bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Characterization of Activated Carbon from Waste Rubber Tires: A Comparison between Physical and Chemical Activation
Authors: Joseph Collin Glen , Krishniah Duduku , Taufiq-Yap Yun Hin , Massuanna Masnah , William Jessica
Published: June 2015

Abstract. Waste tires, which are an abundant waste product of the automobile industry, were used to prepare activated carbon by means of physical and chemical activation. A two-stage process was used, with a semi-carbonization stage as the first stage, followed by an activation stage as the second stage.All experiments were conducted in a laboratory-scale muffle furnace under static conditions in a self-generated atmosphere. During this process, the effects of the parametric variables of semi-carbonization time (for the physical activation process), activation time and temperature and impregnation ratios (for the chemical activation process) on the percentage yield were studied and compared. Varying these parametric variables yielded interesting results, which in turn affected the adsorption process of 2,4-DCP, which was the simulated pollutant in aqueous form. The optimized percentage yields of activated carbon that were obtained were 41.55% and 44.88% ofthe physical and chemical activation treatment processes respectively.Keywords: Physical activation, chemical activation, waste rubber tires, 2,4-dichlorophenol, activated carbon.
Solid State Sintering and Microstructural Evolution on Wide Frequency Range Dielectric Responses of Mechanically Activated CaTiO3 Ceramics
Authors: Yick Jeng Wong , Hassan Jumiah , Hashim Mansor
Published: June 2015

The CaTiO3 samples were prepared by high-energy ball milling process followed by sintering process from 1040 to 1200°C. X-ray diffraction (XRD), microstructural analysis, and dielectric properties over a wide range of frequency varying from 0.01 Hz to 1 GHz at room temperature were investigated. The formation of a single phase CaTiO3 with orthorhombic structure was achieved at 1120°C and above. From a morphological point of view, sintering temperature promoted grain growth. Dielectric properties in the frequency range 0.01 Hz - 1 MHz revealed a relaxation-type process. Interfacial phenomena were the possible physical mechanisms that gave rise to these relaxation-type plots. Extending the frequencies above ~1 MHz yielded a frequency-independent characteristic of dielectric constant (ε'). These turned out to the relatively small dielectric loss (tan δ) values. The origin of the dielectric responses in the frequency range 1 MHz - 1 GHz was attributed to the domination of dipolar polarization. The grain size effect in sintered CaTiO3 samples was prominent, notably in dielectric responses above ~1 MHz. Increase in sintering temperature remarkably led to an enhancement in dielectric constant values and reduction in dielectric loss values. Therefore, a significant correlation existed between microstructural features and dielectric properties.
FTIR and UV-Vis-NIR Spectral Studies of Borotellurite Glass
Authors: Noranizah A. , Azman K. , Azhan H. , Nurbaisyatul E.S. , Abdullah Mardhiah
Published: June 2015

A glass system based on composition of 80TeO2-(10-x) B2O3 -10PbO-xNd2O3, where 0.0mol% ≤ x ≥ 2.5mol% was successfully prepared by melt-quenching method. The structural and optical behavior of the Nd3+ doped borotellurite glasses are well studied by mean of their FTIR, XRD as well as UV-Vis -NIR spectroscopy. The XRD pattern obtained confirms the amorphous nature of the glass. Meanwhile, the infra-red absorption spectra of glass samples obtained are recorded using an FTIR spectrometer in the wave number ranging from 400 to 4000 cm-1. The bands observed were attributed to the different modes of vibrations of Te-O band. From the absorption spectral measurements, the value of optical band gap (Eopt) and the Urbach energy (ΔE) values were calculated with the results were then been discussed nor reported. Quantitative justification of these absorption bands shows that the values of the experimental wave number for most absorption bands are in agreement with the theoretical ones. Optical absorption spectra show that the absorption edge has a tail extending towards lower energies. In general, an increment or a decrement in Urbach’s energy can be considered to be due to a deformation of glass network.
Optical Absorption in Erbium Doped Phosphate Glass Embedded with Cobalt Nanoparticles
Authors: Adnan Nur Aina Mardia , Sahar M.R. , Rohani Md Supar
Published: June 2015

A series of Er3+ doped phosphate glass embedded with CoO nanoparticles (NPs) were synthesized from high purity raw materials by melt quenching and the influence of CoO NPs on the optical absorption were investigated. The glass has been characterized by means of TEM and UV-Vis Spectroscopy. Investigation on TEM image displays the existence of NPs where its distribution is Gaussian with the average size of 5.18 nm. Five absorbtion bands of erbium were evidenced in the UV-Vis measurement. For UV-Vis absorption peaks, the optical band gap energy, Eopt has been estimated in the range of 3.22 3.89 eV, increasing with the increasing of CoO content. Meanwhile, the urbach energy is found to be in the range of 0.98 0.74 eV decreasing with the CoO content. All the results will be discussed with respect to CoO content.
Optical Properties of [(TeO2)0.7 (B2O3)0.3]1-x (Bi2O3)x Glass System
Authors: Amat Azuraida , Halimah Mohamed Kamari , Ahmad Nurazlin
Published: June 2015

Ternary tellurite based glasses [(TeO2)0.7 (B2O3)0.3]1-x (Bi2O3)x was prepared by melt quenching method with suitable melting and quenching temperature. A series of glasses were selected from 0.05 to 0.30 mol % and its glass-forming region was determined. The density, molar volume and refractive index increase when bismuth ions Bi3+ increase, this is due to the increased polarization of the ions Bi3+ and the enhanced formation of non-bridging oxygen (NBO). The values of optical band gap, Eopt decreases when Bi2O3 content increases. Urbach energy for each composition was also calculated and was found to be dependent on the glass composition.
Optical Properties of Eu3+-Doped Lithium Tellurite Glass
Authors: Jupri Siti Aishah , Sahar M.R. , Ghoshal Sib Krishna
Published: June 2015

Improving the optical response of tellurite glasses via controlled doping of rare earth is the key issue in lasing materials. A series of glasses of the form (74.4-x)TeO2(4.3)Li2O(21.3)LiCl (x)Eu2O3 with 0.0 x 2.0 mol% are synthesized using melt-quenching technique and the influence of Eu2O3 content on their UV-Vis absorption properties are examined. The absorption spectra reveal two prominent peaks centered at 464 and 533 nm corresponding to 7F05D2 and 7F15D1 transitions, respectively. The optical band gap energy for direct and indirect transitions are found to be in the range of 3.294-3.173 eV and 3.067-2.971 eV, respectively. The decrease optical band gap energy with the increase of Eu2O3 contents is attributed to the generation of non-bridging oxygen (NBOs). The increase in Urbach energy from 0.226-0.308 eV with the increase of Eu2O3 contents signifies the variation in disorder and compactness of the glass network.
Samarium Concentration and Optical Correlation of Tellurite Glass
Authors: Ghoshal Sib Krishna , Zainuddin Azmirawahida , Arifin Ramli , Sahar M.R. , Rohani Md Supar , Hamzah Khaidzir
Published: June 2015

Modifying the structural and optical properties of inorganic glasses via controlled doping of various rare earth ions by inhibiting the quenching effect is a challenging task. We report the influence of samarium (Sm3+) ions concentration on enhanced optical properties of tellurite glass. A series of glasses with composition (0.80-x)TeO2 + 0.10Li2O + 0.10 Na2O + xSm2O3, where 0.0<x <0.03 mol% are prepared using melt quenching method and optical characterizations are performed. The XRD spectra confirm the amorphous nature of the glass. The Urbach energy decreases and the optical gap for both direcet and indirect transitions increases with the increse of samerium contents. The UV-Vis spectra comprised of eight absorption bands and PL spectra reveal four prominet peaks corresponding to various transitions from the ground state to the excited states of Sm3+ ion. The optical response shows significant enhancement with increasing concentration of samerium ions. Our detail experimental analyses may be useful for the development of tellurite glass based photonic devices. Keywords: Tellurite Glass, Sm3+ ions, Urbach Energy, Direct and Indirect Transition.
Samarium Ions Concentration Dependent Optical Enhancement in Phosphate Glass
Authors: Arifin Ramli , San Lee Pei , Sahar M.R. , Ghoshal Sib Krishna , Hamzah Khaidzir
Published: June 2015

Glasses activated rare earth (RE) ions are demanding for photonic devices. Optimization of rare earth dopants, chemical composition of glass former and modifier decides spectra features. We synthesize a series of glass having composition (50-x)P2O5 - 30Li2O - 20Na2O - (x)Sm2O3, where x = 0 to 2.0 mol% (optimizing RE concentration) via melt-quenching technique. The effects of Sm2O3 concentration on significant enhancement of absorption and luminescence are scrutinized. The UV-Vis-NIR absorption spectra reveal ten band and the emission spectra exhibit four peaks specific to the dopant. The results suggest that samarium doped phosphate glasses are potential for laser and other applications.
First Principles Study on Structural and Electronic Properties of LiFeSO4F Cathode Material for Lithium Ion Batteries
Authors: Badrudin Fadhlul Wafi , Rasiman Mohd Sazwan Affendi , Taib M.F.M. , Hussin Nur Hafiz , Hassan Oskar Hasdinor , Yahya Muhd Zu Azhan
Published: June 2015

One of the fluorosulphate family cathode materials viz. LiFeSO4F is investigated by means of first principle calculation. The effects of lithium extraction on the electronic and structural properties in lithiated and delithiated phases were studied. It can be noted that the iono-covalency particularly in the M-X bond (M=transition metal, X= ligand) has played an important role to determine the redox potential instead of electronegativity. Therefore, the bond length (BL) and bond order (BO) are calculated to depict the ionic and covalent characters of the materials.
Modelling and Simulation Approach for Organic Thin-Film Transistors Using MATLAB Simulation
Authors: Shuib Umar Faruk , Mohamad Khairul Anuar , Alias Afishah , Tabet Tamer A. , Gosh Bablu K. , Saad Ismail
Published: June 2015

As organic transistors are preparing to make improvements towards flexible and low cost electronics applications, the analytical models and simulation methods were demanded to predict the optimized performance and circuit design. In this paper, we investigated the analytical model of an organic transistor device and simulate the output and transfer characteristics of the device using MATLAB tools for different channel length (L) of the organic transistor. In the simulation, the Pool-Frenkel mobility model was used to represent the conductive channel of organic transistor. The different channel length has been simulated with the value of 50 μm, 10 μm and 5 μm. This research paper analyses the performance of organic thin film transistor (TFT) for top contact bottom gate device. From the simulation, drain current of organic transistor was increased as the channel length decreased. Other extraction value such sub-threshold and current on/off ratio is 0.41 V and 21.1 respectively. Thus, the simulation provides significant extraction of information about the behaviour of the organic thin film transistor.
Thermoluminescence Characteristics of Aluminium Oxide Doped Carbon Exposed to Cobalt-60 Gamma Radiation
Authors: Saharin Nurul Syazlin , Wagiran Husin , Tamuri Abdul Rahman
Published: June 2015

This study concerns on the thermoluminescence (TL) characteristics of carbon doped aluminum oxide (Al2O3:C) as ionizing radiation dosimeter. The thermoluminescence response, linearity and sensitivity subjected to Co-60 gamma irradiation were investigated. Carbon doped (0.2 mol %) aluminum oxide samples in form of powder were irradiated to 1.25 MeV Co-60 gamma ray with doses ranging from 1 Gy to 50 Gy. Irradiations were performed by using Co-60 gamma ray model 220 Excel with the source activity, A = 2.310925534 kGy h1 at Universiti Kebangsaan Malaysia. The glow curves were analysed to determine various characterizations of the TLDs. It is shown that the glow curve of the sample contains a single peak at about 180°C with broad peak appears at the right of the spectrum. It is also shown that the TL intensity has linear relationship with delivered dose and the average TL sensitivity was calculated as 3.30 nC mg-1 Gy-1.
Structural and Electronic Properties of Hydrogen-Passivated Silicon Quantum Dots: Density Functional Calculations
Authors: Anas Muhammad Mus-'Ab Anas Mohd , Othman Ahmad Puaad , Gopir Geri
Published: June 2015

Density functional theory (DFT) by numerical basis-set calculations of silicon quantum dots (Si-QDs) passivated by hydrogen, ranging in size up to 1.9 nm are presented. These DFT computation results are used to examine and deduce the properties of 14 spherical Si-QDs including its density of state (DOS), and energy gap from the HOMO-LUMO results. The atomistic model of each silicon QDs was constructed by repeating crystal unit cell of face-centered cubic (FCC) structure, then the QDs surface was passivated by hydrogen atoms. The model was relaxed and optimized using Quasi-Newton method for each size of Si-QDs to get an ideal structure. Exchange-correlation potential (Vxc) of electrons were approximated in this system using the Local Density Approximation (LDA) functional and Perdew-Zunger (PZ) functional. Finally, all results were compared with previous experimental data and other similar theoretical approaches, and these results augured well
Effects of Gamma Ray Irradiation on High Temperature Superconductors YBCO with Nanoparticles Fe3O4 Addition
Authors: Wei Kong , Abd-Ghani Siti Nurdalila , Kah Wye Hon , Ing Kong , Abd-Shukor Roslan
Published: June 2015

The effects of gamma ray irradiation on high temperature superconductors YBa2Cu3O7-δ with nano particles Fe3O4 (20-30 nm) addition were investigated. YBCO superconductor powders were prepared by using high purity oxide powders via solid state reaction method. 0.01 – 0.05 wt.% of nano particles were added into YBCO. Samples were irradiated with 100 kGy gamma ray. The critical temperature (Tc) and transport critical current density (Jc) were determined by using four point probe method. The lattice parameters and morphology of the samples were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The results before and after gamma ray irradiation were compared. All of the samples showed increased Tc-zero after 100 kGy gamma ray irradiation. However, the Jcwas degraded after gamma ray irradiation. There is no significant variation found in the XRD patterns. The porosity of the samples was increased by the gamma ray irradiation. It can be concluded that gamma ray irradiation has enhanced the superconducting properties but degraded the transport properties.
Porosity Effect on Superconducting Properties of YBa2Cu3Oδ and YCaBa4Cu6Oδ
Authors: Senawi S.A. , Azhan H. , Zainal W.N.F.W. , Razali W.A.W. , Nazree A. , Azman K. , Ridzwan H.J.M. , Norazidah A.W. , Hidayah H.N. , Hawa J.S.
Published: June 2015

This paper reports on the properties of YBa2Cu3Od (Y123) and YCaBa4Cu6Oy (Y146) with non-porous and porous structures. The relationship between calcium doping and critical temperature (Tc) was studied to determine the optimal superconducting properties. A series of heating and grinding via solid state reaction method was used to fabricate the ceramic materials. The electrical properties were investigated via critical temperature, TC and critical current density, JC using the resistivity measurement system (RMS). Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) were used to analyze the material morphology and structure, respectively. The orthorhombicity increased due to less porosity of the samples. The calcium presence partially replaced larger Ba(II) site and degraded orthorhombicity. The highest critical current density (JC) was porous YCaBa2Cu3Oy which was 2.32 A/cm2 compared to 0.75 A/cm2 for porous YCaBa4Cu6Oy at 60 K. The critical temperature for porous structure was less than non porous structure for Ca doped Y146 system which was 69.9 K and 67.9 K. SEM micrograph unveiled that the Jc was induced significantly by continuity of grain formation via grain size. Pores homogenized the grains surface quality and connectivity due to strain release thus increasing effective cross section of the sample for current density (Jc) over the vast areas.
Morphological and Optical Properties of Different Mg Percentage of ZnO/Mg Thin Films Prepared by Sol-Gel Spin-Coating and Immersion Method
Authors: Aziz Aadila , Mohamed R. , Abdullah Nurul Afaah , Asib N.A.M. , Rusop M. , Khusaimi Zuraida
Published: June 2015

We have successfully demonstrated ZnO/Mg thin films on Mg seeded-template by using sol-gel spin-coating and immersion technique. By increasing weight percentage of Mg, zinc particles become agglomerate and displayed flower formed as displayed in FESEM characterization. It was observed that the morphology of the zinc particles on Mg seeded-template change from inconsistently distribution for 1 and 3 % into cluster flower-like of zinc particles for 5 and 7 % weight percentage of Mg. The optical properties of the ZnO/Mg thin films were examined by UV-Vis spectroscopy and the Tauc plot methods was used to estimate the optical band gap. The study reveals that, 7 % weight percentage of Mg was recorded as the highest transmittance which is more than 60 % in visible wavelength compared to others. With the rise weight percentage of Mg, the transmittance of the thin films was increased except for 5 %. This gradually downgraded to below 60 % of transmission most probably due to the grain size that becomes bigger. The optical band gap can be tuned by using different Mg percentage to the ZnO/Mg thin films.
Effect of Flexible Substrates on the Structural and Optical Properties of ZnO Films Deposited by Sputtering Method
Authors: Mui Li Lam , Mani Azmizam Manie , Salleh Saafie , Alias Afishah
Published: June 2015

Zinc Oxide (ZnO) has attracted much attention because of its high optical transmittance approximately ~80 % with a wide band gap of (3.3 eV at 300 K) and a relatively low cost material. ZnO thin films were deposited on plastic substrate using RF powered magnetron sputtering method. The target used is ZnO disk with 99.99 % purity. The sputtering processes are carried out with argon gas that flow from 10-15 sccm. Argon is used to sputter the ZnO target because the ability of argon that can remove ZnO layer effectively by sputtering with argon plasma bombardment. The deposited ZnO thin films are characterized using X-Ray Diffraction (XRD) and UV-Vis Spectrometer. The analysis of X-ray diffraction show that good crystalline quality occurs at nominal thickness of 400 nm. The optical studies showed that all the thin films have high average transmittance of approximately 80 % and the estimated value of optical band gap is within 3.1 eV-3.3 eV range.
High Sensitivity Optical POF Sensor for Detecting Low Ethanol Concentration in Water
Authors: Saad Hasnida , Ali Mohd Tarmizi , Abd Rahman M. Kamil
Published: June 2015

This paper presents the preparation of intensity-based plastic optical fiber (POF) sensor and its characteristics in the detection of ethanol concentration in water. Response of the sensor probes were analyzed for 0.02 to 1.00% v/v ethanol concentrations. The POF sensors have high sensitivity of detecting very low concentration of ethanol with 0.02% v/v ethanol in water. The reponsitivity of the polished U-shape sensor was 285 per percent of ethanol concentration. There are three distinct shapes of POF sensor probes that were developed: tapered U-shape; polished U-shape; and polished coil-shape. The POF were shaped into sensor probes by indirectly heating the POF at 80°C for several minutes and rapidly cooled in retaining the shapes. Tapering of POF was done using tensile tester with thermostatic chamber and other sensor probes were polished using fine abrasive for enhancing their sensitivities. The performance of the sensors was tested using He-Ne laser as the light source and the output spectra were analyzed using Ocean Optics spectrometer. The light intensity from the three sensors showed nonlinear response to ethanol concentrations from 0.02% - 1.00%. The POF sensor is more sensitive to 0.02%-0.10% ethanol concentration compared to 0.20% to 1.00%. At lower concentration, water tends to gradually absorb into POF polymer network and causes the fiber to swell more due to volume expansion. Higher ethanol concentration causes the swelling of the fiber to be eventually reduced and reached its detection limit.
Modular Surface Plasmon Resonance (SPR) Biosensor Based on Wavelength Modulation
Authors: Wan Ahamad Wan Mohd Azwady , Kamarun Dzaraini , Abd Rahman Mohd Kamil , Kamarudin Mohamad Shukri
Published: June 2015

This paper deals with a new invention of modular surface plasmon resonance (SPR) biosensor device based on wavelength modulation wherein the angle of incidence of the light source is fixed and the shift in wavelength at resonance is monitored. This device is capable of detecting biomolecular binding interactions of different species such as protein and viruses based on changes in the refractive index of the dielectric environment. White light source mounted with a polarizer is used to excite plasmons on the sensor surface which is thin gold film of ~21 μm thickness coated on BK-7 glass. A variable angle reflection sampling system (VARSS) device from Ocean Optics was modified to incorporate the transducer components and sampling accessories. SPR was observed at the angle of incidence of the light fixed at 29°. At this point, plasmon evanescent wave coupling occurred with highest loss of light intensity. HR4000-UV-NIR photodetector is used to observe the change in resonance wavelength when the dielectric environment around the surface of the transducer was changed. Two liquid samples; water (n=1.33) and ethylene glycol (n=1.43) was introduced onto the sensor surface to model changes in wavelength resonance with difference in refractive index of dielectric environment. It was observed that the resonance wavelength for water and ethylene glycol are 590.10 nm and 594.23 nm respectively when reference to air (n=1.00) indicating the workability of the device.
Simulation of Malaysian Small Angle Neutron Scattering Using Monte Carlo
Authors: Ahmad Firdaus Zainal Abedin , Noordin Ibrahim , Noriza Ahmad Zabidi
Published: June 2015

Small angle neutron scattering (SANS) virtual experiment using silicon dioxide (SiO2) target has been performed. The results showed neutron flux with 1 million neutrons per count from the source in the range of 1.02x108n/s/cm2 and wavelength 5 Å. The neutron intensity was found to decrease after scattered at 1.75x105n/s/cm2 by nuclei in SiO2. We are able to construct a virtual experiment layout of Malaysian Small Angle Neutron Scattering (mySANS) facility using Monte Carlo simulation of neutron instruments (McStas).
Nanoglass: Present Challenges and Future Promises
Authors: Sahar Md Rahim , Ghoshal S.K.
Published: June 2015

This presentation provides a panoramic overview of the recent progress in nanoglass plasmonics, challenges, excitement, applied interests and the future promises. A glimpse of our gamut research activities with some significant results is highlighted and facilely analyzed. The term'nanoglass'refers to the science and technology dealing with the manipulation of the physical properties of rare earth doped inorganic glasses by embedding metallic nanoparticles (NPs) or nanoclusters. On the other hand, the word'plasmonics'refer to the coherent coupling of photons to free electron oscillations (called plasmon) at the interface between a conductor and a dielectric. Nanoglass plasmonis being an emerging concept in advanced optical material of nanophotonics has given photonics the ability to exploit the optical response at nanoscale and opened up a new avenue in metal-based glass optics. There is a vast array of nanoglass plasmonic concepts yet to be explored, with applications spanning solar cells, (bio) sensing, communications, lasers, solid-state lighting, waveguides, imaging, optical data transfer, display and even bio-medicine. Localized surface plasmon resonance (LSPR) can enhance the optical response of nanoglass by orders of magnitude as observed. The luminescence enhancement and surface enhanced Raman scattering (SERS) are new paradigm of research. A thumbnail sketch of the fundamental aspects of SPR, LSPR, SERS and photonic applications of various rare earth doped/co-doped binary glasses containing metallic NPs are presented. The recent development in nanoglass in the context of Malaysia at the outset of international scenario is projected.
Particle Size Distribution of Cerate-Zirconate Powder Prepared via Three Different Methods
Authors: Ibarahim Najwa Adni , Osman Nafisah , Mohd Ishak Mohd Azlan
Published: June 2015

Ceramics powder of BaCe0.54Zr0.36Y0.1O2.95 (BCZY) was synthesized using three different methods namely sol-gel (SG), supercritical fluid (SC) and sol-gel assisted supercritical fluids (SGSF).The respective prepared samples were denoted as S1, S2 and S3. The calcined powder (T= 1100 °C) was analyzed using particle size analyzer (PSA), Pcynometer and scanning electron microscope (SEM). PSA showed a single particle size distribution (PSD) for all samples except for S3 which exhibits bimodial particle distribution. PSD of the samples were in the range of 295-396 nm for the primary powder and 712-820 nm for secondary powder. High relative powder density for S1, S2, S3 were recorded at 95 %, 93 % and 99 %, respectively. Morphology of the calcined powders by SEM micrograph revealed that S1 is in spherical shape, S2 is in cubic structure and S3 showed a mixture of spherical and rod-like structure. It was found that SG and SC produce a single shape of powder with lower density compared with SGSF.
Diffusion of Oxygen in some Binary Ti-Based Alloys Used as Biomaterials
Authors: Grandini Carlos Roberto
Published: June 2015

Ti and its alloys are widely used as biomaterials. Their main properties are excellent corrosion resistance, relatively low elastic modulus, high specific strength, and good biocompatibility. The development of new Ti alloys with properties favorable for use in the human body is desired. To this end, Ti alloys with Mo, Nb, Zr, and Ta are being developed, because these elements do not cause cytotoxicity. The presence of interstitial elements (such as oxygen and nitrogen) induces strong changes in the elastic properties of the material, which leads to hardening or softening of the alloy. By means of anelastic spectroscopy, we are able to obtain information on the diffusion of these interstitial elements present in the crystalline lattice. In this paper, the effect of oxygen on the anelastic properties of some binary Ti-based alloys was analyzed with anelastic spectroscopy. The diffusion coefficients, pre-exponential factors, and activation energies were calculated for oxygen and nitrogen in these alloys.
The use of chemotherapeutics for the treatment of keloid scars
Authors: Jones Christopher David , Guiot Luke , Samy Mike , Gorman Mark , Tehrani Hamid
Published: June 2015

Keloid scars are pathological scars, which develop as a result of exaggerated dermal tissue proliferation following cutaneous injury and often cause physical, psychological and cosmetic problems. Various theories regarding keloidogenesis exist, however the precise pathophysiological events remain unclear. Many different treatment modalities have been implicated in their management, but currently there is no entirely satisfactory method for treating all keloid lesions. We review a number of different chemotherapeutic agents which have been proposed for the treatment of keloid and hypertrophic scars while giving insight into some of the novel chemotherapeutic drugs which are currently being investigated. Non-randomized trials evaluating the influence of different chemotherapeutic agents, such as 5-fluorouracil (5-FU); mitomycin C; bleomycin and steroid injection, either alone or in combination with other chemotherapeutic agents or alternative treatment modalities, for the treatment of keloids were identified using a predefined PubMed search strategy. Twenty seven papers were identified. Scar improvement ≥50% was found in the majority of cases treated with 5-FU, with similar results found for mitomycin C, bleomycin and steroid injection. Combined intralesional 5-FU and steroid injection produced statistically significant improvements when compared to monotherapy. Monotherapy recurrence rates ranged from 0-47% for 5-FU, 0-15% for bleomycin and 0-50% for steroid injection. However, combined therapy in the form of surgical excision and adjuvant 5-FU or steroid injections demonstrated lower recurrence rates; 19% and 6% respectively. Currently, most of the literature supports the use of combination therapy (usually surgery and adjuvant chemotherapy) as the mainstay treatment of keloids, however further investigation is necessary to determine success rates over longer time frames. Furthermore, there is the potential for novel therapies, but further investigation is required to elucidate their true efficacy.
Predicting geographic variations of indoor radon potential across southwestern Ontario using geoscience data
Authors: Ford K L , Harvey B J A , Whyte J , Chen J
Published: June 2015

Estimating indoor radon variations using regional geoscience data for southwestern Ontario generally shows a progressive and clearly positive association. Uranium concentrations measured by airborne gamma ray spectrometry show the strongest positive association
with elevated indoor radon concentrations followed by estimated radon potential derived from regional bedrock geology. Comparisons between relative permeability derived from regional surficial geology and indoor radon concentrations were inconclusive. Closer examination suggests that this may not
always be the case and that permeability is still an important factor at local scales.
The positive associations between selected regional geoscience datasets, in particular uranium concentrations measured by airborne gamma ray spectrometry and elevated indoor radon concentrations, illustrates their use as effective predictive tools for the identification of areas with increased
potential for overexposure to indoor radon, including areas without residential development. These positive associations can be used to support targeted or follow-up radon studies and for future land-use planning decisions.
First molecular isolation of Mycoplasma ovis from small ruminants in North Africa
Authors: Rjeibi Mohamed R. , Darghouth Mohamed A. , Omri Houda , Souidi Khemaïs , Rekik Mourad , Gharbi Mohamed
Published: June 2015

Eperythrozoonosis is a small ruminant disease caused by the bacterium Mycoplasma ovis (formerly known as Eperythrozoon ovis). Whilst acute infection in sheep may result in an anaemia and ill thrift syndrome, most animals do not develop clinical signs. Molecular methods were used to compare and evaluate the prevalence of infection with M. ovis in sheep and goats in Tunisia. A total of 739 whole blood samples from 573 sheep and 166 goats were tested for the M. ovis 16S rRNA gene using PCR. The overall prevalence was 6.28% ± 0.019 (36/573). Only sheep were infected with M. ovis (p < 0.001), and the prevalence was significantly higher in central Tunisia (29.2%) compared with other regions (p < 0.05). The prevalence revealed significant differences according to breed and bioclimatic zones (p < 0.001). Furthermore, the prevalence in young sheep (35/330; 10.6%) was higher than in adults (1/243; 0.41%) (p < 0.001). Only sheep of the Barbarine breed were infected, with a prevalence of 11.8% (p < 0.001). This is the first molecular study and genetic characterisation of M. ovis in North African sheep breeds.
A large and ubiquitous source of atmospheric formic acid
Authors: Millet D. B. , Baasandorj M. , Farmer D. K. , Thornton J. A. , Baumann K. , Brophy P. , Chaliyakunnel S. , de Gouw J. A. , Graus M. , Hu L. , Koss A. , Lee B. H. , Lopez-Hilfiker F. D. , Neuman J. A. , Paulot F. , Peischl J. , Pollack I. B. , Ryerson T. B. , Warneke C. , Williams B. J. , Xu J.
Published: June 2015

Abstract. Formic acid (HCOOH) is one of the most abundant acids in the atmosphere, with an important influence on precipitation chemistry and acidity. Here we employ a chemical transport model (GEOS-Chem CTM) to interpret recent airborne and ground-based measurements over the US Southeast in terms of the constraints they provide on HCOOH sources and sinks. Summertime boundary layer concentrations average several parts-per-billion, 2–3× larger than can be explained based on known production and loss pathways. This indicates one or more large missing HCOOH sources, and suggests either a key gap in current understanding of hydrocarbon oxidation or a large, unidentified, direct flux of HCOOH. Model-measurement comparisons implicate biogenic sources (e.g., isoprene oxidation) as the predominant HCOOH source. Resolving the unexplained boundary layer concentrations based (i) solely on isoprene oxidation would require a 3× increase in the model HCOOH yield, or (ii) solely on direct HCOOH emissions would require approximately a 25× increase in its biogenic flux. However, neither of these can explain the high HCOOH amounts seen in anthropogenic air masses and in the free troposphere. The overall indication is of a large biogenic source combined with ubiquitous chemical production of HCOOH across a range of precursors. Laboratory work is needed to better quantify the rates and mechanisms of carboxylic acid production from isoprene and other prevalent organics. Stabilized Criegee intermediates (SCIs) provide a large model source of HCOOH, while acetaldehyde tautomerization accounts for ~ 15% of the simulated global burden. Because carboxylic acids also react with SCIs and catalyze the reverse tautomerization reaction, HCOOH buffers against its own production by both of these pathways. Based on recent laboratory results, reaction between CH3O2 and OH could provide a major source of atmospheric HCOOH; however, including this chemistry degrades the model simulation of CH3OOH and NOx : CH3OOH. Developing better constraints on SCI and RO2 + OH chemistry is a high priority for future work. The model neither captures the large diurnal amplitude in HCOOH seen in surface air, nor its inverted vertical gradient at night. This implies a substantial bias in our current representation of deposition as modulated by boundary layer dynamics, and may indicate an HCOOH sink underestimate and thus an even larger missing source. A more robust treatment of surface deposition is a key need for improving simulations of HCOOH and related trace gases, and our understanding of their budgets.
Ideas and perspectives: use of tree-ring width as an indicator of tree growth
Authors: Hember R. A. , Kurz W. A. , Metsaranta J. M.
Published: June 2015

Abstract. By taking core samples, dendroecological studies can reconstruct radial growth over the lifespan of a tree, providing a valuable way to estimate the sensitivity of tree productivity to environmental change. With increasing prevalence of such studies in global change science, it is worth cautioning that the incremental growth rate of a sub-dimension of a tree organ, such as annual ring width (w), does not respond to extrinsic perturbations with the same relative magnitude as the primary production of that organ. For example, if an extrinsic force causes a two-fold increase in the absolute growth rate of stemwood biomass (AGR), it should only theoretically translate into a 1.3-fold increase in w, or a 1.7-fold increase in basal area increment (BAI), when a 2:1 ratio in resource allocation to lateral and apical meristems is assumed. Expressing the magnitude of a response in relative terms does not, therefore, provide a valid means of comparing estimates of relative growth derived from measurement of different dimensional traits of the tree. From our perspective, enough conformity to facilitate comparison of environmental sensitivity across studies of tree growth is warranted so we emphasize the benefit of dimension analysis to transform measurements of w and BAI into the AGR. Although conversion to AGR introduces an error from the use of allometric equations, the approach is widely accepted in mainstream ecology and global change science at least partially because it avoids discrepancies in response magnitude owing to differences in dimension. Studies of organ elongation have historically provided invaluable information, yet it must be recognized that they systematically underestimate the response magnitude of primary production, and confound comparisons of growth sensitivity between many dendroecological studies that focus on w and studies of primary production.
libcloudph++ 1.0: a single-moment bulk, double-moment bulk, and particle-based warm-rain microphysics library in C++
Authors: Arabas S. , Jaruga A. , Pawlowska H. , Grabowski W. W.
Published: June 2015

Abstract. This paper introduces a library of algorithms for representing cloud microphysics in numerical models. The library is written in C++, hence the name libcloudph++. In the current release, the library covers three warm-rain schemes: the single- and double-moment bulk schemes, and the particle-based scheme with Monte Carlo coalescence. The three schemes are intended for modelling frameworks of different dimensionalities and complexities ranging from parcel models to multi-dimensional cloud-resolving (e.g. large-eddy) simulations. A two-dimensional (2-D) prescribed-flow framework is used in the paper to illustrate the library features. The libcloudph++ and all its mandatory dependencies are free and open-source software. The Boost.units library is used for zero-overhead dimensional analysis of the code at compile time. The particle-based scheme is implemented using the Thrust library that allows one to leverage the power of graphics processing units (GPU), retaining the possibility of compiling the unchanged code for execution on single or multiple standard processors (CPUs). The paper includes a complete description of the programming interface (API) of the library and a performance analysis including comparison of GPU and CPU set-ups.
Glycosylphosphatidylinositol-anchored proteins as chaperones and co-receptors for FERONIA receptor kinase signaling in Arabidopsis
Authors: Li Chao , Yeh Fang-Ling , Cheung Alice Y , Duan Qiaohong , Kita Daniel , Liu Ming-Che , Maman Jacob , Luu Emily J , Wu Brendan W , Gates Laura , Jalal Methun , Kwong Amy , Carpenter Hunter , Wu Hen-Ming
Published: June 2015

The Arabidopsis receptor kinase FERONIA (FER) is a multifunctional regulator for plant growth and reproduction. Here we report that the female gametophyte-expressed glycosylphosphatidylinositol-anchored protein (GPI-AP) LORELEI and the seedling-expressed LRE-like GPI-AP1 (LLG1) bind to the extracellular juxtamembrane region of FER and show that this interaction is pivotal for FER function. LLG1 interacts with FER in the endoplasmic reticulum and on the cell surface, and loss of LLG1 function induces cytoplasmic retention of FER, consistent with transport of FER from the endoplasmic reticulum to the plasma membrane in a complex with LLG1. We further demonstrate that LLG1 is a component of the FER-regulated RHO GTPase signaling complex and that fer and llg1 mutants display indistinguishable growth, developmental and signaling phenotypes, analogous to how lre and fer share similar reproductive defects. Together our results support LLG1/LRE acting as a chaperone and co-receptor for FER and elucidate a mechanism by which GPI-APs enable the signaling capacity of a cell surface receptor.
Access to Care and Outcomes With the Affordable Care Act for Persons With Criminal Legal Involvement
Authors: Jolin James René , Barsky Benjamin A. , Wade Carrie G. , Rosenthal Meredith B.
Published: August 2024

Importance

By expanding health insurance to millions of people in the US, the Patient Protection and Affordable Care Act (ACA) may have important health, economic, and social welfare implications for people with criminal legal involvement—a population with disproportionately high morbidity and mortality rates.

Objective

To scope the literature for studies assessing the association of any provision of the ACA with 5 types of outcomes, including insurance coverage rates, access to care, health outcomes, costs of care, and social welfare outcomes among people with criminal legal involvement.

Evidence Review

The literature search included results from PubMed, CINAHL Complete, APA Psycinfo, Embase, Social Science Database, and Web of Science and was conducted to include articles from January 1, 2014, through December 31, 2023. Only original empirical studies were included, but there were no restrictions on study design.

Findings

Of the 3538 studies initially identified for potential inclusion, the final sample included 19 studies. These 19 studies differed substantially in their definition of criminal legal involvement and units of analysis. The studies also varied with respect to study design, but difference-in-differences methods were used in 10 of the included studies. With respect to outcomes, 100 unique outcomes were identified across the 19 studies, with at least 1 in all 5 outcome categories determined prior to the literature search. Health insurance coverage and access to care were the most frequently studied outcomes. Results for the other 3 outcome categories were mixed, potentially due to heterogeneous definitions of populations, interventions, and outcomes and to limitations in the availability of individual-level datasets that link incarceration data with health-related data.

Conclusions and Relevance

In this scoping review, the ACA was associated with an increase in insurance coverage and a decrease in recidivism rates among people with criminal legal involvement. Future research and data collection are needed to understand more fully health and nonhealth outcomes among people with criminal legal involvement related to the ACA and other health insurance policies—as well as the mechanisms underlying these relationships.
Neighborhood-Level Disparities in Hypertension Prevalence and Treatment Among Middle-Aged Adults
Authors: Blazel Madeleine M. , Perzynski Adam T. , Gunsalus Paul R. , Mourany Lyla , Gunzler Douglas D. , Jones Robert W. , Pfoh Elizabeth R. , Dalton Jarrod E.
Published: August 2024

Importance

Hypertension in middle-aged adults (35-50 years) is associated with poorer health outcomes in late life. Understanding how hypertension varies by race and ethnicity across levels of neighborhood disadvantage may allow for better characterization of persistent disparities.

Objective

To evaluate spatial patterns of hypertension diagnosis and treatment by neighborhood socioeconomic position and racial and ethnic composition.

Design, Setting, and Participants

In this cross-sectional study of middle-aged adults in Cuyahoga County, Ohio, who encountered primary care in 2019, geocoded electronic health record data were linked to the area deprivation index (ADI), a neighborhood disadvantage measure, at the US Census Block Group level (ie, neighborhood). Neighborhoods were stratified by ADI quintiles, with the highest quintile indicating the most disadvantage. Data were analyzed between August 7, 2023, and June 1, 2024.

Exposure

Essential hypertension.

Main Outcomes and Measures

The primary outcome was a clinician diagnosis of essential hypertension. Spatial analysis was used to characterize neighborhood-level patterns of hypertension prevalence and treatment. Interaction analysis was used to compare hypertension prevalence by racial and ethnic group within similar ADI quintiles.

Results

A total of 56 387 adults (median [IQR] age, 43.1 [39.1-46.9] years; 59.8% female) across 1157 neighborhoods, which comprised 3.4% Asian, 31.1% Black, 5.5% Hispanic, and 60.0% White patients, were analyzed. A gradient of hypertension prevalence across ADI quintiles was observed, with the highest vs lowest ADI quintile neighborhoods having a higher hypertension rate (50.7% vs 25.5%) and a lower treatment rate (61.3% vs 64.5%). Of the 315 neighborhoods with predominantly Black (>75%) patient populations, 200 (63%) had a hypertension rate greater than 35% combined with a treatment rate of less than 70%; only 31 of 263 neighborhoods (11.8%) comprising 5% or less Black patient populations met this same criterion. Compared with a spatial model without covariates, inclusion of ADI and percentage of Black patients accounted for 91% of variation in hypertension diagnosis prevalence among men and 98% among women. Men had a higher prevalence of hypertension than women across race and ADI quintiles, but the association of ADI and hypertension risk was stronger in women. Sex prevalence differences were smallest between Black men and women, particularly in the highest ADI quintile (1689 [60.0%] and 2592 [56.0%], respectively).

Conclusions and Relevance

These findings show an association between neighborhood deprivation and hypertension prevalence, with disparities observed particularly among Black patients, emphasizing a need for structural interventions to improve community health.
Federal program will support Native American SUD research
Authors: Knopf Alison
Published: August 2024

Last week the National Institute on Drug Abuse (NIDA) and other agencies within the National Institutes of Health announced a program to support Native American community leadership on research into substance use, pain and overdose. In an Aug. 15 press release, NIDA stated.
Balancing the Co‐Solvent Content in High Entropy Aqueous Electrolytes to Obtain 2.2 V Symmetric Supercapacitors
Authors: González‐Aguilera Laura , Vicent‐Luna José Manuel , Tao Shuxia , Calero Sofia , Madero‐Castro Rafael M. , Raymundo‐Piñero Encarnación , Lu Xuejun , Gutiérrez María C. , Ferrer M. Luisa , del Monte Francisco
Published: August 2024

The energy storage capability of supercapacitors (SCs) strongly depend on the operating cell voltage of the electrolytes of choice. In this regard, the inherent distinct electrochemical stability of cations and anions is a factor of relevance for the operating cell voltage. The use of double salts sharing one ion has been described as an approach to circumvent this problem, but whether modifying the solvation structure of cations and anions with different solvent molecules (coordinating and/or non‐coordinating) could help balance their electrochemical stability in SCs has not yet been fully addressed. In this work, electrolytes are prepared by combining solvent mixtures and double salts, specifically 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI) and 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIMBF4) in mixtures of water (H2O) and dimethysulfoxide (DMSO) as coordinating co‐solvents and acetonitrile (CH3CN) as a weakly coordinating one. It is found that the presence of this latter one helped to enhanced the cation solvation structure (above 9). This increase of the entropic features allows operating at cell voltages of up to 2.2 V and the subsequent enhancement of the energy storage capabilities and capacitance retentions (up to 15 Wh kg−1 and ≈87% after 10 000 cycles, respectively).