Search

Laccase enzyme has gained popularity due to its wide range of substrates, use of only molecular oxygen as a co-factor and release of water as a by-product. In order to improve its reusability in harsh conditions, various supports have been explored for its immobilization. In this study, laccase was immobilized on zinc oxide-chitosan/polyvinylpolypyrolidone (ZnONPs/CS/PVPP) and silver doped zinc oxide-chitosan/polyvinylpolypyrolidone (Ag@ZnONPs/CS/PVPP) beads. The Ag@ZnONPs/CS/PVPP beads showed a higher immobilization yield and retained enzyme activity (76.0% and 50.0% respectively) compared to the ZnONPs/CS/PVPP beads (50.4% and 41.7% respectively). The biocatalysts demonstrated improved enzyme stability at higher temperatures and longer storage stability compared to the free enzyme hence show potential for further biotechnological applications.

Abstract Photoactive supramolecular porphyrin assemblies are attractive molecules for light‐harvesting applications. This is due to their relatively non‐toxicity, biological activities and charge and energy exchange characteristics. However, the extreme cost associated with their synthesis and requirements for toxic organic solvents during purification pose a challenge to the sustainability characteristics of their applications. This work presents the first report on the sustainable synthesis, spectroscopic and photophysical characterizations of a near‐infrared (NIR) absorbing Ca(II)‐meso‐tetrakis (4‐hydroxyphenyl)porphyrin using an electrolyzed pyrrole solution. The latter was obtained by cycling the pyrrole solution across the silver nanodumbbell particle surface at room temperature. The electrolyzed solution condensed readily with acidified p‐hydroxybenzaldehyde, producing the targeted purple porphyrin. The non‐electrolyzed pyrrole solution formed a green substance with significantly different optical properties. Remarkable differences were observed in the voltammograms of the silver nanodumbbell particles and those of the conventional gold electrode during the pyrrole cycling, suggesting different routes of porphyrin formation. The rationale behind these formations and the associated mechanisms were extensively discussed. Metalation with aqueous Ca2+ ion caused a Stokes shift of 38.75 eV. The current study shows the advantage of the electrochemical method towards obtaining sustainable light‐harvesting porphyrin at room temperature without the need for high‐energy‐dependent conventional processes.

This article describes a novel electrochemical on-chip biosensor that utilises the anti-PSA antibody (Ab) and silver nanoparticles (AgNPs) to enhance the sensing and detection capability of the prostate-specific antigen (PSA) in the blood. The AgNPs are prepared, characterised, and applied to a silicon photonic on-chip biosensing receptor platform designed to enhance the accurate detection of PSA. The AgNPs were synthesised by a chemical reduction method using silver nitrate (AgNO3) as the precursor. Transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersion X-ray spectroscopy (EDS), small angle X-ray scattering (SAXS), X-ray diffraction (XRD), and light microscopy were among the methods used in the characterisation and analysis of the AgNPs. Each stage of the immunosensor fabrication was characterised using cyclic voltammetry. The proposed immunosensor was applied in the detection of PSA, a prostate cancer biomarker, with a high sensitivity and a limit of detection of 0.17 ng/mL over a linear concentration range of 2.5 to 11.0 ng/mL. The immunosensor displayed good stability and was selective in the presence of interfering species like immunoglobulin (Ig) in human serum, ascorbic acid (AA), and diclofenac (Dic). The detectivity and sensitivity are significantly higher than previous reports on similar or related technologies.

Tuberculosis (TB) is a worldwide burden whose total control and eradication remains a challenge due to factors including false positive/negative diagnoses associated with the poor sensitivity of the current diagnostics in immune-compromised and post-vaccinated individuals. As these factors complicate both diagnosis and treatment, the early diagnosis of TB is of pivotal importance towards reaching the universal vision of a TB-free world. Here, an aptasensor for signaling an interferon gamma (IFN-γ) TB biomarker at low levels is reported. The aptasensor was assembled through gold–thiol interactions between poly(3,4-propylenedioxythiophene), gold nanoparticles, and a thiol-modified DNA aptamer specific to IFN-γ. The aptasensor sensitively detected IFN-γ in spiked pleural fluid samples with a detection limit of 0.09 pg/mL within a linear range from 0.2 pg/mL to 1.2 pg/mL. The good performance of the reported aptasensor indicates that it holds the potential for application in the early diagnosis of, in addition to TB, various diseases associated with IFN-γ release in clinical samples.

Herein, a sulphate enhanced photoelectrochemical degradation method using peroxymonosulfate (PEC/PMS) and FTO-Bi2WO6 as photoanode is reported. The FTO-Bi2WO6 electrode was fabricated through electrodeposition and calcination route. The FTO-Bi2WO6 produced a good photocurrent response of up to 6.62 μAcm−2 with an applied potential of 1.5 V (vs Ag/AgCl). When the electrode was applied for PEC/PMS degradation of pharmaceuticals, 98%, 83% and 79% removal was recorded for sulfamethoxazole, diclofenac chloride and tetracycline, respectively within 90 min with a bias potential of 1.0 V and 3 mM PMS. Hence, the PEC/PMS system with FTO-Bi2WO6 photoanode is suitable for the removal of pharmaceuticals in wastewater.

Exfoliated graphite is a 2D carbon material that has recently received great attention owing to its remarkable analytical merits such as fast electron migration, ease of surface regeneration, high-temperature resistance, ability to withstand high-current density, excellent conductivity, and sensitivity. Due to its excellent analytical signature, an exfoliated graphite electrode has been reportedly used in the construction of sensors and biosensors for various applications. This electrode can be used alone or blended with several nanomaterials/semiconductors for the degradation of various organic pollutants in wastewater. Despite the outstanding results reported in the use of exfoliated graphite electrodes for various analytical applications, very few reports were documented in the literature. Therefore, this review elaborated on the importance of exfoliated graphite electrodes for electrochemical analysis.

17β-estradiol (E2) is an important natural female hormone that is also classified as an estrogenic endocrine-disrupting compound (e-EDC). It is, however, known to cause more damaging health effects compared to other e-EDCs. Environmental water systems are commonly contaminated with E2 that originates from domestic effluents. The determination of the level of E2 is thus very crucial in both wastewater treatment and in the aspect of environmental pollution management. In this work, an inherent and strong affinity of the estrogen receptor-α (ER-α) for E2 was used as a basis for the development of a biosensor that was highly selective towards E2 determination. A gold disk electrode (AuE) was functionalised with a 3-mercaptopropionic acid-capped tin selenide (SnSe-3MPA) quantum dot to produce a SnSe-3MPA/AuE electroactive sensor platform. The ER-α-based biosensor (ER-α/SnSe-3MPA/AuE) for E2 was produced by the amide chemistry of carboxyl functional groups of SnSe-3MPA quantum dots and the primary amines of ER-α. The ER-α/SnSe-3MPA/AuE receptor-based biosensor exhibited a formal potential (E0′) value of 217 ± 12 mV, assigned as the redox potential for monitoring the E2 response using square-wave voltammetry (SWV). The response parameters of the receptor-based biosensor for E2 include a dynamic linear range (DLR) value of 1.0–8.0 nM (R2 = 0.99), a limit of detection (LOD) value of 1.69 nM (S/N = 3), and a sensitivity of 0.04 µA/nM. The biosensor exhibited high selectivity for E2 and good recoveries for E2 determination in milk samples.

In this work, the effect of carbon on the electrochemical properties of multiwalled carbon nanotube (MWCNT) functionalized lithium iron manganese phosphate was studied. In an attempt to provide insight into the structural and electronic properties of optimized electrode materials, a systematic study based on a combination of structural and spectroscopic techniques was conducted. The phosphor-olivine LiFe0.5Mn0.5PO4 was synthesized via a simple microwave synthesis using LiFePO4 and LiMnPO4 as precursors. Cyclic voltammetry was used to evaluate the electrochemical parameters (electron transfer and ionic diffusivity) of the LiFe0.5Mn0.5PO4 redox couples. The redox potentials show two separate distinct redox peaks that correspond to Mn2+/Mn3+ (4.1 V vs Li/Li+) and Fe2+/Fe3+ (3.5 V vs Li/Li+) due to interaction arrangement of Fe-O-Mn in the olivine lattice. The electrochemical impedance spectroscopy (EIS) results showed LiFe0.5Mn0.5PO4-MWCNTs have high conductivity with reduced charge resistance. This result demonstrates that MWCNTs stimulate faster electron transfer and stability for the LiFe0.5Mn0.5PO4 framework, which demonstrates to be favorable as a host material for Li+ ions.

The purpose of this paper is to see the potential Batik Bakaran in the district. Pati, Central Java which experienced ups and downs and has not been able to compete with other batik areas. Batik Bakaran is again encouraged through creative government economic program in in order to be able to compete in national level industry. This paper uses descriptive qualitative methods, with data collection techniques using "librarian research" and "interview" techniques. The results of this study indicates that the government has provided support to batik craftsmen. Government assistance is displayed by developing human resources through training to stimulate the innovation of batik craftsmen in terms of the creation of Batik Bakaran motifs and colors to be more attractive to consumers. But apparently it has not been able to improve the competitiveness of Batik Bakaran in the national industry. Solutions to overcome these problems is to apply the concept of competitiveness through the development of the capabilities of the batik Bakaran industry players include: (1) ability to strengthen its market position, (2) ability to connect with its environment, (3) ability to improve nonstop performance, and (4) ability to establish favorable position.

Graphitic carbon nitride (g-C3N4) is a two-dimensional conjugated polymer that has attracted the interest of researchers and industrial communities owing to its outstanding analytical merits such as low-cost synthesis, high stability, unique electronic properties, catalytic ability, high quantum yield, nontoxicity, metal-free, low bandgap energy, and electron-rich properties. Notably, graphitic carbon nitride (g-C3N4) is the most stable allotrope of carbon nitrides. It has been explored in various analytical fields due to its excellent biocompatibility properties, including ease of surface functionalization and hydrogen-bonding. Graphitic carbon nitride (g-C3N4) acts as a nanomediator and serves as an immobilization layer to detect various biomolecules. Numerous reports have been presented in the literature on applying graphitic carbon nitride (g-C3N4) for the construction of electrochemical sensors and biosensors. Different electrochemical techniques such as cyclic voltammetry, electrochemiluminescence, electrochemical impedance spectroscopy, square wave anodic stripping voltammetry, and amperometry techniques have been extensively used for the detection of biologic molecules and heavy metals, with high sensitivity and good selectivity. For this reason, the leading drive of this review is to stress the importance of employing graphitic carbon nitride (g-C3N4) for the fabrication of electrochemical sensors and biosensors.

Dossier Comunicación y Drogas. Al evaluar tres de los informes relevantes de los "think-tanks" conservadores respecto a las drogas en América Latina, las conclusiones son inquietantes. Los documentos del Center for Strategic and International Studies, de la Heritage Foundation y del Comité Santa Fe I comparten un criterio básico: La militarización de la lucha anti-narcótlcos: Las recomendaciones que emanan de estos trabajos son claras: Construir fuerzas anti-droqas de carácter multilateral, incrementar la asistencia militar para combatir el narcotráfico y reforzar las acciones represivas contra el "narco-terrorisrno" y las "narcoquerrillas.

Dossier Comunicación y Drogas. Las campañas de conciencia pública son vitales para el éxito de los programas de reducción de la demanda. Su propósito es hacer que el público comprenda los peligros de consumo de drogas y promover la participación pública en la guerra contra ellas. Estos programas pueden ser bastante efectivos en la creación de un clima que desaliente el uso ilegal de las drogas.

Drainage of peatlands all around the world for agricultural or forestry purposes has resulted in extensive land degradation, in this case the result of changes in soil physical properties resulting from an increase in the rate of microbial decomposition. Changes in the use of tropical peatlands as agricultural or plantation lands will cause an increase in CO2 emissions into the atmosphere. The clearing of peatlands which is preceded by the construction of channels (drainage) will cause the water table in the peatlands to become far away from the surface, this will drive the decomposition rate of organic matter by microorganisms, which finally, the peat becomes susceptible to burning (fires). Therefore, the understanding of CO2 emissions is very important for planning the drainage systems, in order to conserve peatland. The balance of C in the peat ecosystem is the amount of flux or loss of C, which is influenced by fluctuations in the water table or groundwater content and the characteristics of the changing peat, as well as other environmental factors. The results of this study show that: CO2 emission fluctuations are between 126.51±16.22 mg C m-2 hour-1 to 753.23±307.57 mg C m-2 hour-1. The highest CO2 emission is found in plot P1 (open land conditions and only dominated by shrubs, while the lowest CO2 emission is found in plot P3 (plants aged 3 - 4 years). This condition is different in different season conditions, where the highest CO2 emissions found in revegetation locations with Shorea balangeran plant species aged 3 - 4 years (P3), then followed by revegetation locations with Shorea balangeran plant species aged 1 - 2 years and the open location (open area) and changes in land cover will affect CO2 emissions, because the root system of each plant will be different. [ABSTRACT FROM AUTHOR]

We report a simple and cheaper method for the electrochemical detection of Se(IV) using carbon nanodots (CNDTs) prepared from oat. The carbon nanodots were synthesised by a green and facile approach and characterised using scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and Raman spectroscopy. The CNDT was used to fabricate an electrochemical sensor for the quantification of Se(IV) in water. The modification of the glassy carbon electrode (GCE) with carbon nanodots led to an increase in the electroactive surface area of the electrode, which enhances the redox current peak of [Fe(CN)6]3–/4– in comparison to the bare GCE. Using the square wave voltammetry, the detection limit and quantification limit of 0.05 and 0.167 ppb were obtained under the optimised parameters using deposition potential of −200 mV, 0.1 M HNO3 electrolyte, electrodeposition time of 60 s, and pH 1. The results further revealed that the GCE-CNDT was not susceptible to many interfering cations except Cu(II) and Pb(II) and Fe(II). The sensor fabrication involves a one-step electrode modification and was used to detect Se(IV) in a real water sample and the result obtained is in agreement with the inductively coupled plasma technique. Overall, the electrode offers a cheap, fast and sensitive way of detecting selenium in environmental matrices.

Abstract Based on the 2008 DIY Gubernatorial of Number 21 LOD has the authority to supervise to the issue of mismanagement in the public service in Daerah Istimewa Yogyakarta (DIY), LOD is not designed to be an extra judiciary. Institution of the ombudsman as an institution of government control in handling and becamea symbol of the area who want to create good governance, efforts to prevent corruption, protecting the public, and implement democracy by providing good service to the community. Key words: Ombudsman, Authority, Democratic institutions