Simultaneous removal of ortho-dichlorobenzene and ethanol vapors in a biotrickling filter : experimental results and process modeling

This study investigated the possibility of simultaneous removal of vapors of dissimilar volatile organic compounds from air streams in a biotrickling filter (BTF). Using a rricrobial consortium known to utilize ortho-dichlorobenzene (o-DCB) as sole carbon and energy source, a culture was developed on o-DCB/ethanol mixtures and a BTF unit was developed and operated with air streams carrying o-DCB and ethanol vapors. Simultaneous removal of the two compounds was observed in experiments that span a period of over three years. Experiments were performed at air residence times ranging from 4 to 6.5 min, liquid flow rates from 3.6 to 9 Lh-1, and inlet air concentrations from 0.85 to 4.5 gm-3 and 0.95 to I I gM-3 for o-DCB and ethanol, respectively. The maximum removal rate was 40 and 150 gm-3 packing h-1 for o-DCB and ethanol, respectively. It was possible to duplicate results in experiments performed under a given set of operating conditions at time intervals as far as 9 months apart from one another. The presence of the readily degradable ethanol at relatively high concentrations led to the formation of significant amounts of biomass in the liquid recirculating through the BTF resulting in the removal of o-DCB and ethanol both in the liquid phase and the biomass attached to the packing material. The readily biodegradable ethanol led to better coverage of the packing with b1ofilm, resulting in a positive effect on the removal of o-DCB vapor. However, every four months an abrupt increase in pressure drop build-up and concornitant loss in BTF performance was observed over a 5-day period. Once excess biomass was removed from the BTF unit, normal operation was recovered within 3-4 days. Steady state operation of the unit was mathematically described with a model involving mass balances for o-DCB, ethanol, and oxygen in three phases: air, recirculating liquid, and biofilm. The model accounts for reaction in both the liquid and biofilm phases. Through the introduction of the notion of effectiveness factors for o-DCB and ethanol, the equations for the b1ofilm were decoupled from those for the air and liquid allowing for easier numerical solution of the original complex model. The model was found capable of predicting the data on removal rates with a less than 10% - and oftentimes less than 5% error. Independent kinetic experiments led to the following conclusions: o-DCB and ethanol were biodegraded following Andrews self-inhibitory kinetics; no kinetic interactions occurred over the concentration ranges tested in the BTF; there was no biomass diversification along the length of the BTF unit

Enhanced Piezoresponse and Nonlinear Optical Properties of Fluorinated Self-Assembled Peptide Nanotubes

Self-assembled L,L-diphenylalanine (FF) nanostructures offer an attractive platform for photonics and nonlinear optics. The nonlinear optical (NLO) coefficients of FF nanotubes depend on the diameter of the tube [S. Khanra et al. Phys. Chem. Chem. Phys. 19(4), 3084-3093 (2017)]. To further enhance the NLO properties of FF, we search for structural modifications. Here, we report on the synthesis of fluorinated FF dipeptides by replacing one ortho-hydrogen atom in each of the phenyl groups of FF by a fluorine atom. Density-functional theoretical calculations yield insights into minimum energy conformers of fluorinated FF (Fl-FF). Fl-FF self-assembles akin to FF into micron-length tubes. The effects of fluorination are evaluated on the piezoelectric response and nonlinear optical properties. The piezoelectric d15 coefficient of Fl-FF is found to be more than 10 times higher than that of FF nanotubes, and the intensity of second harmonic generation (SHG) polarimetry from individual Fl-FF nanotubes is more than 20 times that of individual FF nanotubes. Furthermore, we obtain SHG images to compare the intensities of FF and Fl-FF tubes. This work demonstrates the potential of fluorine substitution in other self-assembled biomimetic peptides for enhancing nonlinear optical response and piezoelectricity

Consuming the non-human and the less-than-human: A critical study of Sarah Kane’s Blasted (1995)

The epoch of the Anthropocene, with accelerating technological advances and growing economic and social inequalities, have made the spatial reality more violent, intolerable, discriminatory and disintegrating. These growing inequalities set the conditions for exploitation and subjugation. While the privileged section of the human population buys their way out and lives comfortably within the closed spaces of their gated communities amidst the global devastation; the underprivileged, on the other hand, have to confront the consequences. Within the privileged closed space, the food is available in abundance, and is lavishly served, consumed and even wasted; but for those outside the privileged closed space, the scarcity and unavailability of food is an imminent threat. The paper focuses on the fragility of the economy of food within the gradually worsening Anthropocene condition, especially the over-dependence of global food supply chains. The paper places Sarah Kane’s play Blasted (1995) in one such condition, such as conflict or war, in which the food supply is halted and the havoc is unleashed. In Blasted, the object of consumption, the food eaten by human subjects when the food supply chains are unharmed, is the non-human flora and fauna. And when the food supply chains are disrupted or halted, when the bubble of a safe closed space bursts and when the food is hard to come by, the natural instinct to survive kicks in and the human subjects do everything in their power to survive, including cannibalizing the less-that-human or the dehumanized Other

Oxytocin administration during cesarean delivery: Randomized controlled trial to compare intravenous bolus with intravenous infusion regimen

Background: Oxytocin is routinely administered during cesarean delivery for uterine contraction. Adverse effects are known to occur after intravenous oxytocin administration, notably tachycardia, hypotension, and electrokardiogram (EKG) changes, which can be deleterious in high-risk patients. Aims and Objectives: To compare the hemodynamic changes and uterotonic effect of equivalent dose of oxytocin administered as an intravenous bolus versus intravenous infusion. Study Design: Randomized, double-blind, active controlled trial. Materials and Methods: Eighty parturients undergoing elective cesarean delivery, under spinal anesthesia, were randomly allocated to receive 3 IU of oxytocin either as a bolus intravenous injection over 15 seconds (group B, n = 40) or as an intravenous infusion over 5 minutes (group I, n = 40). Uterine tone was assessed as adequate or inadequate by an obstetrician. Intraoperative heart rate, non-invasive blood pressure, and EKG changes were recorded. These data were compared between the groups. Any other adverse events like chest pain, nausea, vomiting, and flushing were noted. Results: There was significant rise in heart rate and significant decrease in mean arterial pressure in bolus group compared to infusion group. Three patients in bolus group had EKG changes in the form of ST-T depression and 5 patients complained of chest pain. No such complications were found in infusion group. Conclusion: Bolus oxytocin (at a dose of 3 IU over 15 seconds) and infusion of oxytocin (at a dose of 3 IU over 5 minutes) have comparable uterotonic effect. However, the bolus regime shows significantly more adverse cardiovascular events

Comparison between general anesthesia and spinal anesthesia in attenuation of stress response in laparoscopic cholecystectomy: A randomized prospective trial

Background: Laparoscopy though minimally invasive produces significant hemodynamic surge and neuroendocrine stress response. Though general anesthesia (GA) is the conventional technique, now-a-days, regional anesthesia has been accepted for laparoscopic diagnostic procedures, and its use is also being extended to laparoscopic surgeries. Objective: The aim was to compare the hemodynamic surge and neuroendocrine stress response during laparoscopic cholecystectomy (LC) under GA and spinal anesthesia (SA) in American Society of Anesthesiologists (ASA) PS 1 patients. Materials and Methods: Thirty ASA physical status I patients, aged 18-65 years were randomly allocated into two equal groups of 15 each. Group A received GA with controlled ventilation. Patients were preoxygenated for 5 min with 100/5 oxygen, premedicated with midazolam 0.03 mg/kg intravenous (i.v), fentanyl 2 mcg/kg i.v; induction was done with thiopentone 3-5 mg/kg i.v; intubation was achieved after muscle relaxation with 0.5 mg/kg atracurium besylate i.v. Anesthesia was maintained with 1-2% sevoflurane and N2O:O2 (60:40) and intermittent i.v injection of atracurium besylate. Group B SA with 0.5% hyperbaric bupivacaine and 25 μg fentanyl along with local anesthetic instillation in the subdiaphragmatic space. Mean arterial pressure, heart rate (HR), oxygen saturation, end tidal carbon-dioxide were recorded. Venous blood was collected for cortisol assay before induction and 30 min after pneumoperitoneum. All data were collected in Microsoft excel sheet and statistically analyzed using SPSS software version 16 (SPSS Inc., Chicago, IL, USA). All numerical data were analyzed using Student′s t-test and paired t-test. Any value <0.05 was taken as significant. Results: Mean arterial pressure and mean HR and postpneumoperitoneum cortisol level were lower in group B than group A though the difference was not statistically significant in hemodynamic parameters but significant in case of cortisol. Conclusion: Spinal anesthesia administered for LC maintained comparable hemodynamics compared to GA and did not produce any ventilatory depression. It also produced less neuroendocrine stress response as seen by reduction in the level of serum cortisol in ASA PS 1 patients put for LC

Lumped kinetic modelling of polyolefin pyrolysis: A non-isothermal method to estimate rate constants

The measurement of kinetic parameters in the pyrolysis of polyolefins requires the use of a lumped kinetic model for predicting the product distribution of wax, oil and gas yields. A non-isothermal method was established, in which a sample is heated in a tube reactor to a desired temperature at a constant rate of temperature rise. This method avoided the error present in the heating up stage which is inherent in any practical isothermal method in which reaction proceeds to a significant extent before the operating temperatures of polyolefin pyrolysis are reached, which results in challenges when defining the reaction time. The non-isothermal measurements were conducted between 450 and 550°C for polypropylene (PP) and polyethylene (HDPE and LDPE) and the temperature and lump yields are non-linearly regressed to achieve the kinetic parameters. The measured kinetic rate constants have the same trend as those reported in the literature using the isothermal method, but are higher than the values reported above 450°C and similar to the values for lower temperatures of 350°C and 370°C. The kinetic parameters derived are then validated by using isothermal experimental data. The calculated data using the measured kinetic parameters are generally in agreement with the experimental data. The non-isothermal method established in this work proves to be a much faster method for the measurement of intrinsic rate constants at high temperatures

Machine Learning and Statistical Analysis for Materials Science: Stability and Transferability of Fingerprint Descriptors and Chemical Insights

In the paradigm of virtual high-throughput screening for materials, we have developed a semiautomated workflow or “recipe” that can help a material scientist to start from a raw data set of materials with their properties and descriptors, build predictive models, and draw insights into the governing mechanism. We demonstrate our recipe, which employs machine learning tools and statistical analysis, through application to a case study leading to identification of descriptors relevant to catalysts for CO₂ electroreduction, starting from a published database of 298 catalyst alloys. At the heart of our methodology lies the Bootstrapped Projected Gradient Descent (BoPGD) algorithm, which has significant advantages over commonly used machine learning (ML) and statistical analysis (SA) tools such as the regression coefficient shrinkage-based method (LASSO) or artificial neural networks: (a) it selects descriptors with greater stability and transferability, with a goal to understand the chemical mechanism rather than fitting data, and (b) while being effective for smaller data sets such as in the test case, it employs clustering of descriptors to scale far more efficiently to large size of descriptor sets in terms of computational speed. In addition to identifying the descriptors that parametrize the <i>d</i>-band model of catalysts for CO₂ reduction, we predict work function to be an essential and relevant descriptor. Based on this result, we propose a modification of the <i>d</i>-band model that includes the chemical effect of work function, and show that the resulting predictive model gives the binding energy of CO to catalyst fairly accurately. Since our scheme is general and particularly efficient in reducing a set of large number of descriptors to a minimal one, we expect it to be a versatile tool in obtaining chemical insights into complex phenomena and development of predictive models for design of materials

Role of Artificial Intelligence in Radiogenomics for Cancers in the Era of Precision Medicine

Radiogenomics, a combination of &ldquo;Radiomics&rdquo; and &ldquo;Genomics,&rdquo; using Artificial Intelligence (AI) has recently emerged as the state-of-the-art science in precision medicine, especially in oncology care. Radiogenomics syndicates large-scale quantifiable data extracted from radiological medical images enveloped with personalized genomic phenotypes. It fabricates a prediction model through various AI methods to stratify the risk of patients, monitor therapeutic approaches, and assess clinical outcomes. It has recently shown tremendous achievements in prognosis, treatment planning, survival prediction, heterogeneity analysis, reoccurrence, and progression-free survival for human cancer study. Although AI has shown immense performance in oncology care in various clinical aspects, it has several challenges and limitations. The proposed review provides an overview of radiogenomics with the viewpoints on the role of AI in terms of its promises for computational as well as oncological aspects and offers achievements and opportunities in the era of precision medicine. The review also presents various recommendations to diminish these obstacles