bluuebunny/crossref_metadata_2025 huggingface dataset:
Advances in Skin Substitutes—Potential of Tissue Engineered Skin for Facilitating Anti-Fibrotic Healing
Authors: Varkey Mathew , Ding Jie , Tredget Edward
Published: July 2015

Skin protects the body from exogenous substances and functions as a barrier to fluid loss and trauma. The skin comprises of epidermal, dermal and hypodermal layers, which mainly contain keratinocytes, fibroblasts and adipocytes, respectively, typically embedded on extracellular matrix made up of glycosaminoglycans and fibrous proteins. When the integrity of skin is compromised due to injury as in burns the coverage of skin has to be restored to facilitate repair and regeneration. Skin substitutes are preferred for wound coverage when the loss of skin is extensive especially in the case of second or third degree burns. Different kinds of skin substitutes with different features are commercially available; they can be classified into acellular skin substitutes, those with cultured epidermal cells and no dermal components, those with only dermal components, and tissue engineered substitutes that contain both epidermal and dermal components. Typically, adult wounds heal by fibrosis. Most organs are affected by fibrosis, with chronic fibrotic diseases estimated to be a leading cause of morbidity and mortality. In the skin, fibroproliferative disorders such as hypertrophic scars and keloid formation cause cosmetic and functional problems. Dermal fibroblasts are understood to be heterogeneous; this may have implications on post-burn wound healing since studies have shown that superficial and deep dermal fibroblasts are anti-fibrotic and pro-fibrotic, respectively. Selective use of superficial dermal fibroblasts rather than the conventional heterogeneous dermal fibroblasts may prove beneficial for post-burn wound healing.
Transitions in Land Use Architecture under Multiple Human Driving Forces in a Semi-Arid Zone
Authors: Ouedraogo Issa , Mbow Cheikh , Balinga Michael , Neufeldt Henry
Published: July 2015

The present study aimed to detect the main shifts in land-use architecture and assess the factors behind the changes in typical tropical semi-arid land in Burkina Faso. Three sets of time-series LANDSAT data over a 23-year period were used to detect land use changes and their underpinning drivers in multifunctional but vulnerable ecologies. Group discussions in selected villages were organized for mapping output interpretation and collection of essential drivers of change as perceived by local populations. Results revealed profound changes and transitions during the study period. During the last decade, shrub and wood savannahs exhibited high net changes (39% and −37% respectively) with a weak net positive change for cropland (only 2%,) while cropland and shrub savannah exhibited high swap (8% and 16%). This suggests that the area of cropland remained almost unchanged but was subject to relocation, wood savannah decreased drastically, and shrub savannah increased exponentially. Cropland exhibited a null net persistence while shrub and wood savannahs exhibited positive and negative net persistence (1.91 and −10.24), respectively, indicating that there is movement toward agricultural intensification and wood savannah tended to disappear to the benefit of shrub savannah. Local people are aware of the changes that have occurred and support the idea that illegal wood cutting and farming are inappropriate farming practices associated with immigration; absence of alternative cash generation sources, overgrazing and increasing demand for wood energy are driving the changes in their ecosystems. Policies that integrate restoration and conservation of natural ecosystems and promote sustainable agroforestry practices in the study zone are highly recommended.
Nitric Oxide-Releasing Aspirin Suppresses NF-κB Signaling in Estrogen Receptor Negative Breast Cancer Cells in Vitro and in Vivo
Authors: Nath Niharika , Chattopadhyay Mitali , Rodes Deborah , Nazarenko Anna , Kodela Ravinder , Kashfi Khosrow
Published: July 2015

Estrogen receptor negative (ER(−)) breast cancer is aggressive, responds poorly to current treatments and has a poor prognosis. The NF-κB signaling pathway is implicated in ER(−) tumorigenesis. Aspirin (ASA) is chemopreventive against ER(+) but not for ER(−) breast cancers. Nitric oxide-releasing aspirin (NO-ASA) is a safer ASA where ASA is linked to an NO-releasing moiety through a spacer. In vitro, we investigated anti-proliferation effects of NO-ASA (para- and meta-isomers) against ER(−) breast cancer cells MDA-MB-231 and SK-BR-23, effects on NF-κB signaling, and reactive oxygen species by standard techniques. In vivo, effects of NO-ASA were evaluated in a mouse xenograft model using MDA-MB-231 cells. p-NO-ASA inhibited the growth of MDA-MB-231 and SK-BR-3 cells at 24 h, the respective IC50s were 13 ± 2 and 17 ± 2 μM; ASA had an IC50 of >3000 μM in both cell lines. The IC50s for m-NO-ASA in MDA-MB-231 and SK-BR-3 were 173 ± 15 and 185 ± 12 μM, respectively, therefore, implying p-NO-ASA as a stronger inhibitor of growth p-NO-ASA reduced cell growth by inhibiting proliferation, inducing apoptosis and causing G0/G1 cell cycle block. Activation of NF-κB was inhibited by both isomers as demonstrated by decreases in NF-κB-DNA binding and luciferase activity at 24 h, However, m-NO-ASA produced transient effects at 3 h such as increased NF-κB-DNA-binding, increased levels of nuclear p50, even though both isomers inhibited IκB degradation. Increase in nuclear p50 by m-NO-ASA was associated with translocation of p50 in to the nucleus as observed by immunoflouresence at 3 h. NO-ASA induced reactive oxygen species (ROS) as evidenced by overall increases in both H2DCFDA (2′,7′-dichlorodihydrofluorescein) and DHE (dihydroethidium)-derived fluorescence. Inhibition of ROS by N-acetyl-cysteine reversed the m-NO-ASA-mediated translocation of p50 in to the nucleus. In xenografts, p-NO-ASA inhibited tumor growth by inhibiting proliferation (PCNA and tumor volume), inducing apoptosis (TUNEL positive cells) and reducing NF-κB expression. Both isomers inhibit cancer cells, inhibit NF-κB pathway and induce ROS, and have potential as anticancer compounds.
Acerogenin A from Acer nikoense Maxim Prevents Oxidative Stress-Induced Neuronal Cell Death through Nrf2-Mediated Heme Oxygenase-1 Expression in Mouse Hippocampal HT22 Cell Line
Authors: Lee Dong-Sung , Cha Byung-Yoon , Woo Je-Tae , Kim Youn-Chul , Jang Jun-Hyeog
Published: July 2015

Oxidative cell damage contributes to neuronal degeneration in many central nervous system (CNS) diseases such as Parkinson’s disease, Alzheimer’s disease, and ischemia. Inducible heme oxygenase (HO)-1 acts against oxidants that are thought to play a key role in the pathogenesis of neuronal diseases. The stem bark of Acer nikoense Maxim (Aceraceae) is indigenous to Japan; it has been used in folk medicine as a treatment of hepatic disorders and eye diseases. Acerogenin A, a natural compound isolated from Japanese folk medicine A. nikoense, showed neuroprotective effects and reactive oxygen species (ROS) reduction on glutamate-induced neurotoxicity by inducing the expression of HO-1 in mouse hippocampal HT22 cells. Furthermore, acerogenin A caused the nuclear accumulation of nuclear factor-E2-related factor 2 (Nrf2) and the activation of the PI3K/AKT signaling pathways. In this study, we demonstrated that acerogenin A effectively prevents glutamate-induced oxidative damage, and HO-1 induction via PI3K/Akt and Nrf2 pathways appears to play a key role in the protection of HT22 cells. Therefore, this study implies that the Nrf2/HO-1 pathway represents a biological target and that acerogenin A might be a candidate for the prevention of neurodegeneration.
Synthesis of Oxygen Heterocycles via Aromatic C-O Bond Formation Using Arynes
Authors: Miyabe Hideto
Published: July 2015

Most of the synthetic approaches to the benzo-fused heterocycles containing an oxygen atom have involved the use of phenol derivatives as a starting material. This review highlights the new synthetic approaches involving the aromatic C-O bond-forming process using arynes. The insertion of arynes into the C=O bond gives the unstable intermediates, [2 + 2] cycloaddition-type adducts, which can be easily converted into a variety of oxygen atom-containing heterocycles in a single operation. In this review, the syntheses of oxygen heterocycles, such as coumarin, chromene, xanthene, dihydrobenzofuran and benzofuran derivatives, via the insertion of arynes into the C=O bond of aldehydes or formamides are summarized.
Rapid Turbidimetric Assay to Determine the Potency of Daptomycin in Lyophilized Powder
Authors: Tótoli Eliane , Salgado Hérida
Published: July 2015

Daptomycin is an important antimicrobial for clinical practice, mainly because it remains very active against Gram-positive resistant strains, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci. Development of microbiological methods for the analysis of antimicrobials is highly recommended, since they can provide important information about their biological activities, which physicochemical methods are not able to provide. Considering that there are no studies in the literature describing microbiological methods for the analysis of daptomycin, the aim of this work was to validate a microbiological method for the quantitation of daptomycin by the turbidimetric assay. Staphylococcus aureus was used as the test microorganism, and the brain heart infusion broth was used as the culture medium. The validation of the method was performed according to the ICH guidelines, and it was shown to be linear, precise, robust, accurate and selective, over a concentration range of 8.0 to 18.0 µg mL−1. Student’s t-test showed the interchangeability of the proposed method with a previously-validated HPLC method. The developed turbidimetric method described in this paper is a convenient alternative for the routine quality control of daptomycin in its pharmaceutical dosage form.
Functional Characterization of Cucumis metuliferus Proteinase Inhibitor Gene (CmSPI) in Potyviruses Resistance
Authors: Lin Chia-Wei , Su Mei-Hsiu , Lin Yu-Tsung , Chung Chien-Hung , Ku Hsin-Mei
Published: July 2015

Proteinase inhibitors are ubiquitous proteins that block the active center or interact allosterically with proteinases and are involved in plant physiological processes and defense responses to biotic and abiotic stresses. The CmSPI gene identified from Cucumis metuliferus encodes a serine type PI (8 kDa) that belongs to potato I type family. To evaluate the effect of silencing CmSPI gene on Papaya ringspot virus resistance, RNA interference (RNAi) with an inter-space hairpin RNA (ihpRNA) construct was introduced into a PRSV-resistant C. metuliferus line. CmSPI was down-regulated in CmSPI RNAi transgenic lines in which synchronously PRSV symptoms were evident at 21 day post inoculation. Alternatively, heterogeneous expression of CmSPI in Nicotiana benthamiana was also conducted and showed that CmSPI can provide resistance to Potato virus Y, another member of Potyvirus, in transgenic N. benthamiana lines. This study demonstrated that CmSPI plays an important role in resistant function against potyviruses in C. metuliferus and N. benthamiana.
Les transformations normatives d'une peinture de paysage en Chine : le cas des œuvres attribuées à Gao Kegong (1248-v.1310)
Authors: Peytavin Muriel
Published: July 2015

L'œuvre aujourd'hui attribuée à Gao Kegong (1248-v.1310) est principalement de deux types : d'une part, quelques œuvres authentiques ou jugées comme reflétant une œuvre authentique et affichant un haut degré d'individualité ; d'autre part, des paysages postérieurs datés des XVIe et XVIIe siècles qui sont attribués à Gao sur la base du style – ou de l'idée que nous en avons – et fortement liés aux caractéristiques du style de Mi Fu (1051-1107). Étudiés conjointement, ces deux ensembles de rouleaux illustrent les problématiques liées à la définition du style d'un artiste et à la perception qui en est forgée au cours du temps. La production attribuée à Gao témoigne à la fois du caractère changeant des limites stylistiques acceptées pour un artiste par les générations postérieures, et de la normalisation qu'engendre la reconnaissance précoce de la valeur du style en Chine, comme incarnant et transmettant les dispositions naturelles de l'artiste mais aussi comme perpétuant un ensemble de concepts philosophiques et spirituels liés à la classe des lettrés.
Kang Sehwang's Scenes of Puan Prefecture – describing actual landscape through literati ideals
Authors: Jungmann Burglind , Zhang Liangren
Published: July 2015

In the early eighteenth century, chin'gyông "true scenery" or "true view," painting emerged in Chosôn Korea as a dominating landscape genre. While earlier artists were preoccupied with legendary or historical landscapes rooted in Chinese tradition, chin'gyông painters turned their eyes to real landscapes in their own country. This paper centers on a handscroll by Kang Sehwang, Scenes of Puan Prefecture, which is diplayed in the collection of the Los Angeles County Museum of Art. It is not only a major work of the artist in a Western collection but it uniquely combines the "Three Treasure", calligraphy, literature and painting and is thus a superb example of Chosôn literati art. We will investigate the relationship between Kang Sehwang's travelogue and his paintings, trying to shed light on his ideas about traveling itself, about writing travelogues, and about rendering actual scenery. A careful analysis of the handscroll and of related texts, published in his anthology P'yoam yugo (Transmitted Writings by P'yoam), will help us to understand the process of the creation of the scroll and the painter's intention, that is, to understand its position within the context of his life and times.
L'about inscrit du musée national du Cambodge (K. 943) : nouveaux éléments sur le bouddhisme tantrique à l'époque angkorienne
Authors: Estève Julia , Vincent Brice
Published: July 2015

Registered by the National Museum of Cambodia in 1933 and still unpublished, the inscription K. 943, engraved on a bronze end-piece, provides interesting information about the date of the object as well as the religious history of the Khmer country and, more specifically, Buddhism. Although it is difficult to understand, this unusually long inscription for a metal Khmer object mentions a single deity, the Kamrateṅ Jagat Chpār Ransī, who appears in a dozen Khmer inscriptions, suggesting that he was an important deity during the Angkor period. Several elements of the text indicate a late Angkorian date, as opposed to a hasty analysis of the object which could lead one to believe otherwise, and thus supply the most recent evidence of this renowned Buddhist deity. Moreover, by virtue of the deity it bears — a Vajrasattva — this finial links the Kamrateṅ Jagat Chpār Ransī with Tantric Buddhism and, by doing so, raises some new questions about the development of this specific way of Buddhism in Khmer history.
Thiazole-induced rigidification in substituted dithieno-tetrathiafulvalene: the effect of planarisation on charge transport properties
Authors: Taylor Rupert G D , Cameron Joseph , Wright Iain A , Thomson Neil , Avramchenko Olena , Kanibolotsky Alexander L , Inigo Anto R , Tuttle Tell , Skabara Peter J
Published: July 2015

Two novel tetrathiafulvalene (TTF) containing compounds 1 and 2 have been synthesised via a four-fold Stille coupling between a tetrabromo-dithienoTTF 5 and stannylated thiophene 6 or thiazole 4. The optical and electrochemical properties of compounds 1 and 2 have been measured by UV–vis spectroscopy and cyclic voltammetry and the results compared with density functional theory (DFT) calculations to confirm the observed properties. Organic field effect transistor (OFET) devices fabricated from 1 and 2 demonstrated that the substitution of thiophene units for thiazoles was found to increase the observed charge transport, which is attributed to induced planarity through S–N interactions of adjacent thiazole nitrogen atoms and TTF sulfur atoms and better packing in the bulk.
A Non-Relative Analysis of So-Called Relative Clauses
Authors: Akiba Katsue
Published: July 2015

Proceedings of the 4th Annual Meeting of the Berkeley Linguistics Society (1978), pp. 1-10
Clitics, Clauses, Closure, and Discourse in Easter Pomo
Authors: McLendon Sally
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 637-646
Double-Cross in Phonology: Why Word-Boundary (Often) Acts Like a Consonant
Authors: Janda Richard D.
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 397-412
How to Ask for Wiper Fluid in Montreal: Struggling with the Terminology of Car Parts in Québecois
Authors: Heller Monica S.
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 567-580
On Discourse Syntactic Consequences of Certain Short Topic Sentences
Authors: Gorbet Larry
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 558-566
Prehistoric Sociolinguistics: The Case for Hopi
Authors: Shaul David Leedom
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 489-499
Temporal Connectives and Logical Form
Authors: Sag Ivan , Wiesler Steven
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 336-349
The Influence of the Social Class in the Verbal Morphology of Certain Dialects of Spanish
Authors: Rivas Alberto M.
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 428-437
Theme and Context Dependency: Thematic Progression
Authors: Keul Norman C.
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 198-205
The Function and Content of Relative Clauses in Spontaneous Oral Narratives
Authors: Bernardo Robert
Published: July 2015

Proceedings of the Fifth Annual Meeting of the Berkeley Linguistics Society (1979), pp. 539-551
DECISION-MAKING MODEL FOR CHOOSING RESIDENTIAL BUILDING REPAIR VARIANTS
Authors: Bucoń Robert , Sobotka Anna
Published: July 2015

During the use of buildings it becomes necessary to carry out repair works including modernisation. Deciding on the choice of repair solutions is a difficult and complex task. Building administrators have to consider both, the benefits of some repair works, and limitations due to the availability of funds. Selection of a repair solution, bearing in mind the above, requires a comprehensive approach that will allow assessment of the building condition and determining the repair scope required. The research conducted by the authors was aimed at developing a decision-making model and its computer-aided implementation, taking into account a number of operating demands. The system algorithm proposed comprises five stages including: building condition assessment, building use value evaluation, repair classification, multiple variants of repair and the choice of repair solutions. The article describes individual stages of the model in detail, giving numerical application examples of the method for repair solution choice for five multi-family houses.
Modeling of Electron Tunneling Current in a p-n Junction Based on Strained Armchair Graphene Nanoribbons with Extended Tight Binding and Transfer Matrix Method
Authors: Syariati Rifky , Suhendi Endi , Noor Fatimah A. , Khairurrijal Khairurrijal
Published: July 2015

A theoretical model of electron tunneling current in a p-n junction based on strained armchair graphenenanoribbons (AGNRs) is developed. The effects of strain to the energy dispersion relation and the band gap of AGNR are formulated under the extended tight binding method. The electron transmittance was derived by utilizing the transfer matrix method. The calculated transmittance was then used to obtain the tunneling current by employing the Landauer formula with Gauss Quadrature computation method. The effects of strain to the energy band gap, AGNR width, and tunneling current are studied thoroughly.
Synthesis and Electrical Characterization of 0.8(K,Na)NbO3-0.2(Ba,Ca)(Zr,Ti)O3 Lead-Free Ceramics
Authors: Rohmah Nur Amaliya , Hikmah Nahariatul , Suasmoro Suasmoro
Published: July 2015

In this research, the physical and electrical properties of 0.8K0.5Na0.5NbO3-0.2Ba0.5Ca0.5Zr0.5Ti0.5O3 (0.8KNN-0.2BCZT) were characterized. Lead-free material, 0.8KNN-0.2BCZT with and without alkaline excess was synthesized via solid state reaction method. KNN and BCZT were calcined at 700°C and 1200°C for 2 hours respectively and mixed by planetary milling. The mixed powder was recalcined at 1250°C for an hour then sintered at 1150°C, 1200°C and 1250°C for 2 and 4 hours. XRD analysis of 0.8KNN-0.2BCZT for excessive (8% Na, 2% K) sample sintered at 1150°C for 4 hours has single phase showing ABO3 structure (A=K, Na, Ba, Ca and B=Ti, Zr, Nb) and multi phases for the other ones. The microstructure analysis (SEM) showed cubic-like grain shape in which excessive sample possessed greater average grain size than other. Dielectric properties and Curie temperature of single phase sample in this research were higher than those of pure KNN. The conductivity analysis reveals two regimes. The first regime (<300°C) showed no significant role of BCZT in KNN and the second one (>300°C) showed that BCZT increased conductivity of KNN and factor dissipation as well.
Synthesis of Bi2O3/Ag3Po4 Composites and their Photocatalytic Activities under Visible Light Irradiation
Authors: Sulaeman Uyi , Yunari Estri , Iswanto Ponco , Yin Shu , Sato Tsugio
Published: July 2015

The Bi2O3/Ag3PO4 composites consisting of the monoclinic α-Bi2O3 and body-centered cubic Ag3PO4 were successfully synthesized by grinding Ag3PO4 and Bi2O3 mixtures in ethanol using an agate mortar, followed by calcination at 500°C for 5 hours, where the Ag3PO4 was synthesized by co-precipitation method using AgNO3 and NaH2PO4.2H2O as starting materials. The Bi2O3 content in the composite materials changed from 5 to 25 mol.%. The composites were characterized using XRD, DRS and BET specific surface area. The photocatalytic activities were evaluated using Rhodamin B degradation under visible light irradiation of blue LED (λ = 445 nm). The highest photocatalytic activities could be obtained at 5 mol.% Bi2O3 in Bi2O3/Ag3PO4 composite. The enhanced photocatalytic activity could be attributed to the effective separation of hole (h+) and electron (e-) pairs in the Bi2O3/Ag3PO4 composite.
Synthesis of Mesoporous Silica Particles with Fibrous Morphology via Self-Assembly Process in Microemulsion System
Authors: Febriyanti Erna , Mukti Rino R. , Suendo Veinardi , Marsih I. Nyoman , Triwahyono Sugeng , Ismadji Suryadi , Ismunandar Ismunandar
Published: July 2015

In this research, several precursors were chosen to solve the drawbacks of using toxic and expensive chemicals in the synthesis of fibrous mesoporous silica particle via self-assembly process in microemulsion system. The synthesis of this emerging material normally is realized by using toxic cetylpyridinium bromide (CPB) as common structure directing agent in conjunction with combined cyclohexane and n-pentanol as expensive solvent and co-solvent, respectively. Less toxic cetyltrimethylammonium bromide (CTAB) can be the replacement for CPB but the use of this surfactant may drastically reduce the surface area of the resulting product. Herein, we report that the use of CTAB with combined toluene and n-butanol as affordable solvents can be used to synthesize fibrous mesoporous silica particle with high surface area. The material was well characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), N2 adsorption/ desorption, X-ray difraction (XRD)and thermal gravimetry (TG). This material might be applied in potential applications such as catalysis, drug delivery and adsorption. Moreover, it can be used as a hard-template for fabricating another novel fibrous materials.
The Influence of Montmorillonite Incorporation in Mn-Doped ZnO Nanoparticles for Photocatalytic Degradation of Organic Dyes
Authors: Djaja Nadia Febiana , Saleh Rosari
Published: July 2015

The present study compares the photocatalytic decolorization ability of bare Mn-doped ZnO and montmorillonite modified Mn-doped ZnO nanoparticles towards aqueous solution of organic dyes (methylene blue and malachite green) under UV light irradiation. Both photocatalysts were synthesized using co-precipitation method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier-transform infrared absorption, electron spin resonance, and diffuse reflectance spectroscopy. Comparison of degradation efficiency demonstrated that montmorillonite modified Mn-doped ZnO nanoparticles exhibited higher activity than bare Mn-doped ZnO nanoparticles.
A Comparative Study of the Synthesis of MFI Zeolite by Using High- and Low-Temperature Heating
Authors: Kadja Grandprix T.M. , Mukti Rino R. , Nyoman Marsih I. , Ismunandar Ismunandar
Published: July 2015

Zeolites are among the main catalysts in the petroleoum and fine-chemical industry. The well-defined channel framework with the acid sites have empowered this kind of material to catalyze many chemical reactions, such as alkylation, isomerization, and hydrocarbon cracking. Controlling the energy consumption towards efficient process in the synthesis of zeolite has been a great interest. In this light, we succesfully show that synthesis of MFI zeolite can be tailored by using high or low temperature heating. Synthesis via high-temperature heating (HTH) at 150 °C, resulted in conventional coffin-type morphology whereas low-temperature heating (LTH) at 90 °C, resulted in a spherical-type morphology. This phenomenon indicates that energy consumption for synthesizing MFI zeolite can be decreased. Moreover, the tetrapropylammonion ion (TPA+) amount as structure-directing agents (SDA) can be lowered, hence reducing the synthesis cost. The obtained samples were charaterized by advanced techniques to compare interesting properties between samples synthesized by HTH and LTH. This concerns on the resulting morphology, textural properties, and Si/Al framework ratio.
Electrochemical Impedance Spectroscopy Study of Supercapacitors Using Deposited Nickel Oxide Nanoparticles Carbon Monolith Electrodes
Authors: Basri N.H. , Deraman Mohamad , Daik Rusli , Ayob Muhammad Taqiyuddin Mawardi , Sahri Muhamad Izhar , Nor N.S.M. , Dolah B.N.M. , Soltaninejad Sepideh
Published: July 2015

Activated carbon monolith porous electrodes of a supercapacitor prepared by carbonization (N2) and activation (CO2) methods from KOH-treated pre-carbonized biomass fibers were deposited with nickel oxide at varying dipping time (from 0 to 60 min) in 20 mL of 0.1 mol Ni(NO3)2 and 20 mL of 0.2 mol NaOH solution followed by annealing at 300°C for 2 h. N2 adsorption-desorption characterization results confirmed the porous characteristic of the bare electrodes (surface area 1656 m2g-1). Energy dispersive X-ray (EDX) analysis and field emission scanning electron microscopy (FESEM) results showed the deposited nickel oxide nanoparticles were homogeneously distributed on the surface of electrodes and X-ray diffraction results revealed the semicrystalline phase of the deposited particles. Electrochemical impedance spectroscopy characterization of the supercapacitor cells fabricated using these electrodes showed that the optimum dipping time (15 – 45 min) can improve the supercapacitor specific capacitance and equivalent series resistance by 27 – 30 % and 6 – 34 %, respectively.
Synthesis and Characterization of Li4Ti5O12 Doped by Na and Al as Anodes Material for Li-Ion Batteries
Authors: Priyono Slamet , Prihandoko Bambang , Zulfia Anne
Published: July 2015

Li4Ti5O12 pure and Li4Ti5O12 with Na and Al doped Li(3-x/3)AlxNaTi(5-2x/3)O12 (x=0, 0.025, 0.05, 0.075) as anodes for Li-ion batteries are synthesized at 850°C via solid state reaction using Li2CO3, TiO2-anatase, Al2O3 and Na2CO3 as precursor. The effect of substitution of Al and Na in Li4Ti5O12 on characterization of precursor and electrochemical performance is studied. It is found that Na doped in Li4Ti5O12 pure affected the formation of three phase i.e NaLiTi3O7, Li4Ti5O12, dan Li2TiO3. Meanwhile, Al doped contributed to the formation of NaLiTi3O7 phase significantly. The SEM images show that the particles have polyhedral shape with uniform size distribution. Na doped in the Li4Ti5O12 affected particle size become larger against Al doped particle size become smaller than undoped material, the best particle size measured by PSA is 30,89 . All characterization of material will determine the electrochemical performance of Li-ion battery.
Enhancement of TiO2 Particles Based-Solar Cells Efficiency by Addition of Copper(II) Nitrate and Post-Treatment with Sodium Hydroxyde
Authors: Rokhmat Mamat , Wibowo Edy , Sutisna Sutisna , Yuliza Elfi , Khairurrijal Khairurrijal , Abdullah Mikrajuddin
Published: July 2015

Efficiency enhancement of solar cells employing TiO2 as the active material has been successfully done by addition of copper(II) nitrate trihydrate (Cu(NO3)2.3H2O) in the TiO2 dispersant, and post-treatment with sodium hydroxide (NaOH) after electroplating of copper particles at spaces inside the TiO2 film. Homogeneously mix of TiO2 particles in the solution of Cu(NO3)2.3H2O was deposited on a transparent conducting electrode using a spray method. To reduce electron-hole recombination, copper particles were deposited on the space between TiO2 particles by electroplating. A sample of solar cell was made by sandwiching a polymer electrolyte between the film and a counter electrode. Copper(II) nitrate trihydrate of 1.4 wt% and 5 volt electroplating voltage are able to produce an optimum power conversion efficiency of 0.35% with a fill factor of 0.31. To achieve higher efficiency, post treatment with NaOH was performed to increase the ionic transfer ability in electrolyte and we observed efficiency up to 1.24% with a fill factor of 0.34.
Photovoltaic and Impedance Characteristics of Quasi Solid-State Dye-Sensitized Solar Cell Using Polymer Gel Electrolytes
Authors: Arsyad Waode Sukmawati , Herman Herman , Fitrilawati Fitrilawati , Hidayat Rahmat
Published: July 2015

In order to overwhelm the electrolyte leakage problem and improve the stability in extreme climate conditions, we have studied the fabrication and characteristics of dye sensitized solar cell (DSSC) using polymer gel electrolyte (PGE), which is developed from siloxane based polymer gel blended with imidazolium ionic liquid. In many cases, the use of PGE often reduces its photovoltaic performance due to the decrease in its ionic mobility. However, such influence was not observed in our present work. In this work, the fabricated DSSC do not exhibit significant degradation in its working performance. The best overall energy conversion efficiency is about 5.25%, as indicated by short circuit photocurrent (Jsc) larger than 12 mA/cm2, which is comparable to performance of reference cell made by using ionic liquid only. We found from the impedance spectroscopy measurements that the electrolyte diffusion coefficient in the DSSC using this PGE is comparable to that in DSSC using ionic liquid electrolyte.
Proton Conducting Biopolymer Electrolytes Based on Starch Incorporated with Ammonium Thiocyanate
Authors: Zulkefli Fatin Nabella , Navaratnam S. , Ahmad Azizah Hanom
Published: July 2015

In the present study, proton conducting biopolymer electrolyte systems based on corn starch and NH4SCN salt were prepared using solution casting method. The sample with 30 wt.% NH4SCN exhibited the highest ionic conductivity of 5.54 x 10-3 S cm-1 at room temperature. Temperature-dependence ionic conductivity relationship obeys Arrhenius model and minimum activation energy of 0.28 eV was obtained for the highest conducting composition.
First Principle Calculation of Li2Fe0.5Cr0.5SiO4 for Li-Ion Battery Cathode
Authors: Kurniawan Sukandi Ganjar , Kencana Wungu Triati Dewi , Iskandar Ferry
Published: July 2015

First principle calculation based on Density Functional Theory and U correction (DFT+U) is used to investigate structural change while losing Li atom, average voltage for couple reaction, phase stability, and electronic structure of Li2Fe0.5Cr0.5SiO4. In this calculation, generalized gradient approach (GGA) of Perdew-Burke-Ernzerhof (PBE) is used for exchange-correlation functional. The initial structure of Li2Fe0.5Cr0.5SiO4 is obtained from the pmn21 structure of Li2FeSiO4 and then the Fe site is substituted by 50 % of Cr. The results of calculation show that the optimized Li2Fe0.5Cr0.5SiO4 has a monoclinic structure, which has little different with Li2FeSiO4 structure. Although the delithiated system (LiFe0.5Cr0.5SiO4) is taken into consideration, the structural geometry does not change significantly. It is indicated that the presence of Cr does not affect to the property of structural change. From the density of states (DOS) analysis, the presence of Cr causes the width of band gap become decrease. Therefore, the electronic properties change from insulator to semiconductor-like behavior. Average voltage for couple reaction M+2/ M+3 of Li2Fe0.5Cr0.5SiO4 is about 3.05 V which is lower than Li2FeSiO4. Furthermore, the formation energy for Li2Fe0.5Cr0.5SiO4 and all delithiation have a relatively positive sign compared with Li2FeSiO4 that mean that they have poor phase stability than Li2FeSiO4.
Optical Band Transitions and Excitonic States in ZnO:Cu Films
Authors: Darma Yudi , Rusydi Andrivo
Published: July 2015

Photoluminescence (PL), ultraviolet-visible (UV-VIS) absorption spectroscopy and spectroscopic ellipsometry (SE) are combining to study the optical transitions and electronic structures of Cu doped ZnO films with Cu concentration of 0, 2 and 8 at. %. By increasing Cu concentration, PL spectra show the enhancement of optical transition through the significantly increase of the green emission. Correspondingly, the in-plane UV visible absorption spectra show the redshift of first interband transition as the evidence of ZnO film become less insulating. More interestingly, extracted optical properties such as n and k clearly shows the mid-gap optical states, interband transitions and excitons. The excitonic peak decrease by increasing Cu concentration accompanied by a new broad structure assigned as a mid-gap state located under the conduction band area. Excitonic states are screened as decreasing its intensities by increasing Cu doping. Our results are beneficial to define interband transition and explain the mid-gap state in the oxide based semiconductor.
On the Role of NaCl Addition to Phase Transformation of TiO2 from TiCl3
Authors: Putri Irana Eka , Ariesta Budiarti Herny , Sawitri Dyah , Risanti Doty D.
Published: July 2015

Phase transformation of TiO2 (titanium dioxide) nanoparticles has been analyzed by observing the effect of NaCl addition to the anatase-to-rutile phase transformation. NaCl is one of key points in the transformation of rutile. Co-precipitation method was employed in which TiCl3 as precursor was reacted with HCl 2M and subsequent NH4OH. Three methods were studied, namely solution without NaCl addition (TiCl3 + HCl + NH4OH) as control solution subjected to route A (TiCl3 + HCl – NaCl– NH4OH – heated at 600°C for 5 hours) and route B (TiCl3 + NaCl – heated 200°C for 5 hours – NH4OH – heated 200°C for 6 hours). Route B was subjected to heating at 200°C. The results show that without NaCl it enhanced the crystal growth of the rutile embryos allowing the ease of rutile formation at 600°C, while route A promoted the transformation of brookite and hindered anatase-to-rutile transformation as indicated by the presence of anatase at 1000°C. On the other hand route B is potential for being further explored.
Comparative Studies on Thermal Barrier between Modified Polyurethane Using Titanium Dioxide to Montmorillonite Nanoclay
Authors: Zakaria Rosnah , Ahmad Azizah Hanom
Published: July 2015

Thermal barrier coatings (TBC) are highly advanced material systems usually applied to metallic surfaces such as gas turbine or aero-engine parts to reduce temperature. Polyurethane was the main component composed from chain of organic units joined by urethane links. 10 samples have been prepared with 5 samples for every combination at 1 to 5 different weight percent for each composition and dried at room temperature for one week. The sample was being characterized based on adhesion using crosshatch test and thermal barrier conductivity to know the k-value of conductivity. PU with 3 and 5 wt% of TiO2 and 1 and 5 wt% of nanoclay (NC) showed the smoothest cross cuts. As a result, modified polyurethane with 5wt% of TiO2 or Nanoclay gives the good adhesion and k-value at 0.093 W.m-1.K-1.
Hot Corrosion of Aluminide Coated Ti-Al-Cr-Nb-Zr-Y Intermetallic Alloys
Authors: Basuki Eddy , Mohammad Fadhli , Fauzi Ahmad , Prajitno Djoko
Published: July 2015

Pack aluminide coatings were performed on a Ti-Al-Cr-Nb alloy doped with zirconium and yttrium having two phase of a2-Ti3Al and g-TiAl microstructure. The high activity TiAl3-based coating was developed from aluminizing process carried out at 850°C for 25 hours in a pack containing 20%-wt Al, 2%wt NH4Cl, and 78%wt Al2O3. During applications at high temperatures, the coating can degrade due to the interaction between the coated system and the environment exhibit high corrosion potentials. This study investigates the hot corrosion behavior of high-activity aluminide coated Zr-Y doped a2-Ti3Al/g-TiAlCrNb intermetallic alloy at 700°C, 800°C, and 900°C in a mixture of 90% Na2SO4 and 10% NaCl. The experimental results showed that the addition of Zr and Y in the alloy reduces significantly the hot corrosion rate of the coating as resulted from the interdiffusion of these elements from the alloy to the coatings and influence the behavior of the TiAl3-based coatings.
Tensile and Flexural Properties of Montmorillonite Nanoclay Reinforced Epoxy Resin Composites
Authors: Alsagayar Zyad Salem , Rahmat Abdul Razak , Arsad Agus , binti Mustaph Siti Noor Hidayah
Published: July 2015

In this work, montmorillonite (MMT) nanoclay reinforced epoxy resin was prepared to study the effect of nano filler on tensile and flexural properties of its nanocomposite. MMT was first sonicated for 2 hours with an acetone where the ratio was 50 mL acetone: 1g clay. After being sonicated the clay was added to an epoxy resin matrix at 80 °C and mixed until the acetone was removed. Tensile and flexural tests were investigated to understand the effect of clay on the mechanical properties of MMT reinforced epoxy nanocomposite. In general, the mechanical properties of MMT/epoxy nanocomposites were slightly increased as the clay loading was increased up to 1 phr. However, for the amount of nanoclay more than 1 phr the result showed significantly decrease in mechanical properties. It was found that by adding the nanoclay up to 1 phr, the Young’s and flexural modulus increased around 6.75% and 6.61%, respectively. Since the nanoclay has higher elastic modulus as compared to epoxy resin, the addition of clay increased the modulus of its nanocomposites. On the other hand, at 2 phr of nanoclay the tensile strength, Young’s modulus, flexural strength and flexural modulus deceased around 44.12%, 17.24%, 17.84% and 10.77% respectively compared to pure epoxy. For more than 1 phr of filler the clay distributions might not be well dispersed and thus more agglomerations occurred in the composites. It can be concluded that, 1 phr of MMT filler was the optimum amount that can be reinforced with epoxy resin in term of tensile and flexural properties.
Dynamic Mechanical Properties of PEG 4000 + Quartz Composites
Authors: Nur Aini Fauziyah , Musyarofah Musyarofah , Triwikantoro Triwikantoro , Mashuri Mashuri , Firdaus Sukma , Suminar Pratapa
Published: July 2015

The complex shear modulus of polyethylene glycol (PEG) 4000 + quartz compositesas a variation of processing temperature and applied temperature has been investigated using a Dynamic Mechanical Analysis (DMA) instrument. The quartz, obtained by processing silica sand from Tanah Laut, South Kalimantan, of as much as 40% by weight was used as the filler of the composite. The processing temperature was room temperature, 50°C, and 70°C after considering the theoretical melting point of PEG 4000. Results showed that such temperaturesgave several phenomena related with the complex modulus values from the pure PEG 4000 and the composite, i.e.they dropped with time indicating the presence of relatively rapid strain relaxation and were in the range of 50-300MPa. Furthermore, theaddition of quartz improved the values wherethe most improvement occurred on the 70°C sample,i.e. almost twice from the pure PEG 4000. Increasing the heating process, however, significantly reduced the values. The reduction was confirmed by further investigation where the result showed that the complex shear modulus value both in the pure PEG 4000 and the composite dropped with applied temperature at around 42°C and 45°C, respectively, whichcan be related to the melting PEG. A severe drop was particulartly observed in the composite which was believed caused by the addition of quartz in a lose powder form.
Development of Statues from Domestic Waste Composites Coated with Carboneus Phosphor Materials
Authors: Nurhanisa Mega , Abdullah Mikrajuddin
Published: July 2015

Various attempts have been made to solve problems of abundant solid wastes in big cities. One approach is the utilization of domestic waste to make composite materials, such as particle board. To increase the attractiveness of the product in this study we develop prototypes of statues using composites of domestic solid wastes and then coated the statues using carboneus phosphor material to produce artistic color under ultraviolet illumination. The composite materials were derived from domestic waste such as leaves, paper, and plastics as a filler and polyvinil acetate as a matrix. The coated material was a luminescent colloidal carbon particles that have been synthesized from urea ((NH2)2CO) and citric acid (C6H8O7) using a simple heating method. The colloidan carbon emits a luminescence peak at around 457 nm (blue color) under UV illumination. The produced statue from the domectic wastes composites we simply coated by a mixture of epoxy resin and phosphor material. Under UV light, the statue surface shows a bluish white luminescence.
Theoretical Investigation on Electronic Properties of ZnO Crystals Using DFT-Based Calculation Method
Authors: Darma Yudi , Setiawan Freddy Giovanni , Majidi Muhammad Aziz , Rusydi Andrivo
Published: July 2015

We study the electronic band structure and density of states (DOS) on ZnO material in various crystal structures : wurtzite (W), zincblende (ZB), and rocksalt (RS) phases. Calculations are based on Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA) for exchange-correlation functional and Hubbard correction to consider the strong electron correlations in 3d orbitals. After structural optimization, GGA results show that wurtzite and zincblende structures have a direct band gap of 0.749 eV and 0.637 eV, respectively, whereas rocksalt structure has an indirect band gap of 0.817 eV. Symmetrical shape of total DOS for spin up and spin down electrons indicates a zero total magnetic moment. For all ZnO structures, the upper valence band is formed by hybridization among O 2p and Zn 3d orbitals, while lower valence and conduction band are primarily filled by O 2s and Zn 4s, respectively. The GGA+U approach is found to improve the calculated band gaps and correct the position of Zn 3d state below Valence Band Maximum (VBM). From GGA+U, the band gaps for W-ZnO, ZB-ZnO, and RS-ZnO are 1.12 eV, 1.00 eV, and 1.11 eV, respectively.
Effect of Curing Temperature and Cross-Linker to Pre-Polymer Ratio on the Viscoelastic Properties of a PDMS Elastomer
Authors: Prabowo Firdaus , Wing-Keung Adrian Law , Shen Hayley H.
Published: July 2015

Viscoelastic samples made from a PDMS elastomer, Sylgard 184 (Dow Corning, USA), were prepared using 9.1% and 3% curing agent (cross-linker) and heat-cured with four curing temperatures from 25° to 150°C and four curing durations from 48 h to 25 min. Small amplitude oscillatory shear (SAOS) rheometry was done to examine their mechanical properties, represented by the storage (G’) and loss (G”) moduli. Generally, G’ and G” are dependent on the frequency, curing agent percentage and curing temperature. The samples were then reheated and SAOS tested again to check the stability of G’ and G”. It was apparent that the stability of G’ and G” are both strongly dependent on the curing temperature. Samples with the curing temperature of 25°C yielded almost up to 4 times change of G” value for 9.1% curing agent and more than 2 times change of G’ value for 3% curing agent. Hence, the usage of 25°C curing temperature at the manufacturer recommended curing time is not suitable for applications where the linear viscoelastic stability is important. In general, the stability also improves as the frequency increases for all samples.
Characterization of Chitosan-Acrylamide Hydrogels as Soil Conditioner
Authors: Basuki Kris Tri , Swantomo Deni , Sigit Sigit , Sanyoto Nugroho Tri
Published: July 2015

Hydrogels can be used as soil conditioner which acts as water reservoirs and release water depending upon the need of plant roots. Soil conditioner based hydrogels were synthesized by graft copolymerization of chitosan-acrylamide using gamma irradiation. In this research, the influence of hydrogels amounts on physical, and chemical properties of the sandy soil characterization were investigated by measuring bulk density of soil, porosity, water retention, and field capacity. Bulk density of the soil was decreased, whereas water retention and porosity were increased with increasing additions of hydrogels. The addition of 0.4% hydrogels increased the field capacity significantly. Biodegradation studies of the hydrogels were carried out by soil burial-test in a composting environment up to 6 weeks. Microscopy analysis shows structural deformation of hydrogels with time. Hydrogels show sharp weight loss until 4 weeks. Soil conditioner based chitosan-acrylamide hydrogels was found to be beneficial for maintaining the physicochemical soil properties as well as plant growth.
Cotton Thread for Size-Based Blood Cells Sorting
Authors: Yazdani Fahimeh , Sadir Sahba , Huyop Fahrul Zaman , Wicaksono Dedy Hermawan Bagus
Published: July 2015

We proposed cotton thread as a low cost platform for fabricating size-based cell sorting microfluidic chip. The cells and beads can be wicked through 3D structures of thread via capillary forces without any external forces. However, the major mechanism of capturing cell inside of thread was mechanical entrapment inside the gaps between the fibers. Cells sorting property based on their size was tuned by using multiple threads having different twist per inch (TPI). The fabricated device has 3 different zones from the inlet to the outlet where each zone has a different TPI which means different sizes of gaps. The results showed that small beads were trapped in thread which has more TPI and smaller gaps, while bigger beads were trapped in thread with less TPI and larger gaps. For proof of concept, blood as a complex mixture of cells with wide range of size was wicked into the fabricated device. The result showed efficient separation of red blood cells, white blood cells and plasma. The capability of cotton threads as a proper material for fabrication of size based cell sorting microfluidic devices was proved with higher simplicity and efficiency.