Narrow Results

Many of the functionally relevant collective vibrations of proteins and other biopolymers are expected to occur at terahertz frequencies. Precise absorption measurements combined with careful titration of biopolymers in water have allowed us to directly measure the terahertz absorption spectra associated with these motions, despite the strong background absorption of the solvent. We have also explored the circular dichroism spectroscopy of biomolecules over this same frequency range. Since circular dichroism requires the presence of net chirality in a molecule and chirality is present in nearly all biomaterial, it has the potential to capture the background free spectral features in biopolymers. To undertake these studies we have developed a broad band terahertz spectrometer suitable for both direct absorption and circular dichroism measurements of proteins in water between 0.75 – 3.72 THz. Direct terahertz absorption spectra of prototypical proteins bovine serum albumin (BSA) and hen egg white lysozyme have been documented and are described here. We have also successfully demonstrated the magnetic circular dichroism in semiconductors, and placed an upper bound on the terahertz circular dichroism signature of solvated BSA. In the terahertz frequency range, it appears that circular dichroism signatures are exceedingly small and detection remains a challenge.

Electron spectra of DNA model compounds, adenosine-thymidine and guanosine-cytidine nucleoside base pairs, as well as the relevant homogeneous stacked base pair steps in A-DNA and B-DNA conformations, were investigated using ZINDO semiempirical quantum-chemical method. This work confirms that, in DNA with intact Watson–Crick hydrogen bonding and base stacking, the highest occupied molecular orbitals (HOMO) are residing on purine base residues, whereas the lowest unoccupied molecular orbitals (LUMO) — on pyrimidine base residues. In general, the present results are satisfactorily comparable with the available experimental data. The role of charge transfer excitations in the polymer DNA 260 nm spectral band is discussed.

We derive the general shape equations in terms of Euler angles for an elastic model of uniform ribbon with noncircular cross section and vanishing spontaneous curvatures. We show that it has in general not a planar solution for a closed ribbon free of external force and torque. We study the conditions to form a helix with the axis along the direction of the applied force for a ribbon under external force and twisting. We find that if the bending rigidity is greater than the twisting rigidity, then no such helical rod can exist. Our stability analysis shows that a helical ribbon is in general stable or at least metastable under arbitrary force and torque. We find that the extension of the ribbon may undergo a discontinuous transition from a twisted straight rod to a helical ribbon. The intrinsic asymmetric elasticity of a helical ribbon under external torque is also studied.

We derive the shape equations in terms of Euler angles for a uniform elastic rod with isotropic bending rigidity and spontaneous curvature, and study within this model the elasticity and stability of a helical filament under uniaxial force and torque. We find that due to the special requirements on the boundary conditions, a static slightly distorted helix cannot exist in this system except in some special cases. We show analytically that the extension of a helix may undergo a one-step sharp transition. This agrees quantitatively with experimental observations for a stretched helix in a chemically-defined lipid concentrate (CDLC). We predict further that under twisting, the extension of a helix in CDLC may also exhibit similar behavior. We find that a negative twist tends to destabilize a helix.

The characteristics of nip-type a-Si:H thin film solar cells based on DNA-CTMA biopolymer was investigated. The DNA-CTMA was used as the buffer layer in nip-type a-Si:H solar cell. The E_opt of the DNA-CTMA biopolymer was measured with UV-VIS spectrometer. The E_opt of DNA-CTMA was determined as 3.96 eV by the plot of (Ahν)² versus hν. All films of amorphous materials were deposited by PECVD method. The solar cell with a simple structure of glass/ITO/n-a-Si:H/i-a-Si:H/p-a-Si:H/DNA-CTMA/Al was fabricated. The various values of V_oc, J_sc, FF, and conversion efficiency η were measured under 100 mW/cm² (AM 1.5) solar simulator irradiation. Consequently, the resulting in solar cell showed an enhancement in conversion efficiency η compared to conventional nip-type a-Si:H solar cell without buffer layer of DNA-CTMA biopolymer.

Hydroxypropyl methylcellulose (HPMC) is a kind of biopolymer that is biodegradable, environmentally friendly and possesses exceptional mechanical and tribological properties. Therefore, it could be used as a suitable alternative to plastic. However, HPMC deforms easily when subjected to loads, causing higher real contact area and adhesive force between HPMC and grinding counter. Therefore, HPMC films are easily damaged because of adhesive wear, which negatively affects wear resistance. Hence, nanoparticles (NPs) of Al, Cu, Al₂O₃ and CuO have been used as fillers to increase the wear resistance of the HPMC composite films. The uniform dispersion of NPs in the suspension is the most important factor, which is greatly related to the wear resistance after film formation. Nanosuspensions with various dispersant concentrations were prepared, and mixed with the HPMC solution to prepare composite solutions and composite films. The results showed that Span 80 could provide steric stabilization, and that it dispersed the NPs effectively in suspension. After mixing the suspension with the HPMC solution, the solution became more stable.

Using an electrospinning device, we determined the optimal conditions for producing nanofibers from a 10% solution of Co–AN. These conditions involved applying a 15kV voltage to the anode, which was connected to the syringe containing the solution, and maintaining a distance of 12–15cm from the needle tip to the collector screen (cathode). The filament diameter (d) ranged from 0.2 to 0.5mm. This setup allowed the formation of nanofibers under the cover. The electrolysis process was conducted for varying durations, ranging from 4 to 14h, while applying currents of 2mA, 4mA, and 8mA. At 4mA and 8mA, a substantial portion (approximately 65–70%) of the macroions in the solution reassembled on the electrode surfaces. These images clearly illustrate the restoration of macroions on the electrode surfaces, achieved through electron exchange processes. This phenomenon results in the combination of macroions and their neutralization, leading to the formation of a composite coating on the titanium, iron plate, and rods.

AUSTRALIA – Second-Generation Diagnostic Achieves 98% Accuracy in Detecting Early Stage Ovarian Cancers

AUSTRALIA – New Center Brings Australian and Chinese Researchers Together to Fight Infectious Diseases

AUSTRALIA – Co-developing New Treatment Guidelines for Melanoma

AUSTRALIA – Australia Leads World's First Global Effort to Improve Genetic Disorders Diagnosis

CHINA – China Bans Illegal Food Additives to Reinforce Food Safety Control

CHINA – China Steps Up Tighter Inspection in Food Safety

CHINA – WHO and China to Do More for Chinese with Hearing Impairment

CHINA – First TCM Drug for Arrhythmia

CHINA – First Human-Human Transmission of Tick-Borne Disease Reported in China

CHINA – Bird Flu Found in Chickens in Eastern China

CHINA – First Bird Flu Death Reported for 2009, No Bird-flu Outbreak

HONG KONG – Hong Kong Alerts New Bird Flu Outbreak

INDIA – India Also Confirmed Bird Flu Incidence

INDIA – India Plans 20 More Biotech Parks for Life Sciences Research

KOREA – An Economic Share in Medical Tourism Market

JAPAN – Brain Tissues Made from Stem Cells

NEW ZEALAND – Newly Merged Research Institute Leverage Greater Synergy

NEW ZEALAND – Kiwi's Green Plastic Well-Acclaimed in International Awards

NEW ZEALAND – Sea Sponge Indigenous to NZ Could Reduce Chemo Side Effects

PHILIPPINES – Ebola-Reston Virus Jumped Species

SINGAPORE – Human Sewage, the Potential Source of Clean Energy

SINGAPORE – No More Heart-stopping Incidents for Heart Patients

SINGAPORE – China Milk Products Get All-Clear from Singapore

SINGAPORE – Discovery of New Properties in Imidazolium Salts Yield Multi Applications

SINGAPORE – S'pore Ranked World's Most Prolific for Eye Research Per Capita

SINGAPORE – Outdoor Sun Reduces Incidence of Myopia in Children

TAIWAN – University Hospital in Taiwan Collaborates with Neuralstem

VIETNAM – Return of Bird Flu, Vietnam Runs High Risk of Human Infection

VIETNAM – Conjoined Twins Successfully Separated

VIETNAM – Rise in Off-Season Dengue Fever Cases

NORTH AMERICA – Epilepsy Drugs Prescription to Carry Suicide Risk Warning

NORTH AMERICA – U.S. Doctors Succeeded Near-total Face Transplant

NORTH AMERICA – Vaccinating Pacific Girls against Cervical Cancer

NORTH AMERICA – Manipulating Love and Emotions by Spray

EUROPE – Cambridge Pips Oxford in Research

EUROPE – Adapting Car Manufacturing Technology to Produce Synthetic Bone Implants

EUROPE – Dioxin-tainted Irish Pork Products Recalled

Magnetite and biopolymer-magnetite nanoparticles coated with polyethylene glycol (PEG) and chitosan have been synthesized. The adsorption of the biopolymers on the magnetite nanoparticles is confirmed using Fourier Transform Infrared (FTIR) Spectroscopy. Atomic Force Microscopy (AFM) imaging revealed magnetite-biopolymer core–shell nanoparticles of typical size range 25–80 nm. We report a novel way of determining the thickness of the biopolymer coating using noncontact AFM imaging. AFM has been used to study the variation of the biopolymer coating thickness as a function of the magnetite core diameter, biopolymer type, and its concentration. The thickness of the chitosan coating varies in the range of 4–11 nm and increases linearly with increase in magnetite core size. PEG coating thickness has similar values as for the chitosan coating.

The optical properties of CdSe quantum dots (QDs) capped by thioglycolic acid (TGA) before and after surface modification with poly (acrylic acid) grafted onto salep (salep-g-PAA), as a biopolymer-based multidentate ligand, were examined. The results showed that the fluorescence intensity as well as the stability of CdSe QDs was incredibly increased after surface modification with the biopolymer-based ligand. To provide more evidence for the occurrence of surface modification, the prepared CdSe–salep-g-PAA QDs were characterized by thermo-gravimetric analysis (TG), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR).

Respiratory disease caused by the presence of bacteria in the atmosphere seriously threatens human health. Air pollution as harmful suspended particles, like haze, is conducive to bacterial spread and growth; it must be prevented to avoid harming the respiratory tract. Herein, filtration membranes possessing superior antibacterial activity are considered as an effective means to protect humans from atmospheres contaminated with bacteria. The aim of this study is to prepare an environmentally friendly and biodegradable multifunctional biopolymer composite nanofibrous membrane, which can be used as a candidate material for air filtration applications. Since traditional air filtration materials do not degrade in the natural environment, we synthesized a nanofibrous membrane composed of gelatin (GT) and silk fibroin (SF), in which antibacterial agent can anchor via electrostatic spinning. Also, both GT and SF can break down in the natural environment, which avoids secondary pollution of the atmosphere. Preliminary experiments show that GS nanofibrous membranes are excellent carriers of antibacterial agent for antibacterial applications. Several characterizations and testing measurements indicate that resultant nanofibrous membranes are effective against Gram-positive and Gram-negative bacteria. Moreover, a water vapor transmission rate test shows the excellent filtration performance of the materials.

The nondegradable nature and toxicity of organic liquid electrolytes reveal the design deficiency of lithium batteries in environmental protection. Biopolymers can be extracted from biomass under mild conditions, thus they are usually low cost and renewable. The unique characteristics of biopolymers such as water solubility, film-forming capability and adhesive property are of importance for lithium battery. The studies on the biopolymer materials for lithium batteries have been reviewed in this work. Although a lot of work on the biopolymer-based battery materials has been reported, it is still a challenge in the design of lithium battery with zero pollution and zero waste.

Biopolymer-based superabsorbent nanohydrogel consisting of N-isopropylacrylamide and itaconic acid (IA) was grafted on to starch backbone in an aqueous solution in the absence of the cross-linker agents. The copolymerization reaction occurred in the presence of ammonium persulfate (APS) as an initiator. The effect of N-isopropylacrylamide-to-IA ratio and different concentrations of initiator were investigated. The nanohydrogel composition was characterized by Fourier transform infrared spectroscopy (FTIR). The thermal stability was analyzed by Thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) studies were employed for determination of lower critical solution temperature in hydrogels. Dynamic light scattering analysis showed a narrow size distribution around 70–200nm for the synthesized nanohydrogels. The effects of pH on swelling behavior of the hydrogel were investigated. The obtained nanohydrogels, due to their pH and thermo dual sensitive properties, have the potential to be used in the drug delivery systems.

Objective: In the present study, we investigate the biological performance of a calcium phosphate ceramics (CPC) bone substitute combined with poly-hydroxybutyrate-co-hydroxyvalerate (PHBV). Materials and Methods: A particulate CPC [45% beta-tricalcium phosphate ($\beta$-TCP) and 55% of dihydrated dicalcium phosphate (DCPD)] was incorporated into a biodegradable copolymer PHBV. Two series of the composite, 1 and 2, with CPC–PHBV weight ratios of (40%–60% and 60%–40%), respectively, were prepared using chloroform for dissolving the polymer and a pressure molding process for shaping the composite samples. After particle size analysis, the two composites were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). In a second step, a 10mm bony segmental defect created in the tibias of 20 New Zealand White Rabbits was filled randomly with either composite 1 for group 1 or composite 2 for group 2. There were 10 animals in each group. Clinical, radiological and histological assessments were then carried out to evaluate the biological properties of developed CPC–PHBV composites. Results: For both variants of the developed CPC–PHBV biocomposite, there was evidence of osseous consolidation within three months. An in vivo investigation revealed the biological properties of the biocomposite, namely, biocompatibility, bioactivity, biodegradability and osteoconductivity. The morphological characteristics, granule size and chemical composition, were indeed found to be favorable for osseous cell development. This study likewise showed lower mortality for the variant with weight ratio (40%CPC–60%PHBV). Conclusion: An in vivo investigation revealed that the new biomaterial composed of CPC and PHBV exhibits manifest osteoconductivity and bioactivity with better degradation kinetics than the CPC. Moreover, the variant with 40%CPC/60%PHBV appeared more resistant to infection than the 60%CPC/40%PHBV which is an indicator of biocompatibility.

Food waste valorisation through the manufacture of value-added products has been studied for nearly a decade in many parts of the world. Despite the prevalence of recent studies, increasing food waste remains a problem. The transformation of food waste into useful products could be harnessed to tackle the coronavirus disease 2019 (COVID-19) pandemic. The current method of extracting nutrients from wasted food and facilitating their utilisation by microbes generates various platform chemicals and fuels, such as succinic acid, lactic acid, ethanol and hydrogen, and polymers, such as homopolymer polyhydroxybutyrate (PHB), copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and polylactic acid (PLA). A thorough review of scientific articles and reports on food waste-based biopolymer production and its possible applications in combating the COVID-19 pandemic is presented in this chapter. The key microbes used to produce either biopolymers or their building blocks are Haloferax mediterranei, Cupravidus necator, and Lactobacillus casei Shirota. The biopolymers and components derived from these microbes can be used to produce green, biodegradable, non-woven fabrics. The flexibility and biodegradability of these biopolymers also make them suitable for applications in the medical sector. Through the process of electrospinning, such fabrics can be used to produce biodegradable personal protective equipment (PPE) and, thereby, combat COVID-19 sustainably. The implementation of food waste valorisation helps not only in managing waste and reducing environmental pollution but also in generating resources, such as medical textiles, that can meet long-term sustainable development goals on a large scale.

Many of the functionally relevant collective vibrations of proteins and other biopolymers are expected to occur at terahertz frequencies. Precise absorption measurements combined with careful titration of biopolymers in water have allowed us to directly measure the terahertz absorption spectra associated with these motions, despite the strong background absorption of the solvent. We have also explored the circular dichroism spectroscopy of biomolecules over this same frequency range. Since circular dichroism requires the presence of net chirality in a molecule and chirality is present in nearly all biomaterial, it has the potential to capture the background free spectral features in biopolymers. To undertake these studies we have developed a broad band terahertz spectrometer suitable for both direct absorption and circular dichroism measurements of proteins in water between 0.75 – 3.72 THz. Direct terahertz absorption spectra of prototypical proteins bovine serum albumin (BSA) and hen egg white lysozyme have been documented and are described here. We have also successfully demonstrated the magnetic circular dichroism in semiconductors, and placed an upper bound on the terahertz circular dichroism signature of solvated BSA. In the terahertz frequency range, it appears that circular dichroism signatures are exceedingly small and detection remains a challenge.

Biopolymer conformations are investigated using the white noise path integral approach. Analytical evaluation of the path integral exhibits various features such as chirality, overwinding of biopolymers when stretched, and the helix-turn-helix structure.