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1.
J Synchrotron Radiat ; 29(Pt 3): 602-614, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35510993

RESUMO

Serial crystallography of membrane proteins often employs high-viscosity injectors (HVIs) to deliver micrometre-sized crystals to the X-ray beam. Typically, the carrier medium is a lipidic cubic phase (LCP) media, which can also be used to nucleate and grow the crystals. However, despite the fact that the LCP is widely used with HVIs, the potential impact of the injection process on the LCP structure has not been reported and hence is not yet well understood. The self-assembled structure of the LCP can be affected by pressure, dehydration and temperature changes, all of which occur during continuous flow injection. These changes to the LCP structure may in turn impact the results of X-ray diffraction measurements from membrane protein crystals. To investigate the influence of HVIs on the structure of the LCP we conducted a study of the phase changes in monoolein/water and monoolein/buffer mixtures during continuous flow injection, at both atmospheric pressure and under vacuum. The reservoir pressure in the HVI was tracked to determine if there is any correlation with the phase behaviour of the LCP. The results indicated that, even though the reservoir pressure underwent (at times) significant variation, this did not appear to correlate with observed phase changes in the sample stream or correspond to shifts in the LCP lattice parameter. During vacuum injection, there was a three-way coexistence of the gyroid cubic phase, diamond cubic phase and lamellar phase. During injection at atmospheric pressure, the coexistence of a cubic phase and lamellar phase in the monoolein/water mixtures was also observed. The degree to which the lamellar phase is formed was found to be strongly dependent on the co-flowing gas conditions used to stabilize the LCP stream. A combination of laboratory-based optical polarization microscopy and simulation studies was used to investigate these observations.


Assuntos
Glicerídeos , Lipídeos , Glicerídeos/química , Proteínas de Membrana/química , Viscosidade , Água/química , Difração de Raios X
2.
Scand J Rheumatol ; 50(4): 314-318, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33682605

RESUMO

Objective: To describe the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in a large population-based study of elderly Icelanders, with particular reference to weight-related factors and the metabolic syndrome.Method: The study population comprised 5321 participants aged 68-96 years (2276 males, mean ± sd age 76 ± 5 , and 3045 females, age 77 ± 6) from the AGES-Reykjavik Study. DISH diagnosis was based on computed tomography (CT) scans, and interpreted strictly by the Resnick criteria and additional suggestions for CT interpretation by Oudkerk et al. Radiology readings were taken by a radiology resident and sample readings by two experienced radiologists.Results: A diagnosis of DISH was made in 13.7% of males and 2.8% of females. There was no association with age, but a strong association was seen with the metabolic syndrome [odds ratio (OR) 2.12, 95% confidence interval (CI) 1.69-2.64, p = 3.9 × 10-11]. Among the components of the metabolic syndrome, the association with DISH was significant for the insulin resistance criterion (OR 1.66, 95% CI 1.32-2.01, p < 0.001) and the body mass index (BMI) criterion (OR 2.16, 95% CI 1.70-2.74, p < 0.001). Other weight-related variables (midlife BMI, weight, and abdominal circumference) showed similar associations.Conclusions: This study, which to our knowledge is the largest published study on the prevalence of DISH, shows an association with the metabolic syndrome, particularly with the insulin resistance and BMI criteria. This is analogous with previous reports linking DISH with metabolic causes. In this age category, we did not observe any increase in prevalence with age.


Assuntos
Hiperostose Esquelética Difusa Idiopática/epidemiologia , Síndrome Metabólica/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Comorbidade , Feminino , Humanos , Hiperostose Esquelética Difusa Idiopática/diagnóstico por imagem , Islândia/epidemiologia , Masculino , Prevalência , Tomografia Computadorizada por Raios X
3.
Proc Natl Acad Sci U S A ; 115(22): 5652-5657, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29760050

RESUMO

The bright ultrafast pulses of X-ray Free-Electron Lasers allow investigation into the structure of matter under extreme conditions. We have used single pulses to ionize and probe water as it undergoes a phase transition from liquid to plasma. We report changes in the structure of liquid water on a femtosecond time scale when irradiated by single 6.86 keV X-ray pulses of more than 106 J/cm2 These observations are supported by simulations based on molecular dynamics and plasma dynamics of a water system that is rapidly ionized and driven out of equilibrium. This exotic ionic and disordered state with the density of a liquid is suggested to be structurally different from a neutral thermally disordered state.


Assuntos
Elétrons , Temperatura Alta , Lasers , Água/química , Cristalografia , Simulação de Dinâmica Molecular , Fatores de Tempo
4.
Scand J Rheumatol ; 47(6): 465-474, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30070923

RESUMO

OBJECTIVES: Large-scale observational cohorts may be used to study the effectiveness and rare side effects of biological disease-modifying anti-rheumatic drugs (bDMARDs) in ankylosing spondylitis (AS), but may be hampered by differences in baseline characteristics and disease activity across countries. We aimed to explore the research infrastructure in the five Nordic countries regarding bDMARD treatment in AS. METHOD: This observational cohort study was based on data from biological registries in Denmark (DANBIO), Sweden (SRQ/ARTIS), Finland (ROB-FIN), Norway (NOR-DMARD), and Iceland (ICEBIO). Data were collected for the years 2010-2016. Registry coverage, registry inventory (patient characteristics, disease activity measures), and national guidelines for bDMARD prescription in AS were described per country. Incident (first line) and prevalent bDMARD use per capita, country, and year were calculated. In AS patients who started first line bDMARDs during 2010-2016 (n = 4392), baseline characteristics and disease activity measures were retrieved. RESULTS: Registry coverage of bDMARD-treated patients ranged from 60% to 95%. All registries included extensive prospectively collected data at patient level. Guidelines regarding choice of first line drug and prescription patterns varied across countries. During the period 2010-2016 prevalent bDMARD use increased (p < 0.001), whereas incident use tended to decrease (p for trend < 0.004), with large national variations (e.g. 2016 incidence: Iceland 10.7/100 000, Finland 1.7/100 000). Baseline characteristics were similar regarding C-reactive protein, but differed for other variables, including the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) (range 3.5-6.3) and Ankylosing Spondylitis Disease Activity Score (ASDAS) (2.7-3.8) (both p < 0.0001). CONCLUSION: Collaboration across the five Nordic biological registries regarding bDMARD use in AS is feasible but national differences in coverage, prescription patterns, and patient characteristics must be taken into account depending on the scientific question.


Assuntos
Antirreumáticos/uso terapêutico , Terapia Biológica/métodos , Padrões de Prática Médica/estatística & dados numéricos , Espondilite Anquilosante/tratamento farmacológico , Adulto , Estudos de Coortes , Feminino , Humanos , Cooperação Internacional , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Sistema de Registros , Países Escandinavos e Nórdicos , Índice de Gravidade de Doença
5.
Phys Chem Chem Phys ; 20(18): 12381-12389, 2018 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-29488514

RESUMO

Single particle imaging (SPI) using X-ray pulses has become increasingly attainable with the advent of high-intensity free electron lasers. Eliminating the need for crystallized samples enables structural studies of molecules previously inaccessible by conventional crystallography. While this emerging technique already demonstrates substantial promise, some obstacles need to be overcome before SPI can reach its full potential. One such problem is determining the spatial orientation of the sample at the time of X-ray interaction. Existing solutions rely on diffraction data and are computationally demanding and sensitive to noise. In this in silico study, we explore the possibility of aiding these methods by mapping the ion distribution as the sample undergoes a Coulomb explosion following the intense ionization. By detecting the ions ejected from the fragmented sample, the orientation of the original sample should be possible to determine. Knowledge of the orientation has been shown earlier to be of substantial advantage in the reconstruction of the original structure. 150 explosions of each of twelve separate systems - four polypeptides with different amounts of surface bound water - were simulated with molecular dynamics (MD) and the average angular distribution of carbon and sulfur ions was investigated independently. The results show that the explosion maps are reproducible in both cases, supporting the idea that orientation information is preserved. Additional water seems to restrict the carbon ion trajectories further through a shielding mechanism, making the maps more distinct. For sulfurs, water has no significant impact on the trajectories, likely due to their higher mass and greater ionization cross section, indicating that they could be of particular interest. Based on these findings, we conclude that explosion data can aid spatial orientation in SPI experiments and could substantially improve the capabilities of the novel technique.


Assuntos
Peptídeos/química , Peptídeos/efeitos da radiação , Animais , Galinhas , Humanos , Íons/química , Lasers , Simulação de Dinâmica Molecular , Água/química , Raios X
6.
Acta Anaesthesiol Scand ; 61(1): 62-72, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27813055

RESUMO

BACKGROUND: Nursing procedures that are routinely performed in the intensive care unit (ICU) are assumed to have minimal side effects. However, these procedures may sometimes cause physiological changes that negatively affect the patient. We hypothesized that physiological changes associated with routine nursing procedures in the ICU are common. METHODS: A clinical observational study of 16 critically ill patients in a nine-bed mixed university hospital ICU. All nursing procedures were observed, and physiological data were collected and subsequently analyzed. Minor physiological changes were defined as minimal changes in respiratory or circulatory variables, and major physiological changes were marked as hyper/hypotension, bradycardia/tachycardia, bradypnea/tachypnea, ventilatory distress, and peripheral blood oxygen desaturation. RESULTS: In the 16 patients, 668 procedures generated 158 major and 692 minor physiological changes during 187 observational hours. The most common procedure was patient position change, which also generated the majority of the physiological changes. The most common major physiological changes were blood oxygen desaturation, ventilatory distress, and hypotension, and the most common minor changes were arterial pressure alteration, coughing, and increase in respiratory rate. CONCLUSION: In this pilot study, we examined physiological changes in connection with all regular routine nursing procedures in the ICU. We found that physiological changes were common and sometimes severe.


Assuntos
Estado Terminal/enfermagem , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea , Feminino , Frequência Cardíaca , Humanos , Intubação Intratraqueal , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Projetos Piloto , Postura , Taxa Respiratória
7.
Water Sci Technol ; 75(5-6): 1034-1050, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28272033

RESUMO

Sewage sludge (SS) contains beneficial plant nutrients and organic matter, and therefore application of SS on agricultural land helps close nutrient loops. However, spreading operations are restricted to certain seasons and hence the SS needs to be stored. Storage and land application of SS are both potential sources of greenhouse gases and ammonia, leading to global warming, acidification and eutrophication. Covering the stored SS, treating it with urea and choosing the correct time for land application all have the potential to reduce emissions from the system. Using life cycle assessment (LCA), this study compares storage and land application options of SS in terms of global warming potential (GWP), acidification potential, eutrophication potential and primary energy use. The system with covered storage has the lowest impact of all categories. Systems with autumn application are preferable to spring application for all impact categories but, when nitrate leaching is considered, spring application is preferable in terms of eutrophication and primary energy use and, for some SS treatments, GWP. Ammonia addition reduces nitrous oxide and ammonia emissions during storage, but increases these emissions after land application. Storage duration has a large impact on GWP, while amount of chemical nitrogen fertiliser substituted has a large impact on primary energy use.


Assuntos
Meio Ambiente , Fertilizantes/análise , Esgotos , Ácidos/química , Poluentes Atmosféricos/análise , Amônia/análise , Sequestro de Carbono , Eutrofização , Aquecimento Global , Metano/análise , Nitratos/análise , Nitrogênio/análise , Óxido Nitroso/análise , Fósforo/análise , Estações do Ano , Fatores de Tempo , Poluentes Químicos da Água/análise
8.
Scand J Immunol ; 83(3): 219-24, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26725858

RESUMO

The aim of this study was to investigate whether complement activation, via the classical and alternative pathways, occurs following a cemented total hip replacement (THR) surgery due to osteoarthritis. Blood samples were collected systematically from 12 patients - six male and six women, with a median age of 75 (range: 59-90 years) - preoperatively, 6 h post-operatively and on the first, second and third post-operative day. Total function of classical (CH50) and alternative pathways (AH50) was evaluated, along with the determination of serum concentrations of the complement proteins C3, C4, C3d, the soluble terminal complement complex (sTCC) sC5b-9, as well as C-reactive protein (CRP) and albumin. Measurements of CRP and albumin levels elucidated a marked inflammatory response following the operation. The CH50, AH50 and C3 and C4 levels were significantly lower 6 h after the surgery compared with the preoperative levels, but elevated above the preoperative levels during the following 3 days. The complement activation product C3d levels increased continually during the whole observation period, from 13.5 AU/ml (range: 8-19 AU/ml) preoperative to 20 AU/ml (range: 12-34 AU/ml) on the third post-operative day. Furthermore, we observed an increase in the sC5b-9 levels between the preoperative and the third post-operative day. These results demonstrate a significant activation of the complement system following cemented THR. Further studies are needed to elucidate the time frame and the pathogenic role of this observed complement activation.


Assuntos
Artroplastia de Quadril , Via Alternativa do Complemento , Via Clássica do Complemento , Osteoartrite/imunologia , Complicações Pós-Operatórias/imunologia , Idoso , Idoso de 80 Anos ou mais , Albuminas/metabolismo , Proteína C-Reativa/metabolismo , Proteínas do Sistema Complemento/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite/etiologia
9.
J Appl Microbiol ; 121(5): 1427-1443, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27545272

RESUMO

AIM: This study evaluated treatment of greywater (GW) by a biochar filter in Jordan and assessed the annual risks of infection (Pi-annual ), annual risk of disease (Pd-annual ) and disease burden (in disability-adjusted life years; DALYs) of gastroenteritis caused by Salmonella spp. and rotavirus due to ingestion of GW during system maintenance and consumption of green onions irrigated with treated and nontreated GW. METHODS AND RESULTS: The biochar filter efficiently removed 93% of biochemical oxygen demand (BOD5 ) and 85% of solids, while removal of Escherichia coli was insignificant. Treatment of GW decreased the median Pd-annual due to ingestion of GW from 1·39 × 10-2 to 6·0 × 10-3 for Salmonella spp. but did not affect Pd-annual caused by rotavirus (9·73 × 10-1 to 1·0). Consumption of onions irrigated with treated GW had a median Pd-annual of 1·25 × 10-9 to 1·2 × 10-8 for Salmonella spp. and 4·96 × 10-4 to 4·37 × 10-3 for rotavirus infection, which was 99·9 and 90% lower, respectively, than the risk when consuming onions irrigated with nontreated GW. The highest risks of gastrointestinal disease were thus associated mainly with direct ingestion of GW when maintaining the system. CONCLUSIONS: Garden produce irrigated with GW treated in biochar filter did not display intolerable risks of rotavirus-based gastroenteritis during summer season in the study area given that the produce is harvested 1 to 2 days, and washed, before consumption. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to scientific-based knowledge on the suitability of biochar filters for onsite greywater treatment and confirms the microbial safety of recycling treated greywater for garden irrigation.


Assuntos
Carvão Vegetal , Gastroenterite/epidemiologia , Eliminação de Resíduos Líquidos , Águas Residuárias/microbiologia , Exposição Ambiental , Gastroenterite/etiologia , Gastroenterite/microbiologia , Humanos , Medição de Risco , Rotavirus/isolamento & purificação , Salmonella/isolamento & purificação , Águas Residuárias/química , Águas Residuárias/virologia , Qualidade da Água
10.
J Synchrotron Radiat ; 22(2): 256-66, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25723927

RESUMO

Serial femtosecond X-ray crystallography of protein nanocrystals using ultrashort and intense pulses from an X-ray free-electron laser has proved to be a successful method for structural determination. However, due to significant variations in diffraction pattern quality from pulse to pulse only a fraction of the collected frames can be used. Experimentally, the X-ray temporal pulse profile is not known and can vary with every shot. This simulation study describes how the pulse shape affects the damage dynamics, which ultimately affects the biological interpretation of electron density. The instantaneously detected signal varies during the pulse exposure due to the pulse properties, as well as the structural and electronic changes in the sample. Here ionization and atomic motion are simulated using a radiation transfer plasma code. Pulses with parameters typical for X-ray free-electron lasers are considered: pulse energies ranging from 10(4) to 10(7) J cm(-2) with photon energies from 2 to 12 keV, up to 100 fs long. Radiation damage in the form of sample heating that will lead to a loss of crystalline periodicity and changes in scattering factor due to electronic reconfigurations of ionized atoms are considered here. The simulations show differences in the dynamics of the radiation damage processes for different temporal pulse profiles and intensities, where ionization or atomic motion could be predominant. The different dynamics influence the recorded diffracted signal in any given resolution and will affect the subsequent structure determination.


Assuntos
Proteínas/efeitos da radiação , Lesões por Radiação , Difração de Raios X/métodos , Cristalografia por Raios X/métodos , Humanos , Lasers , Modelos Moleculares , Modelos Teóricos , Proteínas/química
11.
J Synchrotron Radiat ; 22(2): 225-38, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25723924

RESUMO

Proteins that contain metal cofactors are expected to be highly radiation sensitive since the degree of X-ray absorption correlates with the presence of high-atomic-number elements and X-ray energy. To explore the effects of local damage in serial femtosecond crystallography (SFX), Clostridium ferredoxin was used as a model system. The protein contains two [4Fe-4S] clusters that serve as sensitive probes for radiation-induced electronic and structural changes. High-dose room-temperature SFX datasets were collected at the Linac Coherent Light Source of ferredoxin microcrystals. Difference electron density maps calculated from high-dose SFX and synchrotron data show peaks at the iron positions of the clusters, indicative of decrease of atomic scattering factors due to ionization. The electron density of the two [4Fe-4S] clusters differs in the FEL data, but not in the synchrotron data. Since the clusters differ in their detailed architecture, this observation is suggestive of an influence of the molecular bonding and geometry on the atomic displacement dynamics following initial photoionization. The experiments are complemented by plasma code calculations.


Assuntos
Ferredoxinas/efeitos da radiação , Metaloproteínas/efeitos da radiação , Síncrotrons , Clostridium/efeitos da radiação , Cristalografia por Raios X/métodos , Relação Dose-Resposta à Radiação , Humanos , Modelos Moleculares , Lesões por Radiação , Sensibilidade e Especificidade
12.
Opt Express ; 23(2): 1213-31, 2015 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-25835880

RESUMO

In structural determination of crystalline proteins using intense femtosecond X-ray lasers, damage processes lead to loss of structural coherence during the exposure. We use a nonthermal description for the damage dynamics to calculate the ultrafast ionization and the subsequent atomic displacement. These effects degrade the Bragg diffraction on femtosecond time scales and gate the ultrafast imaging. This process is intensity and resolution dependent. At high intensities the signal is gated by the ionization affecting low resolution information first. At lower intensities, atomic displacement dominates the loss of coherence affecting high-resolution information. We find that pulse length is not a limiting factor as long as there is a high enough X-ray flux to measure a diffracted signal.

13.
Water Sci Technol ; 71(3): 426-33, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25714643

RESUMO

To evaluate the treatment performance of vertical flow sand filters, the HYDRUS wetland module was used to simulate treatment in an experimental set-up. The laboratory filters were intermittently dosed with artificial greywater at a hydraulic loading rate of 0.032 m³ m⁻² day⁻¹ and an organic loading rate of 0.014 kg BOD5 m⁻² day⁻¹. The hydraulic properties of the filter were characterised, as were inflow and outflow concentrations of chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia, nitrate and total nitrogen. The inverse simulation function of the HYDRUS software was used to calibrate the water flow model. The observed effect of water flowing faster along the column wall was included in the inverse simulations. The biokinetic model was calibrated by fitting heterotrophic biomass growth to measurements of potential respiration rate. Emphasis was put on simulating outflow concentrations of organic pollutants. The simulations were conducted using three models of varying degree of calibration effort and output accuracy. The effluent concentration was 245 mg COD L⁻¹ for the laboratory filters, 134 mg COD mg L⁻¹ for the model excluding wall flow effects and 338 mg COD mg L⁻¹ for the model including wall flow effects.


Assuntos
Simulação por Computador , Filtração/instrumentação , Modelos Teóricos , Dióxido de Silício/química , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio , Biomassa , Filtração/métodos , Nitratos , Nitrogênio , Software , Poluentes Químicos da Água/química , Áreas Alagadas
14.
Mol Ecol ; 23(7): 1780-98, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24612293

RESUMO

Millions to billions of DNA sequences can now be generated from ancient skeletal remains thanks to the massive throughput of next-generation sequencing platforms. Except in cases of exceptional endogenous DNA preservation, most of the sequences isolated from fossil material do not originate from the specimen of interest, but instead reflect environmental organisms that colonized the specimen after death. Here, we characterize the microbial diversity recovered from seven c. 200- to 13 000-year-old horse bones collected from northern Siberia. We use a robust, taxonomy-based assignment approach to identify the microorganisms present in ancient DNA extracts and quantify their relative abundance. Our results suggest that molecular preservation niches exist within ancient samples that can potentially be used to characterize the environments from which the remains are recovered. In addition, microbial community profiling of the seven specimens revealed site-specific environmental signatures. These microbial communities appear to comprise mainly organisms that colonized the fossils recently. Our approach significantly extends the amount of useful data that can be recovered from ancient specimens using a shotgun sequencing approach. In future, it may be possible to correlate, for example, the accumulation of postmortem DNA damage with the presence and/or abundance of particular microbes.


Assuntos
Fósseis , Cavalos/microbiologia , Metagenômica/métodos , Microbiota/genética , Análise de Sequência de DNA/métodos , Animais , DNA/isolamento & purificação , Dano ao DNA , Cavalos/genética , Sibéria
15.
Phys Chem Chem Phys ; 15(39): 16542-56, 2013 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-23949215

RESUMO

A transferable potential energy function for describing the interaction between water molecules is presented. The electrostatic interaction is described rigorously using a multipole expansion. Only one expansion center is used per molecule to avoid the introduction of monopoles. This single center approach turns out to converge and give close agreement with ab initio calculations when carried out up to and including the hexadecapole. Both dipole and quadrupole polarizability are included. All parameters in the electrostatic interaction as well as the dispersion interaction are taken from ab initio calculations or experimental measurements of a single water molecule. The repulsive part of the interaction is parametrized to fit ab initio calculations of small water clusters and experimental measurements of ice Ih. The parametrized potential function was then used to simulate liquid water and the results agree well with experiment, even better than simulations using some of the point charge potentials fitted to liquid water. The evaluation of the new interaction potential for condensed phases is fast because point charges are not present and the interaction can, to a good approximation, be truncated at a finite range.


Assuntos
Gelo , Água/química , Dimerização , Modelos Moleculares , Eletricidade Estática
16.
Int J Sports Med ; 34(3): 263-7, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23027361

RESUMO

Symptomatic spondylolysis is a stress reaction caused by microtrauma during physical exercise, an imaging diagnostic subgroup of Adolescent Low Back Pain (ALBP), found in adolescent athletes. Early diagnosis increases the possibility of healing. Thus, it is important to divide ALBP into subgroups. The aim of this study was to evaluate clinical tests that can distinguish symptomatic spondylolysis from other forms of ALBP in order to facilitate early referral for diagnostic imaging. The investigation subjects were a prospective case series with a control group, 25 subjects with ALBP and 13 subjects that had no history of LBP. The 2 groups were examined using the same clinical protocol. MRI of the whole lumbar spine was performed in both the case and control groups and CT investigations of the L4 and L5 vertebrae were performed in the case group. Significant differences between the 2 groups were found in 8 of our clinical tests. No clinical test, alone or in combination, could distinguish between spondylolysis and other forms of ALBP. As 88% of the subjects in the case group had MRI findings and almost 50% had spondylolysis, MRI should be performed at an early age in young athletes with ALBP.


Assuntos
Atletas , Dor Lombar/etiologia , Vértebras Lombares , Imageamento por Ressonância Magnética , Exame Físico/métodos , Espondilólise/diagnóstico , Tomografia Computadorizada por Raios X , Adolescente , Estudos de Casos e Controles , Diagnóstico Diferencial , Feminino , Humanos , Análise dos Mínimos Quadrados , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/patologia , Masculino , Análise Multivariada , Estudos Prospectivos , Espondilólise/complicações , Adulto Jovem
17.
Sci Total Environ ; 859(Pt 2): 160125, 2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36379337

RESUMO

Human introductions have resulted in earthworms establishing in the Arctic, species known to cause cascading ecosystem change. However, few quantitative outdoor experiments have been performed that describe how these soil modifying earthworms are reshaping structures in tundra soils. In this study, we used three-dimensional (3-D) X-ray images of soil cores (approximately 10 cm diameter, 20 cm height, N = 48) to assess how earthworms (Aporrectodea sp. and Lumbricus sp.) affect soil structure and macropore networks in an outdoor mesocosm experiment that lasted four summers. Effects were assessed in both shrub-dominated (heath) and herb-dominated (meadow) tundra. Earthworms almost doubled the macroporosity in meadow soils and tripled macroporosity in heath. Interestingly, the fractal dimension of macropores decreased in response to earthworm burrowing in both systems, indicating that the presence of earthworms reduced the geometric complexity in comparison to other pore-generating processes active in the tundra. Observed effects on soil structure occurred along with a dramatically reduced soil moisture content, which was observed the first winter after earthworm introduction in the meadow. Our findings suggest that predictions of future changes in vegetation and soil carbon pools in the Arctic should include major impacts on soil properties that earthworms induce.


Assuntos
Oligoquetos , Solo , Animais , Humanos , Solo/química , Ecossistema , Tundra , Carbono
18.
Br J Dermatol ; 167(1): 59-67, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22530854

RESUMO

BACKGROUND: Little is known about the associations of metabolic aberrations with malignant melanoma (MM) and nonmelanoma skin cancer (NMSC). OBJECTIVES: To assess the associations between metabolic factors (both individually and combined) and the risk of skin cancer in the large prospective Metabolic Syndrome and Cancer Project (Me-Can). METHODS: During a mean follow-up of 12 years of the Me-Can cohort, 1728 (41% women) incident MM, 230 (23% women) fatal MM and 1145 (33% women) NMSC were identified. Most NMSC cases (76%) were squamous cell carcinoma (SCC) (873, 33% women). Hazard ratios (HRs) were estimated by Cox proportional hazards regression for quintiles and standardized z-scores (with a mean of 0 and SD of 1) of body mass index (BMI), blood pressure, glucose, cholesterol, triglycerides and for a combined metabolic syndrome score. Risk estimates were corrected for random error in the measurements. RESULTS: Blood pressure per unit increase of z-score was associated with an increased risk of incident MM cases in men and women [HR 1·17, 95% confidence interval (CI) 1·04-1·31 and HR 1·18, 95% CI 1·03-1·36, respectively] and fatal MM cases among women (HR 2·39, 95% CI 1·58-3·64). In men, all quintiles for BMI above the reference were associated with a higher risk of incident MM. In women, SCC NMSC risk increased across quintiles for glucose levels (P-trend 0·02) and there was a trend with triglyceride concentration (P-trend 0·09). CONCLUSION: These findings suggest that mechanisms linked to blood pressure may be involved in the pathogenesis of MM. SCC NMSC in women could be related to glucose and lipid metabolism.


Assuntos
Melanoma/etiologia , Síndrome Metabólica/complicações , Neoplasias Cutâneas/etiologia , Adulto , Austrália/epidemiologia , Estudos de Casos e Controles , Feminino , Humanos , Incidência , Masculino , Melanoma/epidemiologia , Melanoma/metabolismo , Síndrome Metabólica/epidemiologia , Pessoa de Meia-Idade , Noruega/epidemiologia , Estudos Prospectivos , Fatores de Risco , Neoplasias Cutâneas/epidemiologia , Neoplasias Cutâneas/metabolismo , Suécia/epidemiologia
19.
Phys Chem Chem Phys ; 14(31): 10844-52, 2012 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-22781964

RESUMO

Kinetic processes play a crucial role in the formation and evolution of molecular layers. In this perspective we argue that adaptive kinetic Monte Carlo is a powerful simulation technique for determining key kinetic processes in molecular solids. The applicability of the method is demonstrated by simulating the diffusion of a CO admolecule on a water ice surface, which is an important process for the formation of organic compounds on interstellar dust grains. CO diffusion is found to follow Arrhenius behavior and the corresponding effective activation energy for diffusion is determined to be 50 ± 1 meV. A coarse graining algorithm is applied which greatly enhances the efficiency of the simulations at low temperatures, down to 10 K, without altering the underlying physical processes. Eventually, we argue that a combination of both on- and off-lattice kinetic Monte Carlo techniques is a good way for simulating large-scale processes in molecular solids over long time spans.

20.
Spinal Cord ; 50(2): 123-6, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21946442

RESUMO

STUDY DESIGN: Retrospective population-based epidemiological study. OBJECTIVES: To assess the nationwide, population-based incidence, causes, age, gender, extent and prevalence of spinal cord injuries (SCIs) in Iceland from 1975 to 2009. SETTING: Landspitali University Hospital in Iceland, the single referral center for SCIs in Iceland. METHODS: A retrospective review of hospital records on all admissions due to SCIs. Analysis of incidence, causes, age, gender, extent of injury and prevalence. RESULTS: A total of 207 patients with traumatic spinal cord injury (TSCI) were admitted: males 72%, females 28%. The percentage of females with TSCI increased to 37% in 2000-2004. Mean age at injury was 38 years. Average incidence per million population per year was 30 in 1975-1979, 12.5 in 1995-1999 and 33.5 in 2005-2009. Thirty-day mortality was 6.3%. Causes of injury were road traffic accidents (RTA) in 42.5% of the cases; the majority did not use seatbelts. Falls amounted to 30.9%, with an increase of low falls among the elderly causing incomplete cervical lesions. Sport/leisure activities were the cause in 18.8%, of which 54% occurred after 2000. The main single cause of TSCI in sport/leisure were horse-riding accidents, followed by winter sport accidents, especially among women. Other causes constituted 7.7%. The injury was complete in 39%; cervical lesions were 57% and thoracic/lumbar lesions were 43%. In December 2009, the crude prevalence rate was 526 per million population. CONCLUSIONS: The findings showed a significant increase of TSCI in 2005-2009, especially in sport/leisure accidents and incomplete cervical lesions due to falls among elderly. Prevention strategies need to focus on these risk groups and on seatbelt use.


Assuntos
Traumatismos da Medula Espinal/epidemiologia , Prevenção de Acidentes , Acidentes por Quedas , Acidentes , Acidentes de Trânsito , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Islândia , Incidência , Atividades de Lazer , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Cintos de Segurança , Traumatismos da Medula Espinal/etiologia , Traumatismos da Medula Espinal/mortalidade , Adulto Jovem
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