Strategies to reduce arsenic (As) in rice grain, below concentrations that represent a serious human health concern, require that the mechanisms of As accumulation within grain be established. ...Therefore, retranslocation of As species from flag leaves into filling rice grain was investigated. Arsenic species were delivered through cut flag leaves during grain fill. Spatial unloading within grains was investigated using synchrotron X-ray fluorescence (SXRF) microtomography. Additionally, the effect of germanic acid (a silicic acid analog) on grain As accumulation in arsenite-treated panicles was examined. Dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) were extremely efficiently retranslocated from flag leaves to rice grain; arsenate was poorly retranslocated, and was rapidly reduced to arsenite within flag leaves; arsenite displayed no retranslocation. Within grains, DMA rapidly dispersed while MMA and inorganic As remained close to the entry point. Germanic acid addition did not affect grain As in arsenite-treated panicles. Three-dimensional SXRF microtomography gave further information on arsenite localization in the ovular vascular trace (OVT) of rice grains. These results demonstrate that inorganic As is poorly remobilized, while organic species are readily remobilized, from leaves to grain. Stem translocation of inorganic As may not rely solely on silicic acid transporters.
Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice ...grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a ± stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols.
Abstract
Background
Falls remain a common and debilitating problem in hospitals worldwide. The aim of this study was to investigate the effects of falls prevention interventions on falls rates and ...the risk of falling in hospital.
Design
Systematic review and meta-analysis.
Participants
Hospitalised adults.
Intervention
Prevention methods included staff and patient education, environmental modifications, assistive devices, policies and systems, rehabilitation, medication management and management of cognitive impairment. We evaluated single and multi-factorial approaches.
Outcome measures
Falls rate ratios (rate ratio: RaR) and falls risk, as defined by the odds of being a faller in the intervention compared to control group (odds ratio: OR).
Results
There were 43 studies that satisfied the systematic review criteria and 23 were included in meta-analyses. There was marked heterogeneity in intervention methods and study designs. The only intervention that yielded a significant result in the meta-analysis was education, with a reduction in falls rates (RaR = 0.70 0.51–0.96, P = 0.03) and the odds of falling (OR = 0.62 0.47–0.83, P = 0.001). The patient and staff education studies in the meta-analysis were of high quality on the GRADE tool. Individual trials in the systematic review showed evidence for clinician education, some multi-factorial interventions, select rehabilitation therapies, and systems, with low to moderate risk of bias.
Conclusion
Patient and staff education can reduce hospital falls. Multi-factorial interventions had a tendency towards producing a positive impact. Chair alarms, bed alarms, wearable sensors and use of scored risk assessment tools were not associated with significant fall reductions.
Rice is more elevated in arsenic than all other grain crops tested to date, with whole grain (brown) rice having higher arsenic levels than polished (white). It is reported here that rice bran, both ...commercially purchased and specifically milled for this study, have levels of inorganic arsenic, a nonthreshold, class 1 carcinogen, reaching concentrations of ∼1 mg/kg dry weight, around 10−20 fold higher than concentrations found in bulk grain. Although pure rice bran is used as a health food supplement, perhaps of more concern is rice bran solubles, which are marketed as a superfood and as a supplement to malnourished children in international aid programs. Five rice bran solubles products were tested, sourced from the United States and Japan, and were found to have 0.61−1.9 mg/kg inorganic arsenic. Manufactures recommend ∼20 g servings of the rice bran solubles per day, which equates to a 0.012−0.038 mg intake of inorganic arsenic. There are no maximum concentration levels (MCLs) set for arsenic or its species in food stuffs. EU and U.S. water regulations, set at 0.01 mg/L total or inorganic arsenic, respectively, are based on the assumption that 1 L of water per day is consumed, i.e., 0.01 mg of arsenic/day. At the manufacturers recommended rice bran solubles consumption rate, inorganic arsenic intake exceeds 0.01 mg/day, remembering that rice bran solubles are targeted at malnourished children and that actual risk is based on mg kg−1 day−1 intake.
Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the ...NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz) or Beta (16 Hz) frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others.
For up to 1 billion people worldwide, insufficient dietary intake of selenium (Se) is a serious health constraint. Cereals are the dominant Se source for those on low protein diets, as typified by ...the global malnourished population. With crop Se content constrained largely by underlying geology, regional soil Se variations are often mirrored by their locally grown staples. Despite this, the Se concentrations of much of the world’s rice, the mainstay of so many, is poorly characterized, for both total Se content and Se speciation. In this study, 1092 samples of market sourced polished rice were obtained. The sampled rice encompassed dominant rice producing and exporting countries. Rice from the U.S. and India were found to be the most enriched, while mean average levels were lowest in Egyptian rice: ∼32-fold less than their North American equivalents. By weighting country averages by contribution to either global production or export, modeled baseline values for both were produced. Based on a daily rice consumption of 300 g day−1, around 75% of the grains from the production and export pools would fail to provide 70% of daily recommended Se intakes. Furthermore, Se localization and speciation characterization using X-ray fluorescence (μ-XRF) and X-ray absorption near edge structure (μ-XANES) techniques were investigated in a Se-rich sample. The results revealed that the large majority of Se in the endosperm was present in organic forms.
Arsenic accumulation in rice grain has been identified as a major problem in some regions of Asia. A study was conducted to investigate the effect of increased organic matter in the soil on the ...release of arsenic into soil pore water and accumulation of arsenic species within rice grain. It was observed that high concentrations of soil arsenic and organic matter caused a reduction in plant growth and delayed flowering time. Total grain arsenic accumulation was higher in the plants grown in high soil arsenic in combination with high organic matter, with an increase in the percentage of organic arsenic species observed. The results indicate that the application of organic matter should be done with caution in paddy soils which have high soil arsenic, as this may lead to an increase in accumulation of arsenic within rice grains. Results also confirm that flooding conditions substantially increase grain arsenic.
► High soil arsenic and organic matter caused a reduction in plant growth. ► A delayed flowering time was observed in high arsenic and organic matter soil. ► Total grain arsenic increased in high arsenic and organic matter soil. ► Percentage organic arsenic in the grain altered in arsenic and organic matter soil.
The addition of high amounts of organic matter to soils led to an increase in total rice grain arsenic, as well as alteration in the percentage arsenic species in the rice grains.
Efficient Se biofortification programs require a thorough understanding of the accumulation and distribution of Se species within the rice grain. Therefore, the translocation of Se species to the ...filling grain and their spatial unloading were investigated. Se species were supplied via cut flag leaves of intact plants and excised panicle stems subjected to a ± stem-girdling treatment during grain fill. Total Se concentrations in the flag leaves and grain were quantified by inductively coupled plasma mass spectrometry. Spatial accumulation was investigated using synchrotron X-ray fluorescence microtomography. Selenomethionine (SeMet) and selenomethylcysteine (SeMeSeCys) were transported to the grain more efficiently than selenite and selenate. SeMet and SeMeSeCys were translocated exclusively via the phloem, while inorganic Se was transported via both the phloem and xylem. For SeMet- and SeMeSeCys-fed grain, Se dispersed throughout the external grain layers and into the endosperm and, for SeMeSeCys, into the embryo. Selenite was retained at the point of grain entry. These results demonstrate that the organic Se species SeMet and SeMeSeCys are rapidly loaded into the phloem and transported to the grain far more efficiently than inorganic species. Organic Se species are distributed more readily, and extensively, throughout the grain than selenite.
PDF
