Handgrip strength is associated with 12-month survival in male patients suffering with advanced chronic liver disease.

BACKGROUND: Advanced chronic liver disease (ACLD) patients are usually malnourished, and both conditions in combination increase the likelihood of unfavourable clinical outcomes. Handgrip strength (HGS) has been suggested as a relevant parameter for nutritional assessment and predictor of adverse clinical outcomes in ACLD. However, the HGS cut-off values for ACLD patients have not yet been reliably established. The aims of this study were to preliminarily identify HGS reference values in a sample population of ACLD male patients and to assess their association with survival over a 12-month follow-up period. METHODS: This was a prospective observational study with preliminary analysis of outpatients and inpatients. A total of 185 male patients with a medical diagnosis of ACLD met the inclusion criteria and were invited to participate in the study. The physiological variation in muscle strength related to the age of the individuals included in the study was considered to obtain cut-off values. RESULTS: After categorising HGS by age group (adults: 18-60 years; elderly: ≥60 years), the reference values obtained were 32.5 kg for the adults and 16.5 kg for the elderly. During the 12-month follow-up, 20.5% of the patients died, and 76.3% of those had been identified with reduced HGS. CONCLUSIONS: Patients with adequate HGS showed significantly higher 12-month survival than those with reduced HGS within the same period. Our findings show that HGS is an important predictive parameter for clinical and nutritional follow-up in ACLD male patients.

Plant water uptake from soil through a vapor pathway.

Water uptake from the soil via a vapor pathway was tested. Viburnum suspensum L. plants were divided into: (1) irrigated, (2) drought with vapor and (3) drought without vapor treatments. Each plant was placed into a larger bucket containing deuterium-labeled water as a vapor source (vapor treatment) or no water (drought and irrigation treatments). We also tested whether uptake via a vapor pathway could mitigate drought effects. Net CO2 assimilation (A), transpiration (E) and stomatal conductance (gs) were measured daily until the first visible signs of stress. Soil water content, stem water potential (Ψ) and the stable hydrogen isotope ratio (δ2 H) of soil and plant xylem water were then measured in all treatments. We show that water is taken up by plants through the vapor phase in dry soils. The δ2 H values of the soil water in the vapor treatment were highly enriched compared to the background isotope ratios of the non-vapor exposed irrigated and drought treatments. Stem water δ2 H values for the vapor treatment were significantly greater than those for irrigation and drought treatments not exposed to isotopically enriched vapor. In this experiment, movement of water to the plant via the vapor phase did not mitigate drought effects. A, E, plant Ψ and gs significantly decreased in the drought and vapor treatments relative to the controls, with no significant differences between vapor and drought treatments.

Water uptake of Alaskan tundra evergreens during the winter-spring transition.

PREMISE OF THE STUDY: The cold season in the Arctic extends over 8 to 9 mo, yet little is known about vascular plant physiology during this period. Evergreen species photosynthesize under the snow, implying that they are exchanging water with the atmosphere. However, liquid water available for plant uptake may be limited at this time. The study objective was to determine whether evergreen plants are actively taking up water while under snow and/or immediately following snowmelt during spring thaw. METHODS: In two in situ experiments, one at the plot level and another at the individual species level, (2)H-labeled water was used as a tracer injected beneath the snow, after which plant stems and leaves were tested for the presence of the label. In separate experiments, excised shoots of evergreen species were exposed to (2)H-labeled water for ∼5 s or 60 min and tested for foliar uptake of the label. KEY RESULTS: In both the plot-level and the species-level experiments, some (2)H-labeled water was found in leaves and stems. Additionally, excised individual plant shoots exposed to labeled water for 60 min took up significantly more (2)H-label than shoots exposed ∼5 s. CONCLUSIONS: Evergreen tundra plants take up water under snow cover, some via roots, but also likely by foliar uptake. The ability to take up water in the subnivean environment allows evergreen tundra plants to take advantage of mild spring conditions under the snow and replenish carbon lost by winter respiration.

Aphids alter host-plant nitrogen isotope fractionation.

Plant sap-feeding insects and blood-feeding parasites are frequently depleted in (15)N relative to their diet. Unfortunately, most fluid-feeder/host nitrogen stable-isotope studies simply report stable-isotope signatures, but few attempt to elucidate the mechanism of isotopic trophic depletion. Here we address this deficit by investigating the nitrogen stable-isotope dynamics of a fluid-feeding herbivore-host plant system: the green peach aphid, Myzus persicae, feeding on multiple brassicaceous host plants. M. persicae was consistently more than 6‰ depleted in (15)N relative to their hosts, although aphid colonized plants were 1.5‰ to 2.0‰ enriched in (15)N relative to uncolonized control plants. Isotopic depletion of aphids relative to hosts was strongly related to host nitrogen content. We tested whether the concomitant aphid (15)N depletion and host (15)N enrichment was coupled by isotopic mass balance and determined that aphid (15)N depletion and host (15)N enrichment are uncoupled processes. We hypothesized that colonized plants would have higher nitrate reductase activity than uncolonized plants because previous studies had demonstrated that high nitrate reductase activity under substrate-limiting conditions can result in increased plant δ(15)N values. Consistent with our hypothesis, nitrate reductase activity in colonized plants was twice that of uncolonized plants. This study offers two important insights that are likely applicable to understanding nitrogen dynamics in fluid-feeder/host systems. First, isotopic separation of aphid and host depends on nitrogen availability. Second, aphid colonization alters host nitrogen metabolism and subsequently host nitrogen stable-isotope signature. Notably, this work establishes a metabolic framework for future hypothesis-driven studies focused on aphid manipulation of host nitrogen metabolism.

Are leaf physiological traits related to leaf water isotopic enrichment in restinga woody species?

During plant-transpiration, water molecules having the lighter stable isotopes of oxygen and hydrogen evaporate and diffuse at a faster rate through the stomata than molecules having the heavier isotopes, which cause isotopic enrichment of leaf water. Although previous models have assumed that leaf water is well-mixed and isotopically uniform, non-uniform stomatal closure, promoting different enrichments between cells, and different pools of water within leaves, due to morpho-physiological traits, might lead to inaccuracies in isotopic models predicting leaf water enrichment. We evaluate the role of leaf morpho-physiological traits on leaf water isotopic enrichment in woody species occurring in a coastal vegetation of Brazil known as restinga. Hydrogen and oxygen stable isotope values of soil, plant stem and leaf water and leaf traits were measured in six species from restinga vegetation during a drought and a wet period. Leaf water isotopic enrichment relative to stem water was more homogeneous among species during the drought in contrast to the wet period suggesting convergent responses to deal to temporal heterogeneity in water availability. Average leaf water isotopic enrichment relative to stem water during the drought period was highly correlated with relative apoplastic water content. We discuss this observation in the context of current models of leaf water isotopic enrichment as a function of the Péclet effect. We suggest that future studies should include relative apoplastic water content in isotopic models.

RISK FACTORS FOR HEPATOCELLULAR CARCINOMA IN PATIENTS WITH NON-ALCOHOLIC FATTY LIVER DISEASE.

Non-alcoholic fatty liver disease is growing in worldwide prevalence and thus, is expected to have a higher number of NAFLD-related hepatocellular carcinoma (HCC) in the following years. This review describes the risk factors associated with HCC in NAFLD-patients. The presence of liver cirrhosis is the preponderant one. Male gender, PNPLA3 variants, diabetes, and obesity also appear to predispose to the development of HCC, even in non-cirrhotic subjects. Thus far, intensive lifestyle modifications, including glycemic control, and obesity treatment, are effective therapies for NAFLD/ non-alcoholic steatohepatitis and, therefore, probably, also for HCC. Some drugs that aimed at decreasing inflammatory activity and fibrosis, as well as obesity, were studied. Other data have suggested the possibility of HCC chemoprevention. So far, however, there is no definitive evidence for the routine utilization of these drugs. We hope, in the future, to be able to profile patients at higher risk of NAFLD-HCC and outline strategies for early diagnosis and prevention.

BETTER LIVING DONOR LIVER TRANSPLANTATION PATIENT SURVIVAL COMPARED TO DECEASED DONOR - A SYSTEMATIC REVIEW AND META-ANALYSIS.

BACKGROUND: Deceased donor liver transplantation (DDLT) is the first choice, but living donor transplantation (LDLT) is an alternative to be considered in special situations, such as lack of donated organs and emergencies. So far, there is no consensus on which transplantation method provides better survival and fewer complications, which is still an open point for discussion. METHODS: This meta-analysis compared the 1, 3, and 5-year patient and graft survival rates of LDLT and DDLT. We included studies published from April-2009 to June-2021 and adopted the generic model of the inverse of variance for the random effect of hazard ratios. The adequacy of the studies was determined using the Newcastle-Ottawa Scale - NOS (WELLS). RESULTS: For patient survival analysis, we included a total of 32,258 subjects. We found a statistically significant better survival for the LDLT group at 1, 3 and 5 years, respectively: 1.35 HR (95%CI 1.10-1.66, P=0.005), 1.26 HR (95%CI 1.09-1.46, P=0.002) and 1.27 HR (95%CI 1.09-1.48, P=0.002). Our meta-analysis evaluated a total of 21,276 grafts. In the overall analysis, the 1-year survival was improved in favor of the LDLT group (1.36 HR, 95%CI 1.16-1.60, P<0.0001), while the 3-year survival (1.13 HR, 95%CI 0.96-1.33, P<0.13), and 5 (0.99 HR, 95%CI 0.74-1.33, P<0.96), did not differ significantly. CONCLUSION: This metanalysis detected a statistically significant greater 1-, 3- and 5-years patient survival favoring LDLT compared to DDLT as well as a statistically significant difference better 1-year graft survival favoring the LDLT group.

How Does Cognitive Effort Influence the Tactical Behavior of Soccer Players?

In the present study, we aimed to investigate the association between soccer players' cognitive effort and their tactical behavior. We assessed 52 young male soccer players from a first division Brazilian club, using FUT-SAT to evaluate tactical behavior efficiency and Mobile Eye Tracking-XG software and a video test protocol to measure pupillary behavior and cognitive effort. Following data collection, statistical analyses were performed using the Kolmogorov-Smirnov normality test, and linear regression. We found a high inverse association between cognitive effort and tactical behavior efficiency; players with less cognitive effort during the task displayed higher values of tactical behavior efficiency on the field. We concluded that sustaining less cognitive effort in game situations helped players realize better tactical behavior and enabled better performance.

Oral health-related quality of life in caregivers of individuals with Cerebral Palsy: a case-control study.

AIM: The object of this study is to evaluate the oral health-related quality of life (OHRQoL) of caregivers of individuals with Cerebral Palsy (CP). METHODS: Ninety-eight caregivers of individuals with CP (SG) and 196 caregivers of individuals without special needs (CG) completed the reduced version of the Oral Health Impact Profile (OHIP-14). In addition, a questionnaire with demographic and socioeconomic questions was used. Groups were matched according to gender, schooling and family income. Fisher's exact tests, Chi square and Mann-Whitney, and bi/multivariate logistic regression were used (p < 0.05). RESULTS: The impact on OHRQoL was similar for SG and CG (OHIP-14 total score). For SG, the high negative impact was in the following OHIP domains: "Functional limitation", "Physical disability", "Psychological incapacity" and "Disadvantages". For SG, a higher number of caregivers was single, unemployed, received government financial aid. There was a statistically significant association between the number of children a caregiver has and a negative impact on OHRQoL. CONCLUSIONS: Being a caregiver of children with or without CP had a negative impact of similar magnitude on ORHQoL. The negative impact on OHRQoL of caregivers of children with CP was associated with having a high number of children; the higher the number of children, the greater the negative impact on their OHRQoL.

Lake and watershed characteristics rather than climate influence nutrient limitation in shallow lakes.

Both nitrogen (N) and phosphorus (P) can limit primary production in shallow lakes, but it is still debated how the importance of N and P varies in time and space. We sampled 83 shallow lakes along a latitudinal gradient (5 degrees 55 degrees S) in South America and assessed the potential nutrient limitation using different methods including nutrient ratios in sediment, water, and seston, dissolved nutrient concentrations, and occurrence of N-fixing cyanobacteria. We found that local characteristics such as soil type and associated land use in the catchment, hydrology, and also the presence of abundant submerged macrophyte growth influenced N and P limitation. We found neither a consistent variation in nutrient limitation nor indications for a steady change in denitrification along the latitudinal gradient. Contrary to findings in other regions, we did not find a relationship between the occurrence of (N-fixing and non-N-fixing) cyanobacteria and the TN:TP ratio. We found N-fixing cyanobacteria (those with heterocysts) exclusively in lakes with dissolved inorganic nitrogen (DIN) concentrations of < 100 microg/L, but notably they were also often absent in lakes with low DIN concentrations. We argue that local factors such as land use and hydrology have a stronger influence on which nutrient is limiting than climate. Furthermore, our data show that in a wide range of climates N limitation does not necessarily lead to cyanobacterial dominance.

Young Soccer Players With Higher Tactical Knowledge Display Lower Cognitive Effort.

The present study aimed to investigate whether the form and amount of declarative tactical knowledge (DTK) and procedural tactical knowledge (PTK) influence cognitive effort during soccer performance among young players. We assessed 36 male players from a Brazilian first-division soccer club; participants averaged 14.89 ( SD = 1.42) years of age. We evaluated DTK from video simulation tests and PTK through the System of Tactical Assessment in Soccer. We assessed cognitive effort by measures of pupil diameter using Mobile Eye Tracking-XG while players viewed soccer video scenes and made game-related play decisions. After the assessment of tactical knowledge, we categorized the sample according to players' tactical knowledge into participants with higher and lower PTK and higher and lower DTK. Subsequently, we examined the both PTK and DTK groups on cognitive effort. Our results suggest that tactical knowledge influences cognitive effort in that players with higher PTK and DTK displayed less cognitive effort during soccer performance tasks. In conclusion, we observed that PTK and DTK influenced the cognitive effort younger soccer players expended while viewing soccer scenes and making soccer performance decisions.

Plants use macronutrients accumulated in leaf-cutting ant nests.

Leaf-cutting ants (Atta spp.) are known for their extensive defoliation in neo-tropical forests and savannahs. Debate about the costs and benefits of their activities has been largely dominated by their detrimental effects on agriculture and agroforestry. However, the large accumulation of nutrients and changes in soil properties near their nests might benefit plants growing near them. Here, we test whether trees use nutrients that accumulate in debris piles near, or refuse chambers within, leaf-cutting ant nests. At two tropical sites (a moist tropical forest site in Panama and a savannah site in Brazil), we fed leaves labelled with the stable isotope 15N to two species of leaf-cutting ants (Atta colombica and Atta laevigata) and traced the stable isotope label in plants surrounding the two nests. Thus, we show that plants in both sites access resources associated with Atta nests. In addition, leaf tissue of trees near the nests labelled with 15N had significantly higher calcium concentrations than those of distal, unlabelled conspecifics. It has been documented that calcium is a limiting macronutrient in tropical forests and savannahs. Atta may thus play an important ecological role through their long-distance transport, redistribution and concentration of critical macronutrients.

Fatores de risco para carcinoma hepatocelular em pacientes com doença gordurosa não alcóolica do fígado / Risk factors for hepatocellular carcinoma in patients with non-alcoholic fatty liver disease

ABSTRACT Non-alcoholic fatty liver disease is growing in worldwide prevalence and thus, is expected to have a higher number of NAFLD-related hepatocellular carcinoma (HCC) in the following years. This review describes the risk factors associated with HCC in NAFLD-patients. The presence of liver cirrhosis is the preponderant one. Male gender, PNPLA3 variants, diabetes, and obesity also appear to predispose to the development of HCC, even in non-cirrhotic subjects. Thus far, intensive lifestyle modifications, including glycemic control, and obesity treatment, are effective therapies for NAFLD/ non-alcoholic steatohepatitis and, therefore, probably, also for HCC. Some drugs that aimed at decreasing inflammatory activity and fibrosis, as well as obesity, were studied. Other data have suggested the possibility of HCC chemoprevention. So far, however, there is no definitive evidence for the routine utilization of these drugs. We hope, in the future, to be able to profile patients at higher risk of NAFLD-HCC and outline strategies for early diagnosis and prevention.

RESUMO A doença metabólica e doença hepática gordurosa metabólica estão aumentando a prevalência mundial e, portanto, espera-se um número maior de carcinoma hepatocelular (CHC) relacionado à doença hepática gordurosa não alcóolica (DHGNA) nos próximos anos. Esta revisão descreve os fatores de risco associados ao CHC em pacientes com DHGNA. A presença de cirrose hepática é a preponderante. Sexo masculino, variantes do gene PNPLA3, diabetes e obesidade também parecem predispor ao desenvolvimento de CHC, mesmo em indivíduos não cirróticos. Até agora, modificações significativas no estilo de vida, incluindo controle glicêmico e tratamento da obesidade, são terapias eficazes para DHGNA/ Esteatohepatite não-alcoolica e, portanto, provavelmente, também para CHC. Alguns medicamentos que propunham-se diminuir a atividade inflamatória e fibrose, bem como a obesidade, foram estudados. Outros dados sugeriram a possibilidade de quimioprevenção do CHC. Até o momento, no entanto, não há evidências definitivas para o uso rotineiro desses medicamentos. Esperamos, no futuro, poder traçar o perfil de pacientes com maior risco de DHGNA-CHC e traçar estratégias para diagnóstico precoce e prevenção.

Sobrevida de pacientes submetidos ao transplante hepático com enxerto de doador vivo é melhor em comparação com doador falecido — uma revisão sistemática e meta-análise / Better living donor liver transplantation patient survival compared to deceased donor — a systematic review and meta-analysis

ABSTRACT Background Deceased donor liver transplantation (DDLT) is the first choice, but living donor transplantation (LDLT) is an alternative to be considered in special situations, such as lack of donated organs and emergencies. So far, there is no consensus on which transplantation method provides better survival and fewer complications, which is still an open point for discussion. Methods This meta-analysis compared the 1, 3, and 5-year patient and graft survival rates of LDLT and DDLT. We included studies published from April-2009 to June-2021 and adopted the generic model of the inverse of variance for the random effect of hazard ratios. The adequacy of the studies was determined using the Newcastle-Ottawa Scale — NOS (WELLS). Results For patient survival analysis, we included a total of 32,258 subjects. We found a statistically significant better survival for the LDLT group at 1, 3 and 5 years, respectively: 1.35 HR (95%CI 1.10—1.66, P=0.005), 1.26 HR (95%CI 1.09—1.46, P=0.002) and 1.27 HR (95%CI 1.09—1.48, P=0.002). Our meta-analysis evaluated a total of 21,276 grafts. In the overall analysis, the 1-year survival was improved in favor of the LDLT group (1.36 HR, 95%CI 1.16—1.60, P<0.0001), while the 3-year survival (1.13 HR, 95%CI 0.96—1.33, P<0.13), and 5 (0.99 HR, 95%CI 0.74—1.33, P<0.96), did not differ significantly. Conclusion This metanalysis detected a statistically significant greater 1-, 3- and 5-years patient survival favoring LDLT compared to DDLT as well as a statistically significant difference better 1-year graft survival favoring the LDLT group.

RESUMO Contexto O transplante de fígado com doador falecido é a primeira escolha, mas o transplante de doador vivo é uma alternativa a ser considerada em situações especiais, como falta de órgãos doados e emergências. Até o momento, não há consenso sobre qual método de transplante proporciona melhor sobrevida e menos complicações, sendo, ainda, um ponto em aberto para discussão. Métodos Esta meta-análise comparou as taxas de sobrevida de pacientes e enxertos de 1, 3 e 5 anos de transplante de doador vivo e transplante de fígado com doador falecido. Incluímos estudos publicados de abril de 2009 a junho de 2021 e adotamos o modelo genérico do inverso da variância para o efeito aleatório das razões de risco. A adequação dos estudos foi determinada por meio da Escala de Newcastle-Ottawa — NOS (WELLS). Resultados Para análise de sobrevida do paciente, incluímos um total de 32.258 indivíduos. Encontramos uma melhor sobrevida estatisticamente significativa para o grupo de transplante de fígado de doador vivo em 1, 3 e 5 anos, respectivamente: 1,35 HR (IC95% 1,10—1,66, P=0,005), 1,26 HR (IC95% 1,09—1,46, P=0,002) e 1,27 HR (IC95% 1,09—1,48, P=0,002). Nossa meta-análise avaliou um total de 21.276 enxertos. Na análise geral, a sobrevida em 1 ano foi melhorada em favor do grupo de transplante de doador vivo (1,36 HR, IC95% 1,16—1,60, P<0,0001), enquanto a sobrevida em 3 anos (1,13 HR, IC95% 0,96—1,33, P<0,13) e 5 (0,99 HR, IC95% 0,74—1,33, P<0,96), não diferiram significativamente. Conclusão Esta meta-análise detectou uma sobrevida estatisticamente significativa maior do paciente em 1, 3 e 5 anos favorecendo o transplante de doador vivo em comparação com o transplante de fígado com doador falecido, bem como uma diferença estatisticamente significativa melhor na sobrevida do enxerto em 1 ano favorecendo o grupo de transplante de doador vivo.

The use of stable isotopes to study ecosystem gas exchange.

Stable isotopes are a powerful research tool in environmental sciences and their use in ecosystem research is increasing. In this review we introduce and discuss the relevant details underlying the use of carbon and oxygen isotopic compositions in ecosystem gas exchange research. The current use and potential developments of stable isotope measurements together with concentration and flux measurements of CO2 and water vapor are emphasized. For these applications it is critical to know the isotopic identity of specific ecosystem components such as the isotopic composition of CO2, organic matter, liquid water, and water vapor, as well as the associated isotopic fractionations, in the soil-plant- atmosphere system. Combining stable isotopes and concentration measurements is very effective through the use of "Keeling plots." This approach allows the identification of the isotopic composition and the contribution of ecosystem, or ecosystem components, to the exchange fluxes with the atmosphere. It also allows the estimation of net ecosystem discrimination and soil disequilibrium effects. Recent modifications of the Keeling plot approach permit examination of CO2 recycling in ecosystems. Combining stable isotopes with dynamic flux measurements requires precision in isotopic sampling and analysis, which is currently at the limit of detection. Combined with the micrometeorological gradient approach (applicable mostly in grasslands and crop fields), stable isotope measurements allow separation of net CO2 exchange into photosynthetic and soil respiration components, and the evapotranspiration flux into soil evaporation and leaf transpiration. Similar applications in conjunction with eddy correlation techniques (applicable to forests, in addition to grasslands and crop fields) are more demanding, but can potentially be applied in combination with the Keeling plot relationship. The advance and potential in using stable isotope measurements should make their use a standard component in the limited arsenal of ecosystem-scale research tools.

Carbon, oxygen and hydrogen isotope abundances inStylites reflect its unique physiology.

Natural abundances of oxygen-18, carbon-14, carbon-13 and deuterium were measured inStylites andicola, a terrestrial vascular plant lacking stomates, and two terrestrial plant species having stomates that grew nearby. No substantial differences in oxygen-18 and carbon-13 abundances were observed among the three species. The deuterium concentration inStylites was much higher than in the other species, confirming a previous report of CAM inStylites. Stylites was depleted in carbon-14 relative to the present day atmosphere, consistent with the proposal that it fixes CO2 derived from decomposing peat.

Photosynthesis in epiphytic and rooted Clusia rosea Jacq.

Clusia rosea Jacq. is a hemiepiphyte having Crassulacean Acid Metabolism (CAM). In its natural habitat Clusia begins its life cycle as an epiphyte and eventually becomes a rooted tree. These two stages of the life cycle of Clusia represent markedly different water regimes. Our CO2 exchange, stomatal conductance, titratable acidity, and stable carbon isotope ratio measurements indicate that Clusia has a flexible photosynthetic mode, where CO2 is fixed mostly via CAM during its epiphytic stage, when water availability is low, and via both CAM and C3 during its rooted stage.

Phosotynthesis in hemiepiphytic species of Clusia and Ficus.

Hemiepiphytic species in the genera Clusia and Ficus were investigated to study their mode of photosynthetic metabolism when growing under natural conditions. Despite growing sympatrically in many areas and having the same growth habit, some Clusia species show Crassulacean acid metabolism (CAM) whereas all species of Ficus investigated are C3. This conclusion is based on diurnal CO2 fixation patterns, diurnal stomatal conductances, diurnal titratable acidity fluctuations, and δ13C isotope ratios. Clusia minor, growing in the savannas adjacent to Barinas, Venezuela, shows all aspects of Crassulacean acid metabolism (CAM) on the basis of nocturnal gas exchange, stomatal conductance, total titratable acidity, and carbon isotope composition when measured during the dry season (February 1986). During the wet season (June 1986), the plants shifted to C3-type gas exchange with all CO2 uptake occurring during the daylight hours. The carbon isotope composition of new growth was-28 to-29‰ typical of C3 plants.

Determination of fosfomycin by indirect spectrophotometric method.

2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) is a sensitive photometric reagent for determination of zirconium, when fosfomycin is added, it can quantitatively replace 5-Br-PADAP by complexing with zirconium, thus, an indirect spectrophotometric method based on ligand exchange has been established. The detection wavelength is at 605 nm, and the apparent molar absorption coefficient was found to be 4.59x10(4) l mol(-1) cm(-1). Beer's law is obeyed in the range of 0-28x10(-6) M. The composition and stability constant of zirconium with 5-Br-PADAP and with fosfomycin has also been estimated. The proposed method is simple and reproducible, it was applicable to the analysis of fosfomycin from pharmaceutical manufacture.

Ephemeral clonal integration in Calathea marantifolia (Marantaceae): Evidence of diminished integration over time.

A major advantage of clonal growth forms is the intergenerational transfer of resources through vascular connections (clonal integration). Connections linking ramets can be persistent or ephemeral. For species with ephemeral connections, whether the extent of clonal integration changes over time is unclear. To address this issue, we tracked water movement using an isotopic label and assessed the demographic performance of parent and offspring ramets over time in a severing experiment. Our study system was the understory herb Calathea marantifolia, which has parent ramets that produce vegetative bulbils (clonal offspring) that pass through distinct pre- and post-rooting stages. Little water was transported between parents and offspring, and the direction of movement was primarily from parent to pre-rooting offspring. Anatomical observations of inter-ramet connections showed that vascular bundles were twice as abundant in parent stems compared to inter-ramet connections. Severing inter-ramet connections reduced the growth of offspring ramets but not parents. Survival of pre-rooting offspring was reduced by 10% due to severing, but post-rooting offspring were not affected. Our results suggest that offspring ramets of C. marantifolia are weaned from their parent as they progress from pre- to post-rooting stages.