Numerical simulation of embedding strength of glued laminated timber for dowel-type fasteners

A non-linear material model is proposed to describe the timber behavior. Anisotropic elasto-plastic constitutive law with hardening according to Hill yield criterion was used for the compressive behavior. Brittle behavior in tension and shear was modeled using the modified Hill failure criterion. The material model was implemented in a finite element code to simulate embedding strength of glued laminated timber for dowel-type fasteners. Reasonable agreement is found between numerical simulations and experimental measurements.     

Changes in the physical properties of two Acacia compost-based growing media and their effects on carob (Ceratonia siliqua L.) seedling development

In arid zones, the use of compost for plant production in forest nurseries is hindered by a lack of water. The main objectives of this study were (1) to evaluate the physical stability of composts produced from shredded branches of Acacia cyanophylla and A. cyclops subjected to a repeated drying and wetting cycles, similar to those used at the operational scale in nurseries in arid regions and to compare these composts with a standard peat-vermiculite (PV) substrate; (2) to identify the relevant substrate physical variables that correlate with seedling growth. Carob (Ceratonia siliqua L.) was cultivated during a production cycle of 27 weeks in a completely randomized block experiment. Substrate physical variables were measured at the beginning, middle and end of the experiment. Seedling growth variables were evaluated over the course of the production cycle, while gas exchange and water-relation variables were measured during a wetting and drying cycle at the end of the experiment. All three substrates produced vigorous seedlings with well-developed root systems that colonized the entire root plug. The growth of seedlings produced in the PV substrate was better than those grown in the compost-based substrates. No significant differences in gas exchange capacities and water relation variables were observed among the three substrates at the end of experiment with the exception of net photosynthesis, which was higher for the PV substrate at high substrate matric potential. Excessive drainage was negatively correlated with growth variables while water availability in the early growth phase and air porosity towards the end of experiment were positively correlated. Performance of the two composts could be increased by improving their initial structure and stability and by adjusting the irrigation regime.     

SOCS proteins in infectious diseases of mammals

As for most biological processes, the immune response to microbial infections has to be tightly controlled to remain beneficial for the host. Inflammation is one of the major consequences of the host's immune response. For its orchestration, this process requires a fine-tuned interplay between interleukins, endothelial cells and various types of recruited immune cells. Suppressors of cytokine signalling (SOCS) proteins are crucially involved in the complex control of the inflammatory response through their actions on various signalling pathways including the JAK/STAT and NF-κB pathways. Due to their cytokine regulatory functions, they are frequent targets for exploitation by infectious agents trying to escape the host's immune response. This review article aims to summarize our current knowledge regarding SOCS family members in the different mammalian species studied so far, and to display their complex molecular interactions with microbial pathogens.     

Serological Prevalence of Brucellosis among Donkeys (Equus asinus) in Some Local Government Areas of Yobe State,Nigeria

A cross-sectional study of prevalence of antibody against Brucella organisms was conducted among donkeys in three local government areas of Yobe State, northeastern Nigeria. Three hundred adult donkeys of both sexes were sampled, with 100 samples each from local government areas Bursari, Gaidam, and Machina. The overall serological prevalence of brucellosis among donkeys in the three local government areas by both rose bengal plate test (RBPT) and microtiter serum agglutination test (MSAT) was 15 (5.0%), of which five (1.7%) were male and 10 (3.3%) were female donkeys. The overall prevalence by competitive enzyme-linked immunosorbent assay (cELISA) was 10 (3.3%), of which four (1.33%) were male and six (2.0%) were female donkeys. There was a significant association between the female sex of the donkeys and the serological reaction to RBPT, MSAT, and cELISA (P < .05). Of the 100 sera sampled from Bursari, five (5%) were positive by RBPT/MSAT, which comprised two (2%) male and three (3.0%) female donkeys. There was no significant association between the sex of the donkeys and the serological reaction (P > .05). Of the 100 samples from Gaidam, four (4.0%) tested positive by RBPT/MSAT, of which one (1.0%) was male and three (3.0%) were female donkeys (P < .05). Six (6.0%) of the 100 donkey sera samples from Machina tested positive by both RBPT and MSAT, which comprised two (2.0%) male and four (4.0%) female donkeys. There was no significant association between the male sex of the donkeys and the serological reaction (P > .05); however, there was a significant association between the female sex of the donkeys and the serological reaction to both RBPT and MSAT (P < .05). Of the 100 samples from Bursari and the 100 samples from Gaidam, three (3%) from each were positive by cELISA, which comprised one (1%) male and two (2%) female donkeys. There was no statistically significant association between the sex of donkeys and the serological reaction (P > .05). Of the 100 samples tested from Machina, two (2%) male and two (2%) female donkeys were positive for Brucella antibodies by cELISA. No statistically significant association was demonstrated between the sex of the donkeys and the serological reaction to cELISA (P > .05). Because of the importance of donkeys to humans as a source of draft power, infected donkeys could be a source of Brucella infection to humans through close contact, through the respiratory system via contaminated dust or droplets, and through aborted fetuses and discharges from the genitalia.     

Sources of wheat resistance to Sunn pest, <Emphasis Type="Italic">Eurygaster integriceps</Emphasis> Puton,in Syria

Sunn pest, Eurygaster integriceps Puton, is the most damaging insect pest of wheat in West and Central Asia and East Europe. Host plant resistance has been investigated as one component of a total integrated pest management program for the control of this pest. In Syria, field screening of artificially infested wheat accessions from the International Center for Agricultural Research in the Dry Areas (ICARDA) gene bank, selected using the Focused Identification of Germplasm Strategy (FIGS), identified one durum wheat and eight bread wheat accessions with good levels of resistance at the vegetative stage to overwintered Sunn pest adults. ICARDA is using these sources of resistance in wheat breeding programs to develop cultivars resistant to overwintered Sunn pest adults, which damage wheat at the vegetative stage (shoots and leaves). This study also demonstrated that the FIGS approach was effective in mining genetic resource collections for useful traits.     

The diversity of rhizobia nodulating chickpea (Cicer arietinum) under water deficiency as a source of more efficient inoculants

Chickpea is an important pulse crop grown mainly in the arid and semi-arid regions. The effect of water deficiency on nodulation, biomass production, and competition for nodule occupancy was evaluated in three different soils with two chickpea cultivars, Amdoun I and Chetoui. Two watering regimes were considered; a control that was irrigated three times per week and a water-deficient treatment that was irrigated only one time a week. Results showed that water deficiency significantly decreased the nodule number and the shoot dry weight for both cultivars. Root-nodule bacteria were isolated and characterized by PCR-RFLP of 16S rDNA and nifD-K intergenic spacer. The results show that water deficiency affects the diversity of nodulating rhizobia. The nodulation by Mesorhizobium mediterraneum was reduced while inefficient nodulation by Ensifer meliloti was favoured. In both treatments, chickpea was preferentially nodulated by nifD-K type N6. Analysis for NaCl tolerance showed that most of rhizobia nodulating chickpea under water deficiency are NaCl tolerant. Inoculation with the selected salt-tolerant strain of M. mediterraneum LILM10 increased significantly nodule number and grain yield in the field.     

Molecular and phenotypic diversity of ICARDA spring barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) collection

Plant breeders are interested in using diverse genotypes in hybridization that can segregate for traits of importance with possibility of selection and genetic gain. Information on molecular and agro-morphological diversity helps the breeders reduce the effort for parental selection and helps the advancement of generations. A phenotypic and molecular diversity study, using 24 traits (agronomic and disease) and 6519 SNPs in a diverse collection of 336 spring barley genotypes, was carried out at Marchouch and Jemma Shiam research stations in Morocco. Based on structure and multivariate analyses, strong differentiation between the two- and six-row types were observed. The linkage disequilibrium (LD) decay of the current collection (for the combined population) was up to 3.58 cM (r ² = 0.15) while LD decay were estimated 3.91 and 2.36 cM for two- and six-row barley, respectively. PCA of agro-morphological traits revealed grain per spike, net form of net blotch (NFNB), spot form of net blotch (SFNB), and 1000 kernel weight were the most discriminatory traits in the current collection. Association mapping in the two independent populations will be ideal for identification of markers, and QTL related to traits. The generated information on relatedness between individuals will help identify diverse genotypes for breeding programs.     

Optimization of Petroleum Refinery Wastewater Treatment by Vertical Flow Constructed Wetlands Under Tropical Conditions: Plant Species Selection and Polishing by a Horizontal Flow Constructed Wetland

Typha latifolia-planted vertical subsurface flow constructed wetlands (VSSF CWs) can be used to treat petroleum refinery wastewater. This study evaluated if the removal efficiency of VSSF CWs can be improved by changing the plant species or coupling horizontal subsurface flow constructed wetlands (HSSF CWs) to the VSSF CW systems. The VSSF CWs had a removal efficiency of 76% for biological oxygen demand (BOD₅), 73% for chemical oxygen demand (COD), 70% for ammonium-N (NH₄⁺-N), 68% for nitrate-N (NO₃^?-N), 49% for phosphate (PO₄^3?-P), 68% for total suspended solids (TSS), and 89% for turbidity. The HSSF CWs planted with T. latifolia further reduced the contaminant load of the VSSF CW-treated effluent, giving an additional removal efficiency of 74, 65, 43, 65, 58, 50, and 75% for, respectively, BOD₅, COD, NH₄⁺-N, NO₃^?-N, PO₄^3?-P, TSS, and turbidity. The combined hybrid CW showed, therefore, an improved effluent quality with overall removal efficiencies of, respectively, 94% for BOD₅, 88% for COD, 84% for NH₄⁺-N, 89% for NO₃^?-N, 78% for PO₄^3?-P, 85% for TSS, and 97% for turbidity. T. latifolia strived well in the VSSF and HSSF CWs, which may have contributed to the high NH₄ ⁺-N, NO₃^?-N, and PO₄^3?-P removal efficiencies. T. latifolia-planted VSSF CWs showed a higher contaminant removal efficiency compared to the unplanted VSSF CW. T. latifolia is thus a suitable plant species for treatment of secondary refinery wastewater. Also a T. latifolia-planted hybrid CW is a viable alternative for the treatment of secondary refinery wastewater under the prevailing climatic conditions in Nigeria.     

Elucidation of maize endosperm starch granule channel proteins and evidence for plastoskeletal structures in maize endosperm amyloplasts

Previously, starch granules of maize (Zea mays), sorghum (Sorghum bicolor), and millet (Pennisetum americanum) were found to contain channels connecting the interior cavity with the outside surface, and the channels of maize starch channels were found to contain, presumably to be lined with, proteins. One objective of this study was to identify and characterize channel proteins of maize starch granules. A putative starch granule channel protein extract was subjected to 2D-PAGE. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry was used to identify the proteins. Data analysis indicated the presence of actin-like and tubulin-like (FtsZ) proteins, ADP-glucose pyrophosphorylase large and small subunits (Shrunken2 [Sh2] and Brittle2 [Bt2], respectively), granule-bound starch synthase (GBSS), and Brittle1 (Bt1, an adenylate translocator). A combination of Western blot analysis and immunolocalization confirmed the presence of an actin-like protein within the starch granule structure. Another objective was to determine the origin of maize starch granule channels. TEM examination of maize endosperm amyloplasts that did not contain a formed starch granule revealed structures that were connected to the amyloplast membrane and extended inward to the center of the plastid.     

Ion flux kinetics in blue light‐grown field dodder (Cuscuta campestris) seedlings

Previous studies have revealed that blue light stimulates coiling and prehaustoria development in young de‐etiolated dodder seedlings prior to host attachment. In this study, the Ca²⁺ and H⁺ flux kinetics that are associated with blue light‐mediated coiling and prehaustoria development in de‐etiolated dodder seedlings were measured uninvasively using the ion‐selective, vibrating microelectrode ion flux system. The findings showed that blue light induces rapid transient changes in the net Ca²⁺ and H⁺ fluxes. A clearly pronounced lag of about several minutes was observed between the blue light‐induced changes in the Ca²⁺ and H⁺ fluxes, with H⁺ being a leading ion. The addition of 1 mol L^?1 vanadate, a known blocker of the plasma‐membrane H⁺‐ATPase, to the bathing solution completely prevented both the H⁺ and the Ca²⁺ flux responses and inhibited coiling and prehaustoria development, suggesting a causal relationship between the blue light‐induced changes in the net Ca²⁺ and H⁺ fluxes and seedling movements. It is concluded that the plasma‐membrane H⁺‐ATPase plays a key role in a dodder's parasitic mode of growth and its adaptive response to the environment.