Statistical Screening of Supplementary Nitrogen Source for Enhanced Production of L-Asparaginase by Aspergillus terreus 1782

In the present work, Latin Square Design (LSD) was applied to find the best supplementary nitrogen source for extracellular L-asparaginase production by Aspergillus terreus MTCC 1782 using corn flour as substrate in submerged fermentation. The independent effect of supplementary nitrogen source such as ammonium chloride, urea and sodium nitrate was studied on growth and production of L-asparaginase by A. terreus. Statistical significance of the nitrogen sources was studied by performing analysis of variance (ANOVA) and graphical ANOVA for LSD using Data plot software. It was found that there is no significant difference on growth due to the change in supplementary nitrogen source studied. Urea was identified as best supplementary nitrogen source with mean L-asparaginase production of 33.25 IU mL–1 and mean biomass production of 12.99 mg mL–1

Residual Service Life Estimation and its Importance for Pretensioned Concrete (PTC) Bridges in Coastal Cities

Many pre-tensioned concrete (PTC) bridges are experiencing premature chloride-induced corrosion. Hence, it is crucial to estimate their residual service life and update it with newer data on a periodic basis - to plan for corrosionpreventionorcontrolmeasuresandensuresafetyofexistingbridges.Criticalchloridethreshold(Cl th) is one of the parameters necessary to estimate the corrosion initiation period. However, quantitative estimates on Clth for prestressing (PS) steel are not well-reported in literature. This paper presents experimental data on the Clth of PS steel, the chloride diffusion coefficient (Dcl), and surface chloride concentration (Cs) of concrete samples obtained from a PTC bridge girder in a coastal city in India. For estimation of Clth, 5 specimens were cast with PS steel wires embedded in ordinary Portland cement (OPC) mortar containing 30% of Class F fly ash (similar composition as that of the bridge girder). They were cured for 28 days and then subjected to cyclic wet-dry exposure using simulated concrete pore solution containing 3.5%sodiumchloride.(Linear polarization resistance (LPR) tests were performed at the end of each exposure cycle, corrosion initiation was detected using statistical methods, and Clth was determined). Using the determined Clth and Dcl, and other relevant parameters, the cumulative distribution functions of time to corrosion initiation was developed. It was found that the average time to corrosion initiation was about 40 years, whereas the structure was designed for 120 years. Also, it was estimated that the corrosion products will accumulate within the interstitial space between the 7 wires in a strand and will not flow through the concrete cover and reach the concrete surface (showing rust stains) until about 5% of strand is corroded (about 10 years). This indicates a dire need for regular data collection, updating the residual life estimates, which will help in developing corrosion prevention strategies for PTC structures

Service Life and Life-Cycle Assessment of Reinforced Concrete with Fly ash and Limestone Calcined Clay Cement

Environmental impact due to the emission of carbon dioxide during concrete production can be taken care by reducing the clinker content in the cement. The clinker content can be reduced by replacing it with fly ash and limestone calcined clay. Such systems can have a potential to exhibit enhanced durability/service life when exposed to chloride and carbon dioxide. However, estimating probabilistic service life of concretes with such alternative binder systems is difficult due to the lack of quantitative estimates of the input parameters such as chloride diffusion coefficient (DCl), ageing coefficient (m), carbonation coefficient (KCO2), and chloride threshold (Clth). This paper presents the experimentally observed estimates of these parameters for the following systems: (i) 100% OPC, (ii) 70% OPC + 30% fly ash, and (iii) limestone calcined clay cement (LC3) – known as OPC, PFA, and LC3 concretes, respectively, herein. A total of three concrete mixes were designed. Also, based on these input parameters, the probabilistic service life estimates of a bridge pier and a girder made of these three concretes and exposed to chlorides and carbon dioxide are presented. For chloride ingress study, Fick’s 2nd Law of diffusion and Clth have been used. For carbonation study, a recently developed model for estimating carbonation depth (using mixture proportion) have been used. Then, the life‑cycle assessment (LCA) of these three concrete systems in terms of the CO2 emissions per unit of concrete per year of estimated service life is presented - for both chloride and carbonation induced corrosion. In chloride laden environments, the service life of the bridge pier and girder systems could be enhanced by about 10 times by using fly ash or LC3 concretes – for similar strength grade concretes. Also, the average annual CO2 emissions (during the expected service life) of PFA and LC3 concretes could be about 3 and 7 times, respectively, lower than that of OPC concretes of similar strength grade. In case of carbonation-induced corrosion, the limited experimental data indicate that the PFA and LC3 concretes could exhibit a lower service life and higher average annual CO2 emissions (during the expected service life) than OPC concretes

Acoustic reporter genes for noninvasive imaging of microorganisms in mammalian hosts

The mammalian microbiome has many important roles in health and disease1,2, and genetic engineering is enabling the development of microbial therapeutics and diagnostics3,4,5,6,7. A key determinant of the activity of both natural and engineered microorganisms in vivo is their location within the host organism8,9. However, existing methods for imaging cellular location and function, primarily based on optical reporter genes, have limited deep tissue performance owing to light scattering or require radioactive tracers10,11,12. Here we introduce acoustic reporter genes, which are genetic constructs that allow bacterial gene expression to be visualized in vivo using ultrasound, a widely available inexpensive technique with deep tissue penetration and high spatial resolution13,14,15. These constructs are based on gas vesicles, a unique class of gas-filled protein nanostructures that are expressed primarily in water-dwelling photosynthetic organisms as a means to regulate buoyancy16,17. Heterologous expression of engineered gene clusters encoding gas vesicles allows Escherichia coli and Salmonella typhimurium to be imaged noninvasively at volumetric densities below 0.01% with a resolution of less than 100 μm. We demonstrate the imaging of engineered cells in vivo in proof-of-concept models of gastrointestinal and tumour localization, and develop acoustically distinct reporters that enable multiplexed imaging of cellular populations. This technology equips microbial cells with a means to be visualized deep inside mammalian hosts, facilitating the study of the mammalian microbiome and the development of diagnostic and therapeutic cellular agents

Acoustic reporter genes for noninvasive imaging of microorganisms in mammalian hosts

The mammalian microbiome has many important roles in health and disease1,2, and genetic engineering is enabling the development of microbial therapeutics and diagnostics3,4,5,6,7. A key determinant of the activity of both natural and engineered microorganisms in vivo is their location within the host organism8,9. However, existing methods for imaging cellular location and function, primarily based on optical reporter genes, have limited deep tissue performance owing to light scattering or require radioactive tracers10,11,12. Here we introduce acoustic reporter genes, which are genetic constructs that allow bacterial gene expression to be visualized in vivo using ultrasound, a widely available inexpensive technique with deep tissue penetration and high spatial resolution13,14,15. These constructs are based on gas vesicles, a unique class of gas-filled protein nanostructures that are expressed primarily in water-dwelling photosynthetic organisms as a means to regulate buoyancy16,17. Heterologous expression of engineered gene clusters encoding gas vesicles allows Escherichia coli and Salmonella typhimurium to be imaged noninvasively at volumetric densities below 0.01% with a resolution of less than 100 μm. We demonstrate the imaging of engineered cells in vivo in proof-of-concept models of gastrointestinal and tumour localization, and develop acoustically distinct reporters that enable multiplexed imaging of cellular populations. This technology equips microbial cells with a means to be visualized deep inside mammalian hosts, facilitating the study of the mammalian microbiome and the development of diagnostic and therapeutic cellular agents

Influence of temperature and applied potential on the permeability of polyphenol films prepared on vitreous carbon in acid and alkaline media

The electrochemical polymerization of phenol is known to rapidly produce a thin insulating film at the anode surface. This film generally blocks further polymerization. The objective of this study is to show that, depending on the operating conditions, polymeric films resulting from phenol oxidation present different properties and that certain films can be so porous that they allow the oxidation of phenol to continue. The deposition of polyphenol films with improved permeability could be attractive in the removal of phenol from polluted solutions. Polyphenol films were prepared in aqueous solution on a vitreous carbon anode either by cyclic voltammetry or by electro-oxidation at constant potential. The apparent permeability P (%) of the films prepared by these techniques was evaluated by monitoring changes in the electrode response towards phenol and potassium ferricyanide at 25 and 85°C and as a function of the potential applied during electropolymerization performed either in acidic (1 mol L-¹H₂SO₄) or in alkaline (1 mol L-¹ NaOH) aqueous solution. It was shown that: (1) the polyphenol film electrosynthesized in alkaline medium was more permeable than that prepared in acidic medium, (2) the apparent permeability was higher when the polyphenol film was electrosynthesized with simultaneous oxygen evolution and (3) the use of a high temperature in the polyphenol film preparation, especially in the presence of a concomitant oxygen evolution, significantly enhanced its apparent permeability (P ≥ 100 %). These results are interpreted in terms of a mixed-transport mechanism involving both pore and membrane diffusion. The effect of the permeability of the polymeric film on the removal of phenol from aqueous solution by electropolymerization is discussed

Influence of temperature and applied potential on the permeability of polyphenol films prepared on vitreous carbon in acid and alkaline media

The electrochemical polymerization of phenol is known to rapidly produce a thin insulating film at the anode surface. This film generally blocks further polymerization. The objective of this study is to show that, depending on the operating conditions, polymeric films resulting from phenol oxidation present different properties and that certain films can be so porous that they allow the oxidation of phenol to continue. The deposition of polyphenol films with improved permeability could be attractive in the removal of phenol from polluted solutions. Polyphenol films were prepared in aqueous solution on a vitreous carbon anode either by cyclic voltammetry or by electro-oxidation at constant potential. The apparent permeability P (%) of the films prepared by these techniques was evaluated by monitoring changes in the electrode response towards phenol and potassium ferricyanide at 25 and 85°C and as a function of the potential applied during electropolymerization performed either in acidic (1 mol L-¹H₂SO₄) or in alkaline (1 mol L-¹ NaOH) aqueous solution. It was shown that: (1) the polyphenol film electrosynthesized in alkaline medium was more permeable than that prepared in acidic medium, (2) the apparent permeability was higher when the polyphenol film was electrosynthesized with simultaneous oxygen evolution and (3) the use of a high temperature in the polyphenol film preparation, especially in the presence of a concomitant oxygen evolution, significantly enhanced its apparent permeability (P ≥ 100 %). These results are interpreted in terms of a mixed-transport mechanism involving both pore and membrane diffusion. The effect of the permeability of the polymeric film on the removal of phenol from aqueous solution by electropolymerization is discussed

Systemic AAV vectors for widespread and targeted gene delivery in rodents

We recently developed adeno-associated virus (AAV) capsids to facilitate efficient and noninvasive gene transfer to the central and peripheral nervous systems. However, a detailed protocol for generating and systemically delivering novel AAV variants was not previously available. In this protocol, we describe how to produce and intravenously administer AAVs to adult mice to specifically label and/or genetically manipulate cells in the nervous system and organs, including the heart. The procedure comprises three separate stages: AAV production, intravenous delivery, and evaluation of transgene expression. The protocol spans 8 d, excluding the time required to assess gene expression, and can be readily adopted by researchers with basic molecular biology, cell culture, and animal work experience. We provide guidelines for experimental design and choice of the capsid, cargo, and viral dose appropriate for the experimental aims. The procedures outlined here are adaptable to diverse biomedical applications, from anatomical and functional mapping to gene expression, silencing, and editing

Cisgenesis and intragenesis as new strategies for crop improvement

Cisgenesis and intragenesis are emerging plant breeding technologies which offer great promise for future acceptance of genetically engineered crops. The techniques employ traditional genetic engineering methods but are confined to transferring of genes and genetic elements between sexually compatible species that can breed naturally. One of the main requirements is the absence of selectable marker genes (such as antibiotic resistance genes) in the genome. Hence the sensitive issues with regard to transfer of foreign genes and antibiotic resistance are overcome. It is a targeted technique involving specific locus; therefore, linkage drag that prolongs the time for crop improvement in traditional breeding does not occur. It has great potential for crop improvement using superior alleles that exist in the untapped germplasm or wild species. Cisgenic and intragenic plants may not face the same stringent regulatory assessment for field release as transgenic plants which is a clear added advantage that would save time. In this chapter, the concepts of cis/intragenesis and the prerequisites for the development of cis/intragenesis plants are elaborated. Strategies for marker gene removal after selection of transformants are discussed based on the few recent reports from various plant species

Comparison of ultrasound-guided transversalis fascia and posterior transversus abdominis plane block for postoperative analgesia following caesarean delivery: A double-blinded randomised controlled trial

Background and Aims: Posterior–transversus abdominus plane (TAP) block and transversalis fascia plane (TFP) block have been used for postoperative analgesia following caesarean delivery. We compared the analgesic efficacy of the TAP vs TFP plane blocks in patients undergoing elective caesarean delivery. Methods: We randomised 90 women undergoing caesarean delivery under spinal anaesthesia to receive either a posterior-TAP (Group-TAP), TFP (Group-TFP) or no block (Group-C) postoperatively. The primary objective was the postoperative analgesic requirements. Secondary objectives were duration of analgesia, pain scores and infra-umbilical sensory loss, which were recorded at specific intervals for 24 h. Statistical analysis was carried out using Statistical Package for Social Sciences version 16.0 software. Results: The patients requiring one, two or nil rescue analgesics were comparable between the interventions and the control (P = 0.32). The duration of analgesia was longer in Group-TAP when compared to Group-C, 4.76 (1.2) vs. 6.89 (2.4); P < 0.001, whereas Group-TFP, 5.64 (2.1) h, was not significantly different from Group-C. The static pain score in Group-TAP was significantly less than that in Group-C at 4 h and beyond 12 h (P < 0.001), whereas Group-TFP was comparable with Group-C at all time points except at 4 h and 24 h (P = 0.002). Only Group-TAP demonstrated midline infraumbilical sensory loss. Conclusion: TAP and TFP blocks did not decrease the rescue analgesic requirement compared with the control group. The posterior-TAP block prolonged the duration of analgesia by 2 h, maintained the median static pain score at 0 beyond 12 h, and demonstrated sensory loss at the infraumbilical dermatomes