Biosensor for detection of dissolved chromium in potable water: A review

The unprecedented deterioration rate of the environmental quality due to rapid urbanization and industrialization causes a severe global health concern to both ecosystem and humanity. Heavy metals are ubiquitous in nature and being used extensively in industrial processes, the exposure to excessive levels could alter the biochemical cycles of living systems. Hence the environmental monitoring through rapid and specific detection of heavy metal contamination in potable water is of paramount importance. Various standard analytical techniques and sensors are used for the detection of heavy metals include spectroscopy and chromatographic methods along with electrochemical, optical waveguide and polymer based sensors. However, the mentioned techniques lack the point of care application as it demands huge capital cost as well as the attention of expert personnel for sample preparation and operation. Recent advancements in the synergetic interaction among biotechnology and microelectronics have advocated the biosensor technology for a wide array of applications due to its characteristic features of sensitivity and selectivity. This review paper has outlined the overview of chromium toxicity, conventional analytical techniques along with a particular emphasis on electrochemical based biosensors for chromium detection in potable water. This article emphasized porous silicon as a host material for enzyme immobilization and elaborated the working principle, mechanism, kinetics of an enzyme-based biosensor for chromium detection. The significant characteristics such as pore size, thickness, and porosity make the porous silicon suitable for enzyme entrapment. Further, several schemes on porous silicon-based immobilized enzyme biosensors for the detection of chromium in potable water are proposed.

Bioactivation of titanium dioxide scaffolds by ALP-functionalization

Three dimensional TiO₂ scaffolds are receiving renewed attention for bone tissue engineering (TE) due to their biocompatibility and attractive mechanical properties. However the bioactivity of these scaffolds is comparatively lower than that of bioactive glass or hydroxyapatite (HA) scaffolds. One strategy to improve bioactivity is to functionalize the surface of the scaffolds using biomolecules. Alkaline phosphatase (ALP) was chosen in this study due to its important role in the bone mineralization process. The current study investigated the ALP functionalization of 3D titanium dioxide scaffolds using self-polymerization of dopamine. Robust titanium scaffolds (compressive strength∼2.7 ± 0.3 MPa) were produced via foam replica method. Enzyme grafting was performed by dip-coating in polydopamine/ALP solution. The presence of ALP was indirectly confirmed by contact angle measurements and enzymatic activity study. The influence of the enzyme on the bioactivity, e.g. hydroxyapatite formation on the scaffold surface, was measured in simulated body fluid (SBF). After 28 days in SBF, 5 mg ALP coated titania scaffolds exhibited increased hydroxyapatite formation. It was thus confirmed that ALP enhances the bioactivity of titania scaffolds, converting an inert bioceramic in an attractive bioactive system for bone TE.

Frequency of rare BCR-ABL1 fusion transcripts in chronic myeloid leukemia patients

INTRODUCTION

The hallmark of chronic myeloid leukemia (CML) is the presence of Philadelphia chromosome, its resultant fusion transcript (BCR-ABL1), and fusion protein (p210). Alternate breakpoints in BCR (m-bcr, μ-bcr, and others) or ABL1 result in the expression of few rare fusion transcripts (e19a2, e1a2, e13a3, e14a3) and fusion proteins (p190, p200, p225) whose exact clinical significance remains to be determined.

METHODS

Our study was designed to determine the type and frequency of BCR-ABL1 fusion transcripts in 1260 CML patients and to analyze the prognosis and treatment response in patients harboring rare BCR-ABL1 fusion transcripts.

RESULTS

The frequency of various BCR-ABL1 fusion transcripts was as follows: e14a2 (60%), e13a2 (34.3%), e1a2 (1.2%), e1a2 + e13a2 (2.0%), e1a2 + e14a2 (1.8%), e19a2 (0.3%), and e14a3 (0.3%). CML patients with e1a2 transcripts had higher rates of disease progression, resistance, or suboptimal response to imatinib and failed to achieve major molecular response.

CONCLUSION

Characterization of the specific fusion transcript in CML patients is important owing to the difference in prognosis and response to therapy in addition to the conventional need for monitoring treatment response. CML patients with e1a2 transcripts have to be closely monitored due to the high incidence of disease progression and treatment resistance/failure.

Draft Genome of the Wheat Rust Pathogen (Puccinia triticina) Unravels Genome-Wide Structural Variations during Evolution

Leaf rust is one of the most important diseases of wheat and is caused by Puccinia triticina, a highly variable rust pathogen prevalent worldwide. Decoding the genome of this pathogen will help in unraveling the molecular basis of its evolution and in the identification of genes responsible for its various biological functions. We generated high quality draft genome sequences (approximately 100- 106 Mb) of two races of P. triticina; the variable and virulent Race77 and the old, avirulent Race106. The genomes of races 77 and 106 had 33X and 27X coverage, respectively. We predicted 27678 and 26384 genes, with average lengths of 1,129 and 1,086 bases in races 77 and 106, respectively and found that the genomes consisted of 37.49% and 39.99% repetitive sequences. Genome wide comparative analysis revealed that Race77 differs substantially from Race106 with regard to segmental duplication (SD), repeat element, and SNP/InDel characteristics. Comparative analyses showed that Race 77 is a recent, highly variable and adapted Race compared with Race106. Further sequence analyses of 13 additional pathotypes of Race77 clearly differentiated the recent, active and virulent, from the older pathotypes. Average densities of 2.4 SNPs and 0.32 InDels per kb were obtained for all P. triticina pathotypes. Secretome analysis demonstrated that Race77 has more virulence factors than Race 106, which may be responsible for the greater degree of adaptation of this pathogen. We also found that genes under greater selection pressure were conserved in the genomes of both races, and may affect functions crucial for the higher levels of virulence factors in Race77. This study provides insights into the genome structure, genome organization, molecular basis of variation, and pathogenicity of P. triticina The genome sequence data generated in this study have been submitted to public domain databases and will be an important resource for comparative genomics studies of the more than 4000 existing Puccinia species.

Rationale and efficacy of proteasome inhibitor combined with arsenic trioxide in the treatment of acute promyelocytic leukemia

Arsenic trioxide (ATO) mediates PML-RARA (promyelocytic leukemia-retinoic acid receptor-α) oncoprotein degradation via the proteasome pathway and this degradation appears to be critical for achieving cure in acute promyeloytic leukemia (APL). We have previously demonstrated significant micro-environment-mediated drug resistance (EMDR) to ATO in APL. Here we demonstrate that this EMDR could be effectively overcome by combining a proteasome inhibitor (bortezomib) with ATO. A synergistic effect on combining these two agents in vitro was noted in both ATO-sensitive and ATO-resistant APL cell lines. The mechanism of this synergy involved downregulation of the nuclear factor-κB pathway, increase in unfolded protein response (UPR) and an increase in reactive oxygen species generation in the malignant cell. We also noted that PML-RARA oncoprotein is effectively cleared with this combination in spite of proteasome inhibition by bortezomib, and that this clearance is mediated through a p62-dependent autophagy pathway. We further demonstrated that proteasome inhibition along with ATO had an additive effect in inducing autophagy. The beneficial effect of this combination was further validated in an animal model and in an on-going clinical trial. This study raises the potential of a non-myelotoxic proteasome inhibitor replacing anthracyclines in the management of high-risk and relapsed APL.

Retention of laryngoscopy skills in medical students: a randomised, cross-over study of the Macintosh, A.P. Advance(™) , C-MAC(®) and Airtraq(®) laryngoscopes

In addition to being effective and easy to learn how to use, the ideal laryngoscope should be associated with minimal reduction in skill performance during gaps in practice over time. We compared the time taken to intubate the trachea of a manikin by novice medical students immediately after training, and then after 1 month, with no intervening practice. We designed a two-period, four-group, randomised, cross-over trial to compare the Macintosh, Venner(™) A.P. Advance(™) with difficult airway blade, C-MAC(®) with D-Blade and Airtraq(®) with wireless video-viewer. A bougie was used to aid intubation with the Macintosh and the C-MAC. After training, there was no significant difference in median (IQR [range]) intubation time using the videolaryngoscopes compared with the Macintosh, which took 30 (26.5-35 [12-118])s. One month later, the intubation time was longer using the C-MAC (41 (29.5-52 [20-119])s; p = 0.002) and A.P. Advance (40 (28.5-57.5 [21-107])s; p = 0.0003)m compared with the Macintosh (27 (21-29 [16-90])s); there was no difference using the Airtraq (27 (20.5-32.5 [15-94])s; p = 0.258) compared with the Macintosh. While skill acquisition after a brief period of learning and practice was equal for each laryngoscope, performance levels differed after 1 month without practice. In particular, the consistency of performance using the C-MAC and A.P. Advance was worse compared with the Macintosh and the Airtraq. While the clinical significance of this is doubtful, we believe that reliable and consistent performance at laryngoscopy is desirable; for the devices that we tested, this requires regular practice.

ASIC-based design of NMR system health monitor for mission/safety-critical applications

N-modular redundancy (NMR) is a generic fault tolerance scheme that is widely used in safety–critical circuit/system designs to guarantee the correct operation with enhanced reliability. In passive NMR, at least a majority (N + 1)/2 out of N function modules is expected to operate correctly at any time, where N is odd. Apart from a conventional realization of the NMR system, it would be useful to provide a concurrent indication of the system’s health so that an appropriate remedial action may be initiated depending upon an application’s safety criticality. In this context, this article presents the novel design of a generic NMR system health monitor which features: (i) early fault warning logic, that is activated upon the production of a conflicting result by even one output of any arbitrary function module, and (ii) error signalling logic, which signals an error when the number of faulty function modules unfortunately attains a majority and the system outputs may no more be reliable. Two sample implementations of NMR systems viz. triple modular redundancy and quintuple modular redundancy with the proposed system health monitoring are presented in this work, with a 4-bit ALU used for the function modules. The simulations are performed using a 32/28 nm CMOS process technology.

Area/latency optimized early output asynchronous full adders and relative-timed ripple carry adders

This article presents two area/latency optimized gate level asynchronous full adder designs which correspond to early output logic. The proposed full adders are constructed using the delay-insensitive dual-rail code and adhere to the four-phase return-to-zero handshaking. For an asynchronous ripple carry adder (RCA) constructed using the proposed early output full adders, the relative-timing assumption becomes necessary and the inherent advantages of the relative-timed RCA are: (1) computation with valid inputs, i.e., forward latency is data-dependent, and (2) computation with spacer inputs involves a bare minimum constant reverse latency of just one full adder delay, thus resulting in the optimal cycle time. With respect to different 32-bit RCA implementations, and in comparison with the optimized strong-indication, weak-indication, and early output full adder designs, one of the proposed early output full adders achieves respective reductions in latency by 67.8, 12.3 and 6.1 %, while the other proposed early output full adder achieves corresponding reductions in area by 32.6, 24.6 and 6.9 %, with practically no power penalty. Further, the proposed early output full adders based asynchronous RCAs enable minimum reductions in cycle time by 83.4, 15, and 8.8 % when considering carry-propagation over the entire RCA width of 32-bits, and maximum reductions in cycle time by 97.5, 27.4, and 22.4 % for the consideration of a typical carry chain length of 4 full adder stages, when compared to the least of the cycle time estimates of various strong-indication, weak-indication, and early output asynchronous RCAs of similar size. All the asynchronous full adders and RCAs were realized using standard cells in a semi-custom design fashion based on a 32/28 nm CMOS process technology.

AN EFFICIENT RECOVERY OF TRANSGENIC PLANTS FROM A TROPICAL INDIAN MAIZE INBRED LINE

Tropical Indian maize inbreds are known for their recalcitrance in tissue culture which is a prerequisite for development of transgenic lines from such cultivars. In the present study, particle bombardment-mediated transformation of a tropical Indian maize inbred line, UMI29 was attempted. Parameters that infulence transforamation efficiency such as size of embryo (1.5 mm and 2.0 mm), micro-carrier flying distance (6 cm and 9 cm) and post-bombardment resting period (2, 7 and 10 days) on transient and stable expression of transgene were investigated. The greatest transformation efficiency of 2.67% was obtained using immature embryos of 1.5 mm at 6 cm of microcarrier flying distance with a resting period of 2 days. Stable inheritance of transgenes, viz., gusA and bar was confirmed in T1 lines.

Importance of Reaction Kinetics and Oxygen Crossover in aprotic Li-O2 Batteries Based on a Dimethyl Sulfoxide Electrolyte

Although still in their embryonic state, aprotic rechargeable Li-O2 batteries have, theoretically, the capabilities of reaching higher specific energy densities than Li-ion batteries. There are, however, significant drawbacks that must be addressed to allow stable electrochemical performance; these will ultimately be solved by a deeper understanding of the chemical and electrochemical processes occurring during battery operations. We report a study on the electrochemical and chemical stability of Li-O2 batteries comprising Au-coated carbon cathodes, a dimethyl sulfoxide (DMSO)-based electrolyte and Li metal negative electrodes. The use of the aforementioned Au-coated cathodes in combination with a 1 M lithium bis(trifluoromethane)sulfonimide (LiTFSI)-DMSO electrolyte guarantees very good cycling stability (>300 cycles) by minimizing eventual side reactions. The main drawbacks arise from the high reactivity of the Li metal electrode when in contact with the O2 -saturated DMSO-based electrolyte.

Fruiting Phenology of a Scrub Forest in Thiruporur, Eastern Ghats, India

This paper describes the fruiting phenology of 110 individuals of woody species belonging to 22 taxa (21 species, 1 variety) belonging to 15 families including 2 species of figs in a scrub forest, Thiruporur, Eastern Ghats. Fruiting peak was observed during July 2009 with 11 species in fruiting, a dip was observed during March 2009 where only 2 species were in fruiting. Season wise fruiting peak was observed during South-west and North-east Monsoon while the dip was during summer.

A maize α-zein promoter drives an endosperm-specific expression of transgene in rice

An alpha-zein promoter isolated from maize containing P-box, E motif sequence TGTAAAGT, opaque-2 box and TATA box was studied for its tissue-specific expression in rice. A 1,098 bp promoter region of alpha-zein gene, fused to the upstream of gusA reporter gene was used for transforming rice immature embryos (ASD 16 or IR 64) via the particle bombardment-mediated method. PCR analysis of putative transformants demonstrated the presence of transgenes (the zein promoter, gusA and hpt). Nineteen out of 37 and two out of five events generated from ASD 16 and IR 64 were found to be GUS-positive. A histological staining analysis performed on sections of mature T1 seeds revealed that the GUS expression was limited to the endosperm and not to the pericarp or the endothelial region. GUS expression was observed only in the following seed development stages : milky (14-15 DAF), soft dough (17-18 DAF), hard dough (20-23 DAF), and mature stages (28-30 DAF) of zein-gusA transformed (T0) plants. On the contrary a constitutive expression of GUS was evident in CaMV35S-gusA plants. PCR and Southern blotting analyses on T1 plants demonstrated a stable integration and inheritance of transgene in the subsequent T1 generation. GUS assay on T2 seeds revealed that the expression of gusA gene driven by alpha-zein promoter was stable and tissue-specific over two generations. Results suggest that this alpha-zein promoter could serve as an alternative promoter to drive endosperm-specific expression of transgenes in rice and other cereal transformation experiments.

Fruiting Phenology and Avian Frugivory of <i>Streblus asper</i> Lour. in a Mixed Dry Deciduous Forest, Western Ghats, India

This paper describes the fruiting phenology and avian frugivory of Streblus asper (Moraceae) in a mixed dry deciduous forest, Anaikatty hills, Western Ghats. Fruiting occurred during April-June. Nine species of birds were found to feed on the ripe fruits of this species. Bulbuls (3 species) belonging to Pycnonotidae, followed by two species of Myna (Sturnidae) made majority of the feeding visits and appear to be the major seed dispersers of this species

Fruiting Phenology and Avian Frugivory of Streblus asper Lour. in a Mixed Dry Deciduous Forest, Western Ghats, India

This paper describes the fruiting phenology and avian frugivory of Streblus asper (Moraceae) in a mixed dry deciduous forest, Anaikatty hills, Western Ghats. Fruiting occurred during April-June. Nine species of birds were found to feed on the ripe fruits of this species. Bulbuls (3 species) belonging to Pycnonotidae, followed by two species of Myna (Sturnidae) made majority of the feeding visits and appear to be the major seed dispersers of this species

Biotrickling filtration of complex pharmaceutical VOC emissions along with chloroform

Biodegradation of chloroform along with a mixture of VOCs (methanol, ethanol, acetone and toluene) commonly found in pharmaceutical emissions using a biotrickling filter (BTF) was evaluated. The performance of the BTF was evaluated for both steady and transient conditions, for different inlet loading rates (ILR), empty bed residence time (EBRT) and inlet chloroform concentrations. Among the VOCs studied before chloroform feeding, toluene removal was the least, under all the operating conditions. Complete removal of all pollutants was achieved up to a chloroform loading rate of 14.22 g/m(3)/h. Increase in loading rate of chloroform adversely affected the removal efficiency of toluene and declined the overall performance of BTF. The results suggest that biodegradation of VOCs is influenced by the inlet loading rate and complexity of pollutants in the inlet air stream. Results from studies on shock loading and starvation indicated that the system was highly resilient to transient operating conditions.