Non-resonant direct p- and d-wave neutron capture by 12C

Discrete gamma-rays from the neutron capture state of 13C to its low-lying bound states have been measured using pulsed neutrons at En = 550 keV. The partial capture cross sections have been determined to be 1.7+/-0.5, 24.2+/-1.0, 2.0+/-0.4 and 1.0+/-0.4 microb for the ground (1/2-), first (1/2+), second (3/2-) and third (5/2+) excited states, respectively. From a comparison with theoretical predictions based on the non-resonant direct radiative capture mechanism, we could determine the spectroscopic factor for the 1/2+ state to be 0.80 +/- 0.04, free from neutron-nucleus interaction ambiguities in the continuum. In addition we have detected the contribution of the non-resonant d-wave capture component in the partial cross sections for transitions leading to the 1/2- and 3/2- states. While the s-wave capture dominates at En < 100 keV, the d-wave component turns out to be very important at higher energies. From the present investigation the 12C(n,gamma)13C reaction rate is obtained for temperatures in the range 10E+7 - 10E+10 K.Comment: Accepted for publication in Phys. Rev. C. - 16 pages + 8 figure

Regeneration versus scarring in vertebrate appendages and heart

Injuries to complex human organs, such as the limbs and the heart, result in pathological conditions, for which we often lack adequate treatments. While modern regenerative approaches are based on the transplantation of stem cell-derived cells, natural regeneration in lower vertebrates, such as zebrafish and newts, relies predominantly on the intrinsic plasticity of mature tissues. This property involves local activation of the remaining material at the site of injury to promote cell division, cell migration and complete reproduction of the missing structure. It remains an unresolved question why adult mammals are not equally competent to reactivate morphogenetic programmes. Although organ regeneration depends strongly on the proliferative properties of cells in the injured tissue, it is apparent that various organismic factors, such as innervation, vascularization, hormones, metabolism and the immune system, can affect this process. Here, we focus on a correlation between the regenerative capacity and cellular specialization in the context of functional demands, as illustrated by appendages and heart in diverse vertebrates. Elucidation of the differences between homologous regenerative and non-regenerative tissues from various animal models is essential for understanding the applicability of lessons learned from the study of regenerative biology to clinical strategies for the treatment of injured human organs

A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses

We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants

Coordinated generation of multiple ocular-like cell lineages and fabrication of functional corneal epithelial cell sheets from human iPS cells

We describe a protocol for the generation of a functional and transplantable corneal epithelium derived from human induced pluripotent stem (iPS) cells. When this protocol is followed, a proportion of iPS cells spontaneously form circular colonies, each of which is composed of four concentric zones. Cells in these zones have different morphologies and immunostaining characteristics, resembling neuroectoderm, neural crest, ocular-surface ectoderm, or surface ectoderm. We have named this 2D colony a 'SEAM' (self-formed ectodermal autonomous multizone), and previously demonstrated that cells within the SEAM have the potential to give rise to anlages of different ocular lineages, including retinal cells, lens cells, and ocular-surface ectoderm. To investigate the translational potential of the SEAM, cells within it that resemble ocular-surface epithelia can be isolated by pipetting and FACS sorting into a population of corneal epithelial-like progenitor cells. These can be expanded and differentiated to form an epithelial layer expressing K12 and PAX6, and able to recover function in an animal model of corneal epithelial dysfunction after surgical transplantation. The whole protocol, encompassing human iPS cell preparation, autonomous differentiation, purification, and subsequent differentiation, takes between 100 and 120 d, and is of potential use to researchers with an interest in eye development and/or ocular-surface regeneration. Experience with human iPS cell culture and sorting via FACS will be of benefit for researchers performing this protocol

State of play and future direction with NOACs: An expert consensus.

Atrial fibrillation (AF) and venous thromboembolism (VTE) are cardiovascular conditions significant in contemporary practice. In both, the use of anticoagulation with vitamin K antagonists (VKAs) has been traditionally used to prevent adverse events. However, VKA therapy is associated with challenges relating to dose maintenance, the need to monitor anticoagulation, and bleeding risks. The non-vitamin K oral anticoagulants (NOACs) are becoming accepted as a clear alternative to VKA therapy for both AF and VTE management. The aim of this paper was to review contemporary evidence on the safety of NOACs in both conditions. A comprehensive literature review was conducted to explore key safety issues and expert consensus was achieved from eight professionals specialised in AF and VTE care. Consensus-based statements were formulated where available evidence was weak or contradictory. The expert statements in this paper form a key overview of the safety of NOACs compared with VKA therapy, and the comparative safety of different NOACs. It is apparent that a detailed patient work-up is required in order to identify and manage individual risk factors for bleeding and thrombosis prior to NOAC therapy. Additional measures, such as dose reductions, may also be used to maintain the safety of NOACs in practice

Passive maternal antibody transfer to eggs and larvae of tiger grouper (Epinephelus fuscoguttatus)

The immune response of Tiger grouper (E. fuscoguttatus) broodstocks and its passive transfer of maternal antibodies to eggs and larvae were evaluated following vaccination with an inactivated V.harveyi. Tiger grouper broodstock (mean BW 8.66 ± 0.09 kg, n=19) were vaccinated intraperitoneally (IP) and followed by a booster two weeks post vaccination, while Controlled Non-vaccinated (CG) broodstock were IP injected with PBS. The serum antibody level against V.harveyi was monitored for two weeks on post-vaccination and monthly up to 5 months post-vaccination. This study showed that the Vaccinated Group (VG) broodstock induced significantly (P<0.05) higher in specific IgM antibody level against V.harveyi as compared to the CG, which in turn induced a marked increased (P<0.05) in specific IgM in eggs and larvae produced from VG broodstock at 14 weeks post vaccination. The findings from this study suggested that inactivated V.harveyi vaccines were able to stimulate the immune response in broodstock and passively transferred the maternal antibody to their eggs and larvae

A novel, lineage-primed prestalk cell subtype involved in the morphogenesis of D-discoideum

Dictyostelium morphogenesis requires the tip, which acts as an organizer and conducts orchestrated cell movement and cell differentiation. At the slug stage the tip region contains prestalk A (pstA) cells, which are usually recognized by their expression of reporter constructs that utilize a fragment of the promoter of the ecmA gene. Here, using the promoter region of the o-methyl transferase 12 gene (omt12) to drive reporter expression, we demonstrate the presence, also within the pstA region, of a novel prestalk cell subtype: the pstVA cells. Surprisingly, a sub-population of the vegetative cells express a pstVA: GFP marker and, sort out to the tip, both when developing alone and when co-developed with an excess of unmarked cells. The development of such a purified GFP-marked population is greatly accelerated: by precocious cell aggregation and tip formation with accompanying precocious elevation of developmental gene transcription. We therefore suggest that the tip contains at least two prestalk cell subtypes: the developmentally-specified pstA cells and the lineage-primed pstVA cells. It is presumably the pstVA cells that play the dominant role in morphogenesis during the earlier stages of development. The basis for the lineage priming is, however, unclear because we can find no correlation between pstVA differentiation and nutrient status during growth or cell cycle position at the time of starvation, the two known determinants of probable cell fate

Multi-decadal shoreline changes in Eastern Ghana—natural dynamics versus human interventions

Human infrastructures, such as dams, seawalls, and ports, can affect both the sedimentary budget and nearshore hydrodynamics, enhancing and accelerating the loss or gain of coastal sediments. Understanding the processes and factors controlling beach morphodynamics is essential for implementing adequate adaptation strategies in coastal areas, particularly in those regions where coastal protection measures are scarce. This study analyzes shoreline changes in the Keta Municipal District, located in southeastern Ghana (West Africa). This area is characterized by the sedimentary input of the Volta River, forming a river delta situated to the west, i.e., updrift, of our study site. Following the construction of two dams (Akosombo and Kpong) on the Volta River in 1965 and 1982, groins and revetments have been built along the coast between 2005 and 2015 to reduce the high rates of coastal erosion in this area. Here, we explore the influence of these dams and the hard protection constructions on beach morphodynamics using historical maps and satellite images complemented by a shoreline survey undertaken with a differential GNSS in 2015. The multi-decadal evolution between 1913 and 2015 reconstructed for 90 km of shoreline suggests that local erosion rates in the region predate the construction of the two dams on the Volta River, indicating that these structures might not be the primary driver of coastal erosion in this area, as previously suggested. We emphasize that delta dynamics under conditions of high-energy longshore drift, modified by anthropogenic drivers such as sand mining, play a key role in the long-term evolution of this coast. Our results also show that the infrastructures built to halt coastal erosion result in localized erosion and accretion down-current along the coastline towards the border with Togo, highlighting the need for a transnational perspective in addressing the problems caused by coastal erosion

Paclobutrazol treatment as a potential strategy for higher seed and oil yield in field-grown camelina sativa L. Crantz

<p>Abstract</p> <p>Background</p> <p><it>Camelina (Camelina sativa </it>L. Crantz) is a non-food oilseed crop which holds promise as an alternative biofuel energy resource. Its ability to grow in a variety of climatic and soil conditions and minimal requirements of agronomical inputs than other oilseed crops makes it economically viable for advanced biofuel production. We designed a study to investigate the effect of paclobutrazol [2RS, 3RS)-1-(4-Chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pentan-3-ol] (PBZ), a popular plant growth regulator, on the seed and oil yield of <it>Camelina sativa </it>(cv. Celine).</p> <p>Results</p> <p>A field-based micro-trial setup was established in a randomized block design and the study was performed twice within a span of five months (October 2010 to February 2011) and five different PBZ treatments (Control: T₀; 25 mg l^-1: T₁; 50 mg l^-1: T₂; 75 mg l^-1: T₃; 100 mg l^-1: T₄; 125 mg l^-1: T₅) were applied (soil application) at the time of initiation of flowering. PBZ at 100 mg l^-1concentration (T₄) resulted in highest seed and oil yield by 80% and 15%, respectively. The seed yield increment was mainly due to enhanced number of siliques per plant when compared to control. The PBZ - treated plants displayed better photosynthetic leaf gas exchange characteristics, higher chlorophyll contents and possessed dark green leaves which were photosynthetically active for a longer period and facilitated higher photoassimilation.</p> <p>Conclusion</p> <p>We report for the first time that application of optimized PBZ dose can be a potential strategy to achieve higher seed and oil yield from <it>Camelina sativa </it>that holds great promise as a biofuel crop in future.</p