Crystallinity And Ultrastructure Of Ammoniated Wood Part II. Ultrastructure

Cell-wall layering, pits, and lumen surfaces of loblolly pine wood were examined in the electron microscope for changes due to ammonia treatment. Both normal and compression wood cell walls were crimped circumferentially after ammoniation as evidenced by deformations in the S3 and/or S1 layers. Such crimping would imply a cell-wall consolidation due to shrinkage in the S2, and the overall phenomenon was probably responsible for the increase in X-ray crystallinity of the same material. Other ultrastructural changes included definite pit aspiration and the deposition of an incmstant-like substance onto both pit structure and lumen surfaces. This incrustant was probably some residual wood extractive or other wall constituent partially solubilized by condensed ammonia in the cell

Development and Composition of the Warty Layer in Balsam Fir. I. Development

The deposition and ultrastructure of the warty layer in developing tracheids of balsam fir [Abies balsamea (L.) Mill.] were studied by means of transmission electron microscopy. The wart structure gradually was developed external to the plasma membrane after secondary wall deposition and the greater part of lignification were complete. Warts were synthesized first in the cell corners and pit cavities and then on the remainder of the cell walls. No cytoplasmic organelle was found to be associated specifically with wart formation. After the warty layer was elaborated, the cytoplasm disappeared from the cell, leaving no discernible trace of disorganized residue. The bulk of the wart structure exhibited staining properties similar to those of lignin. However, the basal portions of individual warts were sometimes less darkly stained than the outer portions, indicating possible heterogeneous composition

Development and Composition of the Warty Layer in Balsam Fir. II. Composition

From its response to various chemical, physical, fungal, and enzymatic treatments, it was concluded that the warty layer in balsam fir consisted largely of a ligninlike material that was visibly more resistant to extraction than a large fraction of other lignin in the fiber cell wall. Since the warts were the cell-wall component most accessible to the treatment solutions, it is probable that the material in the warty layer was more concentrated and condensed than lignin in other parts of the wall. Vacuum drying at 105 C appeared to condense the wart structure still further, making it even more resistant to most treatments. Gel filtration indicated that the warty layer was extracted as a high molecular weight material by certain treatments. The warty layer may act as a barrier that slows the penetration of liquids into the cell wall and thereby may cause different rates of delignification for different wood species. The basal component of individual warts and some of the accompanying encrustant on the inner surface of the cell wall were found to contain an amorphous carbohydrate, probably a pentosan or a pectic substance. Attempts at physical isolation of the warts were largely unsuccessful

Electrospun Nano-fibers for biomedical and tissue engineering applications: A comprehensive review

Pharmaceutical nano-fibers have attracted widespread attention fromresearchers for reasons such as adaptability of the electro-spinning process and ease of production. As a flexible method for fabricating nano-fibers, electro-spinning is extensively used. An electro-spinning unit is composed of a pump or syringe, a high voltage current supplier, a metal plate collector and a spinneret. Optimization of the attained nano-fibers is undertaken through manipulation of the variables of the process and formulation, including concentration, viscosity, molecular mass, and physical phenomenon, as well as the environmental parameters including temperature and humidity. The nano-fibers achieved by electro-spinning can be utilized for drug loading. The mixing of two or more medicines can be performed via electro-spinning. Facilitation or inhibition of the burst release of a drug can be achieved by the use of the electro-spinning approach. This potential is anticipated to facilitate progression in applications of drug release modification and tissue engineering (TE). The present review aims to focus on electro-spinning, optimization parameters, pharmacological applications, biological characteristics, and in vivo analyses of the electro-spun nano-fibers. Furthermore, current developments and upcoming investigation directions are outlined for the advancement of electro-spun nano-fibers for TE. Moreover, the possible applications, complications and future developments of these nano-fibers are summarized in detail. © 2020 by the authors

Arkansas Cooperative Beef Bull Performance Test 1991

Performance testing of beef bulls was initiated to improve productivity of Arkansas beef cattle through breeding. This cooperative testing program provides cattlemen with reliable information for identifying animals with superior breeding value for the traits of production measured in the test. By using the information as a basis for herd sire selection, a breeder can greatly increase the chances of obtaining a bull that will sire rapid-gaining, more efficient, highquality calves. Such calves can increase profits for both the breeder and the feeder. This testing program provides information that is useful to financial institutes in arranging their lending programs and to companies in developing their educational, promotional and marketing programs

Antioxidant, antimicrobial and antiviral properties of herbal materials

Recently, increasing public concern about hygiene has been driving many studies to investigate antimicrobial and antiviral agents. However, the use of any antimicrobial agents must be limited due to their possible toxic or harmful effects. In recent years, due to previous antibiotics’ lesser side effects, the use of herbal materials instead of synthetic or chemical drugs is increasing. Herbal materials are found in medicines. Herbs can be used in the form of plant extracts or as their active components. Furthermore, most of the world’s populations used herbal materials due to their strong antimicrobial properties and primary healthcare benefits. For example, herbs are an excellent material to replace nanosilver as an antibiotic and antiviral agent. The use of nanosilver involves an ROS-mediated mechanism that might lead to oxidative stress-related cancer, cytotoxicity, and heart diseases. Oxidative stress further leads to increased ROS production and also delays the cellular processes involved in wound healing. Therefore, existing antibiotic drugs can be replaced with biomaterials such as herbal medicine with high antimicrobial, antiviral, and antioxidant activity. This review paper highlights the antibacterial, antiviral, and radical scavenger (antioxidant) properties of herbal materials. Antimicrobial activity, radical scavenger ability, the potential for antimicrobial, antiviral, and anticancer agents, and efficacy in eliminating bacteria and viruses and scavenging free radicals in herbal materials are discussed in this review. The presented herbal antimicrobial agents in this review include clove, portulaca, tribulus, eryngium, cinnamon, turmeric, ginger, thyme, pennyroyal, mint, fennel, chamomile, burdock, eucalyptus, primrose, lemon balm, mallow, and garlic, which are all summarized. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

A specific amino acid motif of HLA-DRB1 mediates risk and interacts with smoking history in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease in which genetic risk has been mapped to HLA, but precise allelic associations have been difficult to infer due to limitations in genotyping methodology. Mapping PD risk at highest possible resolution, we performed sequencing of 11 HLA genes in 1,597 PD cases and 1,606 controls. We found that susceptibility to PD can be explained by a specific combination of amino acids at positions 70-74 on the HLA-DRB1 molecule. Previously identified as the primary risk factor in rheumatoid arthritis and referred to as the "shared epitope" (SE), the residues Q/R-K/R-R-A-A at positions 70-74 in combination with valine at position 11 (11-V) is highly protective in PD, while risk is attributable to the identical epitope in the absence of 11-V. Notably, these effects are modified by history of cigarette smoking, with a strong protective effect mediated by a positive history of smoking in combination with the SE and 11-V (P = 10-4; odds ratio, 0.51; 95% confidence interval, 0.36-0.72) and risk attributable to never smoking in combination with the SE without 11-V (P = 0.01; odds ratio, 1.51; 95% confidence interval, 1.08-2.12). The association of specific combinations of amino acids that participate in critical peptide-binding pockets of the HLA class II molecule implicates antigen presentation in PD pathogenesis and provides further support for genetic control of neuroinflammation in disease. The interaction of HLA-DRB1 with smoking history in disease predisposition, along with predicted patterns of peptide binding to HLA, provide a molecular model that explains the unique epidemiology of smoking in PD

Engraftment of neural stem cells in the treatment of spinal cord injury

AbstractSpinal cord injury is one of the main causes of disability in the young population. Based on the underlying pathological changes, many modalities of treatments have been trialed. However, the most promising so far, has been the replacement of lost cellular elements, using stem cells and non-stem cells transplantation. The route of cellular administration and engraftment into the site of injury is an important determining factor for functional outcome, and should be chosen to be safe and efficacious in human patients. Herein, we will review the underlying changes following spinal cord injury, and the possible routes of cellular transplantation

Creating a low-cost virtual reality surgical simulation to increase surgical oncology capacity and capability

Worldwide, more than 80% of people with cancer will require surgery during their disease course, but less than 25% have access to safe, affordable and timely surgery. Among the barriers to increasing surgical capacity are the time and costs required to train novices. Virtual reality (VR) surgical simulations can reduce the time required for novices to reach surgical proficiency, though their costs may exceed USD $100,000. The goal of this study was to determine if a low-cost system, using commercially available technology designed for in-home computer gaming, could be used to create a realistic VR surgical oncology simulation. Standard commercially available VR software and Oculus Rift hardware have been used to provide high-quality visuals and believable surgeon hand interactions. Near identical VR reproduction of an operating room using 1:1 scale matching of real-world elements, including equipment, instruments, supplies and sounds, maintaining frame rate greater than 60 fps to maintain visual fidelity has been created. Internal anatomy was designed as VR replica of human female pelvic anatomy, including organs, veins and other vessels, peritoneum and connective tissue. Internal anatomy was designed to run at 120 fps and to allow for a realistic abdominal radical hysterectomy simulation. Surgical hands were modelled to scale for those with large and small hands. Multiple hand positions were simulated using Oculus touch hardware. Reconstructing the virtual environment to simulate reality as accurately as possible was done to immerse users in the simulator so that they focus on learning and practise without distractions. Training modules were co-designed by experts in learning sciences, human behaviour, VR and gynaecologic oncology. We have successfully created a low-cost VR simulation to help prepare novice surgeons to perform a radical abdominal hysterectomy surgery procedure. The simulation can be used with commercially available computer gaming hardware that currently costs less than USD$1,500. Low-cost VR simulation has the potential to reduce the time and cost to train surgeons to perform surgical oncology procedures, as well as both improve and audit quality. If effective in real-world clinical trials, such simulations have relevance to multiple surgical procedures and applicability in both resource-limited and high-income settings