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2.
J Parasitol ; 104(1): 31-38, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29119858

RESUMO

A novel coccidian species was discovered in the prostate of an Antechinus flavipes (yellow-footed antechinus) in South Australia during the period of postmating male antechinus immunosuppression and mortality. This novel coccidian is unusual because it develops extraintestinally and sporulates endogenously within the prostate gland of its mammalian host. Histological examination of prostatic tissue revealed dense aggregations of spherical and thin-walled tetrasporocystic, dizoic, sporulated coccidian oocysts within tubular lumina, with unsporulated oocysts and gamogonic stages within the cytoplasm of glandular epithelial cells. This coccidian was observed occurring concurrently with dasyurid gammaherpesvirus 1 infection of the antechinus' prostate. Eimeria-specific 18S small-subunit ribosomal (r)DNA polymerase chain reaction amplification was used to obtain a partial 18S rDNA nucleotide sequence from the antechinus coccidian. Bayesian phylogenetic analysis based on 18S rDNA gene sequences revealed that the novel coccidian clusters with reptile-host coccidians, forming an ancestral basal lineage of the eimeriid clade. The species has been named Eimeria taggarti n. sp. on the basis of both sporulated oocyst morphology and molecular characterization. It is suspected that E. taggarti is sexually transmitted via excretion of sporulated oocysts or free sporocysts with prostatic secretions in semen.


Assuntos
Coccidiose/veterinária , Eimeria/isolamento & purificação , Marsupiais/parasitologia , Próstata/parasitologia , Doenças Prostáticas/veterinária , Animais , Sequência de Bases , Coccidiose/parasitologia , DNA de Protozoário/química , DNA de Protozoário/isolamento & purificação , DNA Ribossômico/química , DNA Ribossômico/isolamento & purificação , Eimeria/classificação , Eimeria/genética , Eimeria/ultraestrutura , Tolerância Imunológica , Masculino , Marsupiais/imunologia , Microscopia Eletrônica de Transmissão/veterinária , Oocistos/crescimento & desenvolvimento , Oocistos/ultraestrutura , Filogenia , Doenças Prostáticas/parasitologia , RNA de Protozoário/genética , RNA Ribossômico 18S/genética , Alinhamento de Sequência/veterinária , Austrália do Sul
3.
Stud Health Technol Inform ; 245: 10-14, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29295042

RESUMO

Smartphones that collect user geolocation provid opportunities for mobile Health (mHealth). Although granularity of geolocation data may be high, data completeness depends on the device's operating system, application developer decisions, and user actions. We investigate completeness of geolocation data collected via smartphones of 5601 people that self-reported daily chronic pain symptoms on 349,293 days. On 17% of these days, hourly geolocation data is reported, but days with 0 (16%), 1 (14%) and 2 (13%) geolocations are common. Android phones collect geolocation more often than iPhones (median 17 versus 2 times a day). Factors on operating system level and individual user level influence completeness of geolocation data collected with smartphones. mHealth researchers should be aware of these factors when designing their studies. The mHealth research community should devise standards for reporting geolocation data quality, analysing systematic differences in data quality between participant groups, and methods for data imputation.


Assuntos
Confiabilidade dos Dados , Smartphone , Telemedicina , Telefone Celular , Humanos , Aplicativos Móveis
5.
Rev Sci Instrum ; 83(10): 10D504, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23126848

RESUMO

In this work we analyze magnetic sublevel populations in a neutral beam penetrating a fusion plasma. The collisional-radiative model NOMAD was extended to include magnetic parabolic sublevels with principal quantum numbers n ≤ 10. The collisional parameters were calculated with the advanced atomic-orbital close coupling method and the Glauber approximation. The ionization by the induced electric field was also included in the model. The results of our calculations show significant deviations of the sublevel populations and, accordingly, line intensities of the σ and π components, from the statistical approximation. It is shown, for instance, that for a number of experimental conditions the total intensity of σ components is not equal to the total intensity of π components, which has a strong effect on determination of magnetic field and pitch angle in fusion devices. The results are presented for a wide range of plasma and beam parameters. The most significant deviations are observed for strong magnetic fields and high beam energies typical for the ITER plasma, where component intensity ratios may deviate by more than 20% from the statistical values.

6.
Lupus ; 21(1): 3-12, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21976401

RESUMO

African-American recipients of kidney transplants with lupus have high allograft failure risk. We studied their risk adjusting for: (1) socio-demographic factors: donor age, gender and race-ethnicity; recipient age, gender, education and insurance; donor-recipient race-ethnicity match; (2) immunologic factors: donor type, panel reactive antibodies, HLA mismatch, ABO blood type compatibility, pre-transplant dialysis, cytomegalovirus risk and delayed graft function (DGF); (3) rejection and recurrent lupus nephritis (RLN). Two thousand four hundred and six African-, 1132 Hispanic-, and 2878 Caucasian-Americans were followed for 12 years after transplantation. African- versus Hispanic- and Caucasian-Americans received more kidneys from deceased donors (71.6%, 57.3% and 55.1%) with higher two HLA loci mismatches for HLA-A (50%, 39.6% and 32.4%), HLA-B (52%, 42.8% and 35.6%) and HLA-DR (30%, 24.5% and 21.1%). They developed more DGF (19.5%, 13.6% and 13.4%). More African- versus Hispanic- and Caucasian-Americans developed rejection (41.7%, 27.6% and 35.9%) and RLN (3.2, 1.8 and 1.8%). 852 African-, 265 Hispanic-, and 747 Caucasian-Americans had allograft failure (p < 0.0001). After adjusting for transplant era, socio-demographic-immunologic differences, rejection and RLN, the increased hazard ratio for allograft failure of African- compared with Caucasian-Americans became non-significant (1.26 [95% confidence interval 0.78-2.04]). African-Americans with lupus have high prevalence of risk factors for allograft failure that can explain poor outcomes.


Assuntos
Negro ou Afro-Americano , Rejeição de Enxerto/imunologia , Hispânico ou Latino , Transplante de Rim/imunologia , População Branca , Adulto , Etnicidade , Feminino , Sobrevivência de Enxerto/imunologia , Humanos , Pessoa de Meia-Idade , Fatores de Risco , Transplante Homólogo/imunologia , Resultado do Tratamento , Adulto Jovem
7.
Biomed Sci Instrum ; 47: 24-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21525591

RESUMO

Assistive technology is a rapidly growing field that provides a degree of freedom and self-sufficiency to people of limited mobility. Smart wheelchairs are a subset of assistive technology, and are designed to be operated by people who are unable to use a traditional control system. Instead, smart wheelchairs are equipped with a combination of automated functionality and steering mechanisms specialized to meet a person’s individual needs. One feature common to the automated capabilities of smart wheelchairs is the tracking system. The wheelchair’s microcontroller needs to know how far the chair has travelled, its speed, and the rotational direction of its wheels in order to successfully navigate through an environment. The purpose of this research was to develop an odometer to track the motion of a motorized wheelchair. Due to federal regulations that prohibit changing the structure or internal mechanics of a medical device, the odometer had to be designed as a separate, removable part. The final design for the odometer consisted of two infrared sensors that measure edge transitions of a segmented black and white encoder wheel. The sensor output was then run through two comparator op amps and a high pass filter to produce a clean, crisp square wave signal output. The signal was then fed to an Atmel ATmega164P microcontroller. The microcontroller was programmed to compare the sensor signal with its internal clock, sense edge transitions, and thereby extrapolate the speed, travelled distance, and rotational direction of the wheelchair.

8.
Lupus ; 19(5): 557-74, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20089610

RESUMO

Systemic lupus erythematosus may present with renal manifestations that frequently are difficult to categorize and lupus nephritis is an important predictor of poor outcome. The type and spectrum of renal injury may remain undiagnosed until full-blown nephritic and/or nephrotic syndrome appear with increased risk of end-stage renal disease. These abnormalities occur within the first few years after the diagnosis of lupus is made on clinical grounds and with the support of laboratory tests in high risk patients. An early renal biopsy is helpful in patients with an abnormal urinalysis and/or reduced glomerular filtration rate and the results form the basis for therapeutic decisions. The biopsy also provides vital prognostic information based on histological categorization of different types of lupus nephritis, the degree of activity, chronicity and the immunopathogenesis. In the current armamentarium, the use of cyclophosphamide and azathioprine and recently mycophenolate mofetil, reduce morbidity and maintenance therapies reduce the risk of end-stage renal disease. Clinical trials underway promise new, effective and safe immunosuppressive regimens for the treatment of proliferative lupus nephritis.


Assuntos
Nefrite Lúpica , Humanos , Nefrite Lúpica/classificação , Nefrite Lúpica/tratamento farmacológico , Nefrite Lúpica/epidemiologia , Nefrite Lúpica/etiologia , Nefrite Lúpica/patologia , Guias de Prática Clínica como Assunto , Prognóstico
9.
Phys Rev Lett ; 105(20): 203005, 2010 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-21231229

RESUMO

We demonstrate the creation of vortices in the electronic probability density of an atom subject to short electric field pulses, how these vortices evolve and can be manipulated by varying the applied pulses, and that they persist to macroscopic distances in the spectrum of ejected electrons. This opens the possibility to use practical femtosecond or shorter laser pulses to create and manipulate these vortex quasiparticles at the atomic scale and observe them in the laboratory. Within a hydrodynamic interpretation we also show, since the Schrödinger equation is a particular instance of the Navier-Stokes equations, that for compressible fluids vortices can appear spontaneously and with a certain time delay, which is not expected to occur from the conventional point of view, illustrating applicability of the present study to vortex formation more broadly.

10.
Rev Sci Instrum ; 80(8): 083304, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19725648

RESUMO

The first investigation of the transverse emittance of a hot-cavity laser ion source based on all-solid-state Ti:sapphire lasers is presented. The emittances of (63)Cu ion beams generated by three-photon resonant ionization are measured and compared with that of the (69)Ga and (39)K ion beams resulting from surface ionization in the same ion source. A self-consistent unbiased elliptical exclusion method is adapted for noise reduction and emittance analysis. Typical values of the rms and 90% fractional emittances of the Cu ion beams at 20 keV energy are found to be about 2 and 8 pi mm mrad, respectively, for the ion currents of 2-40 nA investigated. The emittances of the laser-produced Cu ion beams are smaller than those of the surface-ionized Ga and K ion beams.

11.
Phys Rev Lett ; 102(14): 143201, 2009 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-19392436

RESUMO

Vortices are usually associated with systems containing large numbers of particles. Of particular topical interest though are those formed within atomic-scale wave functions and observed in macroscopic systems such as superfluids and quantum condensates. We uncover them here in one of the most fundamental quantum systems consisting of just one electron and two protons. Moreover, the results of novel simulations of the dynamics of this system reveal previously unknown mechanisms of angular momentum transfer and new ways to image atomic-scale quantized vortices at macroscopic distances. Probing of vortices and vortex-driven dynamics in quantum systems is thereby illustrated.

12.
Eur J Surg Oncol ; 35(9): 928-35, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19121564

RESUMO

OBJECTIVES: A set of common epidemiologic risk factors have been associated with the risk of breast cancer despite of its molecular sub-classifications. We implemented a case series study with the primary objective of evaluating if obesity is associated with the diagnostic risk of "ER+ and/or PR+, HER2+", "ER-/PR-, HER2-", or "ER-/PR-, HER2+" relative to the most commonly diagnosed subtype of breast carcinoma, "ER+ and/or PR+, HER2-". METHODS: Demographic, clinical and pathologic data were collected from existing databases. The statuses of HER2/neu biomarker and hormone receptors were dichotomized as either positive or negative. Immunohistochemical staining was used to assess the prevalence of different subtypes. Body mass index was calculated from weight and height data collected at the time of consultation. CONCLUSIONS: Findings from the present study suggest that excess body weight decreases the diagnostic risk of "ER-/PR-, HER2-", or "ER-/PR-, HER2-" relative to "ER+ and/or PR+, HER2-". Obese and overweight women are more likely to be diagnosed with to "ER+ and/or PR+, HER2-", the subtype that has best prognosis and mostly associated with personal lifestyle. Weight gain with the population attributable-risk factor of 21.3% contributes the most to the incidence of invasive post menopausal breast cancer. Younger pre-menopausal women were more likely to be diagnosed with "ER+ and/or PR+, HER2+". In younger women biology of breast cancers with positive expression for hormone receptors and epidermal growth factor is a complex that extends beyond the currently assessed prognostic markers.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/patologia , Obesidade/epidemiologia , Índice de Massa Corporal , Fator de Crescimento Epidérmico/metabolismo , Feminino , Humanos , Modelos Logísticos , Pessoa de Meia-Idade , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Fatores de Risco , Estados Unidos/epidemiologia
13.
Aust Vet J ; 86(3): 106-9, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18304049

RESUMO

OBJECTIVE: To determine the effect of a single intravenous (IV) fluid bolus on the hydration of an avian patient, using packed cell volume (PCV) and plasma total solids (TS) to estimate hydration. PROCEDURE: Ten birds were allocated randomly to one of three groups, and administered 30 mL/kg or 50 mL/kg intravenous fluid, or were part of a control group and did not receive IV fluid. Blood was collected before the IV fluid bolus was administered, and at 1 minute, 3 hours and 6 hours after administration of the fluid. Samples were used to determine PCV and TS and results were compared between groups and between the different time points. RESULTS: Administration of 30 mL/kg or 50 mL/kg compound sodium lactate solution caused a statistically significant decrease in PCV. Within 3 hours, the PCV was not significantly different to the initial value or to the PCV of control birds. Administration of 30 mL/kg compound sodium lactate solution did not result in a significant decrease in TS. However, administration of 50 mL/kg produced a significant decrease in TS, which was still significantly less than controls 6 hours after the fluid was administered. CONCLUSION: These findings suggest that an intravenous bolus of fluid may be safely administered to an anaemic bird, since PCV is significantly decreased for less than 3 hours. Up to 50 mL/kg of fluid may be administered as an intravenous bolus to a bird, to produce significant haemodilution that persists for up to 6 hours.


Assuntos
Doenças das Aves/terapia , Desidratação/veterinária , Hidratação/veterinária , Hematócrito/veterinária , Papagaios , Anemia/terapia , Anemia/veterinária , Animais , Doenças das Aves/sangue , Desidratação/terapia , Relação Dose-Resposta a Droga , Hidratação/métodos , Injeções Intravenosas/veterinária , Papagaios/sangue , Distribuição Aleatória , Resultado do Tratamento
14.
Radiat Prot Dosimetry ; 122(1-4): 22-5, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17132666

RESUMO

The use of heavy ion beams for microbeam studies of mammalian cell response leads to a need to better understand interaction cross sections for collisions of heavy ions with tissue constituents. For ion energies of a few MeV u(-1) or less, ions capture electrons from the media in which they travel and undergo subsequent interactions as partially 'dressed' ions. For example, 16 MeV fluorine ions have an equilibrium charge of 7(+), 32 MeV sulphur ions have an equilibrium charge of approximately 11(+), and as the ion energies decrease the equilibrium charge decreases dramatically. Data for interactions of partially dressed ions are extremely rare, making it difficult to estimate microscopic patterns of energy deposition leading to damage to cellular components. Such estimates, normally obtained by Monte Carlo track structure simulations, require a comprehensive database of differential and total ionisation cross sections as well as charge transfer cross sections. To provide information for track simulation, measurement of total ionisation cross sections have been initiated at East Carolina University using the recoil ion time-of-flight method that also yields cross sections for multiple ionisation processes and charge transfer cross sections; multiple ionisation is prevalent for heavy ion interactions. In addition, measurements of differential ionisation cross sections needed for Monte Carlo simulation of detailed event-by-event particle tracks are under way. Differential, total and multiple ionisation cross sections and electron capture and loss cross sections measured for C(+) ions with energies of 100 and 200 keV u(-1) are described.


Assuntos
Biopolímeros/química , Biopolímeros/efeitos da radiação , Íons Pesados , Modelos Químicos , Modelos Moleculares , Radiação Ionizante , Radiometria/métodos , Simulação por Computador , Transferência Linear de Energia , Método de Monte Carlo , Doses de Radiação , Eletricidade Estática
15.
J Chem Phys ; 125(11): 114302, 2006 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-16999469

RESUMO

We present quantum mechanical close-coupling calculations of collisions between two hydrogen molecules over a wide range of energies, extending from the ultracold limit to the superthermal region. The two most recently published potential energy surfaces for the H(2)-H(2) complex, the so-called Diep-Johnson (DJ) [J. Chem. Phys. 112, 4465 (2000); 113, 3480 (2000)] and Boothroyd-Martin-Keogh-Peterson (BMKP) [J. Chem. Phys. 116, 666 (2002)] surfaces, are quantitatively evaluated and compared through the investigation of rotational transitions in H(2)+H(2) collisions within rigid rotor approximation. The BMKP surface is expected to be an improvement, approaching chemical accuracy, over all conformations of the potential energy surface compared to previous calculations of H(2)-H(2) interaction. We found significant differences in rotational excitation/deexcitation cross sections computed on the two surfaces in collisions between two para-H(2) molecules. The discrepancy persists over a large range of energies from the ultracold regime to thermal energies and occurs for several low-lying initial rotational levels. Good agreement is found with experiment B. Mate et al., [J. Chem. Phys. 122, 064313 (2005)] for the lowest rotational excitation process, but only with the use of the DJ potential. Rate coefficients computed with the BMKP potential are an order of magnitude smaller.

16.
Phys Rev E Stat Nonlin Soft Matter Phys ; 72(5 Pt 1): 051907, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16383645

RESUMO

An exact steady-state solution of the stochastic equations governing the behavior of a gene regulated by a self-generated proteomic atmosphere is presented. The solutions depend on an adiabaticity parameter measuring the relative rate of DNA-protein unbinding and protein degradation. The steady-state solution reveals deviations from the commonly used Ackers et al approximation based on the equilibrium law of mass action, allowing anticooperative behavior in the "nonadiabatic" limit of slow binding and unbinding rates. Noise from binding and unbinding events dominates the shot noise of protein synthesis and degradation up to quite high values of the adiabaticity parameter.


Assuntos
DNA/genética , Regulação da Expressão Gênica/genética , Modelos Genéticos , Proteoma/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica/fisiologia , Animais , Simulação por Computador , Retroalimentação/fisiologia , Humanos , Biossíntese de Proteínas/genética , Processos Estocásticos
17.
Br J Ophthalmol ; 89(9): 1115-9, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16113362

RESUMO

BACKGROUND: The pattern dystrophies (PD) represent a clinically heterogeneous family of inherited macular diseases frequently caused by mutations in the peripherin/RDS gene. Most previous studies have detailed the clinical findings in single families, making it difficult to derive data from which progression and visual outcome can be generalised. METHODS: Families were ascertained and clinically evaluated including angiography and electrophysiology where appropriate. RESULTS: In each of the six families with autosomal dominant PD, a mutation in the peripherin/RDS gene was identified, including a novel Cys250Phe variant. These data suggest that the condition is characterised by the accumulation of yellow to grey subretinal flecks, followed by pigmentary change accompanied by patches of chorioretinal atrophy. Subsequently, 50% (16/32) of individuals with PD developed poor central vision because of chorioretinal geographic atrophy or subretinal neovascularisation. The risk of these complications appears to increase with age. CONCLUSION: PD should not necessarily be considered a benign condition. Instead, patients should be counselled that there is a significant chance of losing central vision in their later years. Some elderly patients with probands showing PD may be misdiagnosed with age related macular degeneration owing to the phenotypic similarities between these conditions in the advanced state.


Assuntos
Proteínas de Filamentos Intermediários/genética , Glicoproteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Mutação Puntual , Degeneração Retiniana/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Corioide/patologia , Neovascularização de Coroide/patologia , Eletrorretinografia , Feminino , Humanos , Macula Lutea/patologia , Degeneração Macular/genética , Degeneração Macular/patologia , Masculino , Pessoa de Meia-Idade , Linhagem , Periferinas , Fenótipo , Retina/patologia , Degeneração Retiniana/patologia , Testes de Campo Visual
18.
Stroke ; 36(6): 1153-9, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15914768

RESUMO

BACKGROUND AND PURPOSE: The Echoplanar Imaging Thrombolysis Evaluation Trial (EPITHET) tests the hypothesis that perfusion-weighted imaging (PWI)-diffusion-weighted imaging (DWI) mismatch predicts the response to thrombolysis. There is no accepted standardized definition of PWI-DWI mismatch. We compared common mismatch definitions in the initial 40 EPITHET patients. METHODS: Raw perfusion images were used to generate maps of time to peak (TTP), mean transit time (MTT), time to peak of the impulse response (Tmax) and first moment transit time (FMT). DWI, apparent diffusion coefficient (ADC), and PWI volumes were measured with planimetric and thresholding techniques. Correlations between mismatch volume (PWIvol-DWIvol) and DWI expansion (T2(Day 90-vol)-DWI(Acute-vol)) were also assessed. RESULTS: Mean age was 68+/-11, time to MRI 4.5+/-0.7 hours, and median National Institutes of Health Stroke Scale (NIHSS) score 11 (range 4 to 23). Tmax and MTT hypoperfusion volumes were significantly lower than those calculated with TTP and FMT maps (P<0.001). Mismatch > or =20% was observed in 89% (Tmax) to 92% (TTP/FMT/MTT) of patients. Application of a +4s (relative to the contralateral hemisphere) PWI threshold reduced the frequency of positive mismatch volumes (TTP 73%/FMT 68%/Tmax 54%/MTT 43%). Mismatch was not significantly different when assessed with ADC maps. Mismatch volume, calculated with all parameters and thresholds, was not significantly correlated with DWI expansion. In contrast, reperfusion was correlated inversely with infarct growth (R=-0.51; P=0.009). CONCLUSIONS: Deconvolution and application of PWI thresholds provide more conservative estimates of tissue at risk and decrease the frequency of mismatch accordingly. The precise definition may not be critical; however, because reperfusion alters tissue fate irrespective of mismatch.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Imagem Ecoplanar/métodos , Angiografia por Ressonância Magnética/métodos , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/patologia , Idoso , Isquemia Encefálica/patologia , Artérias Cerebrais/patologia , Infarto Cerebral , Circulação Cerebrovascular , Difusão , Humanos , Processamento de Imagem Assistida por Computador , Pessoa de Meia-Idade , Perfusão , Terapia Trombolítica , Fatores de Tempo , Resultado do Tratamento
19.
J Chem Phys ; 122(2): 024307, 2005 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-15638586

RESUMO

The two most recently published potential energy surfaces (PESs) for the HeH2 complex, the so-called MR (Muchnick and Russek) and BMP (Boothroyd, Martin, and Peterson) surfaces, are quantitatively evaluated and compared through the investigation of atom-diatom collision processes. The BMP surface is expected to be an improvement, approaching chemical accuracy, over all conformations of the PES compared to that of the MR surface. We found significant differences in inelastic rovibrational cross sections computed on the two surfaces for processes dominated by large changes in target rotational angular momentum. In particular, the H2(nu=1,j=0) total quenching cross section computed using the BMP potential was found to be a factor of 1000 larger than that obtained with the MR surface. A lesser discrepancy persists over a large range of energies from the ultracold to thermal and occurs for other low-lying initial rovibrational levels. The MR surface was used in previous calculations of the H2(nu=1,j=0) quenching rate coefficient and gave results in close agreement with the experimental data of Audibert et al. which were obtained for temperatures between 50 and 300 K. Examination of the rovibronic coupling matrix elements, which are obtained following a Legendre expansion of the PES, suggests that the magnitude of the anisotropy of the BMP potential is too large in the interaction region. However, cross sections for elastic and pure rotational processes obtained from the two PESs differ typically by less than a factor of 2. The small differences may be ascribed to the long-range and anharmonic components of the PESs. Exceptions occur for (nu=10,j=0) and (nu=11,j=1) where significant enhancements have been found for the low-energy quenching and elastic cross sections due to zero-energy resonances in the BMP PES which are not present in the MR potential.

20.
Math Biosci ; 190(2): 203-20, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15234617

RESUMO

Blood flow in a stenosed tube has been modeled in the present studies. Blood flow is assumed to be represented by a couple stress fluid. Flow parameters such as velocity, resistance to flow, and shear stress distribution have been computed for different suspension concentrations (haematocrit), and for the blood diseases; polycythemia, plasma cell dyscrasias, and for Hb SS (sickle cell). The results have been compared with the case of normal blood and for other theoretical models. The importance of size effects in blood flow studies has been highlighted.


Assuntos
Arteriopatias Oclusivas/fisiopatologia , Constrição Patológica/fisiopatologia , Modelos Cardiovasculares , Policitemia/fisiopatologia , Velocidade do Fluxo Sanguíneo , Hematócrito , Humanos , Fluxo Sanguíneo Regional , Resistência Vascular
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