Advances in drying techniques for retention of antioxidants in agro produces.

Antioxidants are compounds that are essential for the human body which prevents cell from disease causing free radicals. Antioxidants are present in a wide range of fruits, vegetables, and spices. However, a considerable amount of antioxidants is lost during the post-harvest drying operation of agro produces for their shelf-life enhancement. Hence, retention of antioxidants becomes utmost importance in preserving the nutritional aspects of fruits and vegetables. Compared to conventional hot air drying, methods like freeze drying, vacuum drying, and dehumidified drying helps in the retention of antioxidants. However, the drawbacks prevalent in current drying practices, such as high-power consumption and high capital cost, could be eliminated by adopting novel drying mechanisms. This review focuses on various pretreatment methods like ultra-sonication, high pressure processing, pulsed electric field and ethanol treatment prior to drying operation helps in enhancing the drying efficiency with maximum retention of antioxidants. In addition, hybrid drying technologies such as microwave assisted drying, IR-radiated drying and electro-magnetic assisted drying methods also could significantly improve the retention of antioxidants.HIGHLIGHTSDrying is the most commonly adopted unit operation for enhancing the shelf life of perishable agro produces.However, drying is accompanied by loss of bioactive, color, texture, and sensory attributes.Compared to conventional drying techniques like hot air drying, methods like freeze drying, vacuum drying and dehumidified drying helps in the retention of antioxidants present in agro/food produces.Pretreatment methods like Ozonation, ultra-sonication, and UV radiation prior to drying are also found to improve the drying performance with good retention of antioxidants.Recent developments like microwave-assisted and IR-assisted drying methods perform well in the retention of antioxidants with less energy consumption.

Development of biogenic bimetallic Pd/Fe nanoparticle-impregnated aerobic microbial granules with potential for dye removal.

The objective of this study was to develop bimetallic core-shell Pd/Fe nanoparticles on the surface of aerobic microbial granules (Bio-Pd/Fe) and to evaluate their dye removal potential using a representative dye, methyl orange (MO). The aerobic microbial granules (1.5 ± 0.32 mm) were grown for 70 days in a 3-L glass sequencing batch reactor (SBR) with a 12-h cycle time. The Bio-Pd/Fe formation was catalyzed by the Bio-H2 gas produced by the granules. The developed Bio-Pd/Fe was further used for MO removal from aqueous solutions, and the reaction parameters were optimized by response surface methodology (RSM). The XRD, SEM, EDAX, elemental mapping, and XPS studies confirmed the formation of Bio-Pd/Fe. Under the optimized removal conditions, 99.33% MO could be removed by Bio-Pd/Fe, whereas removal by Bio-Pd, Bio-Fe, aerobic microbial granules, and heat-killed granules were found to be quite low (68.91 ± 0.2%, 76.8 ± 0.3%, 19.8 ± 0.6%, and 6.59 ± 0.2%, respectively). The mechanism of removal was investigated by UV-visible spectroscopy, redox potential analysis, HR-LCMS analyses of the solution phase, and XRD and XPS analyses of the solid sorbent. The degradation products of MO exhibited m/z values corresponding to 292, 212, and 160 m/z. The remnant toxicity of the intermediate degradation products was analysed using freshwater algae, Scenedesmus sp. And Allium cepa, as indicator organisms. These assays suggested that after the treatment with Bio-Pd/Fe, MO was transformed to a lesser toxic form.

A Comparative Randomized Prospective Clinical Study on Modified Erich Arch Bar with Conventional Erich Arch Bar for Maxillomandibular Fixation.

INTRODUCTION: Erich arch bar used for maxillomandibular fixation (MMF) since decades has several disadvantages such as risks of injury, additional operating room time, and gingival trauma. To overcome these downsides, modified Erich arch bar was introduced; however, there is not much available literature, indicating the efficacy of modified Erich arch bar over that of conventional arch bar wire. Therefore, the present study focuses on comparing efficiency of modified arch bar with conventional arch bar. MATERIALS AND METHODS: This comparative randomized study was conducted on 32 patients that required MMF and were divided into Group A patients who received intermaxillary fixation (IMF) with modified Erich arch bars and Group B patients with conventional Erich arch bars. The parameters recorded were average surgical time required, wire prick injuries, IMF stability, occlusal stability, screw loosening, oral hygiene status, and vitality response of the teeth. The variables were statistically analyzed using Student's t-test and Wilcoxon signed-rank test. RESULTS: The wire prick injury, intraoperative time noted in Group A was significantly reduced in comparison to Group B (P < 0.0001). Debris indices were significantly good in Group A in comparison to Group B (P < 0.0001). Nonvitality response of tooth was significantly more in Group B than in Group A patients (P < 0.05). DISCUSSION: The efficiency of modified Erich arch bar group was superior to the conventional arch bar with very limited restrictions.

Antibacterial and cytotoxic assessment of poly (methyl methacrylate) based hybrid nanocomposites.

Poly (methyl methacrylate) (PMMA) is an extensively used implant material in biomedical devices. Biofilm formation creates issues in PMMA-based biomedical implants, while emergence of drug resistant pathogens poses an additional complication. Hence development of surfaces that resist bacterial colonisation is extremely desirable. In this context, nanomaterials are among the potential choices. In the present work, nanocomposites (NCs) were developed by incorporation of chemically synthesized nanoparticles of CuO, cetyl trimethyl ammonium bromide (CTAB) capped CuO and ZnO (singly and in combination) in PMMA. The efficacy of these NCs was assessed against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria which are prevalent in many implant-associated infections. Results revealed species-specific response of the bacteria towards nanomaterials. CuO NC (0.1% (w/v)) was more effective against E. coli, while CTAB capped CuO NC and ZnO NC were very effective against S. aureus. Furthermore, combination of nanoparticles improved efficacy of nanocomposites against both the bacterial species. In vitro cytotoxicity assay using L6 myoblast cell line showed that all NCs at 0.1% (w/v) were biocompatible, showing >85% cell viability. The present study suggests that combination of NPs is a promising option to combat implant infection by multiple organisms.

Long alkyl-chain imidazolium ionic liquids: Antibiofilm activity against phototrophic biofilms.

Biofilm formation is problematic and hence undesirable in medical and industrial settings. In addition to bacteria, phototrophic organisms are an integral component of biofilms that develop on surfaces immersed in natural waters. 1-Alkyl-3-methyl imidazolium ionic liquids (IL) with varying alkyl chain length were evaluated for their influence on the formation of monospecies (Navicula sp.) and multispecies biofilms under phototrophic conditions. An IL with a long alkyl side chain, 1-hexadecyl-3-methylimidaazolium chloride ([C16(MIM)][Cl]) retarded growth, adhesion and biofilm formation of Navicula sp. at concentrations as low as 5µM. Interestingly, [C16(MIM)][Cl] was very effective in preventing multispecies phototrophic biofilms on fibre reinforced plastic surfaces immersed in natural waters (fresh and seawater). SYTOX® Green staining and chlorophyll leakage assay confirmed that the biocidal activity of the IL was exerted through cell membrane disruption. The data show that [C16(MIM)][Cl] is a potent inhibitor of phototrophic biofilms at micromolar concentrations and a promising agent for biofilm control in re-circulating cooling water systems. This is the first report that ionic liquids inhibit biofilm formation by phototrophic organisms which are important members of biofilms in streams and cooling towers.

Polydimethyl siloxane based nanocomposites with antibiofilm properties for biomedical applications.

Polydimethyl siloxane (PDMS) is an excellent implant material for biomedical applications, but often fails as it is prone to microbial colonization which forms biofilms. In the present study CuO, CTAB capped CuO, and ZnO nanoparticles were tested as nanofillers to enhance the antibiofilm property of PDMS against Staphylococcus aureus and Escherichia coli. In general S. aurues (Gram positive and more hydrophobic) favor PDMS surface than glass while E. coli (Gram negative and more hydrophilic) behaves in a reverse way. Incorporation of nanofillers renders the PDMS surface antibacterial and reduces the attachment of both bacteria. These surfaces are also not cytotoxic nor show any cell damage. Contact angle of the material and the cell surface hydrophobicity influenced the extent of bacterial attachment. Cell viability in biofilms was dependent on the antimicrobial property of the nanoparticles incorporated in the PDMS matrix. Simple regression relationships were able to predict the bacterial attachment and number of dead cells on these nanocomposites. Among the nanocomposites tested, PDMS incorporated with CTAB (cetyl trimethylammonium bromide)-capped CuO appears to be the best antibacterial material with good cyto-compatibility. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1075-1082, 2017.

Removal of trihalomethane from chlorinated seawater using gamma radiation.

Chlorine addition as a biocide in seawater results in the formation of chlorination by-products such as trihalomethanes (THMs). Removal of THMs is of importance as they are potential mutagenic and carcinogenic agents. In this context, a study was conducted that used ionizing radiation to remove THMs from chlorinated (1, 3, and 5 mg/L) seawater by applying various dosages (0.4-5.0 kGy) of gamma radiation. Bromoform (BF) showed a faster rate of degradation as compared to other halocarbons such as bromodichloromethane (BDCM) and dibromochloromethane (DBCM). In chlorine-dosed seawater, total irradiation dose of 0.4 to 5 kGy caused percentage reduction in the range of 6.9 to 76.7%, 2.3 to 99.6%, and 45.7 to 98.3% for BDCM, DBCM, and BF, respectively. During the irradiation process, pH of the chlorinated seawater decreased with increase in the absorbed dose; however, no change in total organic carbon (TOC) was observed. The results show that gamma dose of 2.5 kGy was adequate for maximum degradation of THM; but for complete mineralization, higher dose would be required.

Denitrification accelerates granular sludge formation in sequencing batch reactors.

In this study, the role of denitrification on aerobic granular sludge formation in sequencing batch reactors (SBRs) was investigated. Formation of aerobic granular sludge was faster in SBRs fed with varying concentrations of nitrate or nitrite as compared to control, which received no nitrate or nitrite in the feed. The majority of the fed nitrate or nitrite was denitrified in the anoxic static fill phase, prior to aerobic reaction phase. Sludge characterization showed accumulation of calcium and chemical signature of calcium carbonate in the nitrate-fed SBRs. Feeding of sodium nitroprusside, a known nitric oxide (NO) donor, enhanced aggregation, production of extracellular polymeric substances and formation of aerobic granular sludge. The results support the hypothesis that denitrification facilitates cell aggregation and accelerates aerobic sludge granulation through NO signaling and CaCO3 formation. Nitrate or other intermediates of heterotrophic denitrification, therefore, have a positive effect on aerobic granulation in SBRs.

Biodegradation of tributyl phosphate, an organosphate triester, by aerobic granular biofilms.

Tributyl phosphate (TBP) is commercially used in large volumes for reprocessing of spent nuclear fuel. TBP is a very stable compound and persistent in natural environments and it is not removed in conventional wastewater treatment plants. In this study, cultivation of aerobic granular biofilms in a sequencing batch reactor was investigated for efficient biodegradation of TBP. Enrichment of TBP-degrading strains resulted in efficient degradation of TBP as sole carbon or along with acetate. Complete biodegradation of 2mM of TBP was achieved within 5h with a degradation rate of 0.4 µmol mL(-1) h(-1). TBP biodegradation was accompanied by release of inorganic phosphate in stoichiometric amounts. n-Butanol, hydrolysed product of TBP was rapidly biodegraded. But, dibutyl phosphate, a putative intermediate of TBP degradation was only partially degraded pointing to an alternative degradation pathway. Phosphatase activity was 22- and 7.5-fold higher in TBP-degrading biofilms as compared to bioflocs and acetate-fed aerobic granules. Community analysis by terminal restriction length polymorphism revealed presence of 30 different bacterial strains. Seven bacterial stains, including Sphingobium sp. a known TBP degrader were isolated. The results show that aerobic granular biofilms are promising for treatment of TBP-bearing wastes or ex situ bioremediation of TBP-contaminated sites.

Biogenic nanopalladium production by self-immobilized granular biomass: application for contaminant remediation.

Microbial granules cultivated in an aerobic bubble column sequencing batch reactor were used for reduction of Pd(II) and formation of biomass associated Pd(0) nanoparticles (Bio-Pd) for reductive transformation of organic and inorganic contaminants. Addition of Pd(II) to microbial granules incubated under fermentative conditions resulted in rapid formation of Bio-Pd. The reduction of soluble Pd(II) to biomass associated Pd(0) was predominantly mediated by H2 produced through fermentation. X-ray diffraction and scanning electron microscope analysis revealed that the produced Pd nanoparticles were associated with the microbial granules. The catalytic activity of Bio-Pd was determined using p-nitrophenol and Cr(VI) as model compounds. Reductive transformation of p-nitrophenol by Bio-Pd was ∼20 times higher in comparison to microbial granules without Pd. Complete reduction of up to 0.25 mM of Cr(VI) by Bio-Pd was achieved in 24 h. Bio-Pd synthesis using self-immobilized microbial granules is advantageous and obviates the need for nanoparticle encapsulation or use of barrier membranes for retaining Bio-Pd in practical applications. In short, microbial granules offer a dual purpose system for Bio-Pd production and retention, wherein in situ generated H2 serves as electron donor powering biotransformations.

Time-resolved digital holographic microscopy of laser-induced forward transfer process.

We develop a method for time-resolved digital holographic microscopy to obtain time-resolved 3-D deformation measurements of laser induced forward transfer (LIFT) processes. We demonstrate nanometer axial resolution and nanosecond temporal resolution of our method which is suitable for measuring dynamic morphological changes in LIFT target materials. Such measurements provide insight into the early dynamics of the LIFT process and a means to examine the effect of laser and material parameters on LIFT process dynamics.

Pumping iron to keep fit: modulation of siderophore secretion helps efficient aromatic utilization in Pseudomonas putida KT2440.

Studies of biotechnology applications of Pseudomonas putida KT2440 have been predominantly focused on regulation and expression of the toluene degradation (TOL) pathway. Unfortunately, there is limited information on the role of other physiological factors influencing aromatic utilization. In this report, we demonstrate that P. putida KT2440 increases its siderophore secretion in response to the availability of benzyl alcohol, a model aromatic substrate. It is argued that accelerated siderophore secretion in response to aromatic substrates provides an iron 'boost' which is required for the effective functioning of the iron-dependent oxygenases responsible for ring opening. Direct evidence for the cardinal role of siderophores in aromatic utilization is provided by evaluation of per capita siderophore secretion and comparative growth assessments of wild-type and siderophore-negative mutant strains grown on an alternative carbon source. Accelerated siderophore secretion can be viewed as a compensatory mechanism in P. putida in the context of its inability to secrete more than one type of siderophore (pyoverdine) or to utilize heterologous siderophores. Stimulated siderophore secretion might be a key factor in successful integration and proliferation of this organism as a bio-augmentation agent for aromatic degradation. It not only facilitates efficient aromatic utilization, but also provides better opportunities for iron assimilation amongst diverse microbial communities, thereby ensuring better survival and proliferation.

Transforaminal sacral approach for spinal anesthesia in orthopedic surgery: A novel approach.

Regional anesthesia is preferred world-wide for its distinct advantages. The benefits of regional anesthesia in patients with comorbid conditions are well-established. The administration of regional anesthesia can sometimes pose a challenge to the anesthesiologist due to the structural abnormalities of the spine. The most common difficulty encountered for spinal anesthesia in our hospital (Nalgonda District) is skeletal fluorosis. Apart from the midline approach, paramedian, and Taylor's approaches are advocated for difficult scenarios. This article reports two orthopedic cases, conducted under a novel spinal anesthesia technique, i.e., transforaminal sacral approach under C-arm guidance with a successful outcome. The sacral foraminal subarachnoid block is a method to access the subarachnoid space through the upper posterior sacral foramina.

A novel technique to monitor thermal discharges using thermal infrared imaging.

Coastal temperature is an important indicator of water quality, particularly in regions where delicate ecosystems sensitive to water temperature are present. Remote sensing methods are highly reliable for assessing the thermal dispersion. The plume dispersion from the thermal outfall of the nuclear power plant at Kalpakkam, on the southeast coast of India, was investigated from March to December 2011 using thermal infrared images along with field measurements. The absolute temperature as provided by the thermal infrared (TIR) images is used in the Arc GIS environment for generating a spatial pattern of the plume movement. Good correlation of the temperature measured by the TIR camera with the field data (r(2) = 0.89) make it a reliable method for the thermal monitoring of the power plant effluents. The study portrays that the remote sensing technique provides an effective means of monitoring the thermal distribution pattern in coastal waters.

Influence of cultivar and maturity at harvest on the essential oil composition, oleoresin and [6]-gingerol contents in fresh ginger from northeast India.

Severe flooding of the Brahmaputra River during the monsoon season and continuous rainfall in the northeast region (NER) of India cause an enormous loss of ginger crop every year. In this context, the present study investigates the variation in the essential oil composition and oleoresin and [6]-gingerol contents in 10 different fresh ginger cultivars harvested at 6- and 9-month maturity from five different states of NER. Monoterpenes, sesquiterpenes, and citral composition in the essential oil were evaluated to ascertain their dependence upon the maturity of ginger. Except Mizoram Thinglaidum, Mizoram Thingria, Nagaland Nadia, and Tripura I ginger cultivars, all other cultivars showed an increase in the citral content during the maturity that was observed for the first time. At 6-month maturity, a higher undecanone level was found in Nagaland Nadia (7.36 ± 0.61%), Tripura I (6.23 ± 0.61%), and Tripura III (9.17 ± 0.76%) cultivars, and these data can be used as a benchmark to identify those immature varieties. Interestingly, the Nagaland Nadia cultivar showed higher ar-curcumene (9.57 ± 0.58%) content than zingiberene (5.84 ± 0.24%), which was unique among all cultivars. Ginger harvested at 9-month maturity from the Tripura II cultivar had the highest citral content (22.03 ± 0.49%), and the Meghalaya Mahima cultivar had the highest zingiberene content (29.89 ± 2.92%). The oleoresin content was found to decrease with maturity in all cultivars, except Assam Fibreless and Manipur I. Moreover, the highest oleoresin (11.43 ± 0.58 and 9.42 ± 0.63%) and [6]-gingerol (1.67 ± 0.03 and 1.67 ± 0.05 g) contents were observed for Tripura II and Nagaland Nadia, respectively. This study suggests that Tripura and Nagaland are the most ideal locations in NER for ginger cultivation to obtain high yields of oleoresin and [6]-gingerol contents and harvesting at the 6-month maturation will compensate for the loss of ginger crop caused by the Brahmaputra River flooding in NER every year.

The ionic liquid 1-alkyl-3-methylimidazolium demonstrates comparable antimicrobial and antibiofilm behavior to a cationic surfactant.

Biofilms are problematic in health and industry because they are resistant to various antimicrobial treatments. Ionic liquids are a novel class of low temperature liquid salts consisting of discrete anions and cations, and have attracted considerable interest as safer alternatives to organic solvents. Ionic liquids have interesting antimicrobial properties and some could find use in the development of novel antiseptics, biocides and antifouling agents. The antimicrobial and antibiofilm activity of 1-dodecyl-3-methylimiazolium iodide ([C(12)MIM]I) was studied using the clinically important bacterial pathogens, Staphylococcus aureus SAV329 and Pseudomonas aeruginosa PAO1. The ionic liquid increased cell membrane permeability in both S. aureus and P. aeruginosa cells and impaired their growth, attachment and biofilm development. The ionic liquid exhibited superior antimicrobial and antibiofilm activity against the Gram-positive S. aureus compared to the Gram-negative P. aeruginosa cells. BacLight™ staining and confocal microscope imaging confirmed that the ionic liquid treatment increased the cell membrane permeability of both the Gram-positive and Gram-negative bacteria. In addition, the antimicrobial and antibiofilm properties of [C(12)MIM]I were similar or superior to those of cetyltrimethylammonium bromide (CTAB), a well-known cationic surfactant. It is concluded that the ionic liquid induced damage to bacterial cells by disrupting cell membrane, leading to inhibition of growth and biofilm formation. Overall, the results indicate that the ionic liquid 1-dodecyl-3-methylimiazolium iodide was effective in preventing S. aureus and P. aeruginosa biofilms and could have applications in the control of bacterial biofilms.

Chlorination-induced cellular damage and recovery in marine microalga, Chlorella salina.

Power plants employ chlorination for controlling biofouling in the cooling water system. Phytoplankton drawn into the cooling water system could be impacted by chemical stress induced by the oxidizing biocide. It is likely that microalgae, being sensitive to chlorine, could suffer damage to their cellular structure and function. In this study, we present data on the effect of in-use concentrations of chlorine on the unicellular microalga, Chlorella salina. Chlorophyll autofluorescence was measured in terms of mean fluorescence intensity per cell for rapid assessment of toxicity. Viability of the cells exposed to chlorine was determined by fluorescein diacetate staining. Functionality of the photosynthetic machinery was assessed by gross primary productivity. Results from the study, which combined confocal laser scanning microscopy with image analysis, showed a significant dose-dependant reduction in chlorophyll autofluorescence, esterase activity and gross primary productivity in chlorine-treated cells. Interestingly, the cells injured by chlorination could not recover in terms of autofluorescence, esterase activity or productivity even after 18 h incubation in healthy media. Among the test points evaluated, esterase activity appeared to be sensitive for determining the chlorination-induced impact. Our results demonstrate that low-dose chlorination causes significant decrease in chlorophyll autofluorescence, intracellular esterase activity and primary productivity in Chlorella cells.

Dynamics of primary and secondary microbubbles created by laser-induced breakdown of an optically trapped nanoparticle.

Laser-induced breakdown of an optically trapped nanoparticle is a unique system for studying cavitation dynamics. It offers additional degrees of freedom, namely the nanoparticle material, its size, and the relative position between the laser focus and the center of the optically trapped nanoparticle. We quantify the spatial and temporal dynamics of the cavitation and secondary bubbles created in this system and use hydrodynamic modeling to quantify the observed dynamic shear stress of the expanding bubble. In the final stage of bubble collapse, we visualize the formation of multiple submicrometer secondary bubbles around the toroidal bubble on the substrate. We show that the pattern of the secondary bubbles typically has its circular symmetry broken along an axis whose unique angle rotates over time. This is a result of vorticity along the jet towards the boundary upon bubble collapse near solid boundaries.