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Validation of a geologically based radon risk map: are the indoor radon concentrations higher in high-risk areas?

Since geographically coded information is frequently used in studies of the relationships between environmental factors and illness at the population level and by authorities for promotion of mitigation, knowledge about the validity of proxy measures is essential. This study was an evaluation of a geologically based map describing the risk for high radon levels, which was used by the municipal authorities to determine the necessity of remedial actions. Annual mean radon gas concentrations for a random sample of one-family homes selected from high-risk areas (n = 252) were compared with those of a random sample of homes from normal and low-risk areas (n = 259). No difference in geometric mean radon concentration was found between the areas, 101 Bq m(-3) and 103 Bq m(-3), respectively. The proportion of homes in each area with radon gas concentrations above the current Swedish administrative limit value for mitigation (400 Bq m(-3)) was similar, approximately 10%. We conclude that the radon risk map was unsuitable for identifying areas of concern. The findings also indicate that geologically based and geographically coded information as a proxy for human exposures can be safely used for scientific and administrative purposes only following validation.

Air Pollution, Indoor↗

Regulation of gastroduodenal bicarbonate secretion by capsaicin-sensitive sensory neurons in rats.

We investigated the role of capsaicin-sensitive sensory neurons in regulation of gastroduodenal HCO3- secretion in anesthetized rats. The stomach (under acid inhibition by omeprazole 60 mg/kg i.p.) or the duodenum was perfused with saline (pH 4.5) and HCO3- output was determined by pH change in the perfusate. Both the duodenum and stomach responded to prostaglandin E2 (PGE2; 300 micrograms/kg i.v.) or luminal acid by a significant increase in pH and HCO3- output. These tissues also responded to luminal application of capsaicin (0.3-6 mg/ml for 30 min), resulting in a significant increase of pH and HCO3- output in a concentration-related manner. The HCO3- stimulatory action of capsaicin was markedly attenuated by functional ablation of capsaicin-sensitive sensory neurons, significantly mitigated by indomethacin, and exhibited tachyphylaxis after repeated application at a high concentration. The acid-induced pH and HCO3- responses were also significantly mitigated by sensory deafferentation and by indomethacin, whereas those induced by PGE2 remained unaffected. In addition, defunctionalization of these sensory nerves resulted in macroscopically visible damage in the duodenum when acid secretion was concomitantly stimulated by histamine. We conclude that capsaicin-sensitive sensory neurons may be involved in the regulatory mechanism of gastroduodenal HCO3- secretion and contribute to protection of the mucosa against acid. Endogenous PGs may be involved in the HCO3- stimulatory action mediated by capsaicin-sensitive sensory neurons.

Afferent Pathways↗

Mechanism of gastric hyperemic response during acid secretion in rats: relation to nitric oxide, prostaglandins, and sensory neurons.

The mechanism of gastric mucosal hyperemic response during pentagastrin-induced acid secretion was investigated in anesthetized rats in relation to prostaglandins (PGs), nitric oxide (NO), and sensory neurons. A rat stomach was mounted in an ex vivo chamber and perfused with saline or glycine (200 mM), and the mucosal blood flow (GMBF), determined by laser Doppler flowmetry, and acid secretion was measured simultaneously. Intravenous infusion with a submaximal dose of pentagastrin (60 micrograms/kg/h) caused a significant increase in GMBF as well as acid secretion. Such GMBF responses were totally attenuated when acid secretion was inhibited by omeprazole and cimetidine or when the luminal H+ was buffered by mucosal perfusion with glycine (200 mM). Tripelennamine, an H1 antagonist, did not have any affect on acid secretory and GMBF responses to pentagastrin. On the other hand, prior administration of NG-nitro-L-arginine methyl ester (L-NAME), the NO synthase inhibitor, significantly mitigated the increase of GMBF induced by pentagastrin without any influence on acid secretion, and this effect was antagonized by simultaneous administration of L-arginine. The gastric hyperemic response to pentagastrin was also significantly mitigated by indomethacin or sensory deafferentation after capsaicin pretreatment, with no effect on acid secretion, and was totally inhibited by combined treatments with indomethacin plus L-NAME in addition to sensory deafferentation. Pentagastrin infusion for 8 h did not by itself cause macroscopic damage in the stomach, but additional treatments with L-NAME and indomethacin plus sensory deafferentation provoked severe lesions in the gastric mucosa. These results suggest that the gastric hyperemic response to pentagastrin (submaximal dose) is totally dependent on H+ and that this process is mediated by endogenous NO and PGs as well as by capsaicin-sensitive sensory neurons and plays a pivotal role in maintaining mucosal integrity during acid secretion.

Animals↗

Hospital restructuring and nursing leadership: a journey from research question to research program.

The 1990s brought new fiscal realities to healthcare, leading to nursing job loss estimates in tens of thousands following widespread hospital restructuring to manage costs and improve efficiency. This research aimed at examining (a) how multiple episodes of hospital restructuring leading to layoff of nurses affected nurses who remained employed and (b) whether and how nursing leadership mitigated or intensified the negative effects of hospital restructuring on nurses. This dissertation comprised 3 empirical studies leading to 5 publications. The first study was a systematic literature review; the second and third used structural equation modeling to develop and test theoretical models addressing nursing practice environments and effects of hospital restructuring on nurses. The combined findings in this dissertation illustrate that hospital restructuring had significant negative physical/emotional health effects on nurses who remained employed. Nurses who worked for resonant (emotionally intelligent) leadership reported positive health and well-being, and opportunities to provide quality patient care. Nurses who worked for dissonant leadership reported greater negative effects of hospital restructuring. These findings led to a beginning theory of relational energy--a mechanism of mitigation whereby resonant nursing leaders invest energy into collaborative relationships with nurses, thereby positively influencing health and well-being, and, ultimately, outcomes for patients.

Alberta↗

Therapeutic efficacy of continuous arterial infusion of an antibiotic and a protease inhibitor via the superior mesenteric artery for acute pancreatitis in an animal model.

The major cause of death in acute pancreatitis is severe infection owing to bacterial translocation. As a new strategy, we investigated the effects of continuous intra-arterial infusion of an antibiotic (imipenem) or protease inhibitor (nafamostat mesylate) via the superior mesenteric artery (SMA) on bacterial translocation in acute pancreatitis. Infusion of saline (group I), nafamostat mesylate (group II), or imipenem (group III) was started 6 hours after inducing acute pancreatitis in dogs by infusing autologous gallbladder bile into the main pancreatic duct. The survival rate in group III was significantly improved compared to group I(100 vs. 30% at 24 hours), and bacterial infection of the peritoneal fluid, mesenteric lymph nodes, and pancreas was completely prevented in group III. Intestinal damage assessed by light and scanning electron microscopy and by biochemical parameters (mucosal protein content and myeloperoxidase activity) was also significantly mitigated in group III, which showed milder pancreatic necrosis as well. There was little beneficial effect in preventing bacterial translocation in group II, although the survival rate at 24 hours (70%) was improved. Continuous arterial infusion of an antibiotic via the SMA is effective in mitigating intestinal mucosal damage and preventing bacterial translocation in acute pancreatitis, thereby improving survival.

Acute Disease↗

The effects of gamma-glutamylcysteine ethyl ester, a prodrug of glutathione, on ischemia-reperfusion-induced liver injury in rats.

This study was designed to clarify the effects of changes in liver tissue glutathione (GSH) concentration on postischemic liver injury together with the effects of gamma-glutamylcysteine ethyl ester (GCE), a prodrug of GSH, and GSH. Rats were pretreated with GSH (50 mg/kg, i.v.), or GCE (50 mg/kg, i.v.), or untreated. In each rat, liver was isolated, and liver mitochondria were prepared after 2 h of ischemia or 1 h of reperfusion following 2 h of ischemia. Mitochondrial function was measured polarographically. Liver adenine nucleotide concentrations were also determined using high-performance liquid chromatography. Liver tissue GSH, an oxidized form of glutathione (GSSG) concentrations, and activities of GSH peroxidase and GSSG reductase were determined enzymatically. Liver hypoxanthine and xanthine concentrations were determined by HPLC. Liver tissue concentration of lipid peroxide was measured. Leakages of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and adenine nucleotides into the hepatic vein after reperfusion were also measured. Administration of GCE improved the recovery of mitochondrial function and maintained tissue GSH concentration concomitantly. Increases in liver lipid peroxide concentration after reperfusion, and leakage of liver cell enzymes and adenine nucleotides were mitigated by administration of GCE. Administration of GSH itself failed to maintain tissue GSH concentration and had no protective effects. From these results, it is concluded that in the postischemic process, free radical formation might be enhanced, and the radical scavenging system deteriorated. To enhance the radical scavenging system is a possible maneuver to prevent radical-related cell damage associated with reperfusion, because pharmacological reduction of breakdown of ATP to hypoxanthine and xanthine seems to be difficult. GCE maintained liver GSH concentrations and mitigated postischemic liver injury, concomitantly. Clinical use of GCE might be recommended.

Adenine Nucleotides↗

Gene therapy research for Duchenne and Becker muscular dystrophies.

Gene therapy is a promising option for the definitive treatment of Duchenne and Becker muscular dystrophies. Presently, gene therapy for Duchenne and Becker muscular dystrophies is still in the preclinical stage with dystrophin-deficient animals (the mdx mouse and a golden retriever dog strain) serving as convenient models. The thrust of research during the past 18 months has focused on two approaches: adenovirus-mediated dystrophin gene transfer and upregulation of a natural dystrophin analogue, utrophin. In the area of adenovirus-mediated gene transfer, substantial progress has been made in characterizing and mitigating the deleterious immune responses to the vector and transgene proteins. Furthermore, new adenovirus vectors have been created with reduced immunogenicity and increased insert gene capacity, which enhance the longevity of the transgene expression. Additional efforts are underway to develop safe and efficient routes of administration of the adenovirus vector carrying the dystrophin expression cassette. The prospects of utrophin upregulation as an attractive strategy for treatment of Duchenne and Becker muscular dystrophies was greatly enhanced by the demonstration of a substantial mitigation of the dystrophic phenotype of the transgenic mdx mouse overexpressing utrophin.

Animals↗

Obesity and hypertension.

An increasing number of clinical trials have demonstrated that obese patients are more likely than lean individuals to be hypertensive. Moreover, both obesity and arterial hypertension have been identified as independent risk factors for cardiovascular disease. Pathophysiologically, obesity appears to have a major influence on the hemodynamic changes associated with hypertension. The available evidence suggests that at any given level of arterial pressure, obese hypertensive patients have a higher cardiac output and lower total peripheral resistance than do lean patients. Recent reports have indicated that obesity exerts a disparate effect on target organs in hypertension. Whereas at rest obesity seems to mitigate cardiovascular changes in the systemic vascular bed caused by hypertension, no such mitigation was observed in the renovasculature; left ventricular hypertrophy as a major cardiovascular risk factor was even exacerbated by the presence of obesity. The different hemodynamic patterns in obese hypertensive patients have recently been shown clinically relevant for treating hypertensive patients.

Antihypertensive Agents↗

Reflex muscle contraction in the unaware occupant in whiplash injury.

STUDY DESIGN: Computer modeling and parametric analysis were used to determine the effect of reflex contraction of the neck muscles in the unaware occupant in whiplash. OBJECTIVE: To delineate effects of reflex contraction on spinal segmental kinematics during the retraction phase. SUMMARY OF BACKGROUND DATA: The ability of reflex neck muscle contraction to mitigate whiplash injury in the unaware occupant remains unclear. Analyzing relative timing between electromyographic and head-neck kinematics, previous investigators theorized that muscle contraction alters spinal kinematics, decreasing injury likelihood. Other investigators suggested that injury occurs during the initial (retraction) phase of head-neck kinematics, before significant muscle force generation. METHODS: Computer modeling was used to determine reflex contraction effects on segmental angulations, implementing parametric analysis techniques to vary reflex delay and impact severity. RESULTS: Shorter reflex delays had a greater effect on segmental angulations later in the event and at lower impact severities. However, the magnitude of this effect, particularly at higher impact severities and during maximum cervical S-curvature (factors implicated in the whiplash injury mechanism) was minimal, altering segmental angulations by a maximum of 19%. CONCLUSIONS: Because reflex contraction did not substantially alter spinal kinematics, muscle contraction likely does not initiate in sufficient time to mitigate whiplash injuries that may occur during the retraction phase.

Cervical Vertebrae↗

Attenuation of inflammation with short-term dietary intervention is associated with a reduction of arterial stiffness in subjects with hypercholesterolaemia.

BACKGROUND: Increased arterial stiffness has been found in patients with chronic high-grade inflammatory diseases. Whether mitigation of low-grade systemic inflammation, through a low-cholesterol/low-saturated fat diet, may have a role in improving arterial stiffness is still untested. DESIGN: We investigated whether variations in blood lipids and plasma C-reactive protein induced by low-cholesterol/low-saturated fat diet are associated with variations in large-artery stiffness in hypercholesterolaemia. METHODS: Thirty-five patients with primary hypercholesterolaemia and 15 normal control subjects were recruited for the study. Hypercholesterolaemic patients followed an 8-week low-cholesterol/low-saturated fat diet (30% total fat, 5% saturated fat, cholesterol <200 mg/daily). Anthropometric characteristics, blood lipids, plasma C-reactive protein and arterial stiffness were measured at baseline and after the diet. RESULTS: Arterial stiffness and C-reactive protein levels were higher in hypercholesterolaemic patients than in controls. Significant reductions in body weight (2 kg, 3%), plasma total cholesterol (13.4 mg/dl, 5.3%), low-density lipoprotein cholesterol (11.2 mg/dl, 6.4%), C-reactive protein (0.7 mg/l, 39%) and arterial stiffness (from 8.9+/-2.0 to 8.1+/-1.9 m/s, 11%) were achieved among hypercholesterolaemic patients after the 8-week diet (P<0.05 for all). Bivariate correlations and multivariate analysis showed reduction in arterial stiffness after short-term diet to be associated with reduction of plasma C-reactive protein levels (r=0.59, beta=0.38, P<0.05 for both). CONCLUSIONS: Short-term low-cholesterol/low-saturated fat diet in hypercholesterolaemia may be effective in improving large artery stiffness, likely through the mitigation of low-grade systemic inflammation.

Arteries↗

Schizophrenia and the cultural epidemiology of stigma in Bangalore, India.

Illness-related stigma is a complex and important issue, and its social impact contributes to a hidden burden of many health problems. Mitigating effects of stigma are a priority for mental health policy, especially for schizophrenia. Although numerous studies document its impact on patients and their families, health studies of stigma typically regard it in global terms without adequate attention to the conceptual and practical importance of sociocultural contexts and the particular features of illness that evoke stigma. Research at a psychiatric referral center in Bangalore, India, studied the cultural epidemiology of schizophrenia and stigma in interviews with family caretakers of 60 patients, using a locally adapted EMIC interview and the Positive and Negative Symptom Scale. An index of 13 stigma queries based on Goffman's formulation covered relevant aspects and proved to be internally consistent (Cronbach alpha = 0.81). Multivariate statistical regression and qualitative analysis of narratives were used to analyze this stigma index and identify explanatory variables based on cultural patterns of distress (PD), perceived causes (PC), and previous help seeking (HS). Significant variables included suspiciousness and inappropriate sexual behavior (PD), heredity and bad deeds (PC), and informal help seeking (HS). Previous allopathic help seeking was negatively associated with stigma. Analysis of coded text segments from respondent narratives showed how these variables were related to family-perceived stigma, with reference to marriage practices, moral meanings of schizophrenia, and ways in which effective allopathic care minimized stigma. Findings identify features of schizophrenia-related stigma in India, contribute to comparative culture studies, and inform practical approaches to mitigate stigma through community awareness and improved mental health services.

Culture↗

Contribution of the Brain-Gut-Microbiome Axis to Intergenerational Abnormalities in a Rat Model of Perioperative Neurocognitive Disorder.

BACKGROUND: The brain-gut-microbiome (BGM) axis is a communication network through which the brain and gastrointestinal microbiota interact via neural, hormonal, immune, and gene expression mechanisms. Gut microbiota dysbiosis is thought to contribute to neurocognitive disorders, including perioperative neurocognitive disorder, and to various metabolic abnormalities. Recently, the authors reported that sevoflurane induces neurocognitive deficits in exposed rats as well as their future offspring, with male offspring being particularly affected (intergenerational perioperative neurocognitive disorder). In this study, the authors examined in the same animals whether the intergenerational effects of sevoflurane involve abnormalities in the BGM axis, and whether they are mitigated by paternal pretreatment with either the Na + -K + -Cl - (NKCC1) Cl - transporter inhibitor bumetanide or the glucocorticoid receptor inhibitor RU486, as previously demonstrated for neurocognitive deficits. METHODS: Male Sprague-Dawley rats (F0 generation) were exposed to 2.1% sevoflurane for 3&#x2009;h on postnatal days 56, 58, and 60 (F0M_S group). Before each sevoflurane exposure, distinct experimental groups of F0 males received bumetanide (F0M_BS group) or RU486 (F0M_RS group). These males were mated on postnatal day 90 to produce offspring (F1 generation). Gut microbiota were profiled using 16S rRNA gene sequencing, and brain changes analyzed via RNA sequencing of hippocampal samples. RESULTS: F1 male offspring of F0M_S sires exhibited heightened corticosterone responses to stress, increased inflammatory markers, altered hippocampal transcriptomes, gut microbiota dysbiosis, elevated serum low-density lipoprotein cholesterol levels, and increased body weight. The only abnormality observed in F1 females was a shift in microbial diversity. F0M_S displayed profound alterations in hippocampal transcriptome, while microbial diversity was the only parameter affected in their gut microbiota. Bumetanide or RU486 mitigated most abnormalities, except increased body weight in F1 males. CONCLUSIONS: Paternal sevoflurane exposure in rats induces BGM axis abnormalities, particularly in male offspring, despite the absence of direct anesthetic exposure. Pretreatment with bumetanide or RU486 showed therapeutic efficacy.

Animals↗

Intraspecific divergence within Microcystis aeruginosa mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios.

Intraspecific biodiversity can have ecosystem-level consequences and may affect the accuracy of ecological forecasting. For example, rare genetic variants may have traits that prove beneficial under future environmental conditions. The cyanobacterium responsible for most freshwater harmful algal blooms worldwide, Microcystis aeruginosa, occurs in at least three types. While the dominant type occurs in eutrophic environments and is adapted to thrive in nutrient-rich conditions, two additional types have recently been discovered that inhabit oligotrophic and eutrophic environments and have genomic adaptations for survival under nutrient limitation. Here, we show that these oligotrophic types are widespread throughout the Eastern USA. By pairing an experimental warming study with gene expression analyses, we found that the eutrophic type may be most susceptible to climate warming. In comparison, oligotrophic types maintained their growth better and persisted longer under warming. As a mechanistic explanation for these patterns, we found that oligotrophic types responded to warming by widespread elevated expression of heat shock protein genes. Reduction of nutrient loading has been a historically effective mitigation strategy for controlling harmful algal blooms. Our results suggest that climate warming may benefit oligotrophic types of M. aeruginosa, potentially reducing the effectiveness of such mitigation efforts. In-depth study of intraspecific variation may therefore improve forecasting for understanding future whole ecosystem dynamics.

Microcystis↗

Forests, carbon and global climate.

This review places into context the role that forest ecosystems play in the global carbon cycle, and their potential interactions with climate change. We first examine the natural, preindustrial carbon cycle. Every year forest gross photosynthesis cycles approximately one-twelfth of the atmospheric stock of carbon dioxide, accounting for 50% of terrestrial photosynthesis. This cycling has remained almost constant since the end of the last ice age, but since the Industrial Revolution it has undergone substantial disruption as a result of the injection of 480 PgC into the atmosphere through fossil-fuel combustion and land-use change, including forest clearance. In the second part of this paper we review this 'carbon disruption', and its impact on the oceans, atmosphere and biosphere. Tropical deforestation is resulting in a release of 1.7 PgC yr(-1) into the atmosphere. However, there is also strong evidence for a 'sink' for carbon in natural vegetation (carbon absorption), which can be explained partly by the regrowth of forests on abandoned lands, and partly by a global change factor, the most likely cause being 'fertilization' resulting from the increase in atmospheric CO(2). In the 1990s this biosphere sink was estimated to be sequestering 3.2 PgC yr(-1) and is likely to have substantial effects on the dynamics, structure and biodiversity of all forests. Finally, we examine the potential for forest protection and afforestation to mitigate climate change. An extensive global carbon sequestration programme has the potential to make a particularly significant contribution to controlling the rise in CO2 emissions in the next few decades. In the course of the whole century, however, even the maximum amount of carbon that could be sequestered will be dwarfed by the magnitude of (projected) fossil-fuel emissions. Forest carbon sequestration should only be viewed as a component of a mitigation strategy, not as a substitute for the changes in energy supply, use and technology that will be required if atmospheric CO(2) concentrations are to be stabilized.

Air Pollution↗

An overview of a free-market approach to climate change and conservation.

This paper describes the convergence of environmental and financial markets, reviews the evolution of market-based environmental programmes as an example of the seven-stage evolutionary process witnessed in a variety of markets and summarizes the emergence of greenhouse-gas-mitigation markets and their potential role in advancing land stewardship, biodiversity and other environmental services. Emissions trading has been developed to meet the demand to reduce pollution while avoiding economic disruption. Consistent with the seven-stage pattern of market evolution, the US programme to reduce the damage from acid rain established a standardized environmental commodity, developed 'evidence of ownership' necessary for financial instruments and provided the infrastructure to efficiently transfer title. The success of the system in reducing pollution at low cost has provided a model for other market-based environmental protection initiatives. The demand for cost-effective action to reduce the threat of climate change has initiated the same evolutionary process for markets to reduce greenhouse-gas emissions. Many of the land- and forest-management practices that can capture and store atmospheric CO(2) can also provide other environmental benefits, such as biodiversity preservation and enhanced water quality. The presence of a carbon-trading market will introduce a clear financial value for capture and mitigation of CO(2) emissions, thus introducing a new source of funding for land stewardship and forest rehabilitation. The market is now emerging through a variety of 'bottom-up' developments being undertaken through governmental, multilateral, private-sector and non-governmental-organization initiatives. The extension of markets to other emerging environmental issues is now underway, and the linkages between environmental sustainability and capital markets are being more deeply understood. The early evidence indicates that environmental sustainability can be compatible with maximization of shareholder value.

Air Pollution↗

Climate change and food security.

Dynamic interactions between and within the biogeophysical and human environments lead to the production, processing, distribution, preparation and consumption of food, resulting in food systems that underpin food security. Food systems encompass food availability (production, distribution and exchange), food access (affordability, allocation and preference) and food utilization (nutritional and societal values and safety), so that food security is, therefore, diminished when food systems are stressed. Such stresses may be induced by a range of factors in addition to climate change and/or other agents of environmental change (e.g. conflict, HIV/AIDS) and may be particularly severe when these factors act in combination. Urbanization and globalization are causing rapid changes to food systems. Climate change may affect food systems in several ways ranging from direct effects on crop production (e.g. changes in rainfall leading to drought or flooding, or warmer or cooler temperatures leading to changes in the length of growing season), to changes in markets, food prices and supply chain infrastructure. The relative importance of climate change for food security differs between regions. For example, in southern Africa, climate is among the most frequently cited drivers of food insecurity because it acts both as an underlying, ongoing issue and as a short-lived shock. The low ability to cope with shocks and to mitigate long-term stresses means that coping strategies that might be available in other regions are unavailable or inappropriate. In other regions, though, such as parts of the Indo-Gangetic Plain of India, other drivers, such as labour issues and the availability and quality of ground water for irrigation, rank higher than the direct effects of climate change as factors influencing food security. Because of the multiple socio-economic and bio-physical factors affecting food systems and hence food security, the capacity to adapt food systems to reduce their vulnerability to climate change is not uniform. Improved systems of food production, food distribution and economic access may all contribute to food systems adapted to cope with climate change, but in adopting such changes it will be important to ensure that they contribute to sustainability. Agriculture is a major contributor of the greenhouse gases methane (CH4) and nitrous oxide (N2O), so that regionally derived policies promoting adapted food systems need to mitigate further climate change.

Agriculture↗

Comparative genomics of Gossypium and Arabidopsis: unraveling the consequences of both ancient and recent polyploidy.

Both ancient and recent polyploidy, together with post-polyploidization loss of many duplicated gene copies, complicates angiosperm comparative genomics. To explore an approach by which these challenges might be mitigated, genetic maps of extant diploid and tetraploid cottons (Gossypium spp.) were used to infer the approximate order of 3016 loci along the chromosomes of their hypothetical common ancestor. The inferred Gossypium gene order corresponded more closely than the original maps did to a similarly inferred ancestral gene order predating an independent paleopolyploidization (alpha) in Arabidopsis. At least 59% of the cotton map and 53% of the Arabidopsis transcriptome showed correspondence in multilocus gene arrangements based on one or both of two software packages (CrimeStatII, FISH). Genomic regions in which chromosome structural rearrangement has been rapid (obscuring gene order correspondence) have also been subject to greater divergence of individual gene sequences. About 26%-44% of corresponding regions involved multiple Arabidopsis or cotton chromosomes, in some cases consistent with known, more ancient, duplications. The genomic distributions of multiple-locus probes provided early insight into the consequences for chromosome structure of an ancient large-scale duplication in cotton. Inferences that mitigate the consequences of ancient duplications improve leveraging of genomic information for model organisms in the study of more complex genomes.

Arabidopsis↗

Progress toward ignition with noncryogenic double-shell capsules

Inertial confinement fusion implosions using capsules with two concentric shells separated by a low density region (double shells) are reported which closely follow one dimensional (1D) radiatively driven hydrodynamics simulations. Capsule designs which mitigate Au M-band radiation asymmetries appear to correspond more closely to 1D simulations than targets lacking mitigation of hohlraum drive M-band nonuniformities. One capsule design achieves over 50% of the unperturbed 1D calculated yield at a convergence ratio of 25.5, comparable to that of a double-shell design for an ignition capsule at the National Ignition Facility.

Journal Article↗