High-Throughput Yield Prediction of Diallele Crossed Sugar Beet in a Breeding Field Using UAV-Derived Growth Dynamics.

Data-driven techniques could be used to enhance decision-making capacity of breeders and farmers. We used an RGB camera on an unmanned aerial vehicle (UAV) to collect time series data on sugar beet canopy coverage (CC) and canopy height (CH) from small-plot breeding fields including 20 genotypes per season over 3 seasons. Digital orthomosaic and digital surface models were created from each flight and were converted to individual plot-level data. Plot-level data including CC and CH were calculated on a per-plot basis. A multiple regression model was fitted, which predicts root weight (RW) (r = 0.89, 0.89, and 0.92 in the 3 seasons, respectively) and sugar content (SC) (r = 0.79, 0.83, and 0.77 in the 3 seasons, respectively) using individual time point CC and CH data. Individual CC and CH values in late June tended to be strong predictors of RW and SC, suggesting that early season growth is critical for obtaining high RW and SC. Coefficient of parentage was not a strong factor influencing SC. Integrals of CC and CH time series data were calculated for genetic analysis purposes since they are more stable over multiple growing seasons. Calculations of general combining ability and specific combining ability in F1 offspring demonstrate how growth curve quantification can be used in diallel cross analysis and yield prediction. Our simple yet robust solution demonstrates how state-of-the-art remote sensing tools and basic analysis methods can be applied to small-plot breeder fields for selection purpose.

MORE PANICLES 3, a natural allele of OsTB1/FC1, impacts rice yield in paddy fields at elevated CO2 levels.

Improving crop yield potential through an enhanced response to rising atmospheric CO2 levels is an effective strategy for sustainable crop production in the face of climate change. Large-sized panicles (containing many spikelets per panicle) have been a recent ideal plant architecture (IPA) for high-yield rice breeding. However, few breeding programs have proposed an IPA under the projected climate change. Here, we demonstrate through the cloning of the rice (Oryza sativa) quantitative trait locus for MORE PANICLES 3 (MP3) that the improvement in panicle number increases grain yield at elevated atmospheric CO2 levels. MP3 is a natural allele of OsTB1/FC1, previously reported as a negative regulator of tiller bud outgrowth. The temperate japonica allele advanced the developmental process in axillary buds, moderately promoted tillering, and increased the panicle number without negative effects on the panicle size or culm thickness in a high-yielding indica cultivar with large-sized panicles. The MP3 allele, containing three exonic polymorphisms, was observed in most accessions in the temperate japonica subgroups but was rarely observed in the indica subgroup. No selective sweep at MP3 in either the temperate japonica or indica subgroups suggested that MP3 has not been involved and utilized in artificial selection during domestication or breeding. A free-air CO2 enrichment experiment revealed a clear increase of grain yield associated with the temperate japonica allele at elevated atmospheric CO2 levels. Our findings show that the moderately increased panicle number combined with large-sized panicles using MP3 could be a novel IPA and contribute to an increase in rice production under climate change with rising atmospheric CO2 levels.

Five-year soil warming changes soil C and N dynamics in a single rice paddy field in Japan.

Soil temperature is an important determinant of carbon (C) and nitrogen (N) cycling in terrestrial ecosystems, but its effects on soil organic carbon (SOC) and total nitrogen (TN) dynamics as well as rice biomass in rice paddy ecosystems are not fully understood. We conducted a five-year soil warming experiment in a single-cropping paddy field in Japan. Soil temperatures were elevated by approximate 2 °C with heating wires during the rice growing season and by approximate 1 °C with nighttime thermal blankets during the fallow season. Soil samples were collected in autumn after rice harvest and in spring after fallow each year, and anaerobically incubated at 30 °C for four weeks to determine soil C decomposition and N mineralization potentials. The SOC and TN contents, rice biomass, dissolved organic carbon (DOC) and microbial biomass carbon (MBC) concentrations were measured in the study. Soil warming did not significantly enhance rice aboveground and root biomasses, but it significantly decreased SOC and TN contents and thus decreased soil C decomposition and N mineralization potentials due to depletion of available C and N. Moreover, soil warming significantly decreased DOC concentration but significantly increased MBC concentration. The ratios of C decomposition potential to N mineralization potential, decomposition potential to SOC, and N mineralization to TN were not affected by soil warming. There were significant seasonal and annual variations in SOC, C decomposition and N mineralization potentials, soil DOC and MBC under each temperature treatments. Our study implied that soil warming can decrease soil C and N stocks in paddy ecosystem probably via stimulating microbial activities and accelerating the depletion of DOC. This study further highlights the importance of long-term in situ observation of C and N dynamics and their availabilities in rice paddy ecosystems under increasing global warming scenarios.

Author Correction: Increasing CO2 threatens human nutrition.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

A High-Yielding Rice Cultivar "Takanari" Shows No N Constraints on CO2 Fertilization.

Enhancing crop yield response to elevated CO2 concentrations (E-[CO2]) is an important adaptation measure to climate change. A high-yielding indica rice cultivar "Takanari" has recently been identified as a potential candidate for high productivity in E-[CO2] resulting from its large sink and source capacities. To fully utilize these traits, nitrogen should play a major role, but it is unknown how N levels influence the yield response of Takanari to E-[CO2]. We therefore compared grain yield and quality of Takanari with those of Koshihikari, a standard japonica cultivar, in response to Free-Air CO2 enrichment (FACE, +200 µmol mol-1) under three N levels (0, 8, and 12 g m-2) over three seasons. The biomass of both cultivars increased under E-[CO2] at all N levels; however, the harvest index decreased under E-[CO2] in the N-limited treatment for Koshihikari but not for Takanari. The decreased harvest index of Koshihikari resulted from limited enhancement of spikelet number under N-limitation. In contrast, spikelet number increased in E-[CO2] in Takanari even without N application, resulting in significant yield enhancement, averaging 18% over 3 years, whereas Koshihikari exhibited virtually no increase in yield in E-[CO2] under the N-limited condition. Grain appearance quality of Koshihikari was severely reduced by E-[CO2], most notably in N-limited and hot conditions, by a substantial increase in chalky grain, but chalky grain % did not increase in E-[CO2] even without N fertilizer. These results indicated that Takanari could retain its high yield advantage over Koshihikari with limited increase in chalkiness even under limited N conditions and that it could be a useful genetic resource for improving N use efficiency under E-[CO2].

How elevated CO2 affects our nutrition in rice, and how we can deal with it.

Increased concentrations of atmospheric CO2 are predicted to reduce the content of essential elements such as protein, zinc, and iron in C3 grains and legumes, threatening the nutrition of billions of people in the next 50 years. However, this prediction has mostly been limited to grain crops, and moreover, we have little information about either the underlying mechanism or an effective intervention to mitigate these reductions. Here, we present a broader picture of the reductions in elemental content among crops grown under elevated CO2 concentration. By using a new approach, flow analysis of elements, we show that lower absorption and/or translocation to grains is a key factor underlying such elemental changes. On the basis of these findings, we propose two effective interventions-namely, growing C4 instead of C3 crops, and genetic improvements-to minimize the elemental changes in crops, and thereby avoid an impairment of human nutrition under conditions of elevated CO2.

Role of dental sleep medicine in management of patients with obstructive sleep apnea disorders using a team approach.

OBJECTIVE: Obstructive sleep apnea (OSA) is a significant social and health issue. An integrated multidisciplinary approach to OSA management may be the most effective owing to its multifactorial etiology. In this study, we evaluated the frequency and efficacy of various treatment modalities for OSA administered via an integrated care delivery model, and assessed the role of dental sleep medicine as part of a multidisciplinary team. MATERIALS AND METHODS: We retrospectively evaluated 1115 patients with OSA treated at the Tokyo Medical University Hospital's Outpatient Clinic for OSA by a multidisciplinary team under one roof. The various treatment methods included the following: continuous positive airway pressure (CPAP), oral appliance (OA), surgery, and behavioral treatment. RESULTS: The patient number of study group was as follows: 771 (69.1%) CPAP; 240 (21.5%) OA; 76 (6.8%) behavioral treatment and 28 (3%) surgery. Because significantly fewer patients underwent surgery, there was a discrepancy between the recommended first-choice treatment and the actual treatment. A statistically significant number of younger patients in each treatment group underwent surgery. Success rate of OA and MMA were 74.4 and 80%, respectively. CONCLUSIONS: Proper selection of primary treatment to manage patients with OSA was possible under one-roof system that included dental sleep medicine.

Effects of Elevated Atmospheric CO2 on Respiratory Rates in Mature Leaves of Two Rice Cultivars Grown at a Free-Air CO2 Enrichment Site and Analyses of the Underlying Mechanisms.

Respiratory CO2 efflux and O2 uptake rates in leaves change in response to the growth CO2 concentration ([CO2]). The degrees of change vary depending on the responses of cellular processes such as nitrogen (N) assimilation and accumulation of organic acids to growth [CO2]. However, the underlying mechanisms remain unclear. Here, we examined the respiratory characteristics of mature leaves of two rice varieties with different yield capacities at different growth stages under ambient and elevated [CO2] conditions at a free-air CO2 enrichment site. We also examined the effect of increased water temperature on leaf respiration. We measured the rates of CO2 efflux and O2 uptake, and determined N contents, primary metabolite contents and maximal activities of respiratory enzymes. The leaf CO2 efflux rates decreased in plants grown at elevated [CO2] in both varieties, and were higher in high-yielding Takanari than in Koshihikari. The leaf O2 uptake rates showed little change with respect to growth [CO2] and variety. The increased water temperature did not significantly affect the CO2 efflux and O2 uptake rates. The N and amino acid contents were significantly higher in Takanari than in Koshihikari. The enhanced N assimilation in Takanari may have consumed more respiratory NADH, leading to higher CO2 efflux rates. In Koshihikari, the ratio of tricarboxylic acid (TCA) cycle intermediates changed and maximal activities of enzymes in the TCA cycle decreased at elevated [CO2]. Therefore, the decreased rates of CO2 efflux in Koshihikari may be due to the decreased activities of TCA cycle enzymes at elevated [CO2].

Increasing canopy photosynthesis in rice can be achieved without a large increase in water use-A model based on free-air CO2 enrichment.

Achieving higher canopy photosynthesis rates is one of the keys to increasing future crop production; however, this typically requires additional water inputs because of increased water loss through the stomata. Lowland rice canopies presently consume a large amount of water, and any further increase in water usage may significantly impact local water resources. This situation is further complicated by changing the environmental conditions such as rising atmospheric CO2 concentration ([CO2 ]). Here, we modeled and compared evapotranspiration of fully developed rice canopies of a high-yielding rice cultivar (Oryza sativa L. cv. Takanari) with a common cultivar (cv. Koshihikari) under ambient and elevated [CO2 ] (A-CO2 and E-CO2 , respectively) via leaf ecophysiological parameters derived from a free-air CO2 enrichment (FACE) experiment. Takanari had 4%-5% higher evapotranspiration than Koshihikari under both A-CO2 and E-CO2 , and E-CO2 decreased evapotranspiration of both varieties by 4%-6%. Therefore, if Takanari was cultivated under future [CO2 ] conditions, the cost for water could be maintained at the same level as for cultivating Koshihikari at current [CO2 ] with an increase in canopy photosynthesis by 36%. Sensitivity analyses determined that stomatal conductance was a significant physiological factor responsible for the greater canopy photosynthesis in Takanari over Koshihikari. Takanari had 30%-40% higher stomatal conductance than Koshihikari; however, the presence of high aerodynamic resistance in the natural field and lower canopy temperature of Takanari than Koshihikari resulted in the small difference in evapotranspiration. Despite the small difference in evapotranspiration between varieties, the model simulations showed that Takanari clearly decreased canopy and air temperatures within the planetary boundary layer compared to Koshihikari. Our results indicate that lowland rice varieties characterized by high-stomatal conductance can play a key role in enhancing productivity and moderating heat-induced damage to grain quality in the coming decades, without significantly increasing crop water use.

Quantitative trait loci for large sink capacity enhance rice grain yield under free-air CO2 enrichment conditions.

The global atmospheric CO2 concentration has been increasing annually. To determine the trait that effectively increases rice (Oryza sativa L.) grain yield under increased atmospheric CO2 concentrations, as predicted in the near future, we grew a chromosome segment substitution line (CSSL) and a near-isogenic line (NIL) producing high spikelet numbers per panicle (CSSL-GN1 and NIL-APO1, respectively) under free-air CO2 enrichment (FACE) conditions and examined the effects of a large sink capacity on grain yield, its components, and growth-related traits under increased atmospheric CO2 concentrations. Under ambient conditions, CSSL-GN1 and NIL-APO1 exhibited a similar grain yield to Koshihikari, as a result of the trade-off between increased spikelet number and reduced grain filling. However, under FACE conditions, CSSL-GN1 and NIL-APO1 had an equal or a higher grain yield than Koshihikari because of the higher number of spikelets and lower reduction in grain filling. Thus, the improvement of source activity by increased atmospheric CO2 concentrations can lead to enhanced grain yield in rice lines that have a large sink capacity. Therefore, introducing alleles that increase sink capacity into conventional varieties represents a strategy that can be used to develop high-yielding varieties under increased atmospheric CO2 concentrations, such as those predicted in the near future.

Effect of Elevated CO2 Concentration, Elevated Temperature and No Nitrogen Fertilization on Methanogenic Archaeal and Methane-Oxidizing Bacterial Community Structures in Paddy Soil.

Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions.

Obstructive Sleep Apnea as Possible Causal Factor for Visit-to-Visit Blood Pressure Variability.

BACKGROUND: Recent studies have shown that visit-to-visit blood pressure variability (BPV) is an independent risk factor for cardiovascular disease. However, it has not been clarified whether obstructive sleep apnea (OSA) is associated with visit-to-visit BPV. METHODS AND RESULTS: The 56 subjects with OSA and 26 control subjects without OSA were examined. Office BP was measured on 5 separate consecutive occasions prior to a polysomnography examination. The visit-to-visit BPV was expressed as the standard deviation and the coefficient of variation of the 5 systolic BP measurements. In subjects with an apnea-hypopnea index (AHI) of more than 20 episodes per hour, the visit-to-visit BPV was also measured after the start of continuous positive airway pressure (CPAP) therapy. Overall, the AHI positively correlated with the standard deviation and the coefficient of variation of systolic BP. In a multivariate analysis, the plasma noradrenaline level and the AHI were independently and positively correlated with the standard deviation and the coefficient of variation of the systolic BP. Among the patients who underwent CPAP therapy, good adherence with CPAP therapy significantly reduced the visit-to-visit BPV. CONCLUSIONS: OSA is associated with abnormal visit-to-visit BPV and sympathetic activation seems to be related in some way. (Circ J 2016; 80: 1787-1794).

Nocturnal Intermittent Hypoxia Is Associated With Left Ventricular Hypertrophy in Middle-Aged Men With Hypertension and Obstructive Sleep Apnea.

BACKGROUND: Obstructive sleep apnea (OSA) and left ventricular (LV) hypertrophy are considered to be closely associated. However, the relationship has not yet been fully demonstrated and is hence still controversial. The purpose of this study was to assess in hypertensive male patients the relationship between OSA and cardiac structure using a new index, namely, integrated area of desaturation (IAD), in addition to the apnea-hypopnea index (AHI) that is currently the most frequently used index of sleep-disordered breathing. METHODS: In our cross-sectional study, 223 hypertensive men younger than 65 years with sleep apnea and normal cardiac function were enrolled. All subjects were evaluated by fully attended polysomnography. Cardiac structure and function were evaluated by echocardiography. RESULTS: LV mass index significantly correlated with IAD (r = 0.203, P < 0.05), but not with AHI. Multivariate linear regression analyses showed that IAD, brain natriuretic peptide (BNP), and age are independent variables affecting the LV mass index (ß = 0.262, 0.237, and 0.173, respectively, P < 0.05). IAD was the one and only determinant among the indices of sleep-disordered breathing. CONCLUSIONS: Nocturnal intermittent hypoxia defined by IAD may be associated with LV hypertrophy in men with well-controlled hypertension and obstructive sleep apnea.

Rice grain yield and quality responses to free-air CO2 enrichment combined with soil and water warming.

Rising air temperatures are projected to reduce rice yield and quality, whereas increasing atmospheric CO2 concentrations ([CO2 ]) can increase grain yield. For irrigated rice, ponded water is an important temperature environment, but few open-field evaluations are available on the combined effects of temperature and [CO2 ], which limits our ability to predict future rice production. We conducted free-air CO2 enrichment and soil and water warming experiments, for three growing seasons to determine the yield and quality response to elevated [CO2 ] (+200 µmol mol(-1) , E-[CO2 ]) and soil and water temperatures (+2 °C, E-T). E-[CO2 ] significantly increased biomass and grain yield by approximately 14% averaged over 3 years, mainly because of increased panicle and spikelet density. E-T significantly increased biomass but had no significant effect on the grain yield. E-T decreased days from transplanting to heading by approximately 1%, but days to the maximum tiller number (MTN) stage were reduced by approximately 8%, which limited the panicle density and therefore sink capacity. On the other hand, E-[CO2 ] increased days to the MTN stage by approximately 4%, leading to a greater number of tillers. Grain appearance quality was decreased by both treatments, but E-[CO2 ] showed a much larger effect than did E-T. The significant decrease in undamaged grains (UDG) by E-[CO2 ] was mainly the result of an increased percentage of white-base grains (WBSG), which were negatively correlated with grain protein content. A significant decrease in grain protein content by E-[CO2 ] accounted in part for the increased WBSG. The dependence of WBSG on grain protein content, however, was different among years; the slope and intercept of the relationship were positively correlated with a heat dose above 26 °C. Year-to-year variation in the response of grain appearance quality demonstrated that E-[CO2 ] and rising air temperatures synergistically reduce grain appearance quality of rice.

Impacts of elevated atmospheric CO2 on nutrient content of important food crops.

One of the many ways that climate change may affect human health is by altering the nutrient content of food crops. However, previous attempts to study the effects of increased atmospheric CO2 on crop nutrition have been limited by small sample sizes and/or artificial growing conditions. Here we present data from a meta-analysis of the nutritional contents of the edible portions of 41 cultivars of six major crop species grown using free-air CO2 enrichment (FACE) technology to expose crops to ambient and elevated CO2 concentrations in otherwise normal field cultivation conditions. This data, collected across three continents, represents over ten times more data on the nutrient content of crops grown in FACE experiments than was previously available. We expect it to be deeply useful to future studies, such as efforts to understand the impacts of elevated atmospheric CO2 on crop macro- and micronutrient concentrations, or attempts to alleviate harmful effects of these changes for the billions of people who depend on these crops for essential nutrients.

Characterization of leaf blade- and leaf sheath-associated bacterial communities and assessment of their responses to environmental changes in CO2, temperature, and nitrogen levels under field conditions.

Rice shoot-associated bacterial communities at the panicle initiation stage were characterized and their responses to elevated surface water-soil temperature (ET), low nitrogen (LN), and free-air CO2 enrichment (FACE) were assessed by clone library analyses of the 16S rRNA gene. Principal coordinate analyses combining all sequence data for leaf blade- and leaf sheath-associated bacteria revealed that each bacterial community had a distinct structure, as supported by PC1 (61.5%), that was mainly attributed to the high abundance of Planctomycetes in leaf sheaths. Our results also indicated that the community structures of leaf blade-associated bacteria were more sensitive than those of leaf sheath-associated bacteria to the environmental factors examined. Among these environmental factors, LN strongly affected the community structures of leaf blade-associated bacteria by increasing the relative abundance of Bacilli. The most significant effect of FACE was also observed on leaf blade-associated bacteria under the LN condition, which was explained by decreases and increases in Agrobacterium and Pantoea, respectively. The community structures of leaf blade-associated bacteria under the combination of FACE and ET were more similar to those of the control than to those under ET or FACE. Thus, the combined effects of environmental factors need to be considered in order to realistically assess the effects of environmental changes on microbial community structures.

Elevated atmospheric CO2 levels affect community structure of rice root-associated bacteria.

A number of studies have shown that elevated atmospheric CO2 ([CO2]) affects rice yields and grain quality. However, the responses of root-associated bacteria to [CO2] elevation have not been characterized in a large-scale field study. We conducted a free-air CO2 enrichment (FACE) experiment (ambient + 200 µmol.mol(-1)) using three rice cultivars (Akita 63, Takanari, and Koshihikari) and two experimental lines of Koshihikari [chromosome segment substitution and near-isogenic lines (NILs)] to determine the effects of [CO2] elevation on the community structure of rice root-associated bacteria. Microbial DNA was extracted from rice roots at the panicle formation stage and analyzed by pyrosequencing the bacterial 16S rRNA gene to characterize the members of the bacterial community. Principal coordinate analysis of a weighted UniFrac distance matrix revealed that the community structure was clearly affected by elevated [CO2]. The predominant community members at class level were Alpha-, Beta-, and Gamma-proteobacteria in the control (ambient) and FACE plots. The relative abundance of Methylocystaceae, the major methane-oxidizing bacteria in rice roots, tended to decrease with increasing [CO2] levels. Quantitative PCR revealed a decreased copy number of the methane monooxygenase (pmoA) gene and increased methyl coenzyme M reductase (mcrA) in elevated [CO2]. These results suggest elevated [CO2] suppresses methane oxidation and promotes methanogenesis in rice roots; this process affects the carbon cycle in rice paddy fields.

Severe obstructive sleep apnea increases left atrial volume independently of left ventricular diastolic impairment.

PURPOSE: Severe obstructive sleep apnea (OSA) directly impairs left ventricular (LV) diastolic function. Left atrial volume index (LAVI), an independent predictor of future cardiovascular events, is also related to OSA severity. This study aimed to assess whether OSA is associated with an increase in LAVI independently of LV diastolic function. METHODS: Two hundred six OSA patients (apnea hypopnea index, AHI ≥ 5/h) without cardiac disease, hypertension, and diabetes were enrolled. They underwent overnight fully attended polysomnography and 2-dimensional echocardiography in order to estimate LA volumes and LV diastolic function which was assessed by the ratio of transmitral early diastolic flow velocity to late diastolic flow velocity (E/A), deceleration time, and mitral annular velocity (e') which was derived from tissue Doppler imaging. Patients were divided into two groups based on AHI, namely, group M (5 ≤ AHI < 30/h) and group S (AHI ≥ 30/h). RESULTS: The LAVI value in group S was significantly larger than that in group M (20 ± 5 vs. 23 ± 5 mL/m(2), P < 0.001). E/A in group S was significantly lower than that in group M (P < 0.001), whereas the ratio of E to e' (E/e') in group S was significantly higher than that in group M (P < 0.001). AHI showed a statistically significant correlation with LAVI (P < 0.001). On multivariate linear regression analysis, severe OSA was independently related with LAVI even after adjusting for age, sex, systolic blood pressure, body mass index, and measurements of LV diastolic function (P = 0.04). CONCLUSIONS: Severe OSA itself might directly increase LAVI, independently of LV diastolic function.

Continuous positive airway pressure treatment improves cardiovascular outcomes in elderly patients with cardiovascular disease and obstructive sleep apnea.

Obstructive sleep apnea (OSA) is associated with the progression of cardiovascular disease (CVD), particularly in the middle-aged population. However, the clinical importance of OSA as a risk for CVD in the elderly population remains controversial. Moreover, evidence for the effectiveness of continuous positive airway pressure (CPAP) treatment for the secondary prevention of CVD in elderly patients is lacking. We assessed whether CPAP treatment improves cardiovascular outcomes in elderly patients with OSA and CVD. In this retrospective cohort study, we enrolled 130 elderly patients aged 65-86 years with moderate to severe OSA (apnea-hypopnea index ≥15/h) and a history of hospitalization due to CVD, who underwent polysomnography between November 2004 and July 2011. Patients were divided into the CPAP group (n = 64) or untreated OSA group (n = 66). The main outcome measures were cardiovascular death and hospitalization due to CVD. During the mean follow-up period of 32.9 ± 23.8 (standard deviation) months, 28 (21.5 %) patients either died or were hospitalized. The Kaplan-Meier curves indicated that event-free survival was significantly lower in the untreated OSA group than in the CPAP group (P < 0.005). A multivariate analysis showed that the risk was significantly increased in the untreated OSA group (hazard ratio 5.13; 95 % confidence interval 1.01-42.0; P < 0.05). Moderate to severe OSA not treated with CPAP was an independent risk factor for relapse of a CVD event, and adequate CPAP treatment improved cardiovascular outcomes in elderly patients.

Fully automated, high-throughput instrumentation for measuring the δ13C value of methane and application of the instrumentation to rice paddy samples.

RATIONALE: The stable carbon isotope ratio ((13)C/(12)C or δ(13)C value) of methane (CH4) produced in methanogenic environments contains information about primary source material, CH4 production pathways, degree of oxidation, and transport. However, the availability of δ(13)C-CH4 data is severely limited because isotope analysis methods are low throughput, owing primarily to the need for manual processing steps. High-throughput, fully automated measurement is necessary to facilitate the use of the δ(13)C signature in understanding CH4 biogeochemistry. METHODS: We modified a conventional continuous-flow (CF) gas chromatography/combustion/isotope ratio mass spectrometry (IRMS) instrument system by incorporating (i) automated sample injection, (ii) a newly developed temperature-control unit for preconcentration and cryofocus traps, and (iii) an automatic system for liquid-nitrogen refilling. The system, which could run unattended for 1 day, was used to obtain δ(13)C-CH4 data for CH4 samples collected from an irrigated rice paddy with an automated closed-chamber system. RESULTS: Using the fully automated CF-IRMS system, we measured δ(13)C-CH4 data for 77 samples during a 21.5-h continuous run (17 min per sample) with high precision (1σ = 0.11‰, reproducibility) and moderate consumption of liquid nitrogen (11 L). Application of the system to CH4 samples obtained from the rice paddy revealed distinct seasonal and diurnal variations in δ(13)C values with the highest temporal resolution ever reported. CONCLUSIONS: A fully automated, high-throughput system for the measurement of δ(13)C-CH4 values was developed and used to analyze air samples obtained from a rice paddy. Our results demonstrate the high potential of this system for obtaining δ(13)C data useful for process-level understanding of CH4 biogeochemistry with respect to spatiotemporal variation of CH4 sources and how that variation is affected by environmental and management factors.