Chloropicrin Soil Fumigation Reduces <Emphasis Type="Italic">Spongospora subterranea</Emphasis> Soil Inoculum Levels but Does Not Control Powdery Scab Disease on Roots and Tubers of Potato

The effect of chloropicrin fumigation on the soil populations of Spongospora subterranea and the development of powdery scab, formation of root galls and tuber yield was investigated in seven field trials conducted in Minnesota and North Dakota. Sixteen potato cultivars, with different levels of susceptibility to disease on roots and tubers, were planted in plots treated with chloropicrin at rates ranging from zero to 201.8 kg a.i. ha^?1. The amount of S. subterranea DNA in soil was determined using qPCR. Bioassays were conducted to further assess the effect of chloropicrin fumigation on root colonization by S. subterranea in two potato cultivars with contrasting disease susceptibility. In the field, chloropicrin applied at rates between 70.1 to 201.8 kg a.i. ha^?1 significantly decreased S. subterranea initial inoculum in soil but increased the amount of disease observed on roots and tubers of susceptible cultivars. The effect of increasing disease was confirmed in controlled conditions experiments. Although the amount of S. subterranea DNA in roots of bioassay plants increased with increasing chloropicrin rates, it remained similar among potato cultivars. Chloropicrin fumigation significantly increased tuber yield which in cultivars such as Shepody and Umatilla Russet were associated with the amount root galls (r = 0.30; P < 0.03). Results of these studies contradict earlier reports on the use of chloropicrin fumigation for the control of powdery scab. Factors other than inoculum level, such as environmental conditions that affect inoculum efficiency and host susceptibility, may be significant contributors to the development of powdery scab and root gall formation.     

Amplification of the <Emphasis Type="Italic">Phytophthora infestans</Emphasis> RG57 loci Facilitates <Emphasis Type="Italic">in planta</Emphasis> T-RFLP Identification of Late Blight Genotypes

Late blight, caused by the oomycete Phytophthora infestans (Mont.) de Bary, is a devastating disease in potato and tomato and causes yield and quality losses worldwide. The disease first emerged in central America and has since spread in North America including the United States and Canada. Several new genotypes of P. infestans have recently emerged, including US-22, US-23 and US-24. Due to significant economic and environmental impacts, there has been an increasing interest in the rapid identification of P. infestans genotypes. In addition to providing details regarding the various phenotypic characteristics such as fungicide resistance, host preference, and pathogenicity associated with various P. infestans genotypes, information related to pathogen movement and potential recombination may also be determined from the genetic analyses. Restriction fragment length polymorphism (RFLP) analysis with the RG57 loci is one of the most reliable procedures used to genotype P. infestans. However, the RFLP procedure requires propagation and isolation of the pathogen and relatively large amounts of DNA. Isolation of the late blight pathogen is sometimes impossible due to the poor condition of the infected tissues or the presence of fungicide residues. In this study, we describe a procedure to identify P. infestans at the molecular level in planta using terminal restriction fragment length polymorphism (T-RFLP) of the RG57 loci. This T-RFLP assay is sufficiently sensitive to detect and differentiate P. infestans genotypes directly in planta without propagation and isolation of the pathogen, to facilitate the timely implementation of best management practices.     

Antibacterial Bombyx Mori silk fabric modified with reactive chitosan quaternary ammonium salt and its laundering durability

A new fiber-reactive chitosan derivative was synthesized in two steps from a chitosan of low molecular weight. First, a water-soluble chitosan derivative, N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride (short for HTCC), was prepared by reacting chitosan with 2,3-epoxypropyltrimethylammonium chloride. Second, HTCC was further modified by reacting with N-(hydroxymethyl)-acrylamide to prepare a fiber-reactive chitosan derivative, O-methyl acrylamide quaternary ammonium salt of chitosan (short for NMA-HTCC), which can form covalent bonds with silk fiber under alkaline conditions. The chemical structure of NMA-HTCC was characterized by Fourier transform infrared spectrum (FTIR) and nuclear magnetic resonance (NMR). The substitution degree of HTCC and the double-bond content of NMA-HTCC were tested. Then NMA-HTCC was used for antibacterial finishing of Bombyx Mori silk fabric. The results showed that silk fabric treated with NMA-HTCC had a significantly improved antibacterial activity to Staphylococcus aureus and Escherichia coli, and the antibacterial activity of silk fabric finished by NMA-HTCC was much better than that finished by chitosan and HTCC. Bombyx Mori silk fabric modified with NMA-HTCC demonstrated excellent durable antibacterial activity, even after 50 repeated launderings, the bacterial reduction rate of silk fabric maintained over 95 %.     

Fabrication of electropsun PLGA and small intestine submucosa-blended nanofibrous membranes and their biocompatibility for wound healing

In recent decades, tremendous research has focused on the production of nanoscale fibers using synthetic polymers, with the goal of fabricating nanofibrous scaffolds for wound healing. However, the hydrophobicity of such polymers typically hinders attachment and proliferation of the cells. In this study, we combined poly-d,l-lactide-co-glycolide (PLGA) and small intestine submucosa (SIS) to fabricate blended nanofibers for wound healing by electrospinning. PLGA and SIS were dissolved in 1,1,1,3,3,3-hexafluoro isopropanol to produce different weight ratios of PLGA/SIS-blended nanofibrous membranes (NFM). Physicochemical characterization of the electrospun NFM was performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, water contact angle analysis, degradation test and tensile testing. The PLGA/SIS-blended NFM showed improved hydrophilicity and tensile strength. Better infiltration, attachment and proliferation of rat granulation fibroblasts of PLGA/SIS-blended NFMs compared to PLGA NFMs were identified by morphological differences determined by SEM and a water-soluble tetrazolium salt assay kit. Based on our results, the PLGA/SIS blended NFMs were found to be suitable for use as a potential material for wound dressing.     

A novel method based on loop shape for simulating knitted fabric using mass spring model

Fabric simulation is result of combining various methods that have been dramatically evolved during the decade. However, there still exist some limitations. One of the limitations in fabric simulation is lack of using fabric properties such as material, weave structure, density and so on in mass spring modeling. In knitted fabrics, this issue is more important due to their different fabric structures. In this paper, a new mesh based on loop shape for simulating 1×1 rib fabric is proposed which is called Loop mesh. By using the Loop and common meshes, 3D model of drape behavior in 18 types of knitted fabric are simulated. Results of simulation are compared with 3D shape of actual drape behavior in fabric samples which are achieved by depth camera. Results show that the Loop mesh is able to predict the drape behavior of knitted fabric with error value of 5 percent as compared with the real result. It can be found that the Loop mesh produced a closest drape shape to the actual fabric drape than other mesh models.     

Mechanical behavior of nylon 66 tyre cord under monotonic and cyclic extension: Experiments and constitutive modeling

Many industrial products are made of cord-rubber composite materials. Their mechanical behavior not only depends on rubber but also depends on cord. Nylon 66 cord is one of the most important reinforcement in these products. This paper research the mechanical behavior of nylon 66 cord under various load cases. A series of experiments were carried out to obtaining stress-strain curves under different load cases. Complex changes of the modulus and Mullins effect can be found in monotonic and cyclic tension, respectively. Mechanism of these behaviors has been analyzed considering both the twisted structure and material. A phenomenological constitutive model, accounting for different loading conditions, has been firstly proposed base on strain energy density function and damage mechanics method. The proposed model has been verified by comparing the predicted results with experimental data. It has been found that the proposed model predicted the stress-strain curves that were consistent with the experimental data. The proposed model can be implemented in finite element software for engineering design and application.     

Improvement of ink-jet printing performances using β-cyclodextrin forming inclusion complex on cotton fabric

Cotton fabric was modified with β-cyclodextrin (β-CD) forming inclusion complex to yield color strength, pattern sharpness, and color fastness for ink-jet printing. The modified cotton fabric was confirmed with the presence of new strong absorption peaks around 1713 cm^-1 and 1243 cm^-1 in FT-IR. β-CD had been covalently grafted on cotton fabric via the esterification reaction of citric acid (CTR) with cellulose and β-CD. The results indicated that printing performances of the ink-jet printed fabric were enhanced through β-CD modification. The K/S value was enhanced from 4.21 to 6.72, the width of printed line was decreased from 1.48 mm to 1.25 mm, and the color fastness was improved to 3-4 level. These improvements were due to the truncated cone structure of β-CD, which can form inclusions with water-based pigment. Meanwhile, the crease recovery performance was also improved with the aid of CTR. A comparison between the unmodified and modified cotton fabric suggested that the crease recovery angle of β-CD modified cotton fabric was increased by 25.0 % in the warp direction. Therefore, printing performance and crease recovery performance of β-CD modified and water-based pigment printed cotton fabric were enhanced remarkably.     

Application of silver nanoparticles as an antibacterial mordant in wool natural dyeing: Synthesis,antibacterial activity,and color characteristics

Madder is a natural colorant which is commonly applied with metal salts as a mordant to improve its affinity to fibers and color fastness. Madder produces an insoluble complex or lake in the presence of metal ions on mordanted fabric. In this study, wool fabric was pretreated with AgNPs (silver nanoparticles) as a mordant, then dyed with madder. The wool fabric samples were examined by scanning electron microscopy (SEM) and their colorimetric characteristics were evaluated. The formation of spherical silver nanoparticle was confirmed using UV-Visible spectroscopy, SEM images, and elemental analysis. The average size of synthesized silver nanoparticles on the surface of wool fibers is around 73 nm. The dyed wool samples were pretreated with different concentration of Ag⁺ ions or AgNPs, which showed higher color strength value compared to untreated dyed wool fabric. This pretreatment also presented good antibacterial activity.     

Thermal,swelling and stability kinetics of chitosan based semi-interpenetrating network hydrogels

The present study is focused on studying the swelling kinetics, thermal and aqueous stabilities, and determination of various forms of water in the chitosan (CS) and polyacrylonitrile (PAN) blend and semi-interpenetrating polymer network (sIPN). CS/PAN blend hydrogel films were prepared by solution casting technique. The blend film with optimum swelling properties was selected for the synthesis of sIPN. CS in the blend was crosslinked with the vapors of Glutaraldehyde (GTA) to prepare sIPN. The fabricated CS/PAN blend and sIPN hydrogels films were characterized with Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA) and field emission scanning electron microscope (FESEM). The kinetics of swelling, bound and unbound waters and aqueous stability were determined experimentally. FESEM showed good miscibility between CS and PAN, FTIR showed no chemical interaction between CS and PAN; however, it did show a doublet for the sIPN, TGA showed improved thermal stability and swelling kinetic followed second order kinetics. The degree of swelling of the sIPN hydrogels samples at room temperature varied from ~2200 % (with a fair degree of stability (~30 %)) to ~1000 % (with high degree of aqueous stability (43 %)) with increase in the crosslinking time. The calculated unbound water (W_UB) max., for the blend was 52.3 % whereas for the bound (W_B) the max., was 41.9 %. However, for sIPN hydrogel films, the W_UB water decreased (max. 21.0 %) where as the W_B increased (max. 52.0 %). The decrease in W_UB and increase in the W_B is attributed to the formation of a compact structure and increase in the contact area between the water and polymers in sIPN hydrogels due to the induction of new water contacting point in these hydrogel films, respectively.     

Fabrication of hydrophobic/oleophilic cotton fabric by mussel-inspired chemistry for oil/water separation

A straightforward approach was proposed to modify cotton fabric for oil/water separation based on musselinspired reaction. The poly(DMA-Octadecyl acrylate) was designed to contain key chemical constituents present in mussel adhesive proteins by free radical polymerization of dopamine hydrochloride and octadecyl acrylate, which strongly adsorbed to fabric substrates, providing a special surface for fabric. The chemical structure, surface topography, and surface wettability of the fabric were characterized. The results showed that as-prepared cotton fabric displayed a high CA of >150° when dripped water droplets were on the modified fabric surface, and the oil contact angle (OCA) was close to 0°, it had excellent potential to be used in practical applications and has created a new method of fabric modification for oil/water separation.