130 research outputs found

    Insect Pollinated Crops, Insect Pollinators and US Agriculture: Trend Analysis of Aggregate Data for the Period 1992–2009

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    In the US, the cultivated area (hectares) and production (tonnes) of crops that require or benefit from insect pollination (directly dependent crops: apples, almonds, blueberries, cucurbits, etc.) increased from 1992, the first year in this study, through 1999 and continued near those levels through 2009; aggregate yield (tonnes/hectare) remained unchanged. The value of directly dependent crops attributed to all insect pollination (2009 USD) decreased from 14.29billionin1996,thefirstyearforvaluedatainthisstudy,to14.29 billion in 1996, the first year for value data in this study, to 10.69 billion in 2001, but increased thereafter, reaching 15.12billionby2009.ThevaluesattributedtohoneybeesandnonApispollinatorsfollowedsimilarpatterns,reaching15.12 billion by 2009. The values attributed to honey bees and non-Apis pollinators followed similar patterns, reaching 11.68 billion and 3.44billion,respectively,by2009.Thecultivatedareaofcropsgrownfromseedsresultingfrominsectpollination(indirectlydependentcrops:legumehays,carrots,onions,etc.)wasstablefrom1992through1999,buthassincedeclined.Productionofthosecropsalsodeclined,albeitnotasrapidlyasthedeclineincultivatedarea;thisasymmetrywasduetoincreasesinaggregateyield.Thevalueofindirectlydependentcropsattributedtoinsectpollinationdeclinedfrom3.44 billion, respectively, by 2009. The cultivated area of crops grown from seeds resulting from insect pollination (indirectly dependent crops: legume hays, carrots, onions, etc.) was stable from 1992 through 1999, but has since declined. Production of those crops also declined, albeit not as rapidly as the decline in cultivated area; this asymmetry was due to increases in aggregate yield. The value of indirectly dependent crops attributed to insect pollination declined from 15.45 billion in 1996 to 12.00billionin2004,buthassincetrendedupward.ThevalueofindirectlydependentcropsattributedtohoneybeesandnonApispollinators,exclusiveofalfalfaleafcutterbees,hasdeclinedsince1996to12.00 billion in 2004, but has since trended upward. The value of indirectly dependent crops attributed to honey bees and non-Apis pollinators, exclusive of alfalfa leafcutter bees, has declined since 1996 to 5.39 billion and 1.15billion,respectivelyin2009.Thevalueofalfalfahayattributedtoalfalfaleafcutterbeesrangedbetween1.15 billion, respectively in 2009. The value of alfalfa hay attributed to alfalfa leafcutter bees ranged between 4.99 and $7.04 billion. Trend analysis demonstrates that US producers have a continued and significant need for insect pollinators and that a diminution in managed or wild pollinator populations could seriously threaten the continued production of insect pollinated crops and crops grown from seeds resulting from insect pollination

    Long term in-vivo studies of a photo-oxidized bovine osteochondral transplant in sheep

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    BACKGROUND: Articular cartilage has limited capacity to repair. Defects greater than 3 mm heal with formation of inferior fibrous cartilage. Therefore, many attempts have been made to find the ideal graft for larger cartilage lesions. Different grafts, such as untreated or cryopreserved osteochondral transplants, have been used with variable success. METHODS: Photo-oxidized osteochondral grafts were implanted in both femoral condyles of one ovine knee. Untreated xenogeneic and autogeneic grafts served as controls. Three groups of 8 sheep each were formed and they were sacrificed 6, 12 or 18 months after surgery. RESULTS: The macroscopic evaluation of the condyle and graft showed a well-maintained cartilage surface in most grafts at all time points. However, the host cartilage matrix deteriorated considerably in all xenogeneic, most autogeneic and fewer of the photo-oxidized grafts at 12 and 18 months, respectively. The blue colour of the photo-oxidized grafts resulting from the process of photo-oxidation was visible in all grafts at 6 months, had diminished at 12 months and had completely disappeared at 18 months after surgery. Histologically a loss of matrix staining was almost never noticed in untreated xenografts, transiently at 6 months in photo-oxidized grafts and increased at 12 and 18 months. Fusion between graft and host cartilage could be seen in photo-oxidized grafts at 12 and 18 months, but was never seen in autografts and xenografts. CONCLUSIONS: The photo-oxidation of osteochondral grafts and its use as transplant appears to have a beneficial effect on cartilage and bone remodelling. Osteochondral grafts pre-treated with photo-oxidation may be considered for articular cartilage replacement and therefore may delay artificial joint replacements in human patients

    Tracking Membrane Protein Association in Model Membranes

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    Membrane proteins are essential in the exchange processes of cells. In spite of great breakthrough in soluble proteins studies, membrane proteins structures, functions and interactions are still a challenge because of the difficulties related to their hydrophobic properties. Most of the experiments are performed with detergent-solubilized membrane proteins. However widely used micellar systems are far from the biological two-dimensions membrane. The development of new biomimetic membrane systems is fundamental to tackle this issue

    Synthesis of 5-Hydroxyectoine from Ectoine: Crystal Structure of the Non-Heme Iron(II) and 2-Oxoglutarate-Dependent Dioxygenase EctD

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    As a response to high osmolality, many microorganisms synthesize various types of compatible solutes. These organic osmolytes aid in offsetting the detrimental effects of low water activity on cell physiology. One of these compatible solutes is ectoine. A sub-group of the ectoine producer's enzymatically convert this tetrahydropyrimidine into a hydroxylated derivative, 5-hydroxyectoine. This compound also functions as an effective osmostress protectant and compatible solute but it possesses properties that differ in several aspects from those of ectoine. The enzyme responsible for ectoine hydroxylation (EctD) is a member of the non-heme iron(II)-containing and 2-oxoglutarate-dependent dioxygenases (EC 1.14.11). These enzymes couple the decarboxylation of 2-oxoglutarate with the formation of a high-energy ferryl-oxo intermediate to catalyze the oxidation of the bound organic substrate. We report here the crystal structure of the ectoine hydroxylase EctD from the moderate halophile Virgibacillus salexigens in complex with Fe3+ at a resolution of 1.85 Å. Like other non-heme iron(II) and 2-oxoglutarate dependent dioxygenases, the core of the EctD structure consists of a double-stranded β-helix forming the main portion of the active-site of the enzyme. The positioning of the iron ligand in the active-site of EctD is mediated by an evolutionarily conserved 2-His-1-carboxylate iron-binding motif. The side chains of the three residues forming this iron-binding site protrude into a deep cavity in the EctD structure that also harbours the 2-oxoglutarate co-substrate-binding site. Database searches revealed a widespread occurrence of EctD-type proteins in members of the Bacteria but only in a single representative of the Archaea, the marine crenarchaeon Nitrosopumilus maritimus. The EctD crystal structure reported here can serve as a template to guide further biochemical and structural studies of this biotechnologically interesting enzyme family

    The impact of ICT on the efficiency of HRM in Cameroonian enterprises: Case of the Mobile telephone industry

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    The objective of this study is to determine the impact of Information and Communication Technology on the efficiency of Human Resource Management in the Cameroon mobile Telecommunication Sector. It specifically seeks to investigate how the use of ICT affects the following human resources management practices; Human resource planning, training and development, selection and recruitment, human resource evaluation and compensation. An exploratory research design was employed in the study. A sample of 120 management, senior, junior and contract staffs of the 03 (three) main mobile telephone operators responded to a structured questionnaire. The data collected was coded and entered into SPSS version 17. Pearson correlation coefficient was used to establish the relationship between the variables in the study, regression analysis was used to establish the combined effect of study variables on the dependent variable. The results show a significant positive relationship between the use of ICT in selection and recruitment, training and development, Human resource planning, evaluation and compensation and human resource management efficiency. This highlights the use of ICT as an efficient tool in Human resource management of enterprises. The use of ICT assures Human resource management efficiency, we therefore suggest that regular Information and Communication Technology training and development should be enhanced so as to allow proper interactions between Human Resource Management and the different departments which could lead to the organizational efficiency

    Complex regional pain syndrome - phenotypic characteristics and potential biomarkers

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    Complex regional pain syndrome (CRPS) is a pain condition that usually affects a single limb, often following an injury. The underlying pathophysiology seems to be complex and probably varies between patients. Clinical diagnosis is based on internationally agreed-upon criteria, which consider the reported symptoms, presence of signs and exclusion of alternative causes. Research into CRPS biomarkers to support patient stratification and improve diagnostic certainty is an important scientific focus, and recent progress in this area provides an opportunity for an up-to-date topical review of measurable disease-predictive, diagnostic and prognostic parameters. Clinical and biochemical attributes of CRPS that may aid diagnosis and determination of appropriate treatment are delineated. Findings that predict the development of CRPS and support the diagnosis include trauma-related factors, neurocognitive peculiarities, psychological markers, and local and systemic changes that indicate activation of the immune system. Analysis of signatures of non-coding microRNAs that could predict the treatment response represents a new line of research. Results from the past 5 years of CRPS research indicate that a single marker for CRPS will probably never be found; however, a range of biomarkers might assist in clinical diagnosis and guide prognosis and treatment
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