117 research outputs found
A New Precision Measurement of the 3He(4He,gamma)7Be Cross section
The 3He(4He,gamma)7Be reaction plays an important role in determining the
high energy solar neutrino flux and in understanding the abundances of
primordial 7Li. The present paper reports a new precision measurement of the
cross sections of this direct capture reaction, determined by measuring the
ensuing 7Be activity in the region of Ec.m.=400 keV to 950 keV. Various recent
theoretical fits to our data result in a consistent extrapolated value of
S34(0)=0.53(2)(1).Comment: 10 pages 3 figure
Neonatology/Paediatrics – Guidelines on Parenteral Nutrition, Chapter 13
There are special challenges in implementing parenteral nutrition (PN) in paediatric patients, which arises from the wide range of patients, ranging from extremely premature infants up to teenagers weighing up to and over 100 kg, and their varying substrate requirements. Age and maturity-related changes of the metabolism and fluid and nutrient requirements must be taken into consideration along with the clinical situation during which PN is applied. The indication, the procedure as well as the intake of fluid and substrates are very different to that known in PN-practice in adult patients, e.g. the fluid, nutrient and energy needs of premature infants and newborns per kg body weight are markedly higher than of older paediatric and adult patients. Premature infants <35 weeks of pregnancy and most sick term infants usually require full or partial PN. In neonates the actual amount of PN administered must be calculated (not estimated). Enteral nutrition should be gradually introduced and should replace PN as quickly as possible in order to minimise any side-effects from exposure to PN. Inadequate substrate intake in early infancy can cause long-term detrimental effects in terms of metabolic programming of the risk of illness in later life. If energy and nutrient demands in children and adolescents cannot be met through enteral nutrition, partial or total PN should be considered within 7 days or less depending on the nutritional state and clinical conditions
Gene conversion in human rearranged immunoglobulin genes
Over the past 20 years, many DNA sequences have been published suggesting that all or part of the V<sub>H</sub> segment of a rearranged immunoglobulin gene may be replaced in vivo. Two different mechanisms appear to be operating. One of these is very similar to primary V(D)J recombination, involving the RAG proteins acting upon recombination signal sequences, and this has recently been proven to occur. Other sequences, many of which show partial V<sub>H</sub> replacements with no addition of untemplated nucleotides at the V<sub>H</sub>–V<sub>H</sub> joint, have been proposed to occur by an unusual RAG-mediated recombination with the formation of hybrid (coding-to-signal) joints. These appear to occur in cells already undergoing somatic hypermutation in which, some authors are convinced, RAG genes are silenced. We recently proposed that the latter type of V<sub>H</sub> replacement might occur by homologous recombination initiated by the activity of AID (activation-induced cytidine deaminase), which is essential for somatic hypermutation and gene conversion. The latter has been observed in other species, but not in human Ig genes, so far. In this paper, we present a new analysis of sequences published as examples of the second type of rearrangement. This not only shows that AID recognition motifs occur in recombination regions but also that some sequences show replacement of central sections by a sequence from another gene, similar to gene conversion in the immunoglobulin genes of other species. These observations support the proposal that this type of rearrangement is likely to be AID-mediated rather than RAG-mediated and is consistent with gene conversion
Nuclear Reaction Network for Primordial Nucleosynthesis: a detailed analysis of rates, uncertainties and light nuclei yields
We analyze in details the standard Primordial Nucleosynthesis scenario. In
particular we discuss the key theoretical issues which are involved in a
detailed prediction of light nuclide abundances, as the weak reaction rates,
neutrino decoupling and nuclear rate modeling. We also perform a new analysis
of available data on the main nuclear processes entering the nucleosynthesis
reaction network, with particular stress on their uncertainties as well as on
their role in determining the corresponding uncertainties on light nuclide
theoretical estimates. The current status of theoretical versus experimental
results for 2H, 3He, 4He and 7Li is then discussed using the determination of
the baryon density as obtained from Cosmic Microwave Background anisotropies.Comment: LaTeX, 83 pages, 30 .pdf figures. Some typos in the units of
R-functions in appendix D and relative plots fixe
Tectono-stratigraphic response of the Sandino Forearc Basin (N-Costa Rica and W-Nicaragua) to episodes of rough crust and oblique subduction
The southern Central American active margin is a world-class site where past and
present subduction processes have been extensively studied. Tectonic erosion/accretion
and oblique/orthogonal subduction are thought to alternate in space and time
along the Middle American Trench. These processes may cause various responses
in the upper plate, such as uplift/subsidence, deformation, and volcanic arc migration/
shut-off. We present an updated stratigraphic framework of the Late Cretaceous–
Cenozoic Sandino Forearc Basin (SFB) which provides evidence of
sedimentary response to tectonic events. Since its inception, the basin was predominantly
filled with deep-water volcaniclastic deposits. In contrast, shallow-water
deposits appeared episodically in the basin record and are considered as tectonic
event markers. The SFB stretches for about 300 km and varies in thickness from
5 km (southern part) to about 16 km (northern part). The drastic, along-basin, thickness
variation appears to be the result of (1) differential tectonic evolutions and (2)
differential rates of sediment supply. (1) The northern SFB did not experience major
tectonic events. In contrast, the reduced thickness of the southern SFB (5 km) is the
result of at least four uplift phases related to the collision/accretion of bathymetric
reliefs on the incoming plate: (i) the accretion of a buoyant oceanic plateau (Nicoya
Complex) during the middle Campanian; (ii) the collision of an oceanic plateau (?)
during the late Danian–Selandian; (iii) the collision/accretion of seamounts during
the late Eocene–early Oligocene; (iv) the collision of seamounts and ridges during
the Pliocene–Holocene. (2) The northwestward thickening of the SFB may have
been enhanced by high sediment supply in the Fonseca Gulf area which reflects
sourcing from wide, high relief drainage basins. In contrast, sedimentary input has
possibly been lower along the southern SFB, due to the proximity of the narrow,
lowland isthmus of southern Central America. Moreover, two phases of strongly
oblique subduction affected the margin, producing strike-slip faulting in the forearc
basin: (1) prior to the Farallon Plate breakup, an Oligocene transpressional phase
caused deformation and uplift of the basin depocenter, triggering shallowing-upward
of the Nicaraguan Isthmus in the central and northern SFB; (2) a Pleistocene–Holocene transtensional phase drives the NW-directed motion of a forearc sliver
and reactivation of the graben-bounding faults of the late Neogene Nicaraguan
Depression. We discuss arguments in favour of a Pliocene development of the
Nicaraguan Depression and propose that the Nicaraguan Isthmus, which is the
apparent rift shoulder of the depression, represents a structure inherited from the Oligocene
transpressional phase
21-Hydroxylase Genotyping in Australasian Patients with Congenital Adrenal Hyperplasia
Mutations in CYP21 (21-hydroxylase) lead to congenital adrenal hyperplasia (CAH). We genotyped 26 probands with CAH by PCR-sequencing the entire CYP21 gene. 25/26 had homozygous or compound heterozygous mutations. The frequencies of mutations were similar to other populations with deletion/hybrid, 12 G splice and 1172N the most common. Five patients with a 1172N allele predicting simple-virilising CAH had a salt-wasting phenotype. Two other probands also had a more severe phenotype than predicted by genotype. Two families had both non-classic and salt-wasting phenotypes arising from combinations of three deleterious alleles. Two novel CYP21 alleles were detected: D106N and a large deletion encompassing CYP21 and adjacent pseudogene. Two rare CYP21 alleles were also found. Three of these four novel/rare alleles were only detected as a result of sequencing the entire CYP21 gene. Entire CYP21 sequencing will increase the number of mutations detected in CAH, and in combination with functional studies should contribute a greater understanding of phenotype-genotype correlations.
German National Consensus Recommendations on Nutrition and Lifestyle in Pregnancy by the ‘Healthy Start - Young Family Network’
Diet and physical activity before and during pregnancy affect short- andlong-term health of mother and child. The energy needs at the end ofpregnancy increase only by about 10% compared to nonpregnant women. Anexcessive energy intake is undesirable since maternal overweight andexcessive weight gain can increase the risks for a high birth weight andlater child overweight and diabetes. Maternal weight at the beginning ofpregnancy is especially important for pregnancy outcome and childhealth. Women should strive to achieve normal weight already beforepregnancy. Regular physical activity can contribute to a healthy weightand to the health of pregnant women. The need for certain nutrientsincreases more than energy requirements. Before and during pregnancy,foods with a high content of essential nutrients should bepreferentially selected. Supplements should include folic acid andiodine, iron (in case of suboptimal iron stores), the omega-3 fatty aciddocosahexaenoic acid (in case of infrequent consumption of ocean fish)and vitamin D (in case of decreased sun exposure and decreasedendogenous vitamin D synthesis). Pregnant women should not smoke and notstay in rooms where others smoke or have smoked before (passivesmoking). Alcohol consumption should be avoided, since alcohol can harmunborn children
German National Consensus Recommendations on Nutrition and Lifestyle in Pregnancy by the ‘Healthy Start - Young Family Network’
Diet and physical activity before and during pregnancy affect short- andlong-term health of mother and child. The energy needs at the end ofpregnancy increase only by about 10% compared to nonpregnant women. Anexcessive energy intake is undesirable since maternal overweight andexcessive weight gain can increase the risks for a high birth weight andlater child overweight and diabetes. Maternal weight at the beginning ofpregnancy is especially important for pregnancy outcome and childhealth. Women should strive to achieve normal weight already beforepregnancy. Regular physical activity can contribute to a healthy weightand to the health of pregnant women. The need for certain nutrientsincreases more than energy requirements. Before and during pregnancy,foods with a high content of essential nutrients should bepreferentially selected. Supplements should include folic acid andiodine, iron (in case of suboptimal iron stores), the omega-3 fatty aciddocosahexaenoic acid (in case of infrequent consumption of ocean fish)and vitamin D (in case of decreased sun exposure and decreasedendogenous vitamin D synthesis). Pregnant women should not smoke and notstay in rooms where others smoke or have smoked before (passivesmoking). Alcohol consumption should be avoided, since alcohol can harmunborn children
Wild bitter gourd improves metabolic syndrome: A preliminary dietary supplementation trial
<p>Abstract</p> <p>Background</p> <p>Bitter gourd (<it>Momordica charantia </it>L.) is a common tropical vegetable that has been used in traditional or folk medicine to treat diabetes. Wild bitter gourd (WBG) ameliorated metabolic syndrome (MetS) in animal models. We aimed to preliminarily evaluate the effect of WBG supplementation on MetS in Taiwanese adults.</p> <p>Methods</p> <p>A preliminary open-label uncontrolled supplementation trial was conducted in eligible fulfilled the diagnosis of MetS from May 2008 to April 2009. A total of 42 eligible (21 men and 21 women) with a mean age of 45.7 ± 11.4 years (23 to 63 years) were supplemented with 4.8 gram lyophilized WBG powder in capsules daily for three months and were checked for MetS at enrollment and follow-up monthly. After supplementation was ceased, the participants were continually checked for MetS monthly over an additional three-month period. MetS incidence rate were analyzed using repeated-measures generalized linear mixed models according to the intention-to-treat principle.</p> <p>Results</p> <p>After adjusting for sex and age, the MetS incidence rate (standard error, <it>p </it>value) decreased by 7.1% (3.7%, 0.920), 9.5% (4.3%, 0.451), 19.0% (5.7%, 0.021), 16.7% (5.4%, 0.047), 11.9% (4.7%, 0.229) and 11.9% (4.7%, 0.229) at visit 2, 3, 4, 5, 6, and 7 compared to that at baseline (visit 1), respectively. The decrease in incidence rate was highest at the end of the three-month supplementation period and it was significantly different from that at baseline (<it>p </it>= 0.021). The difference remained significant at end of the 4th month (one month after the cessation of supplementation) (<it>p </it>= 0.047) but the effect diminished at the 5th and 6th months after baseline. The waist circumference also significantly decreased after the supplementation (<it>p </it>< 0.05). The WBG supplementation was generally well-tolerated.</p> <p>Conclusion</p> <p>This is the first report to show that WBG improved MetS in human which provides a firm base for further randomized controlled trials to evaluate the efficacy of WBG supplementation.</p
Premature ovarian failure and ovarian autoimmunity
Premature ovarian failure (POF) is defined as a syndrome characterized by
menopause before the age of 40 yr. The patients suffer from anovulation
and hypoestrogenism. Approximately 1% of women will experience menopause
before the age of 40 yr. POF is a heterogeneous disorder with a
multicausal pathogenesis involving chromosomal, genetic, enzymatic,
infectious, and iatrogenic causes. There remains, however, a group of POF
patients without a known etiology, the so-called "idiopathic" form. An
autoimmune etiology is hypothesized for the POF cases with a concomitant
Addison's disease and/or oophoritis. It is concluded in this review that
POF in association with adrenal autoimmunity and/or Addison's disease
(2-10% of the idiopathic POF patients) is indeed an autoimmune disease.
The following evidence warrants this view: 1) The presence of
autoantibodies to steroid-producing cells in these patients; 2) The
characterization of shared autoantigens between adrenal and ovarian
steroid-producing cells; 3) The histological picture of the ovaries of
such cases (lymphoplasmacellular infiltrate around steroid-producing
cells); 4) The existence of various autoimmune animal models for this
syndrome, which underlines the autoimmune nature of the disease. There is
some circumstantial evidence for an autoimmune pathogenesis in idiopathic
POF patients in the absence of adrenal autoimmunity or Addison's disease.
Arguments in support of this are: 1) The presence of cellular immune
abnormalities in this POF patient group reminiscent of endocrine
autoimmune diseases such as IDDM, Graves' disease, and Addison's disease;
2) The more than normal association with IDDM and myasthenia gravis. Data
on the presence of various ovarian autoantibodies and anti-receptor
antibodies in these patients are, however, inconclusive and need further
evaluation. A strong argument against an autoimmune pathogenesis of POF in
these patients is the nearly absent histological confirmation (the
presence of an oophoritis) in these cases (< 3%). However, in animal
models using ZP immunization, similar follicular depletion and fibrosis
(as in the POF women) can be detected. Accepting the concept that POF is a
heterogenous disorder in which some of the idiopathic forms are based on
an abnormal self-recognition by th
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