Biochar : A review of its history, characteristics, factors that influence its yield, methods of production, application in wastewater treatment and recent development

Biochar can alleviate several issues, and it should also be inexpensive to produce. Most biochars have a high pore structure and diverse functional groups that assist in the adsorption process. Due to the attributed properties of biochar, several studies have demonstrated that biochar is getting more attention for its efficiency in facilitating wastewater treatment. However, to ensure the feasibility of biochar in wastewater treatment, the factors involved in the preparation of biochar that influences its characteristics and adsorption capacity must be understood. This study reviews the history, characteristics, factors that influence its yield, production methods, application, and recent development of biochar in wastewater treatment

Effect of heating duration on the synthesis of silicon carbide nanotubes by microwave heating of MWCNTs and silica

In this article, the effect of heating duration on the synthesis of silicon carbide nanotubes (SiCNTs) was reported. SiCNTs were synthesized from blend of silicon dioxide (SiO2) and multi-walled carbon nanotubes (MWCNTs) in the ratio of 1:3 by using the microwave heating at 1400°C and maintained at duration of 20, 40 and 60 min, respectively. SiCNTs synthesized at heating duration of 40 and 60 min showed the presence of single phase β-SiC in X-ray diffraction patterns. Meanwhile, field emission scanning electron microscope images showed that SiCNTs were formed and no residual of SiO2 and MWCNTs was observed for SiCNTs formed at heating duration of 40 and 60 min. Transmission electron microscopy images showed the SiCNTs have inter-planar spacing of 0.263 nm and tubular structure of nanotube were retained. The peak corresponded to β-SiC was observed at wavelength of 465 nm from the photoluminescence spectroscopy and associated with energy band gap of 2.67 eV. Absorption bands of Si-C bond were detected at 806.23 cm-1 from the Fourier transform infrared spectra. High purity SiCNTs was obtained at 40 and 60 min as indicated by low weight loss by thermo-gravimetric analysis. 40 min is the most suitable heating duration for the synthesis of single phase β-SiCNTs

Voltammetric determination of human papillomavirus 16 DNA by using interdigitated electrodes modified with titanium dioxide nanoparticles

A gene sensor for rapid detection of the Human Papillomavirus 16 (HPV 16) which is associated with the appearance of cervical cancer was developed. The assay is based on voltammetric determination of HPV 16 DNA by using interdigitated electrodes modified with titanium dioxide nanoparticles. Titanium dioxide nanoparticles (NPs) were used to modify a semiconductor-based interdigitated electrode (IDE). The surface of the NPs was then functionalized with a commercial 24-mer oligomer DNA probe for HPV 16 that was modified at the 5′ end with a carboxyl group. If the probe interacts with the HPV 16 ssDNA, the current, best measured at a working voltage of 1.0 V, increases. The gene sensor has has a ∼ 0.1 fM limit of detection which is comparable to other sensors. The dielectric voltammetry analysis was carried out from 0 V to 1 V. The electrochemical sensitivity of the IDE is 2.5 × 10⁻⁵ μA·μM⁻¹·cm⁻². Graphical abstractSchematic of an interdigitated electrode (IDE) modified with titanium dioxide nanoparticles for voltammetric determination of HPV 16 DNA by using an appropriate DNA probe

Expression of truncated chalcone synthase from Boesenbergia rotunda L. mansf. in Escherichia coli

Chalcone synthase (CHS) is an entrance enzyme in the biosynthetic pathway of different flavonoids compound and become a critical regulatory enzyme. Truncated CHS was isolated from Boesenbergia rotunda (B. rotunda), also known as Chinese ginger, which is a medicinal and culinary herb from China and Southeast Asia. The popularity of its medicinal usage has drawn the attention of scientists to investigate on its medicinal properties. This research is a fundamentals works to study on the mechanism of truncated CHS from B. rotunda in E. coli. This study is new for this plant but CHS has been studied by many researchers in other plants. Optimization of B. rotunda specific CTAB RNA extraction method developed in this study was able to produce high yield of RNA with minimum polysaccharide contamination. The value of RNA yield for optimization of B. rotunda specific CTAB RNA extraction method was 2.0 μg/g. A reverse transcriptase-polymerase chain reaction (RT-PCR) based approach was used to identify and isolate a partial-length cDNA coding for CHS gene. The gene encoding truncated CHS from B. rotunda was cloned into pTrcHis2 expression vector and placed under the control of the trc promoter for high level expression in E. coli. The effect of inducer concentration and induction time on CHS production from inducible system was evaluated. The recombinant truncated CHS protein was characterized and optimized for higher expression. The optimization of the recombinant truncated CHS production of inducible system in 50 ml culture was done for the best clone truncated CHS from E.coli TOP10. The effect of IPTG concentration and induction time on truncated CHS production from inducible system was evaluated. A time course profile of recombinant truncated CHS production with the optimized condition was performed and produced after 16 h of induction time from recombinant truncated CHS5, while optimal IPTG concentration was 0.5 mM. The recombinant truncated CHS was purified by using affinity chromatography and Ion-Exchange Chromatography (IEX). The expressed CHS protein had a molecular weight of about 21 kDa, a size that matched with the prediction by bioinformatic analysis. Truncated CHS was highly active at 40oC, pH 8.0 with a half-life of 1 h 10 min at 30oC. 3D structure of truncated CHS from B. rotunda was predicted using CHS from alfalfa (Medicago sativa) as a template with sequence identity 74.87%. Tyr-42, His-130 and Asp-163 were assigned as catalytic triad residues. Truncated CHS was evaluated with Ramachandran plot, Verify 3D and ERRAT to validate the structure. This study may provide useful information on this enzyme and its function in the flavonoids biosynthetic pathway in B. rotunda that offers significant pharmaceutical properties for human health

Human Papillomavirus E6 biosensing: current progression on early detection strategies for cervical cancer

Prognosis of early cancer detection becomes one of the tremendous issues in the medical health system. Medical debates among specialist doctor and researcher in therapeutic approaches became a hot concern for cervix cancer deficiencies early screening, risk factors cross-reaction, portability device, rapid and free labeling system. The electrical biosensing based system showed credibility in higher specificity and selectivity due to hybridization of DNA duplex between analyte target and DNA probes. Electrical DNA sensor for cervix cancer has attracted too many attentions to researcher notification based on high performance, easy to handle, rapid system and possible to miniaturize. This review explores the current progression and future insignificant for HPV E6 genobiosensing for early Detection Strategies of Cervical Cancer

Electrochemical sensory detection of Sus scrofa mtDNA for food adulteration using hybrid Ferrocenylnaphthalene Diimide intercalator as hybridization indicator

In this study, an electrochemical DNA biosensor was developed based on the fabrication of silicon nanowires/platinum nanoparticles (SiNWs/PtNPs) on a screen-printed carbon electrode (SPCE) for the detection of Sus scrofa mitochondrial DNA (mtDNA) in food utilizing a new hybrid indicator, ferrocenylnaphthalene diimide (FND). The morphology and elemental composition of the SiNWs/PtNPs-modified SPCE was analyzed by field emission scanning electron microscopy (FESEM) combined with energy dispersive X-ray spectroscopy (EDX). Cyclic voltammetry (CV) was used to study the electrical contact between the PtNPs and the screen-printed working electrode through SiNWs, while electrochemical impedance spectroscopy (EIS) was used to measure the charge transfer resistance of the modified electrode. The results clearly showed that the SiNWs/PtNPs were successfully coated onto the electrode and the effective surface area for the SiNWs/PtNPs-modified SPCE was increased 16.8 times as compared with that of the bare SPCE. Differential pulse voltammetry used for the detection of porcine DNA with FND as an intercalator confirmed its specific binding to the double-stranded DNA (dsDNA) sequences. The developed biosensor showed a selective response towards complementary target DNA and was able to distinguish non-complementary and mismatched DNA oligonucleotides. The SiNWs/PtNPs-modified SPCE that was fortified with DNA hybridization demonstrated good linearity in the range of 3 × 10−9 M to 3 × 10−5 M (R2 = 0.96) with a detection limit of 2.4 × 10−9 M. A cross-reactivity study against various types of meat and processed food showed good reliability for porcine samples

Electrochemical DNA biosensor based on 30 nM gold nanoparticle modified electrode by electro less deposition for Human Papillomavirus (HPV) 18 E6 Region

The aim of this work was to develop a novel, simple, inexpensive, sensitive an electrochemical DNA biosensor based on interdigitated electrodes (IDEs) integrated gold nanoparticle modified electrode by electro less deposition for HPV 18. The biosensor was designed with a 30 mer E6 region of HPV 18 DNA modified probe. The E6 region has been used for their clinical importance properties and suitable as recognition biomarker region. Three different target types were tested which complementary target, non complementary target and mismatch target. All target were analyzed for detection of HPV 18 in early stages by using Dielectric Analyzer (DA), Alpha-A High- performance Frequency Analyzer, Novocontrol Technologies, Handsagen, Germany associated with the software package Windeta. Complementary target gives a positive result in HPV detection, while noncomplementary and mismatch target give negative results. IDE device with 5 nm gap sizes has demonstrated a high performance towards the detection of HPV18 ssDNA target by modified with 30 nm gold nanoparticle. The electrochemical biosensor showed better performance compared to agarose gel electrophoresis assay. This technology can be used as a new and attractive sensor development for detection of virus infection in human bodies

Controlling Arsenic Accumulation in Rice Grain under Nanomaterials-Assisted Optimal Greenhouse Set-Up

Rice is being increasingly exposed to inorganic arsenic and this affects half of the world population because they are rice consumers. In this study, pot experiments were carried out to investigate the effect of two dose-dependent nanomaterials (silica and graphene) treatment on varied arsenic levels (2, 7 and 12 mg/kg). The results showed that both nanomaterials were affected significantly with 1 mg/mL of nanomaterial. Arsenic adversely affected the plant height, tillering, number of grains, and grain weight and when high concentrations of arsenic were applied at 12 mg/kg, the plant could not withstand it and died before 75 days even in the presence of graphene. Based on inductively coupled plasma mass spectrometry analysis, silica nanoparticles showed the highest inhibition on the total accumulation of arsenic as 93% (control plant), 84% (2 mg/kg), 67% (7 mg/kg) to 35 % (12 mg/kg), whereas graphene showed lower inhibition percentages. This outcome confirms that silica nanoparticles prevent arsenic uptake, because they translocate from the root to the grains and are able to offer a promising way to reduce consumer health risk

Designing DNA probe from HPV 18 and 58 in the E6 region for sensing element in the development of genosensor-based gold nanoparticles

The E6 region has higher protuberant probability annealing than consensus probe focusing on another region in the human papillomavirus (HPV) genome in terms of detection and screening method. Here, we designed the first multiple virus single-stranded deoxyribonucleic acid (ssDNA) for multiple detections in an early phase of screening for cervical cancer in the E6 region and became a fundamental evolution of detection electrochemical HPV biosensor. Gene profiling of the virus ssDNA sequences has been carried by high-end bioinformatics tools such as GenBank, Basic Local Alignment Searching Tools (BLAST), and Clustal OMEGA in a row. The output from bioinformatics tools resulted in 100% of similarities between our virus ssDNA probe and HPV complete genome in the databases. The cross-validation between HPV genome and our designed virus ssDNA provided high specificity and selectivity during screening methods compared with Pap smear. The DNA probe for HPV 18, 5' COOH-GAT CCA GAA GGT ACA GAC GGG GAG GGC ACG 3', while 5'COOH-GGG CGC TGT GCA GTG TGT TGG AGA CCC CGA3' as DNA probe for HPV 58 designed with 66.77% guanine (G) and cytosine (C) content for both. Our virus ssDNA probe for the HPV biosensor promises high sensitivity, specificity, selectivity, repeatability, low fluid consumption, and will be useful in mini-size diagnostic devices for cervical cancer detection