A Dual-Network Nerve Adhesive with Enhanced Adhesion Strength Promotes Transected Peripheral Nerve Repair

Peripheral nerve transection has a high prevalence and results in functional loss of affected limbs. The current clinical treatment using suture anastomosis significantly limits nerve recovery due to severe inflammation, secondary damage, and fibrosis. Fibrin glue, a commercial nerve adhesive as an alternative, avoids secondary damage but suffers from poor adhesion strength. To address their limitations, a highly efficacious nerve adhesive based on dual-cross-linking of dopamine-isothiocyanate modified hyaluronic acid and decellularized nerve matrix is reportedr. This dual-network nerve adhesive (DNNA) shows controllable gelation behaviors feasible for surgical applications, robust adhesion strength, and promotes axonal outgrowth in vitro. The in vivo therapeutic efficacy is tested using a rat-based sciatic nerve transection model. The DNNA decreases fibrosis and accelerates axon/myelin debris clearance at 10 days post-surgery, compared to suture and commercial fibrin glue treatments. At 10 weeks post-surgery, the strong adhesion and bioactivity allow DNNA to significantly decrease intraneural inflammation and fibrosis, enhance axon connection and remyelination, aid motor and sensory function recovery, as well as improve muscle contraction, compared to suture and fibrin treatments. Overall, this dual-network hydrogel with robust adhesion provides a rapid and highly efficacious nerve transection treatment to facilitate nerve repair and neuromuscular function recovery.     

A Comparative Study on the Flexural Behaviour of Waffle and Solid Slab Models When Subjected to Point Load

The determinations of flexural behavior of some engineering structures are based on different theories and equations, but it has been observed that some of these equations may not give true representation. This work has looked into the difference that may occur between theoretical and experimental results. An experimental test carried out on models of waffle and solid slabs structures were described and results from twenty test samples are presented. Each specimen was subjected to an incremental axial loading of 1 kN interval after 28 days of casting. The flexural moments, deflections and crack width at failure were obtained. The experimental flexural crack and theoretical flexural cracks for both types of slabs were compared. The result for flexural moments for waffle was 5.526 kNm, while solid slab was 3.684 kNm. The deflections showed that waffle slabs has 3.64 mm while solid has 9.28 mm, hence waffle has a higher structural stiffness than solid slabs, but the flexural cracks did not give the same results especially for the estimated crack width. It was concluded that estimated results based on developed equations may not be accurate because it is based on ideal situation.     

Response of multi-step compound pre-equilibrium reaction cross sections for the (p,n) reactions to forms of optical model parameters

In furtherance to improving agreement between calculated and experimental nuclear data, the nuclear reaction code GAMME was used to calculate the multistep compound(MSC) nucleus double differential cross sections(DDCs) for proton-induced neutron emission reactions using the Feshbach-Kerman-Koonin(FKK) formalism. The cross sections were obtained for reactor structural materials involving ~(52)Cr(p, n)~(52)Mn,~(56)Fe(p,n)~(56)Co, and ~(60)Ni(p, n)~(60)Cu reactions at 22.2 MeV incident energy using the zero-range reaction mechanism. Effective residual interaction strength was 28 MeV, and different optical potential parameters were used for the entrance and exit channels of the proton-neutron interactions. The calculated DDCs were fitted to experimental data at the same backward angle of 150°, where the MSC processes dominate. The calculated and experimental data agree well in the region of pre-equilibrium(MSC) reaction dominance against a weaker fit at the lower emission energies. We attribute underestimations to contributions from the other reaction channels and disagreement at higher outgoing energies to reactions to collectively excited states. Contrary to the FKK multi-step direct calculations, contributions from the higher stages to the DDCs are significant. Different sets of parameters resulted in varying levels of agreement of calculated and experimental data for the considered nuclei.     

Behavioral Responses of the Leafhopper, <Emphasis Type="Italic">Cicadulina storeyi</Emphasis> China,a Major Vector of Maize Streak Virus,to Volatile Cues from Intact and Leafhopper-Damaged Maize

The chemical ecology of the leafhopper, Cicadulina storeyi China (Homoptera: Cicadellidae), an important vector of Maize Streak Virus (MSV), was studied with a view to developing novel leafhopper control strategies in sub-Saharan Africa. Choice tests using a Y-tube olfactometer revealed that odors from uninfested maize seedlings (Zea mays cv. Delprim) were significantly more attractive to C. storeyi than odors from C. storeyi-infested seedlings. Headspace samples of volatile organic compounds (VOCs) collected from 10 to 12 day-old uninfested seedlings were more attractive than those collected from infested seedlings. While VOCs collected from uninfested maize seedlings were attractive, VOCs collected from C. storeyi-infested seedlings were significantly repellent. Analysis of the collected VOCs by gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS) led to the identification of myrcene, linalool, (E)-2-decen-1-ol, and decanal from uninfested seedlings, and (Z)-3-hexenyl acetate, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), methyl salicylate, benzyl acetate, indole, geranyl acetate, (E)-caryophyllene, α-bergamotene, (E)-β-farnesene, β-sesquiphellandrene, and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT) from infested seedlings. Of these, methyl salicylate, (E)-caryophyllene, (E)-β-farnesene, and TMTT were identified previously as volatile semiochemicals involved in plant defense against other sucking insect pests. When tested individually for behavioral activity, all compounds were repellent for C. storeyi. Moreover, when these induced VOCs were added to the blend of VOCs from uninfested maize seedlings, a shift from attraction to repellency was observed. Addition of methyl salicylate, (E)-β-farnesene, or TMTT resulted in a choice for the solvent control (i.e., repulsion), whereas addition of (E)-caryophyllene resulted in no reduction in host VOC attractiveness. These results show that VOCs induced in maize have the potential to be exploited in the control of viruliferous leafhoppers in sub-Saharan Africa.     

Chemical composition and nutritional attributes of selected newly developed lines of soybean (Glycine max (L) Merr)

The chemical composition and nutritional properties of raw, autoclaved and boiled samples of three promising advanced breeding lines of soybean (TG_x 923 ? 2^EN, TG_x 1019 ? 2^EN and TG_x 1497 ? 1^D), part of a larger collection evaluated in agronomic field trials in Nigeria, were investigated. Protein quality was evaluated using weanling albino rats fed diets which were formulated to supply 10% protein using soybean samples, with casein as a control. Raw seeds contained 35.6–42.4% crude protein, 8.9–9.8 mg iron per 100 g, 8.62–18.21 mg trypsin inhibitor g^?1 and 2.25–6.15 mg phytic acid g^?1 seed flour. TG_x 923 ? 2^EN possessed higher crude protein contents and lower amounts of trypsin inhibitor, polyphenol and phytic acid compared with TG_x 1019 ? 2^EN or TG_x 1497 ? 1^D. Boiling proved more effective than autoclaving for reducing the levels of antinutrients and improving the protein quality of the beans, as shown by the higher values for weight gain, protein efficiency ratio (PER), net protein ratio (NPR) and true digestibility (TD) of boiled samples. There were no significant (p > 0.05) differences between the values obtained for PER, NPR and TD of diets containing boiled samples of TG_x 923 ? 2^EN and casein, indicating the nutritional superiority of this soybean line compared with TG_x 1019 ? 2^EN and TG_x 1497 ? 1^D. © 2002 Society of Chemical Industry     

Anti-Corrosion and Tribo-Mechanical Properties of Co-deposited Zn–SnO_2 Composite Coating

Zn–Sn O2 composite coatings were prepared by direct potential using electrolytic co-deposition technique from sulfate solution.The effect of Zn2?and Sn O2 concentrations in deposited bath on the mechanical properties and morphological characteristics of the composite coatings were examined.The characterizations of the sample were analyzed using scanning electron microscopy couple with energy dispersive spectroscopy(SEM/EDS),X-ray diffraction(XRD) and atomic force microscopy(AFM).The electrochemical degradation behavior of the samples in 3.65 wt.% Na Cl solution was studied using potentiodynamic polarization technique and characterized by high-resolution optical microscope.From all the fabricated composite coatings,obvious diffraction peaks were observed with Zn-7Sn-S-0.3V film with Zn2Sn7,Sn,Zn2Sn5 and Zn phases,confirming the presence and formation of Zn–Sn O2 coating.The XRD pattern shows that the presences of Sn O2 particle remarkably play a major role in the precipitation and orientation of the alloy matrix.From the SEM/EDS and AFM results,the deposits show that composite particle and proper bath composition have strong influence on the microstructure.An enhanced corrosion resistance was attained as a result of the induced particles.     

The Mechanism for Coarse Nb-Rich Particle Formation in Steel

Fine and coarse Nb-containing particles (Nb(C,N) and NbC) can be found in steel alloyed with niobium. The fine Nb-containing particles (precipitates) are of the order of several nanometers, typically ≤ 50 nm, in diameter, while the coarse Nb-containing particles (coarse Nb-rich particles) can have lengths ranging from submicron to hundreds of microns. The mechanism for the formation of the fine niobium carbide or carbonitride precipitates is well established, and their beneficial effects on strength and toughness are well documented. On the other hand, coarse Nb-rich particles are detrimental to the performance of the steel. Despite the plethora of studies on coarse Nb-rich particles, no experimental evidence has been offered for the proposed mechanisms of their formation. In this paper, the results of detailed and comprehensive experimental work that provide a novel understanding of the mechanism of formation of coarse Nb-rich particles are presented.

     

Antihypertensive and free radical scavenging properties of enzymatic rapeseed protein hydrolysates

In this study, rapeseed protein isolate (RPI) was digested with various proteases to produce rapeseed protein hydrolysates (RPHs), which were then separated into different peptide fractions (<1, 1–3, 3–5, and 5–10 kDa) by membrane ultrafiltration. Membrane fractionation showed that peptides with sizes <3 kDa had significantly (p < 0.05) reduced surface hydrophobicity when compared to the RPHs and peptide fractions with sizes >3 kDa. In contrast, the <3 kDa peptides showed significantly (p < 0.05) higher oxygen radical scavenging ability when compared to the >3 kDa peptides and RPHs. In vitro inhibition of angiotensin I-converting enzyme (ACE) was significantly (p < 0.05) higher for the Thermolysin, Proteinase K and Alcalase RPHs when compared to the pepsin + pancreatin (PP) and Flavourzyme RPHs. The Alcalase RPH had significantly (p < 0.05) higher renin inhibition among the RPHs, while with the exception of Thermolysin, the 5–10 kDa peptide fraction had the least renin-inhibitory ability when compared to the <5 kDa peptide fractions. Oral administration (100 mg/kg body weight) of the RPHs and RPI to spontaneously hypertensive rats (SHR) showed the Alcalase RPH to be the most effective in blood pressure (BP) reduction (∼24 mm Hg) while Proteinase K RPH was the least effective (∼5 mm Hg) after 8 h. However, the PP RPH had the most prolonged effect with BP reduction of ∼20 mm Hg after 24 h of oral administration. We conclude that the strong BP-lowering ability of Alcalase and PP RPHs could be due to high resistance of the peptides to structural degradation coupled with high absorption rate within the gastrointestinal tract.