Exploration of the performance of iron-based superhydrophilic meshes for oil-water separation

This study investigates the oil-water separation capability of iron-based superhydrophilic meshes. It also intends to provide an optimistic view of their potential for industrial application. Oil-water separation performance of the 150 mesh, 300 mesh, and 400 mesh is primarily examined by analyzing the efficiency and speediness of separation as well as the limit of oil intrusion using petroleum based oils. The superhydrophilic meshes are further applied for oil-water separation of locomotive wash effluent. The superhydrophilic meshes showed good oil-water separation behavior. The 300 mesh is observed to have superior separation performance. It is also tested to have good reusability and resistance in harsh conditions. The separation effectiveness of 94.7%, reduced turbidity of 21.8 NTU, and chemical oxygen demand of around 70 ppm, along with reasonable flux and intrusion pressure values of 73.28 Lm-2min-1 and 0.848 kPa, respectively, are noticed for the separation study conducted for locomotive wash effluent using the designated superhydrophilic mesh. This study hence as well demonstrates a prospective future of superhydrophilic mesh for practical utility.

Heterostructured γ-Fe2O3/FeTiO3 magnetic nanocomposite: An efficient visible-light-driven photocatalyst for the degradation of organic dye

The catalyst recovery is the major concern in commercialization of photocatalysts for the industrial effluent treatment process. To overcome this major issue, Fe₂O₃ based magnetic photocatalytic heterostructure ɣ-Fe₂O₃/FeTiO₃ nanocomposite was synthesized by hydrothermal method. Fe₂O₃ is the cheapest visible active magnetic photocatalytic material, but it has the limitation of fast e^-/h + recombination. Titanium (Ti) was loaded on γ-Fe₂O₃ to overcome this issue. The loaded Ti has grown as FeTiO₃ on the surface of ɣ-Fe₂O₃ nanocrystals and emerged as heterostructure ɣ- Fe₂O₃/FeTiO₃ nanocomposites, which was confirmed by XRD and TEM results. The loading concentration of Ti on γ-Fe₂O₃ was optimized to achieve the maximum photocatalytic efficiency without compromising the magnetic property of γ-Fe₂O₃ to facilitate the magnetic separation. DRS-UV spectra revealed the strong visible light response of γ- Fe₂O₃/FeTiO₃ nanocomposite. The photocatalytic efficiencies of the synthesized materials were evaluated using methylene blue (MB) as a model pollutant under sunlight. The built-in electric field between p-n junction between FeTiO₃ and Fe₂O₃ and type II charge transfer mechanism extended the lifetime of the charge carriers at the heterojunction of γ- Fe₂O₃/FeTiO₃, which was confirmed by PL spectra. The vibrating sample magnetometer (VSM) study revealed the decreasing magnetization, coercivity (Hc), and retentivity (Mr) of γ-Fe₂O₃ with increasing concentration of Ti. 92% of the used-up 20 wt% Ti loaded γ-Fe₂O₃/FeTiO₃ magnetic nanocomposite was recovered from the treated wastewater using an electromagnet. Both magnetic properties and efficiency of the nanocomposite increased up to 20 wt% of Ti loading, beyond that decreased due to the increasing composition of antiferromagnetic FeTiO₃ and the increasing number of defect sites as recombination centers. Hence, 20 wt% loading of Ti was concluded as the optimum to enhance the efficiency and to retain the magnetic properties. This work aims the commercialization of magnetic photocatalytic materials for the industrial effluent treatment.

Excellent photocatalytic performances of Co3O4-AC nanocomposites for H2 production via wastewater splitting

Natural sunlight-driven photocatalytic hydrogen production from wastewater is one of the most desirable techniques that can realize future green energy technology. Herein, we report the synthesis and the characterization of the biomass activated carbon (AC)-decorated cobalt oxide (Co₃O₄) nanocomposites for solar-stimulated photocatalytic hydrogen production from sulphide wastewater. The Co₃O₄-AC nanocomposites were ultrasonically synthesized by using hydrothermally-grown spinel Co₃O₄ nanoflakes and biomass-derived AC nanoflakes. Co₃O₄-AC showed a nanobundle-like aggregated morphology, and exhibited a large specific surface area (~133 m²/g). Through utilizing Co₃O₄-AC as a photocatalyst for photocatalytic splitting of sulphide wastewater (0.2 M) under solar irradiance with 730 W/m², an enhanced H₂ production efficiency (~70 mL/h) was achieved owing to the synergic effects from 2-dimentionally configured Co₃O₄ and AC microstructures; i.e., large surface area of Co₃O₄ and high electrical conductivity of AC. These findings suggest the nanocomposites of Co₃O₄-AC to hold great promise for the green approach of photocatalytic wastewater splitting.

Synthesis of tri-metallic surface engineered nanobiochar from cynodon dactylon residues in a single step - Batch and column studies for the removal of copper and lead ions

Superparamagnetic nanocomposites integrated with multiple metals, and surface engineered nanoparticles play a vital role in the removal of heavy metals. In the present study, amino-functional silica-coated magnetic nanocomposites with biochar synthesised from Cynodon dactylon plant residues are prepared in a single step reaction process. The synthesised nanocomposites are characterized using various analytical techniques such as FTIR to determine their functional entities, SEM, TEM, EDX and VSM to analyse the size (~50 nm), elements and magnetic nature of the nanocomposites. Characterization reveals that the prepared nanobiochar was coated with silica and a specific amine group. The magnetic saturation value of 50 emu/g confirms the prepared sorbent was superparamagnetic. Kinetics, isotherm and thermodynamics parameters are evaluated to study the metal interaction mechanism with the nanocomposites where the system follows pseudo-second-order kinetics and the four-parameter Fritz Schlunder model for both metal ions. The nanocomposites showed the enhanced adsorption capacity of copper (Cu(II)) ions with 220.4 mg/g and 185.4 mg/g for lead (Pb(II)) ions. The nanocomposites also showed the excessive reusing ability of 15 times with the maximum removal efficiency for Cu(II) and Pb(II) metal ions. Column studies are evaluated to demonstrate the vital performance in the removal of Cu(II) ions and the breakthrough point was inferred for the parameters such as concentration (100-300 mg/L), bed height (1-3 cm) and flow rate (2-4 mL/min). The breakthrough point was attained at 1400 min and the removal efficiency of about 64.58% was obtained.

Profile of complications in pterygium surgery - A retrospective analysis

Purpose:

Analysis of complication profile after pterygium excision, in primary and recurrent pterygia.

Methods:

Retrospective analysis of all the patients who had undergone pterygium excision in a tertiary center in South India from 2010 to 2018 was analyzed. A total of 2356 eyes in 2028 patients were included in the study. Patients who had undergone conjunctival autografting for primary pterygium, conjunctival limbal autografting for recurrent pterygium, vertical split conjunctival autografting for double head pterygium were included in the study. In all the surgical procedures fibrin glue was used for fixation of the autograft. The follow-up period ranged from 6 months to 75 months, with an average of 17 months. Patients with less than 6 months of follow-up were excluded from the study.

Results:

The following postoperative complications were noted, Sub-conjunctival hemorrhage in 912 eyes (38.7%), edema of the graft in 522 cases (22.15%), graft loss in 22 cases (0.93%), graft retraction in 692 cases (29.37%) and sliding of the graft was seen in 9 cases (0.38%). Granuloma was seen in 4 cases (0.16%) at the host site and 5 cases (0.21%) at the donor site. Recurrence was seen in 34 patients (1.44%). Other severe complications like corneal melt were seen in only 1 case (0.04%) who was operated on for recurrent pterygium. In comparison between primary and recurrent pterygia; subconjunctival hemorrhage, edema of the graft, graft loss, and recurrence was significantly (P < 0.05%) higher in recurrent pterygia.

Conclusion:

Various complications can occur post pterygium surgery as listed above. Selecting a proper procedure for a particular type of pterygium with a proper graft fixation technique will improve the outcome with minimal complications.

Efficacy of second donor conjunctival graft from the same site for pterygium - A retrospective analysis

Purpose

To know the efficacy of the second donor conjunctival graft from the same site as that of the previous donor area in pterygium treatment.

Methods

Case record of patients were retrospectively analysed and those patients who had undergone pterygium excision previously, either for nasal or temporal pterygium excision and came with complaints of pterygium growth in opposite side of the bulbar conjunctiva in the same eye were included in the study. The patients with double head pterygium previously treated only over one side were also included. Total of 23 such patients were included in the study. The patients were followed up on post-operative day 1, 2 weeks, 6 weeks, 6 months and 1 year. The outcome measures like recurrence, graft edema, graft retraction, graft loss and other complications were noted in each follow up.

Results

Among the 23 patients included in the study 9 were male and 14 were female patients with a mean age of 44±7.2 years (range 24-57 years). On an average follow up period of 15±8.5 months, only 1 patient among 23 patients had recurrence (4.43%). Other complications noted were graft retraction in 4 eyes (17.4%), sub conjunctival hemorrhage in 8 eyes (34.8%) and graft edema in 11 eyes (47.8%). Only one patient presented with granuloma (4.34%).

Conclusion

The second conjunctival graft from the same site is safe and effective with encouraging results in indicated cases.

Study of change in contrast sensitivity in relation to depth of ablation after wavefront optimized myopic laser-assisted in situ keratomileusis

Purpose:

The aim of this work was to study the change in contrast sensitivity (CS) in relation to depth of stromal ablation after wavefront-optimized (WFO) myopic laser in situ keratomileusis (LASIK).

Methods:

This was as prospective, longitudinal, comparative study. The study participants were divided into two groups: Group 1 ≤50 μ ablation depth; 60 eyes and group 2 >50 μ ablation depth; 60 eyes. All underwent WFO LASIK. Uncorrected and corrected distance visual acuity (UDVA and CDVA) and CS were measured preoperatively and postoperatively at 1 week, 2 weeks, and 2 and 6 months. Two-way repeated-measures analysis of variance (ANOVA), Unpaired t test and one-way repeated measures ANOVA were used to test differences across time periods within each treatment group. A value of P < 0.05 was considered as statistically significant.

Results:

The mean ablation depths in groups 1 and 2 were 39.30 μ ± 7.22 μ and 69.90 μ ± 12.09 μ, respectively; the maximum depth was 94.62 μ. In group 1, the preoperative mean CS was 1.91 ± 0.07, which improved postoperatively at 1 week (1.93 ± 0.06) and remained stable in subsequent follow-ups (1.94 ± 0.05). In group 2, the mean CS preoperatively was 1.87 ± 0.12, which postoperatively at 1 week and 6 months were 1.93 ± 0.07 and 1.94 ± 0.03, respectively (P < 0.05). Between the groups, preoperative CS was significantly different (P = 0.04), but the change in CS post-LASIK was insignificant (P > 0.05).

Conclusion:

There was a significant improvement in CS after WFO myopic LASIK in all patients irrespective of ablation depth (up to 94.62 μ).

Carbonyl Cytotoxicity Affects Plant Cellular Processes and Detoxifying Enzymes Scavenge These Compounds to Improve Stress Tolerance

Oxidative stress is ubiquitous in environmental stresses and prevails over the cellular metabolic and phenotypic responses in plants. Reactive oxygen species (ROS) generated under stress affect macromolecules to form another group of toxic compounds called reactive carbonyl compounds (RCCs). These molecules have a longer half-life than ROS and cause carbonyl stress that affects cellular metabolism, cellular homeostasis, and crop productivity. The later effect of oxidative stress in terms of the generation of RCCs and glycation products and their effects on plant processes have not been explored well in plant biology. Therefore, how these molecules are produced and a few important effects of RCCs on plants have been discussed in this review article. Further, the plant adaptive detoxification mechanisms of RCCs have been discussed. The enzymes that were identified in plants to detoxify these cytotoxic compounds have broad substrate specificity and the potential for use in breeding programs. The review should provide a comprehensive understanding of the cytotoxic compounds beyond ROS and subsequently their mitigation strategies for crop improvement programs.

Optimization of operating parameters for gas-phase photocatalytic splitting of H2S by novel vermiculate packed tubular reactor

Hydrogen production by gas-phase photocatalytic splitting of Hydrogen Sulphide (H2S) was investigated on four semiconductor photocatalysts including CuGa1.6Fe0.4O2, ZnFe2O3, (CdS + ZnS)/Fe2O3 and Ce/TiO2. The CdS and ZnS coated core shell particles (CdS + ZnS)/Fe2O3 shows the highest rate of hydrogen (H2) production under optimized conditions. Packed bed tubular reactor was used to study the performance of prepared photocatalysts. Selection of the best packing material is a key for maximum removal efficiency. Cheap, lightweight and easily adsorbing vermiculate materials were used as a novel packing material and were found to be effective in splitting H2S. Effect of various operating parameters like flow rate, sulphide concentration, catalyst dosage, light irradiation were tested and optimized for maximum H2 conversion of 92% from industrial waste H2S.

Determinants of ventilator associated pneumonia and its impact on prognosis: A tertiary care experience

Background:

Ventilator associated pneumonia (VAP) is a major cause of poor outcome among patients in the intensive care units (ICU) world-wide. We sought to determine the factors associated with development of VAP and its prognosis among patients admitted to different ICUs of a Tertiary Care Hospital in India.

Methodology:

We did a matched case control study during October 2009 to May 2011 among patients, ≥18 years with mechanical ventilation. Patients who developed pneumonia after 48 h of ventilation were selected in the case group and those who did not develop pneumonia constituted the control group. Patients’ history, clinical and laboratory findings were recorded and analyzed.

Results:

There were 52 patients included in each group. Among cases, early onset ventilator associated pneumonia (EVAP) occurred in 27 (51.9%) and late onset ventilator associated pneumonia (LVAP) in 25 (48.1%). Drug resistant organisms contributed to 76.9% of VAP. Bacteremia (P = 0.002), prior use of steroid/immunosuppressant (P = 0.004) and re-intubations (P = 0.021) were associated with the occurrence of VAP. The association of Acinetobacter (P = 0.025) and Pseudomonas (P = 0.047) for LVAP was found to be statistically significant. Duration of mechanical ventilation (P = 0.001), ICU stay (P = 0.049) and requirement for tracheostomy (P = 0.043) were significantly higher in VAP. Among each case and control groups, 19 (36.5%) expired.

Conclusion:

We found a higher proportion of LVAP compared with EVAP and a higher proportion of drug resistant organisms among LVAP, especially Pseudomonas and Acinetobacter. Drug resistant Pseudomonas was associated with higher mortality.

Trichomoniasis: An update

Trichomoniasis is one of the most common sexually transmitted infections (STIs) with a prevalence of 5-75%. In India, trichomoniasis accounts for 2-7% of all STIs. Infection with Trichomonas vaginalis is known to cause vaginitis. Significant association has also been noted between trichomoniasis and cervical cancer, atypical pelvic inflammatory disease, infertility, low birth weight, and respiratory-tract infection in neonates. Of interest are the recent documentations of association of this parasite with human immunodeficiency virus. Use of fluorescent dyes such as acridine orange has increased the sensitivity of the direct microscopy. Culture has been found to be more sensitive than the direct microscopy but has its own limitations. Antigen detection systems have hastened the proce ss of diagnosis tremendously. Molecular methods have been found to be very sensitive and specific. Once the presence of T. vaginalis has been documented, other STIs should also be actively looked for in that particular individual. Therapy should involve both the partners for proper control and eradication of the disease.

Ozonation of tannery effluent for removal of cod and color

Ozonation of leather dye effluent for removal of color and COD reduction covering wide range in operating parameters forms the scope of the present work. The influence of parameters such as influent pH, ozone flow rate and initial effluent concentration on ozonation efficiency has been critically examined. It has been observed from the present investigation that a maximum of COD removal efficiency of 92% has been achieved under optimum operating conditions. Further the biodegradability index of the tannery effluent has increased from an initial value of 0.18 to 0.49 during ozonation indicating favorable adaptation of ozonation as a primer to the biochemical technique to enhance the efficiency of biochemical treatment.