Guided bone regeneration with beta-tricalcium phosphate and poly L-lactide-co-glycolide-co-epsilon-caprolactone membrane in partial defects of canine humerus

This study was performed to evaluate the effect of beta-tricalcium phosphate and poly L-lactide-co-glycolide-co-epsilon-caprolactone (TCP/PLGC) membrane in the repair of partial bone defects in canine proximal humerus. Three adult mixed-breed dogs were used during the experimental period. The length of the defect was quarter of the full length of humerus, and width of the defect was quarter of middle diameter of the lateral aspect of humerus. The humeri of each dog were divided into treatment (TCP/PLGC) and control groups. The defect was covered with TCP/PLGC membrane in treatment group. To evaluate regeneration of the bone, computerized tomography (CT) and histopathologic examination were performed. The radiopaque lines were appeared at the original defect sites in TCP/PLGC group but below the original site in control at 4th week. Radiopacity and thickness of the defect sites, and radiopaque lines were more increased at 8th week than those of 4th week. Histopathologic findings revealed fibrous connective tissue migration into the defect and the migration inhibited the structure of new cortex to be placed in the original level in control whereas new cortex growth was found in the level of original line in TCP/PLGC group. However, the new cortical bone in the TCP/PLGC group was thinner and less organized than the adjacent intact cortex, and the amount of new cancellous bones were also scanty. The result suggested that TCP/PLGC membrane is a good guided bone regeneration material to restore the original morphology of humerus in partial defect.     

Linking monitoring and intervention for improved management of tigers in the Sundarbans of Bangladesh

Baseline data on distribution and abundance of tigers in the Sundarbans is required to identify problem areas and evaluate management strategies. This paper outlines a khal (creek) bank survey of track set frequency throughout the Bangladesh Sundarbans to aid formulation of a management-driven monitoring program. Three teams of two observers surveyed a total of 1 201 km of waterways throughout the Sundarbans, recording 1 338 tiger track sets. These sets became unrecognizable as tiger sign after a mean 10 days (range 6-14). Proportion of detectable sign recorded was 0.91. Mean (±standard error) sample unit track frequency was 1.12 ± 0.86 track sets/km of khal. The mean coefficient of variance in sample unit track rate, estimated by multiple counts of six sample units, was 0.21 (range 0.06-0.34). Track frequency generally increased from northeast to southwest. Four sample units (6%) had signs of reproduction, with a mean litter size of 1.75 ± 0.5. Monte Carlo simulation suggests a monitoring program of one complete survey every two years will have power of 0.8 (α = 0.2), to detect track frequency declines of ?19% and increases of ?17%. We recommend this monitoring scheme be implemented on the Indian side of the Sundarbans to provide a standard assessment of the tiger population and to form the basis for setting management objectives and evaluating transboundary conservation initiatives.     

Effect of Tree Diversity on Soil Organic Carbon Content in the Homegarden Agroforestry System of North-Eastern Bangladesh

Small-scale Forestry - Tropical agroforestry systems have immense potential to sequester carbon both in aboveground and belowground biomass and soil. Homegarden agroforestry is a popular land-use...     

Properties of waterborne polyurethane (WBPU) coatings: Effect of alkyl chain length of tertiary amines of carboxylic acid salt groups

Waterborne polyurethane (WBPU) dispersions were prepared via a pre-polymer process using 4,4-dicyclohexylmethane diisocyanate (H₁₂MDI), poly(tetramethyleneoxideglycol) (PTMG), 2,2-dimethylol propionic acid (DMPA), ethylene diamine (EDA), and tertiary amines (TAs) with varying amounts of DMPA and TAs. Three TAs with different alkyl chain lengths were used to neutralize the DMPA carboxylic group: N,N-dimethylbutylamine (DMBA, C4), N,N-dimethylhexylamine (DMHA, C6), and N,N-dimethyloctylamine (DMOA, C8). The structures of the synthesized WBPUs were determined via FT-IR and ¹H NMR spectroscopic techniques. The effects of DMPA and TA content and the TA alkyl chain length on stability of dispersions and properties such as water swelling (%), glass transition temperature (T _g ), tensile strength, binding energy and adhesive strength were investigated. The initial adhesive strength of the intact coatings increased with increasing DMPA and TA content and increasing alkyl chain length of TA. However, after immersion of the coatings in water, the adhesive strength decreased. The maximum adhesive strength under water was observed at a DMPA content of 20.20 mol% with 5.30 wt% DMOA, which has the longest alkyl chain.     

Properties of crosslinked waterborne polyurethane adhesives with modified melamine: Effect of curing time, temperature, and HMMM content

A series of crosslinked waterborne polyurethane (WBPU) adhesives were prepared by prepolymer synthesis. Modified melamine, hexamethoxymethyl melamine (HMMM) was used as the crosslinking agent. It was elucidated by FTIR and ¹H-NMR spectroscopy that the crosslinking reaction occurred between the polyurethane carboxyl acid salt groups and the HMMM methoxy groups. The hydrophobicity of the WBPU films increased after HMMM crosslinking. As the HMMM content was increased (increasing mole ratio of HMMM/dimethylol propionic acid (DMPA)), the water uptake (%) of the film decreased, and the water contact angle increased. The thermal stability, tensile strength, and initial modulus increased with increasing HMMM content up to an optimum value (mole ratio of HMMM/DMPA=0.5) at which point the maximum thermal stability, tensile strength, and initial modulus were recorded. The adhesive strength was found to be dependent on HMMM content, curing time, and temperature. The adhesive strength of crosslinked WBPU in the case of optimum HMMM content (8.46 wt%) was only slightly affected after immersing adhesive bonded nylon fabrics in water (for up to 2 days).     

Nitrogen transformation and carbon sequestration in wetland paddy field of Bangladesh

Paddy and Water Environment - Rice-based cropping systems in Bangladesh have received little consideration of changing nitrogen (N) and carbon (C) in soil. Therefore, this study was conducted at...     

Alpha(1)-acid glycoprotein is contained in bovine neutrophil granules and released after activation

The present study was designed to investigate the capability of bovine neutrophil granulocytes to produce the minor acute phase protein alpha(1)-acid glycoprotein (AGP, Orososmucoid). Bovine neutrophils contain a high MW (50-60kDa) AGP isoform (PMN-AGP), as determined by Western blotting and confirmed by fluorescence microscopy. The presence of AGP in bovine neutrophils has been confirmed by fluorescence immunocytometry. In addition, bovine neutrophils contain also a 42-45kDa isoform, which has the same MW as plasma-, liver-delivered, AGP. cDNA sequence of plasma- and PMN-AGP revealed that (i) the two proteins are products of the same gene; (ii) the differences in molecular weight are due do different post-translational modifications. This result was confirmed by deglycosylation of the two glycoforms. Exocytosis studies showed that isolated neutrophils exposed to several challengers, including Zymosan activated serum (ZAS) and phorbol 12-myristate 13-acetate (PMA), which mimic the inflammatory activation, released PMN-AGP as early as 15min. AGP's mRNA is physiologically expressed by mature resting neutrophils. Real-time PCR on LPS, ZAS and PMA challenged cells revealed that the level of expression apparently does not increase after inflammatory activation. Collectively, the findings reported in this paper proved that PMN-AGP: (i) is a hyperglycosylated glycoform of plasma AGP, (ii) is stored in granules, and (iii) is released by neutrophils in response to activation. Due to its anti-inflammatory activity, PMN-AGP may work as a fine tuning of the neutrophils functions in the inflammatory focus, i.e. it can reduce the damages caused by an excess of inflammatory response.     

Development of a male sterile eggplant by utilizing the cytoplasm of Solanum virginianum and a biparental transmission of chloroplast DNA in backcrossing

To develop a male sterile line of eggplant (Solanum melongena L.) utilizing the cytoplasm of S. virginianum, an interspecific F₁ hybrid between S. virginianum and S. melongena ‘Senryo Nigou’ was continuously backcrossed to S. melongena ‘Uttara’ using ‘Uttara’ as a recurrent pollen parent and four backcross generations, BC₁, BC₂, BC₃ and BC₄ were produced. All the plants in backcross generations were anther indehiscent although the F₁ hybrid, S. virginianum and S. melongena were dehiscent. Pollen stainability with acetic carmine and in vitro germination ability of pollen in all the backcross progenies were quite lower than those of the parental species. Fruit set percentage, number of seeds per fruit and seed germination rate were high in all the backcross progenies. The present results indicate that anther indehiscent type of functional male sterile line of eggplant could be developed by utilizing the cytoplasm of S. virginianum. PCR-RFLP analysis of chloroplast DNA (cpDNA) and mitochondrial DNA (mtDNA) were performed to identify the organelle inheritance. The F₁ hybrid and all the backcross progenies displayed maternal inheritance of mtDNA. The cpDNA of the examined single BC₁ plant exhibited the recombinant cpDNA pattern of the parental F₁ hybrid and ‘Uttara’, indicating occurrence of the biparental inheritance of cpDNA. As all the BC₂, BC₃ and BC₄ progenies showed the same recombinant cpDNA patterns of the BC₁ plant, the recombinant cpDNA might be stable and harmonize with the nuclear genome of S. melongena. The present male sterile line can contribute to expand the male sterility source of eggplant.