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1.
Data Brief ; 54: 110291, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38524845

RESUMO

Sustainable fuel initiatives in the United States such as the Environmental Protection Agency's Renewable Fuel Standard and the Department of Energy's Sustainable Aviation Fuel Grand Challenge have increased the production of corn ethanol and soybean biodiesel. However, the lack of precise information regarding biomass sourcing at a localized level has hindered accurate understanding of both biofuel costs and environmental impact of these production pathways. By harnessing the power of geospatial analysis and leveraging United States Department of Agriculture (USDA) crop census data, this dataset fills this critical knowledge gap. This dataset offers a novel estimation of geospatial biomass sourcing for biofuel production in the United States by synthesizing 2017 USDA crop census data, biorefinery data from the United States Energy Information Administration, and publicly available information about biomass sourcing for biofuel production. This dataset provides a detailed understanding of biomass use for first generation biofuel production, enabling stakeholders to make informed decisions about resource allocation, investment strategies, and infrastructure development. Furthermore, the county-level granularity of the dataset allows for increased fidelity in the techno-economic assessments and life-cycle analyses of first-generation biofuels in the United States.

2.
Qual Quant ; 56(5): 2875-2906, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34629554

RESUMO

Blockchain can function as a foundational technology with numerous applications in smart cities. The objective of this paper is twofold. First, it provides a detailed overview of the extant literature on blockchain applications in smart cities; second, it reveals the trends and suggests future research directions for scholars who wish to contribute to this rapidly growing field. We conducted a bibliometric review using a keyword co-occurrence network and article co-citation analysis. The analysis includes the assessment of 148 articles published between 2016 and 2020 in 76 academic journals. The review results demonstrate that the number of articles devoted to the study of blockchain applications and smart cities has increased exponentially in recent years. More importantly, the research identifies some of the most influential studies in this area. The paper discusses trends and highlights the challenges related to the deployment of blockchain in smart cities. To the authors' best knowledge, this represents the first study to review the literature from leading journals on blockchain applications in smart cities using bibliometric techniques.

3.
Bone ; 81: 562-572, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26318907

RESUMO

Bone loss associated with microgravity exposure poses a significant barrier to long-duration spaceflight. Osteoprotegerin-Fc (OPG-Fc) is a receptor activator of nuclear factor kappa-B ligand (RANKL) inhibitor that causes sustained inhibition of bone resorption after a single subcutaneous injection. We tested the ability of OPG-Fc to preserve bone mass during 12 days of spaceflight (SF). 64-day-old female C57BL/6J mice (n=12/group) were injected subcutaneously with OPG-Fc (20mg/kg) or an inert vehicle (VEH), 24h prior to launch. Ground control (GC) mice (VEH or OPG-Fc) were maintained under environmental conditions that mimicked those in the space shuttle middeck. Age-matched baseline (BL) controls were sacrificed at launch. GC/VEH, but not SF/VEH mice, gained tibia BMD and trabecular volume fraction (BV/TV) during the mission (P<0.05 vs. BL). SF/VEH mice had lower BV/TV vs. GC/VEH mice, while SF/OPG-Fc mice had greater BV/TV than SF/VEH or GC/VEH. SF reduced femur elastic and maximum strength in VEH mice, with OPG-Fc increasing elastic strength in SF mice. Serum TRAP5b was elevated in SF/VEH mice vs. GC/VEH mice. Conversely, SF/OPG-Fc mice had lower TRAP5b levels, suggesting that OPG-Fc preserved bone during spaceflight via inhibition of osteoclast-mediated bone resorption. Decreased bone formation also contributed to the observed osteopenia, based on the reduced femur periosteal bone formation rate and serum osteocalcin level. Overall, these observations suggest that the beneficial effects of OPG-Fc during SF are primarily due to dramatic and sustained suppression of bone resorption. In growing mice, this effect appears to compensate for the SF-related inhibition of bone formation, while preventing any SF-related increase in bone resorption. We have demonstrated that the young mouse is an appropriate new model for SF-induced osteopenia, and that a single pre-flight treatment with OPG-Fc can effectively prevent the deleterious effects of SF on mouse bone.


Assuntos
Reabsorção Óssea/prevenção & controle , Fragmentos Fc das Imunoglobulinas/farmacologia , Osteoprotegerina/farmacologia , Proteínas Recombinantes de Fusão/farmacologia , Voo Espacial , Ausência de Peso/efeitos adversos , Fosfatase Alcalina/sangue , Animais , Biomarcadores/sangue , Fenômenos Biomecânicos , Densidade Óssea/efeitos dos fármacos , Conservadores da Densidade Óssea/farmacologia , Reabsorção Óssea/etiologia , Reabsorção Óssea/fisiopatologia , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Osteocalcina/sangue , Ligante RANK/antagonistas & inibidores
4.
In Vivo ; 25(3): 297-305, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21576402

RESUMO

BACKGROUND/AIM: Insulin-like growth factor-1 (IGF-1) and macrophage colony-stimulating factor (MCSF) are critical to skeletal homeostasis. We investigated the effects of combined IGF-1 plus MCSF on mice. MATERIALS AND METHODS: C57BL/6J mice, aged 7 weeks, were assigned to baseline, vehicle, IGF-1, MCSF, or combined IGF-1 plus MCSF (1 mg/kg/day each, n=12-13/group, 28-day duration). RESULTS: IGF-1 or MCSF had no effect on bone formation rate; however, IGF-1 plus MCSF produced a 169% increase in periosteal bone formation rate. Combined therapy increased femoral mechanical properties (+25% elastic force), while IGF-1, and MCSF alone did not. Combined therapy affected trabecular bone volume fraction (+40%), number (+13%), and spacing (-13%). MCSF produced similar trabecular changes, while IGF-1 had no effect. Combined therapy and MCSF alone increased bone mineral content. CONCLUSION: We have demonstrated the superior effects of combined IGF-1 and MCSF. Together, these agents may promote bone modeling to a greater extent than either therapy alone.


Assuntos
Osso e Ossos/efeitos dos fármacos , Fator de Crescimento Insulin-Like I/farmacologia , Fator Estimulador de Colônias de Macrófagos/farmacologia , Animais , Peso Corporal/efeitos dos fármacos , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/metabolismo , Calcificação Fisiológica/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Radiografia
5.
J Muscle Res Cell Motil ; 31(2): 141-53, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20632203

RESUMO

In this study, we examined the effects of 2-week hindlimb un-loading in mice followed by re-ambulation with voluntary access to running wheels. The recovery period was terminated at a time point when physical performance--defined by velocity, time, and distance ran per day--of the suspended group matched that of an unsuspended group. Mice were assigned to one of four groups: unsuspended non-exercise (Control), 14 days of hindlimb suspension (HS), 7 days of access to running wheels (E7), or 14 days of HS plus 7 days access to running wheels (HSE7). HS resulted in significant decreases in body and muscle mass, hindlimb strength, soleus force, soleus specific force, fatigue resistance, and fiber cross sectional area (CSA). Seven days of re-ambulation with access to running wheels following HS recovered masses to Control values, increased fiber CSA, increased resistance to fatigue and improved recovery from fatigue in the soleus. HS resulted in a myosin heavy chain (MHC) phenotype shift from slow toward fast-twitch fibers, though running alone did not influence the expression of MHC fibers. Compared to the Control group, HSE7 mice did not recover functional hindlimb strength as assessed through measurements either in vivo or ex vivo. Results from this study demonstrate that 7 days of muscle re-loading with access to wheel-running following HS can stimulate muscle to regain mass and fiber CSA and exhibit improved metrics of fatigue resistance and recovery, yet muscles remain impaired in regard to strength. Understanding this mismatch between muscle morphology and strength may prove of value in designing effective exercise protocols for disuse muscle atrophy rehabilitation.


Assuntos
Fadiga Muscular/fisiologia , Força Muscular/fisiologia , Atrofia Muscular/fisiopatologia , Condicionamento Físico Animal , Recuperação de Função Fisiológica/fisiologia , Animais , Elevação dos Membros Posteriores , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Contração Muscular , Músculo Esquelético/ultraestrutura , Atrofia Muscular/etiologia , Atrofia Muscular/patologia , Cadeias Pesadas de Miosina/metabolismo
6.
J Bone Miner Metab ; 27(5): 546-54, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19326045

RESUMO

Macrophage colony-stimulating factor (M-CSF) is a hematopoietic growth factor that plays a critical role in early osteoclastogenesis. To characterize the skeletal effects of M-CSF, we administered soluble M-CSF to mice. It was hypothesized that M-CSF would stimulate bone formation through coupled activity of osteoclasts and osteoblasts. Twenty-four male C57BL/6 J mice (n = 12/group, aged 7 weeks) received subcutaneous injections of human M-CSF [5 mg/(kg day)] or inert vehicle (VEH) for 21 days. M-CSF increased serum bone turnover markers (+57% TRAP-5b and +44% osteocalcin). Microcomputed tomography revealed an anabolic effect on tibial trabecular bone, with higher bone volume fraction (+35%), connectivity density (+79%), and number (+18%), as well as lower trabecular separation (-18%). M-CSF had no significant effect on cortical bone mineral content, geometry, or strength. There was no change in quantitative histomorphometry parameters of femoral cortical bone. These results reveal the complex, site-specific effects of M-CSF. In particular, we have demonstrated an anabolic effect of M-CSF on trabecular bone achieved through coupled activation of osteoblasts. However, in contrast to previous studies, M-CSF was found to have no effect on cortical bone. M-CSF was demonstrated to significantly influence both bone modeling and remodeling in relatively young animals.


Assuntos
Remodelação Óssea/efeitos dos fármacos , Fator Estimulador de Colônias de Macrófagos/administração & dosagem , Fator Estimulador de Colônias de Macrófagos/farmacologia , Animais , Biomarcadores/sangue , Fenômenos Biomecânicos/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Densidade Óssea/efeitos dos fármacos , Calcificação Fisiológica/efeitos dos fármacos , Relação Dose-Resposta a Droga , Fêmur/anatomia & histologia , Fêmur/diagnóstico por imagem , Fêmur/efeitos dos fármacos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tamanho do Órgão/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Projetos Piloto , Baço/anatomia & histologia , Baço/efeitos dos fármacos , Tíbia/anatomia & histologia , Tíbia/diagnóstico por imagem , Tíbia/efeitos dos fármacos , Microtomografia por Raio-X
7.
IEEE Trans Neural Netw ; 18(3): 931-5, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17526360

RESUMO

This letter introduces a new algorithm for the restoration of a noisy blurred image based on the support vector regression (SVR). Experiments show that the performance of the SVR is very robust in blind image deconvolution where the types of blurs, point spread function (PSF) support, and noise level are all unknown.


Assuntos
Algoritmos , Inteligência Artificial , Interpretação de Imagem Assistida por Computador/métodos , Armazenamento e Recuperação da Informação/métodos , Modelos Teóricos , Reconhecimento Automatizado de Padrão/métodos , Simulação por Computador , Redes Neurais de Computação , Análise de Regressão
8.
Artigo em Inglês | MEDLINE | ID: mdl-17282196

RESUMO

Most current Holter devices monitor the ECG for 24 to 72 hours. However, for the accurate diagnosis of many cardiac diseases, especially for the wide variety of asymptomatic cases, continuous ECG monitoring for weeks or even months may be required. In this paper, we focus on the issue of ECG compression during long-term monitoring of the patient. The patient may be at home, at work, or even on a trip. A scalable compression scheme is proposed which ensures optimal signal quality given the limited physical storage on the wearable device. When necessary, the signal quality is progressively and gently degraded in order to adapt to environmental and the patient's conditions. Details of the proposed scheme are described and sample results are presented.

9.
Biomed Sci Instrum ; 40: 93-8, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15133941

RESUMO

Macrophage-Colony Stimulating Factor (M-CSF) is critical for osteoclast differentiation and development. It has been previously observed that M-CSF administration and over-expression in mice causes an increase in cortical bone formation. We hypothesize that M-CSF increases osteoblast activity indirectly via coupling of these two bone cells. This study examined the impact on bone properties of relatively low doses of M-CSF in mice. Four groups of seven-week old C57BL/6J mice were used: (1) baseline controls, (2) placebo controls, (3) 10 micrograms/kg/day M-CSF, (4) 100 micrograms/kg/day M-CSF. Injections were administered daily for the 21-day study. Three bone labels of calcein and tetracycline were alternately administrated (days 0, 9 and 18) to allow quantification of new bone formation. MicroCT scans (15 micron resolution) were performed on the proximal end of the right tibiae (1.0 mm section of trabecular bone) and left femur mid-diaphysis (0.25 mm cortical section). Dry mass, mineral content and percent mineral composition were obtained from the left tibiae. Functional changes were not detected in the bones of the mice receiving low doses of M-CSF. In particular, as previous studies have reported in mice receiving high doses of M-CSF or transgenic mice overexpressing bone specific M-CSF, changes to cortical bone did not occur with the lower doses. This may indicate that high doses of M-CSF and/or longer periods of administration may be required to observe the anabolic effect of M-CSF on mouse cortical bone.


Assuntos
Densidade Óssea/efeitos dos fármacos , Desenvolvimento Ósseo/efeitos dos fármacos , Fêmur/efeitos dos fármacos , Fêmur/fisiologia , Fator Estimulador de Colônias de Macrófagos/administração & dosagem , Tíbia/efeitos dos fármacos , Tíbia/fisiologia , Animais , Relação Dose-Resposta a Droga , Fêmur/citologia , Fêmur/diagnóstico por imagem , Camundongos , Camundongos Endogâmicos C57BL , Radiografia , Tíbia/citologia , Tíbia/diagnóstico por imagem
10.
Biomed Sci Instrum ; 40: 105-10, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15133943

RESUMO

Osteoporosis is a disease characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility and increased susceptibility to fractures. The microgravity of space creates an extreme environment that provides a model for osteoporosis in humans. This greatly accelerated form of osteopenia results in a 0.5-2% loss of bone mass per month. Rat models for this osteoporosis have been examined on many occasions, but STS-108 was the first Space Shuttle flight to use mice. Data reported to date indicate that spaceflight experiments with mice hold promise in predicting some spaceflight effects on humans. Due to the cost and infrequency of flights, ground-based models have been developed to mimic the deleterious effects of the microgravity environment. Hindlimb suspension is one such localized model. This model removes gravitational loading from the hindlimbs by suspending the animal by its tail to a guy wire that runs lengthwise across the cage. Because mice had not flown before STS-108, a direct comparison of this model's ability to predict spaceflight results has not been examined. The objective of this research is to closely repeat the STS-108 profile, with hindlimb suspension replacing spaceflight. This includes examining the ability of the protein osteoprotegerin, an osteoclast-inhibiting therapeutic, to mitigate the deleterious effects of skeletal unloading. It is expected that the results will lead to better understanding of the mechanisms of mineralization and bone remodeling to aid in development of countermeasures to prevent spaceflight induced osteoporosis and aid the treatment of osteoporosis here on earth.


Assuntos
Densidade Óssea , Fêmur/patologia , Fêmur/fisiopatologia , Elevação dos Membros Posteriores/fisiologia , Transtornos Musculares Atróficos/patologia , Transtornos Musculares Atróficos/fisiopatologia , Ausência de Peso/efeitos adversos , Animais , Peso Corporal , Fêmur/efeitos dos fármacos , Glicoproteínas/uso terapêutico , Membro Posterior/efeitos dos fármacos , Membro Posterior/patologia , Membro Posterior/fisiopatologia , Camundongos , Camundongos Endogâmicos C57BL , Transtornos Musculares Atróficos/etiologia , Transtornos Musculares Atróficos/prevenção & controle , Osteoprotegerina , Receptores Citoplasmáticos e Nucleares/uso terapêutico , Receptores do Fator de Necrose Tumoral , Voo Espacial , Simulação de Ausência de Peso/efeitos adversos
11.
Microgravity Sci Technol ; 15(3): 3-11, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15770772

RESUMO

The number one priority for any manned space mission is the health and safety of its crew. The study of the short and long term physiological effects on humans is paramount to ensuring crew health and mission success. One of the challenges associated in studying the physiological effects of space flight on humans, such as loss of bone and muscle mass, has been that of readily attaining the data needed to characterize the changes. The small sampling size of astronauts, together with the fact that most physiological data collection tends to be rather tedious, continues to hinder elucidation of the underlying mechanisms responsible for the observed changes that occur in space. Better characterization of the muscle loss experienced by astronauts requires that new technologies be implemented. To this end, we have begun to validate a 360 degree ultrasonic scanning methodology for muscle measurements and have performed empirical sampling of a limb surrogate for comparison. Ultrasonic wave propagation was simulated using 144 stations of rotated arm and calf MRI images. These simulations were intended to provide a preliminary check of the scanning methodology and data analysis before its implementation with hardware. Pulse-echo waveforms were processed for each rotation station to characterize fat, muscle, bone, and limb boundary interfaces. The percentage error between MRI reference values and calculated muscle areas, as determined from reflection points for calf and arm cross sections, was -2.179% and +2.129%, respectively. These successful simulations suggest that ultrasound pulse scanning can be used to effectively determine limb cross-sectional areas. Cross-sectional images of a limb surrogate were then used to simulate signal measurements at several rotation angles, with ultrasonic pulse-echo sampling performed experimentally at the same stations on the actual limb surrogate to corroborate the results. The objective of the surrogate sampling was to compare the signal output of the simulation tool used as a methodology validation for actual tissue signals. The disturbance patterns of the simulated and sampled waveforms were consistent. Although only discussed as a small part of the work presented, the sampling portion also helped identify important considerations such as tissue compression and transducer positioning for future work involving tissue scanning with this methodology.


Assuntos
Simulação por Computador , Modelos Anatômicos , Músculo Esquelético/diagnóstico por imagem , Voo Espacial , Ultrassom , Ausência de Peso/efeitos adversos , Animais , Braço , Humanos , Perna (Membro) , Imageamento por Ressonância Magnética , Sus scrofa , Ultrassonografia
12.
Bone ; 33(3): 387-98, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-13678781

RESUMO

The objective of this study was to examine changes in the long bones of male C57BL/6J mice with growth and aging, and to consider the applicability of this animal for use in studying Type II osteoporosis. Male C57BL/6J mice were aged in our colony between 4 and 104 weeks (n=9-15/group). The right femur and humeri were measured for length and subjected to mechanical testing (3-point flexure) and compositional analysis. The left femurs were embedded and thick slices at the mid-diaphysis were assessed for morphology, formation indices, and bone structure. In young mice, rapid growth was marked by substantial increases in bone size, mineral mass, and mechanical properties. Maturity occurred between 12 and 42 weeks of age with the maintenance of bone mass and mechanical properties. From peak levels, mice aged for 104 weeks experienced decreased whole femur mass (12.1 and 18.6% for dry and ash mass, respectively), percentage mineralization (7.4%), diminished whole bone stiffness (29.2%), energy to fracture (51.8%), and decreased cortical thickness (20.1%). Indices of surface-based formation decreased rapidly from the onset of the study. However, the periosteal perimeter and, consequently, the cross-sectional moments of inertia continued to increase through 104 weeks, thus maintaining structural properties. This compensated for cortical thinning and increased brittleness due to decreased mineralization and stiffness. The shape of the mid-diaphysis became increasingly less elliptical in aged mice, and endocortical resorption and evidence of subsequent formation were present in 20-50% of femurs aged > or =78 weeks. This, combined with the appearance of excessive endocortical resorption after 52 weeks, indicated a shift in normal mechanisms regulating bone shape and location, and was suggestive of remodeling. The pattern of bone loss at the femoral mid-diaphysis in this study is markedly similar to that seen in cortical bone in the human femoral neck in Type II osteoporosis. This study has thus demonstrated that the male C57BL/6J mouse is a novel and appropriate model for use in studying endogenous, aging-related osteopenia and may be a useful model for the study of Type II osteoporosis.


Assuntos
Envelhecimento/fisiologia , Desenvolvimento Ósseo/fisiologia , Osteoporose/fisiopatologia , Envelhecimento/patologia , Animais , Peso Corporal , Doenças Ósseas Metabólicas/patologia , Doenças Ósseas Metabólicas/fisiopatologia , Calcificação Fisiológica/fisiologia , Diáfises/citologia , Diáfises/crescimento & desenvolvimento , Diáfises/fisiologia , Fêmur/citologia , Fêmur/crescimento & desenvolvimento , Fêmur/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL
13.
J Appl Physiol (1985) ; 94(5): 2085-94, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12514166

RESUMO

There are several aspects of the spaceflight environment that may lead to changes in immunity: mission-related psychological stress, radiation, and changes in gravity. On December 5, 2001, the space shuttle Endeavor launched for a 12-day mission to examine these effects on C57BL/6 mice for the first time. On their return, assays were performed on the spleen, blood, and bone marrow. In response to flight, there were no significant differences in the general circulating leukocyte proportions. In contrast, there was an increase in splenic lymphocyte percentages, with a corresponding decrease in granulocytes. There was an overall shift in splenic lymphocytes away from T cells toward B cells, and a decrease in the CD4-to-CD8 ratios due to a decrease in T helpers. In contrast, there were proportional increases in bone marrow T cells, with decreases in B cells. Although the blast percentage and count were decreased in flight mice, the CD34(+) population was increased. The data were more consistent with a shift in bone marrow populations rather than a response to changes in the periphery. Many of the results are similar to those using other models. Clearly, spaceflight can influence immune parameters ranging from hematopoiesis to mature leukocyte mechanisms.


Assuntos
Imunidade/fisiologia , Voo Espacial , Animais , Medula Óssea/imunologia , Medula Óssea/fisiologia , Feminino , Citometria de Fluxo , Granulócitos/imunologia , Imunidade Celular/imunologia , Imunidade Celular/fisiologia , Contagem de Leucócitos , Sistema Linfático/imunologia , Sistema Linfático/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Baço/citologia , Baço/imunologia , Células-Tronco/fisiologia
14.
J Appl Physiol (1985) ; 94(5): 2095-103, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12506046

RESUMO

This portion of the study quantified the effects of a 12-day space shuttle mission (Space Transport System-108/UF-1) on body and lymphoid organ masses, activation marker expression, cytokine secretion, and erythrocyte and thrombocyte characteristics in C57BL/6 mice. Animals in flight (Flt group) had 10-12% lower body mass compared with ground controls housed either in animal enclosure modules or under standard vivarium conditions (P < 0.001) and the smallest thymus and spleen masses. Percentages of CD25(+) lymphocytes, CD3(+)/CD25(+) T cells, and NK1.1(+)/CD25(+) natural killer cells from Flt mice were higher compared with both controls (P < 0.05). In contrast, CD71 expression was depressed in the Flt and animal enclosure module control mice compared with vivarium control animals (P < 0.001). Secretion of interferon-gamma, IL-2, and IL-4, but not tumor necrosis factor-alpha and IL-5, by splenocytes from Flt mice was decreased relative to either one or both ground controls (P < 0.05). Flt mice also had high red blood cell and thrombocyte counts compared with both sets of controls; low red blood cell volume and distribution width, percentage of reticulocytes, and platelet volume were also noted (P < 0.05) and were consistent with dehydration. These data indicate that relatively short exposure to the spaceflight environment can induce profound changes that may become significant during long-term space missions.


Assuntos
Plaquetas/fisiologia , Citocinas/biossíntese , Eritrócitos/fisiologia , Imunidade/fisiologia , Voo Espacial , Animais , Biomarcadores , Peso Corporal/fisiologia , Sobrevivência Celular/fisiologia , Ingestão de Líquidos/fisiologia , Ingestão de Alimentos/fisiologia , Contagem de Eritrócitos , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Tamanho do Órgão/fisiologia , Contagem de Plaquetas , Baço/citologia
15.
J Bone Miner Res ; 17(6): 1044-50, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12054159

RESUMO

To determine whether the mouse loses bone with aging and whether the changes mimic those observed in human aging, we examined the changes in the tibial metaphysis and diaphysis in the male C57BL/6J mouse over its life span using microcomputed tomography (microCT). Cancellous bone volume fraction (BV/TV) decreased 60% between 6 weeks and 24 months of age. Loss was characterized by decreased trabecular number (Tb.N), increased trabecular spacing (Tb.Sp), and decreased connectivity. Anisotropy decreased while the structure model index increased with age. Cortical bone thickness increased between 6 weeks and 6 months of age and then decreased continuously to 24 months (-12%). Cortical bone area (Ct.Ar) remained constant between 6 and 24 months. Fat-free weight reached a peak at 12 months and gradually declined to 24 months. Total mass lost between 12 and 24 months reached 10%. Overall, the age-related changes in skeletal mass and architecture in the mouse were remarkably similar to those seen in human aging. Furthermore, the rapid early loss of cancellous bone suggests that bone loss is not just associated with old age in the mouse but rather occurs as a continuum from early growth. We conclude that the C57BL/6J male mouse maybe a useful model to study at least some aspects of age-related bone loss in humans.


Assuntos
Envelhecimento/fisiologia , Osso e Ossos/anatomia & histologia , Tamanho do Órgão , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tomografia Computadorizada por Raios X
16.
Biomed Sci Instrum ; 38: 47-52, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12085652

RESUMO

We investigated the effect of major histocompatibility complex class II (MHC II) knockout on the development of the mouse peripheral skeleton. These C2D mice had less skeletal development at 8, 12 and 16 weeks of age compared to wild-type C57BL/6J (B6) male mice. The C2D mice had decreased femur mechanical, geometric and compositional measurements compared to wild type mice at each of these ages. C2D femur stiffness (S), peak force in 3-pt bending (Pm), and mineral mass (Min-M) were 74%, 64% and 66%, respectively, of corresponding B6 values at 8 weeks of age. Similar differences were measured at 12 weeks (for which C2D femoral S, Pm and Min-M were 71%, 72% and 73%, respectively, of corresponding B6 values) and at 16 weeks (for which C2D femoral S, Pm and Min-M were 80%, 66% and 61%, respectively, of corresponding B6 values). MHC II knockout delays the development of adult bone properties and is accompanied by lower body mass compared to wild-type controls.


Assuntos
Desenvolvimento Ósseo/genética , Genes MHC da Classe II/genética , Animais , Densidade Óssea/fisiologia , Desenvolvimento Ósseo/fisiologia , Corticosterona/sangue , Fêmur/crescimento & desenvolvimento , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
17.
Microbiology (Reading) ; 143 ( Pt 2): 449-455, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9043122

RESUMO

Previous investigations have reported that space flight may produce a stimulating effect on microbial metabolism; however, the specific underlying mechanisms associated with the observed changes have not yet been identified. In an effort to systematically evaluate the effect of space flight on each phase of microbial growth (lag, exponential and stationary), a series of experiments was carried out using in vitro suspension cultures of Escherichia coli aboard seven US Space Shuttle missions. The results indicated that, as a result of space flight, the lag phase was shortened, the duration of exponential growth was increased, and the final cell population density was approximately doubled. A model was derived from these cumulative data in an attempt t associate gravity-dependent, extracellular transport phenomena with unique changes observed in each specific phase of growth. It is suggested that a cumulative effect of gravity may have a significant impact on suspended cells via their fluid environment, where an immediate, direct influence of gravity might otherwise be deemed negligible.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Voo Espacial , Ausência de Peso , Técnicas Bacteriológicas/instrumentação , Transporte Biológico , Estudos de Avaliação como Assunto , Modelos Biológicos , Astronave
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