , Adolescente , Adulto , Idoso , Analgésicos/administração & dosagem , Analgésicos/farmacologia , Analgésicos não Narcóticos/administração & dosagem , Analgésicos não Narcóticos/farmacologia , Anestésicos Locais/administração & dosagem , Anestésicos Locais/farmacologia , Bupivacaína/administração & dosagem , Clonidina/administração & dosagem , Dexmedetomidina/administração & dosagem , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Injeções Espinhais , Extremidade Inferior/lesões , Extremidade Inferior/cirurgia , Masculino , Pessoa de Meia-Idade , Bloqueio Nervoso/métodos , Índice de Gravidade de Doença , Fatores de Tempo , Ferimentos e Lesões/cirurgia , Adulto Jovem
12.
J Food Sci Technol ; 50(2): 257-65, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24425915

RESUMO

A simple analytical heat flow model for a closed rectangular food package containing fruits or vegetables is proposed for predicting time temperature distribution during transient cooling in a controlled environment cold room. It is based on the assumption of only conductive heat transfer inside a closed food package with effective thermal properties, and convective and radiative heat transfer at the outside of the package. The effective thermal conductivity of the food package is determined by evaluating its effective thermal resistance to heat conduction in the packages. Food packages both as an infinite slab and a finite slab have been investigated. The finite slab solution has been obtained as the product of three infinite slab solutions describe in ASHRAE guide and data book. Time temperature variation has been determined and is presented graphically. The cooling rate and the half cooling time were also obtained. These predicted values, are compared with the experimentally measured values for both the finite and infinite closed packages containing oranges. An excellent agreement between them validated the simple proposed model.

13.
Iran J Parasitol ; 7(2): 61-6, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23109947

RESUMO

BACKGROUND: The present study deals with the effect of helminthic infection as Nematode parasite like Aspiculuris tetraptera on the haematological parameters of infected and vaccinated mice. METHODS: Totally 15 mice were used. Five mice were used for positive control, 5 mice used for negative control and 5 mice used for experiment. The hematological parameters were studied viz. RBC, Hb, and serum protein values. RESULTS: The mice carrying heavy infection showed decrease in the Hb, RBC, and serum protein but in the vaccinated mice, all studied parameters were become on normal range. The level of immune response was assessed based on above studied hematological parameters in infected and vaccinated mice with Aspiculuris tetraptera. CONCLUSION: The increased value of RBC, Hb and Serum protein in infected and vaccinated mice compared to infected and non vaccinated suggested the involvement of blood parameters in immune response. This study also proves that somatic antigen of A. tetraptera was effective in imparting immunity in mice.

14.
J Pharm Bioallied Sci ; 4(Suppl 1): S74-6, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23066214

RESUMO

Spray formulation can minimize pain and irritation experience during the application of conventional dosage forms. Econazole Nitrate is an active ingredient of the aerosol concentrate to be used for twice-daily application because of its long durability in the superficial layers of the fungal infected skin. The aim of this study is preliminary investigation of Econazole Nitrate spray by varying the concentrations of different constituents of the spray. The ratios of Propylene glycol (PG) and isopropyl myristate (IPM) were selected as independent variables in 2(2) full factorial designs, keeping the concentration of solvent, co-solvent and propellant LPG constant. Aerosol also contained Ethanol as solvent and Isopropyl alcohol as co-solvent. All ingredients of the aerosol were packaged in an aluminum container fitted with continuous-spray valves. Physical properties evaluated for the Econazole Nitrate spray included delivery rate, delivery amount, pressure, minimum fill, leakage, flammability, spray patterns, particle image and plume angle. Glass containers were used to study incompatibility between concentrate and propellant due to the ease of visible inspection. Isopropyl myristate at lower concentrate showed turbidity, while at high concentration it met the requirements for aerosol and produced Econazole Nitrate spray with expected characteristics.

15.
Nature ; 431(7012): 1084-7, 2004 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-15510145

RESUMO

Direct observations of sunspot numbers are available for the past four centuries, but longer time series are required, for example, for the identification of a possible solar influence on climate and for testing models of the solar dynamo. Here we report a reconstruction of the sunspot number covering the past 11,400 years, based on dendrochronologically dated radiocarbon concentrations. We combine physics-based models for each of the processes connecting the radiocarbon concentration with sunspot number. According to our reconstruction, the level of solar activity during the past 70 years is exceptional, and the previous period of equally high activity occurred more than 8,000 years ago. We find that during the past 11,400 years the Sun spent only of the order of 10% of the time at a similarly high level of magnetic activity and almost all of the earlier high-activity periods were shorter than the present episode. Although the rarity of the current episode of high average sunspot numbers may indicate that the Sun has contributed to the unusual climate change during the twentieth century, we point out that solar variability is unlikely to have been the dominant cause of the strong warming during the past three decades.


Assuntos
Atividade Solar , Atmosfera/química , Radioisótopos de Carbono/análise , Efeito Estufa , Gelo , Magnetismo , Luz Solar , Fatores de Tempo , Árvores/química , Árvores/crescimento & desenvolvimento
16.
Nature ; 425(6959): 692-5, 2003 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-14562096

RESUMO

Flares and X-ray jets on the Sun arise in active regions where magnetic flux emerges from the solar interior amd interacts with the ambient magnetic field. The interactions are believed to occur in electric current sheets separating regions of opposite magnetic polarity. The current sheets located in the corona or upper chromosphere have long been thought to act as an important source of coronal heating, requiring their location in the corona or upper chromosphere. The dynamics and energetics of these sheets are governed by a complex magnetic field structure that, until now, has been difficult to measure. Here we report the determination of the full magnetic vector in an interaction region near the base of the solar corona. The observations reveal two magnetic features that characterize young active regions on the Sun: a set of rising magnetic loops and a tangential discontinuity of the magnetic field direction, the latter being the observational signature of an electric current sheet. This provides strong support for coronal heating models based on the dissipation of magnetic energy at current sheets.

18.
Appl Opt ; 40(34): 6292-300, 2001 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-18364935

RESUMO

Results of an intercalibration between the extreme-ultraviolet spectrometers Coronal Diagnostic Spectrometer (CDS) and Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on board the Solar and Heliospheric Observatory (SOHO) are reported. The results of the joint observing program Intercal_01 are described, and intercalibration results up to July 2000 of both SUMER detectors A and B and of the CDS Normal Incidence Spectrometer (NIS) are presented. The instruments simultaneously observed radiance of emission lines at the center of the Sun, and three lines have been chosen for intercomparison: He i 584 A, Mg x 609 A, and Mg x 624 A. Initially the same area was observed by both instruments, but, after restrictions were imposed by the scanning mechanism of SUMER in November 1996, the instruments viewed areas of different sizes. Nevertheless, the temporal correlation between the two instruments remained good through June 1998, when contact with the SOHO spacecraft was lost. Until then the CDS instrument measured (33 ? 5)% and (38 ? 7)% (?1varsigma) higher intensity than SUMER in the He i 584-A line on average for detectors A and B, respectively. Data from SUMER detector B agreed well for Mg x 609 A and Mg x 624 A with the CDS intensities, showing offsets of (2 ? 10)% and (9 ? 15)%, much less than the data of detector A with offsets of (7 ? 8)% and (16 ? 7)% for the two lines, respectively, relative to CDS. Finally, the intercalibration measurements after the loss and recovery of the SOHO spacecraft are analyzed. The data for observations from November 1998 to July 2000 are compared, and it is shown that, although the responses of the instruments have changed, the CDS and the SUMER still perform well, and their temporal correlation is good.

19.
Nature ; 408(6811): 445-7, 2000 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-11100720

RESUMO

The most striking feature of the Sun's magnetic field is its cyclic behaviour. The number of sunspots, which are dark regions of strong magnetic field on the Sun's surface, varies with a period of about 11 years. Superposed on this cycle are secular changes that occur on timescales of centuries and events like the Maunder minimum in the second half of the seventeenth century, when there were very few sunspots. A part of the Sun's magnetic field reaches out from the surface into interplanetary space, and it was recently discovered that the average strength of this interplanetary field has doubled in the past 100 years. There has hitherto been no clear explanation for this doubling. Here we present a model describing the long-term evolution of the Sun's large-scale magnetic field, which reproduces the doubling of the interplanetary field. The model indicates that there is a direct connection between the length of the sunspot cycle and the secular variations.

20.
Appl Opt ; 38(34): 7035-46, 1999 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-18324248

RESUMO

The results of an intercalibration between the extreme ultraviolet spectrometers Coronal Diagnostic Spectrometer (CDS) and Solar Ultraviolet Measurements of Emitted Radiation (SUMER) onboard the Solar and Heliospheric Observatory (SOHO) are presented. During the joint observing program Intercal_01, CDS and SUMER were pointed at the same locations in quiet Sun areas and observed in the same wavelength bands located around the spectral lines He i 584 A, Mg x 609 A, and Mg x 624 A. The data sets analyzed here consist of raster images recorded by the CDS normal-incidence spectrometer and SUMER detector A and span the time from March 1996 to August 1996. Effects of the different spatial and spectral resolutions of both instruments have been investigated and taken into account in the analysis. We find that CDS measures generally a 30% higher intensity than SUMER in the He i 584-A line, while it measures 9% and 17% higher intensities in Mg x 609 A and Mg x 624 A, respectively. Both instruments show very good temporal correlation and stability, indicating that solar variations dominate over changes in instrumental sensitivity. Our analysis also provides in-flight estimates of the CDS spatial point-spread functions.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...