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1.
Langmuir ; 37(29): 8687-8695, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34270898

RESUMO

Solute transport in a narrow space is the most elemental process in chromatography and biological pattern formation. However, the observation of such transport has been quite difficult, and theoretical investigations have therefore preponderated. Here, using a space- and time-resolved surface plasmon resonance (SPR) method, we measured the nanoscale near-wall (next to the wall) transport rate in a narrow channel after a solution and its solvent had come into contact. By combining the SPR method with a capillary injection method, which enables two solution plugs to flow immediately after they have made contact, we were able to measure the solute concentration evolution at the channel wall. We tested three combinations of two plugs of solution-water-glucose, sodium chloride-water, and glucose-sodium chloride-and succeeded in measuring diffusion-coefficient-dependent changes in the concentration of solute flowing through a rectangular microchannel in less than 0.4 s. A numerical analysis of this system revealed the acceleration of the solute/solution boundary moving on the wall and its deceleration at the center of the channel cross section. The observed experimental transport rate agreed with the numerical result quantitatively. These results show that the solute transport followed a laminar flow with a no-slip model and that the molecules were transported in the order of their diffusivity. In the third combination, when the two solutions made contact and started flowing, the interdiffusion of the solutes resulted in temporal concentrations lower than either of the solutions before contact, which indicated that the contact between the two solutions quickly led to separation by the advection-diffusion processes. We found that such a concentration profile could actually be measured. Our techniques are simple and applicable to a wide range of molecules; the method opens the way to direct observation of the space-time near-wall solute transport process and can be used for the rapid determination of diffusivity.


Assuntos
Modelos Teóricos , Água , Transporte Biológico , Difusão , Soluções
2.
Sci Rep ; 9(1): 16961, 2019 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-31740758

RESUMO

The addition of biochar to the forest floor should facilitate efficient carbon sequestration. However, little is known about how biochar addition effects litter decomposition, which is related to carbon and nutrient dynamics in forest ecosystems. This study evaluated the effect of biochar addition on leaf litter decomposition in a forest ecosystem. To examine whether leaf litter decomposition was stimulated above and below biochar, litterbag experiments were carried out for about 3 years in a field site where biochar was added at the rate of 0, 5 and 10 t ha-¹ (C0, C5 and C10 plots) to the forest floor in a temperate oak forest, Japan. Biochar addition at C10 significantly enhanced litter decomposition below biochar for 2 years after treatment and above biochar for 1 year after treatment. Litter water content in biochar plots tended to increase under dry conditions. Biochar addition enhanced litter decomposition because of increased microbial activity with increased moisture content and accelerated the decomposition progress rather than changing the decomposition pattern. However, the carbon emission through changing leaf litter decomposition was small when compared with the carbon addition by biochar, indicating that biochar could be an effective material for carbon sequestration in forest ecosystems.

3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 3797-3800, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28269113

RESUMO

An adaptive Kalman filter-based fusion algorithm capable of estimating respiration rate for unobtrusive respiratory monitoring is proposed. Using both signal characteristics and a priori information, the Kalman filter is adaptively optimized to improve accuracy. Furthermore, the system is able to combine the respiration-related signals extracted from a textile ECG sensor and an accelerometer to create a single robust measurement. We measured derived respiratory rates and, when compared to a reference, found root-mean-square error of 2.11 breaths-per-minute (BrPM) while lying down, 2.30 BrPM while sitting, 5.97 BrPM while walking, and 5.98 BrPM while running. These results demonstrate that the proposed system is applicable to unobtrusive monitoring for various applications.


Assuntos
Eletrocardiografia/métodos , Taxa Respiratória/fisiologia , Processamento de Sinais Assistido por Computador , Acelerometria/métodos , Algoritmos , Eletrocardiografia/instrumentação , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica/métodos , Postura , Têxteis , Caminhada
4.
Nihon Jinzo Gakkai Shi ; 57(5): 878-83, 2015.
Artigo em Japonês | MEDLINE | ID: mdl-26625471

RESUMO

A previously healthy 67-year-old woman visited our institution because of cough that had persisted for 3 months, fever at night, left tinnitus, and hearing loss from 1 month prior. She lost 2 kg in weight over the last 6 months, and her C-reactive protein level and leukocyte count were increased. Computed tomography revealed multiple small nodules in both lung fields. She was admitted to our hospital for further examination to determine the optimal medical treatment. Because the myeloperoxidase antineutrophil cytoplasmic antibody (ANCA) titer was 132.5 U/mL and microscopic hematuria was observed, vasculitis was considered. A percutaneous kidney biopsy was performed and revealed microscopic polyangiitis. For this reason, the case was diagnosed as ANCA-associated vasculitis. Esophageal stenosis and pseudodiverticulosis were observed on upper gastrointestinal endoscopy. Pathological changes due to inflammation were observed in the biopsy and esophagography. Pulse therapy with methylprednisolone at 1,000 mg/day was administered to the patient as the first-line treatment, followed by prednisolone at 40 mg/day as remission induction treatment. Bloody urine and lung shadows disappeared, and the steroid dose was tapered at hospital discharge. The patient's hearing ability and the esophageal pathological change that was considered to be ANCA-associated vasculitis were improved. Although a few studies have reported that esophageal stenosis and pseudodiverticulosis accompany ANCA-associated vasculitis, we think that examination for the possible presence of gastrointestinal tract lesions is important.


Assuntos
Anticorpos Antinucleares/imunologia , Estenose Esofágica/etiologia , Vasculite/tratamento farmacológico , Idoso , Biópsia , Estenose Esofágica/patologia , Esofagoscopia , Feminino , Humanos , Tomografia Computadorizada por Raios X , Vasculite/etiologia , Vasculite/patologia
5.
Nihon Jinzo Gakkai Shi ; 55(1): 63-70, 2013.
Artigo em Japonês | MEDLINE | ID: mdl-23461212

RESUMO

An eighty-one-year-old male with lower leg edema and proteinuria was diagnosed as having nephrotic syndrome and was hospitalized for a detailed examination. Kidney biopsy and immunostaining revealed nodular glomerulosclerosis and deposition of lambda chains, respectively. Because these findings indicate the occurrence of light chain deposition disease (LCDD), the underlying disease was found to be multiple myeloma BJ-lambda. After the administration of melphalan and prednisolone, followed by further addition of zoledronic acid, the patient's nephrosis remitted. However, renal dysfunction gradually deteriorated further and hemodialysis was instituted. He eventually died of gastrointestinal bleeding and biliary infection. The period of time from the initial diagnosis to death was thirty months. Autopsy revealed pervasive infiltration of plasma cells and light chain deposition in multiple organs. The uncontrollable gastrointestinal bleeding appears to have been caused by light chain deposition in the vascular walls of a bile duct. Although medical treatment for elderly LCDD cases depends on chemotherapy alone, it is difficult to obtain a complete remission with melphalan and prednisolone, according to the literature. Reports on the validities of biological agents, such as bortezomib, are beginning to appear, and accumulation of further therapeutic experience is eagerly awaited.


Assuntos
Rim/ultraestrutura , Mieloma Múltiplo/patologia , Síndrome Nefrótica/patologia , Idoso de 80 Anos ou mais , Autopsia , Humanos , Cadeias Leves de Imunoglobulina/metabolismo , Masculino , Melfalan/uso terapêutico , Microscopia Eletrônica , Mieloma Múltiplo/tratamento farmacológico , Síndrome Nefrótica/diagnóstico , Prednisolona/uso terapêutico
6.
Appl Magn Reson ; 41(1): 1-18, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21957330

RESUMO

Infestation of harvested apple fruits by the peach fruit moth (Carposina sasakii Matsumura) was studied using a dedicated magnetic resonance imaging (MRI) apparatus equipped with a 0.2-T permanent magnet. Infested holes on the three-dimensional (3-D) images tracked ecological movements of peach fruit moth larvae within the food fruits, and thus in their natural habitat. Sensitive short solenoid coil and surface coil detectors were devised to shorten measurement times. The short solenoid coil detected infestation holes at a rate of 6.4 s per image by the single-slice 2-D measurement. The multi-slice 2-D measurement provided six slice images of a fruit within 2 min taken by the two detectors. These results indicate that the 0.2-T MRI apparatus allows one to distinguish sound fruits from infested ones, and also as a means for plant protection and the preservation of natural ecological systems in foreign trade.

7.
Gan To Kagaku Ryoho ; 37(10): 1957-60, 2010 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-20976991

RESUMO

We report a case of alphafetoprotein (AFP)-producing gastric cancer that accompanied early gastric cancer and was treated effectively by chemotherapy. The patient was a 73-year-old male. A type 1 tumor was observed in the upper gastric body and a 0-IIa tumor was noted on the anterior wall of the lower gastric body. Abdominal CT showed multiple metastatic lesions in the liver. A subtotal gastrectomy was performed, and the pathological examination revealed that the type 1 tumor was positive for AFP and the 0-IIa tumor was negative for AFP. After 5 courses of postoperative administration of S-1, hepatic metastatic lesions disappeared on imaging. The serum AFP level, which had increased to the maximum of 49,660 ng/ml, was normalized. After 60 months, there has been no sign of recurrence. We encountered a case of AFP-producing gastric cancer that accompanied early gastric cancer and was treated effectively by S-1. Various therapies for AFP-producing gastric cancer have been reported; however, a standardized regimen has not been established. Since the concurrence of AFP-producing gastric cancer and tubular adenocarcinoma is rare, and hepatic metastatic lesions disappeared, the case under study is considered to be of interest. Therefore, we report this case with a review of the literature.


Assuntos
Neoplasias Hepáticas/tratamento farmacológico , Ácido Oxônico/uso terapêutico , Neoplasias Gástricas/tratamento farmacológico , Tegafur/uso terapêutico , alfa-Fetoproteínas/metabolismo , Idoso , Combinação de Medicamentos , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/secundário , Neoplasias Gástricas/sangue , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia , Tomografia Computadorizada por Raios X
8.
Clin Oral Implants Res ; 21(8): 830-4, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20666797

RESUMO

OBJECTIVE: To assess effects of dose reduction on image quality in evaluating maxilla and mandible for pre-surgical implant planning using cadavers. MATERIALS AND METHODS: Six cadavers were used for the study using multi-detector computed tomography (CT) operated at 120 kV and the variable tube current of 80, 40, 20 and 10 mA. A slice thickness of 0.625 mm and pitch 1 were used. Multi-planar images perpendicular and parallel to dentitions were created. The images were evaluated by five oral radiologists in terms of visibility of the anatomical landmarks including alveolar crest, mandibular canal, floors of the maxillary sinus and nasal cavity, contours/cortical layer of jaw bones and the details of trabecular bone. Observers were asked to determine the quality of the images in comparison with 80 mA images based on the criteria: excellent, good, fair or non-diagnostic. The average scores of all observers were calculated for each specimen in all exposure conditions. RESULTS: The 40 mA images could visualize such landmarks and were evaluated to be same or almost equivalent in quality to the 80 mA images. Even the 20 mA images could be accepted just for diagnostic purpose for implant with substantial deterioration of the image quality. The 10 mA images may not be accepted because of the obscured contour caused by image noise. CONCLUSION: Significant dose reduction by lowering mA can be utilized for pre-surgical implant planning in multi-detector CT.


Assuntos
Implantação Dentária Endóssea , Mandíbula/diagnóstico por imagem , Maxila/diagnóstico por imagem , Planejamento de Assistência ao Paciente , Tomografia Computadorizada por Raios X/métodos , Cadáver , Humanos , Doses de Radiação
9.
Artigo em Inglês | MEDLINE | ID: mdl-20598589

RESUMO

OBJECTIVE: The purpose of this study was to evaluate the effect of tube current reduction on the quality of cone-beam computerized tomography (CBCT) images of the maxilla and mandible for presurgical implant planning. STUDY DESIGN: Six cadaver heads were imaged with a CBCT (3D Accuitomo) operated at 80 kVp and variable tube current (8, 4, 2, or 1 mA) in full-scan mode. For the posterior region of maxilla and mandible, half-scans were also performed at similar settings. The images were evaluated independently by 5 oral radiologists for 15 anatomic landmarks regarding presurgical implant planning. The quality of images were compared with their respective reference images at 8 mA and ranked on a 4-point rating scale as excellent, good, fair, or nondiagnostic. The scores of all observers were averaged for each landmark at every exposure condition, and Bonferroni test (P<.05) was performed. RESULTS: The 4 mA images at full-scan mode could visualize each landmark of maxilla and mandible and were evaluated to be the same or almost equivalent in quality as the 8 mA images. Even 2 mA images in full-scan mode and 4 mA in half-scan mode could be used for implant planning. The 1 mA images were unacceptable owing to the substantial degradation in image quality. CONCLUSION: Significant dose reduction can be achieved by reducing tube current without substantial loss of image quality for presurgical implant planning in CBCT.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Implantação Dentária Endóssea/métodos , Mandíbula/diagnóstico por imagem , Maxila/diagnóstico por imagem , Planejamento de Assistência ao Paciente , Tomografia Computadorizada de Feixe Cônico/instrumentação , Diagnóstico por Computador , Humanos , Imageamento Tridimensional/instrumentação , Mandíbula/anatomia & histologia , Maxila/anatomia & histologia , Cuidados Pré-Operatórios , Doses de Radiação , Radiografia Dentária Digital/instrumentação
10.
J Plant Res ; 123(4): 463-72, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20339895

RESUMO

Quantification of carbon budgets and cycling in Japanese cedar (Cryptomeria japonica D. Don) plantations is essential for understanding forest functions in Japan because these plantations occupy about 20% of the total forested area. We conducted a biometric estimate of net ecosystem production (NEP) in a mature Japanese cedar plantation beneath a flux tower over a 4-year period. Net primary production (NPP) was 7.9 Mg C ha(-1) year(-1) and consisted mainly of tree biomass increment and aboveground litter production. Respiration was calculated as 6.8 (soil) and 3.3 (root) Mg C ha(-1) year(-1). Thus, NEP in the plantation was 4.3 Mg C ha(-1) year(-1). In agreement with the tower-based flux findings, this result suggests that the Japanese cedar plantation was a strong carbon sink. The biometric-based NEP was higher among most other types of Japanese forests studied. Carbon sequestration in the mature plantation was characterized by a larger increment in tree biomass and lower mortality than in natural forests. Land-use change from natural forest to Japanese cedar plantation might, therefore, stimulate carbon sequestration and change the carbon allocation of NPP from an increment in coarse woody debris to an increase in tree biomass.


Assuntos
Agricultura , Biometria/métodos , Carbono/metabolismo , Cryptomeria/crescimento & desenvolvimento , Cryptomeria/metabolismo , Ecossistema , Biomassa , Respiração Celular , Processos Heterotróficos , Japão , Modelos Biológicos , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , Caules de Planta/crescimento & desenvolvimento , Solo , Temperatura
11.
New Phytol ; 186(2): 451-60, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20136719

RESUMO

*We examined the photosynthetic characteristics and net primary production of biological soil crusts to evaluate their contribution to the carbon cycle in the High Arctic glacier foreland. *Biological soil crust samples were collected from a deglaciated area in Ny-Alesund, Svalbard, Norway. Net photosynthetic rates (Pn) and dark respiration rates (R) of biological soil crusts were determined using CO(2) gas exchange rates. We examined the effects of moisture conditions, temperature and photon flux density on Pn and R, and estimated the net primary production by a model based on the relationships between abiotic factors and Pn and R. *The maximum Pn value occurred at 50% of the maximum water-holding capacity. Pn decreased with increasing temperature and dropped below zero at high temperatures (c. > 13 degrees C). The estimated net primary production of the biological soil crust was greater than the net primary production of other vegetation when based on ground surface area, during the early stage of primary succession. Model simulation showed that the net primary production of the biological soil crust decreased with increasing temperature. *These results suggest that biological soil crust productivity plays an important role in the carbon cycle during the early stage of succession of the High Arctic glacier foreland, and is susceptible to temperature increases from global warming.


Assuntos
Camada de Gelo , Plantas/metabolismo , Solo , Regiões Árticas , Respiração Celular/efeitos da radiação , Geografia , Luz , Modelos Biológicos , Noruega , Fotossíntese/efeitos da radiação , Chuva , Temperatura
12.
J Plant Res ; 123(4): 473-83, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20157756

RESUMO

We investigated carbon dioxide (CO(2)) exchange and its environmental response during two years with contrasting climate (2006 and 2007) in a cool-temperate mixed evergreen coniferous forest dominated by Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa). The study, which was conducted in a mountainous region of central Japan, used the eddy-covariance technique. Our results (crosschecked using the common u (*) approach and van Gorsel's alternative approach) showed that annual gross primary production (GPP) and ecosystem respiration (RE) were at least 6% higher in the dry year than in the wet year, whereas net ecosystem exchange (NEE) was similar in both years. Without soil water stress, strong light stress or seasonality of plant area index during most of the study period, the forest had high metabolic activity. GPP and RE differed greatly between the two years, especially in spring (April-May) and summer (July-September), respectively. The spring GPP difference (>20%) was influenced by different winter air temperatures and snow melt timing, which controlled photosynthetic capacity in spring, and by different spring light intensities. The annual NEE differed depending on the evaluation method used, but the mean 2-year NEE estimated by the u (*) threshold approach [-3.39 +/- 0.11 (SD) MgC ha(-1) year(-1)] appears more reasonable in comparison with results from other forests.


Assuntos
Dióxido de Carbono/metabolismo , Clima Frio , Ecossistema , Traqueófitas/metabolismo , Árvores/metabolismo , Carbono/metabolismo , Geografia , Japão , Microclima , Fotossíntese , Chuva , Estações do Ano , Solo/análise , Água/análise
13.
J Plant Res ; 123(1): 79-85, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19760136

RESUMO

We examined factors controlling temporal changes in net ecosystem production (NEP) in a high Arctic polar semi-desert ecosystem in the snow-free season. We examined the relationships between NEP and biotic and abiotic factors in a dominant plant community (Salix polaris-moss) in the Norwegian high Arctic. Just after snowmelt in early July, the ecosystem released CO(2) into the atmosphere. A few days after snowmelt, however, the ecosystem became a CO(2) sink as the leaves of S. polaris developed. Diurnal changes in NEP mirrored changes in light incidence (photosynthetic photon flux density, PPFD) in summer. NEP was significantly correlated with PPFD when S. polaris had fully developed leaves, i.e., high photosynthetic activity. In autumn, NEP values decreased as S. polaris underwent senescence. During this time, CO(2) was sometimes released into the atmosphere. In wet conditions, moss made a larger contribution to NEP. In fact, the water content of the moss regulated NEP during autumn. Our results indicate that the main factors controlling NEP in summer are coverage and growth of S. polaris, PPFD, and precipitation. In autumn, the main factor controlling NEP is moss water content.


Assuntos
Ecossistema , Estações do Ano , Regiões Árticas , Briófitas/crescimento & desenvolvimento , Clima Frio , Clima Desértico , Fotossíntese/fisiologia , Salix/crescimento & desenvolvimento , Solo , Luz Solar , Água
14.
J Plant Res ; 123(4): 563-76, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20020173

RESUMO

Revealing the seasonal and interannual variations in forest canopy photosynthesis is a critical issue in understanding the ecological mechanisms underlying the dynamics of carbon dioxide exchange between the atmosphere and deciduous forests. This study examined the effects of temporal variations of canopy leaf area index (LAI) and leaf photosynthetic capacity [the maximum velocity of carboxylation (V (cmax))] on gross primary production (GPP) of a cool-temperate deciduous broadleaf forest for 5 years in Takayama AsiaFlux site, central Japan. We made two estimations to examine the effects of canopy properties on GPP; one is to incorporate the in situ observation of V (cmax) and LAI throughout the growing season, and another considers seasonality of LAI but constantly high V (cmax). The simulations indicated that variation in V (cmax) and LAI, especially in the leaf expansion period, had remarkable effects on GPP, and if V (cmax) was assumed constant GPP will be overestimated by 15%. Monthly examination of air temperature, radiation, LAI and GPP suggested that spring temperature could affect canopy phenology, and also that GPP in summer was determined mainly by incoming radiation. However, the consequences among these factors responsible for interannual changes of GPP are not straightforward since leaf expansion and senescence patterns and summer meteorological conditions influence GPP independently. This simulation based on in situ ecophysiological research suggests the importance of intensive consideration and understanding of the phenology of leaf photosynthetic capacity and LAI to analyze and predict carbon fixation in forest ecosystems.


Assuntos
Clima Frio , Ecossistema , Fotossíntese/fisiologia , Folhas de Planta/anatomia & histologia , Folhas de Planta/fisiologia , Estações do Ano , Árvores/crescimento & desenvolvimento , Ar , Japão , Luz , Modelos Biológicos , Árvores/fisiologia
15.
J Plant Res ; 123(4): 519-30, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20033467

RESUMO

The ecosystem carbon budget was estimated in a Japanese Zoysia japonica grassland. The green biomass started to grow in May and peaked from mid-July to September. Seasonal variations in soil CO(2) flux and root respiration were mediated by changes in soil temperature. Annual soil CO(2) flux was 1,121.4 and 1,213.6 g C m(-2) and root respiration was 471.0 and 544.3 g C m(-2) in 2007 and 2008, respectively. The root respiration contribution to soil CO(2) flux ranged from 33% to 71%. During the growing season, net primary production (NPP) was 747.5 and 770.1 g C m(-2) in 2007 and 2008, respectively. The biomass removed by livestock grazing (GL) was 122.1 and 102.7 g C m(-2), and the livestock returned 28.2 and 25.6 g C m(-2) as fecal input (FI) in 2007 and 2008, respectively. The decomposition of FI (DL, the dry weight loss due to decomposition) was very low, 1.5 and 1.4 g C m(-2), in 2007 and 2008. Based on the values of annual NPP, soil CO(2) flux, root respiration, GL, FI, and DL, the estimated carbon budget of the grassland was 1.7 and 22.3 g C m(-2) in 2007 and 2008, respectively. Thus, the carbon budget of this Z. japonica grassland ecosystem remained in equilibrium with the atmosphere under current grazing conditions over the 2 years of the study.


Assuntos
Carbono/metabolismo , Ecossistema , Poaceae/metabolismo , Animais , Biomassa , Dióxido de Carbono/metabolismo , Bovinos , Respiração Celular , Fezes , Japão , Raízes de Plantas/citologia , Raízes de Plantas/metabolismo , Poaceae/crescimento & desenvolvimento , Chuva , Estações do Ano , Solo/análise , Temperatura
16.
J Plant Res ; 123(4): 393-401, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20033468

RESUMO

Secondary mixed forests are one of the dominant forest cover types in human-dominated temperate regions. However, our understanding of how secondary succession affects carbon cycling and carbon sequestration in these ecosystems is limited. We studied carbon cycling and net ecosystem production (NEP) over 4 years (2004-2008) in a cool-temperate deciduous forest at an early stage of secondary succession (18 years after clear-cutting). Net primary production of the 18-year-old forest in this study was 5.2 tC ha(-1 )year(-1), including below-ground coarse roots; this was partitioned into 2.5 tC ha(-1 )year(-1) biomass increment, 1.6 tC ha(-1 )year(-1) foliage litter, and 1.0 tC ha(-1 )year(-1) other woody detritus. The total amount of annual soil surface CO(2) efflux was 6.8 tC ha(-1 )year(-1), which included root respiration (1.9 tC ha(-1 )year(-1)) and heterotrophic respiration (RH) from soils (4.9 tC ha(-1 )year(-1)). The 18-year forest at this study site exhibited a great increase in biomass pool as a result of considerable total tree growth and low mortality of tree stems. In contrast, the soil organic matter (SOM) pool decreased markedly (-1.6 tC ha(-1 )year(-1)), although further study of below-ground detritus production and RH of SOM decomposition is needed. This young 18-year forest was a weak carbon sink (0.9 tC ha(-1 )year(-1)) at this stage of secondary succession. The NEP of this 18-year forest is likely to increase gradually because biomass increases with tree growth and with the improvement of the SOM pool through increasing litter and dead wood production with stand development.


Assuntos
Carbono/metabolismo , Ecossistema , Árvores/crescimento & desenvolvimento , Árvores/metabolismo , Biomassa , Dióxido de Carbono/metabolismo , Respiração Celular , Processos Heterotróficos , Modelos Biológicos , Dinâmica Populacional , Estações do Ano , Especificidade da Espécie , Temperatura , Árvores/citologia
17.
J Plant Res ; 122(1): 3-20, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18958540

RESUMO

There is a growing requirement for ecosystem science to help inform a deeper understanding of the effects of global climate change and land use change on terrestrial ecosystem structure and function, from small area (plot) to landscape, regional and global scales. To meet these requirements, ecologists have investigated plant growth and carbon cycling processes at plot scale, using biometric methods to measure plant carbon accumulation, and gas exchange (chamber) methods to measure soil respiration. Also at the plot scale, micrometeorologists have attempted to measure canopy- or ecosystem-scale CO(2) flux by the eddy covariance technique, which reveals diurnal, seasonal and annual cycles. Mathematical models play an important role in integrating ecological and micrometeorological processes into ecosystem scales, which are further useful in interpreting time-accumulated information derived from biometric methods by comparing with CO(2) flux measurements. For a spatial scaling of such plot-level understanding, remote sensing via satellite is used to measure land use/vegetation type distribution and temporal changes in ecosystem structures such as leaf area index. However, to better utilise such data, there is still a need for investigations that consider the structure and function of ecosystems and their processes, especially in mountainous areas characterized by complex terrain and a mosaic distribution of vegetation. For this purpose, we have established a new interdisciplinary approach named 'Satellite Ecology', which aims to link ecology, remote sensing and micrometeorology to facilitate the study of ecosystem function, at the plot, landscape, and regional scale.


Assuntos
Ecossistema , Plantas , Astronave , Tempo (Meteorologia) , Dióxido de Carbono/metabolismo , Meio Ambiente , Temperatura Alta , Fotossíntese , Folhas de Planta/fisiologia , Transpiração Vegetal , Dinâmica Populacional , Fatores de Tempo
18.
J Plant Res ; 121(2): 137-45, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18189119

RESUMO

Studies on terrestrial ecosystems in the high Arctic region have focused on the response of these ecosystems to global environmental change and their carbon sequestration capacity in relation to ecosystem function. We report here our study of the photosynthetic characteristics and biomass distribution of the dominant vascular plant species, Salix polaris, Dryas octopetala and Saxifraga oppositifolia, in the high Arctic tundra ecosystem at Ny-Alesund, Svalbard (78.5 degrees N, 11.5 degrees E). We also estimated net primary production (NPP) along both the successional gradient created by the proglacial chronosequence and the topographical gradient. The light-saturated photosynthesis rate (A (max)) differed among the species, with approximately 124.1 nmol CO(2) g(-1)leaf s(-1) for Sal. polaris, 57.8 for D. octopetala and 24.4 for Sax. oppositifolia, and was highly correlated with the leaf nitrogen (N) content for all three species. The photosynthetic N use efficiency was the highest in Sal. polaris and lowest in Sax. oppositifolia. Distributions of Sal. polaris and D. octopetala were restricted to the area where soil nutrient availability was high, while Sax. oppositifolia was able to establish at the front of a glacier, where nutrient availability is low, but tended to be dominated by other vascular plants in high nutrient areas. The NPP reflected the photosynthetic capacity and biomass distribution in that it increased with the successional status; the contribution of Sal. polaris reached as high as 12-fold that of Sax. oppositifolia.


Assuntos
Biomassa , Carbono/metabolismo , Fotossíntese , Salix/metabolismo , Saxifragaceae/metabolismo , Clima Frio , Geografia , Noruega , Folhas de Planta/metabolismo , Rosaceae/metabolismo
19.
Artigo em Inglês | MEDLINE | ID: mdl-18003320

RESUMO

Hypertension is a world wide issue, and it is now generally accepted that its diurnal pattern has a prognostic significance. The purpose of this study is to develop a novel blood pressure (BP) monitoring device that causes less discomfort and is less disruptive of users' daily activities than conventional ambulatory blood pressure monitoring (ABPM) devices. The proposed device is worn at an ear orifice and measures BP at the tragus. This paper first covers the concept of the device, including the validity of measuring BP at the tragus, and describes the device's newly designed applicator, pad-type cuffs, electric circuit, and pressure reduction method. It then presents a preliminary validation of the basic function as BP measurement device. The developed device causes almost no discomfort and produces signals whose quality is high enough to be used for detecting BP values and useful for health care services.


Assuntos
Determinação da Pressão Arterial/instrumentação , Orelha Externa/irrigação sanguínea , Orelha Externa/fisiopatologia , Microfluídica/instrumentação , Monitorização Ambulatorial/instrumentação , Fotopletismografia/instrumentação , Determinação da Pressão Arterial/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Microfluídica/métodos , Miniaturização , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
20.
Nat Mater ; 5(5): 357-60, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16617345

RESUMO

The rechargeable lithium-ion cell is an advanced energy-storage system. However, high cost, safety hazards, and chemical instability prohibit its use in large-scale applications. An alternative cathode material, LiFePO(4), solves these problems, but has a kinetic problem involving strong electron/hole localization. One reason for this is believed to be the limited carrier density in the fixed monovalent Fe(3+)PO(4)/LiFe(2+)PO(4) two-phase electrode reaction in LixFePO4. Here, we provide experimental evidence that LixFePO4, at room temperature, can be described as a mixture of the Fe(3+)/Fe(2+) mixed-valent intermediate LialphaFePO4 and Li1-betaFePO4 phases. Using powder neutron diffraction, the site occupancy numbers for lithium in each phase were refined to be alpha=0.05 and 1-beta=0.89. The corresponding solid solution ranges outside the miscibility gap (0

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