Current strategies of regenerative medicine are focused on the restoration of pathologically altered tissue architectures by transplantation of cells in combination with supportive scaffolds and biomolecules. In recent years, considerable interest has been given to biologically active scaffolds which are based on similar analogs of the extracellular matrix that have induced synthesis of tissues and organs. To restore function or regenerate tissue, a scaffold is necessary that will act as a temporary matrix for cell proliferation and extracellular matrix deposition, with subsequent ingrowth until the tissues are totally restored or regenerated. Scaffolds have been used for tissue engineering such as bone, cartilage, ligament, skin, vascular tissues, neural tissues, and skeletal muscle and as vehicle for the controlled delivery of drugs, proteins, and DNA. Various technologies come together to construct porous scaffolds to regenerate the tissues/organs and also for controlled and targeted release of bioactive agents in tissue engineering applications. In this paper, an overview of the different types of scaffolds with their material properties is discussed. The fabrication technologies for tissue engineering scaffolds, including the basic and conventional techniques to the more recent ones, are tabulated.

/pdf/polymeric-scaffolds-in-tissue-engineering-application-a-2sbenjc1po.pdf

Polymeric scaffolds in tissue engineering application: a review

Overcoming the recalcitrance (resistance of plant cell walls to deconstruction) of lignocellulosic biomass is a key step in the production of fuels and chemicals. The recalcitrance is due to the highly crystalline structure of cellulose which is embedded in a matrix of polymers-lignin and hemicellulose. The main goal of pretreatment is to overcome this recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have shown that pretreatment can improve sugar yields to higher than 90% theoretical yield for biomass such as wood, grasses, and corn. This paper reviews different leading pretreatment technologies along with their latest developments and highlights their advantages and disadvantages with respect to subsequent hydrolysis and fermentation. The effects of different technologies on the components of biomass (cellulose, hemicellulose, and lignin) are also reviewed with a focus on how the treatment greatly enhances enzymatic cellulose digestibility.

/pdf/chemical-and-physicochemical-pretreatment-of-lignocellulosic-4eshdcsnor.pdf

Chemical and physicochemical pretreatment of lignocellulosic biomass: a review.

Cellulose macro- and nanofibers have gained increasing attention due to the high strength and stiffness, biodegradability and renewability, and their production and application in development of composites. Application of cellulose nanofibers for the development of composites is a relatively new research area. Cellulose macro- and nanofibers can be used as reinforcement in composite materials because of enhanced mechanical, thermal, and biodegradation properties of composites. Cellulose fibers are hydrophilic in nature, so it becomes necessary to increase their surface roughness for the development of composites with enhanced properties. In the present paper, we have reviewed the surface modification of cellulose fibers by various methods. Processing methods, properties, and various applications of nanocellulose and cellulosic composites are also discussed in this paper.

/pdf/cellulose-based-bio-and-nanocomposites-a-review-5484pyqycf.pdf

Cellulose-Based Bio- and Nanocomposites: A Review

Optimization of the ammonia fiber explosion (AFEX) treatment parameters for enzymatic hydrolysis of corn stover.

A large number of enzymes from bacteria, fungi, and plants have been reported to be involved in the biodegradation of toxic organic pollutants. Bioremediation is a cost effective and nature friendly biotechnology that is powered by microbial enzymes. The research activity in this area would contribute towards developing advanced bioprocess technology to reduce the toxicity of the pollutants and also to obtain novel useful substances. The information on the mechanisms of bioremediation-related enzymes such as oxido-reductases and hydrolases have been extensively studied. This review attempts to provide descriptive information on the enzymes from various microorganisms involved in the biodegradation of wide range of pollutants, applications, and suggestions required to overcome the limitations of their efficient use.

/pdf/role-of-microbial-enzymes-in-the-bioremediation-of-2uov3ks5gc.pdf

Role of microbial enzymes in the bioremediation of pollutants: a review.

Intensive poultry production generates over 100,000 t of litter annually in West Virginia and 9×106 t nationwide. Current available technological alternatives based on thermophilic anaerobic digestion for residuals treatment are diverse. A modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost. A 40-m3 pilot plant digester was used for performance evaluation considering energy input and methane production. Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance.

Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions.

AP is involved in the destruction of harmful H202 In soybean (Glycine max [L] Merr) root nodules, AP initiates a sequence of coupled redox reactions (ascorbate-GSH pathway) that results in peroxide scavenging (Dalton et al, 1986) The ascorbate-GSH pathway occurs in other plant tissues and has been extensively studied in chloroplasts where photoreducing conditions lead to the production of H202 (Asada, 1992) Two forms of AP are present in plant cells, a chloroplast form and a cytosol form Both forms of AP are quite distinct from other types of plant peroxidases that occur in the vacuole, cell wall, or cytosol (Asada, 1992) The molecular cloning and sequencing of cytosolic AP cDNA from pea (Mittler and Zilinskas, 1991) and a cDNA from Arabidopsis (Kubo et al, 1992) as well as a characterization of the pea gene (Mittler and Zilinskas, 1992) have been described We report the isolation of a full-length cDNA clone that encodes an AP subunit (Table I) The isolation strategy was to screen a nodule cDNA expression library with a polyclonal antibody prepared from purified (Dalton et al, 1987) root nodule AP Putative AP clones were isolated at a frequency of 1 in 800, and 80% of the isolates contained a 11-kb insert Double-stranded dideoxy sequencing of one clone resulted in a 1054-nucleotide sequence with a 3' poly(A) tail and an open reading frame encoding 249 amino acids Comparison of the N-terminal amino acid sequence obtained by automated Edman sequencing (20 residues) confirmed that the clone was authentic AP A comparison of deduced protein sequences (249 amino acids) revealed a sequence identity of 90% with that of pea (Mittler and Zilinskas, 1991) and 78% with that of Arabidopsis (Kubo et al, 1992) The high activity of AP (Dalton et al, 1987) in nodules suggests that this pathway may provide an essential protective action in processes related to nitrogen fixation This analysis was a first step to studies addressing the genetic regulation of the ascorbate-GSH pathway and ultimately the criticalness of this pathway to nitrogen fixation

http://www.plantphysiol.org/content/plantphysiol/103/2/661.full.pdf

Ascorbate Peroxidase from Soybean Root Nodules

The effect of feed-loading frequency on digester performance was studied on a thermophilic anaerobic digester with a working volume of 27.43 m3. The digester was fed 0.93 m3 of chicken-litter slurry/d, containing 50.9 g/L chemical oxygen demand. The treatments were loading frequencies of 1, 2, 6, and 12 times/d. The hourly pH, biogas production, and methane percent of the biogas were less stable at lower feed frequencies. There was no statistical difference among treatments in methanogenic activity. The feed-loading frequency of six times per day treatment provided the greatest biogas production.

Thermophilic Anaerobic Digester Performance Under Different Feed-Loading Frequency

Neisseria gonorrhoeae antimicrobial resistance (NG AMR) has become an urgent concern globally. The World Health Organization, the United States of America Centers for Disease Control, and other regulators have called to improve resistance-testing methods to enhance NG AMR surveillance. NG AMR surveillance remains critical in informing treatment; unfortunately, this is often lacking in settings with limited resources, such as Papua New Guinea (PNG). We conducted a systematic review and a prevalence meta-analysis, and provided an overview of NG AMR in PNG. We showed the lack of NG AMR data in the last decade, and emphasized the need for NG AMR surveillance in PNG. Since NG AMR testing by the NG culture method is unreliable in PNG, we suggested using molecular tests to complement and enhance NG AMR surveillance.

/pdf/the-prevalence-of-antimicrobial-resistant-neisseria-1kj0a2o0.pdf

Mark Chatfield

Papers

Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions.

Ascorbate Peroxidase from Soybean Root Nodules

Thermophilic Anaerobic Digester Performance Under Different Feed-Loading Frequency

The Prevalence of Antimicrobial Resistant Neisseria gonorrhoeae in Papua New Guinea: A Systematic Review and Meta-Analysis