CO2 utilization: Turning greenhouse gas into fuels and valuable products

This study critically reviews the recent developments and future opportunities pertinent to the conversion of CO₂ as a potent greenhouse gas (GHG) to fuels and valuable products. CO₂ emissions have reached an alarming level of around 410 ppm and have become the primary driver of global warming and climate change leading to devastating events such as droughts, hurricanes, torrential rains, floods, tornados and wildfires across the world. These events are responsible for thousands of deaths and have adversely affected the economic development of many countries, loss of billions of dollars, across the globe. One of the promising choices to tackle this issue is carbon sequestration by pre- and post-combustion processes and oxyfuel combustion. The captured CO₂ can be converted into fuels and valuable products, including methanol, dimethyl ether (DME), and methane (CH₄). The efficient use of the sequestered CO₂ for the desalinization might be critical in overcoming water scarcity and energy issues in developing countries. Using the sequestered CO₂ to produce algae in combination with wastewater, and producing biofuels is among the promising strategies. Many methods, like direct combustion, fermentation, transesterification, pyrolysis, anaerobic digestion (AD), and gasification, can be used for the conversion of algae into biofuel. Direct air capturing (DAC) is another productive technique for absorbing CO₂ from the atmosphere and converting it into various useful energy resources like CH₄. These methods can effectively tackle the issues of climate change, water security, and energy crises. However, future research is required to make these conversion methods cost-effective and commercially applicable.

Editorial: Diagnostic Testing for SARS-Coronavirus-2 in the Nursing Facility: Recommendations of a Delphi Panel of Long-Term Care Clinicians

With the COVID-19 pandemic progressing, guidance on strategies to mitigate its devastating effects in nursing facilities (NFs) is critical to preventing additional tragic outcomes. Asymptomatic spread of COVID-19 from nursing facility staff and residents is a major accelerator of infection. Facility-wide point-prevalence testing is an emerging strategy in disease mitigation. Because time is not available to await the results of randomized controlled trials before implementing strategies in this high-risk setting, an expert Delphi panel composed of experienced long-term care medicine professionals has now met to provide testing guidance for SARS-Coronavirus-2 to NFs. After many email and telephone discussions, the panel responded to a questionnaire that included six different scenarios, based on varying availability of Polymerase Chain Reaction (RT-PCR) testing and personal protective equipment (PPE). The panel endorsed facility-wide testing of staff and residents without dissent when diagnostic RT-PCR was available. While the panel recognized the limitations of RT-PCR testing, it strongly recommended this testing for both staff and residents in NFs that were either COVID-19 naive or had limited outbreaks. There was also consensus on testing residents with atypical symptoms in a scenario of limited testing capability. The panel favored testing every 1 to 2 weeks if testing was readily available, reducing the frequency to every month as community prevalence declined or as the collection of additional data further informed clinical critical thinking and decision-making. The panel recognized that frequent testing would have consequences in terms of potential staff shortages due to quarantine after positive tests and increased PPE use. However, the panel felt that not testing would allow new clusters of infection to form. The resulting high mortality rate would outweigh the potential negative consequences of testing. The panel also recognized the pandemic as a rapidly evolving crisis, and that new science and increasing experience might require an updating of its recommendations. The panel hopes that its recommendations will be of value to the long-term care industry and to policy makers as we work together to manage through this challenging and stressful time.

Spigelian Hernia: A Complication of Laparoscopic Cholecystectomy

Spigelian hernia is a rare abdominal wall hernia. It constitutes about 0.12% of all abdominal wall herniae; the peak occurrence being between the ages of 40-70 years with a male to female ratio of 1:1.18. Owing to the rarity of the disease, lack of physician experience and absence of typical hernia-like symptoms, it is a fairly difficult condition to diagnose. There is a 20% incidence of strangulation reported in the literature. The elective treatment of a Spigelian hernia is surgical: open or laparoscopic. The latter is preferred due to reduced mortality, shorter hospital stay, better cosmetic result and perhaps a lower recurrence rate. Reported here is a case of Spigelian hernia that presented to our institution, a level 1 trauma centre, as a complication of laparoscopic abdominal surgery.

Plasmonic Moon: A Fano-Like Approach for Squeezing the Magnetic Field in the Infrared

Outstanding results have been achieved in the localization of optical electric fields via ultrasmall plasmonic cavities, paving the way to the subdiffractive confinement of local electromagnetic fields. However, due to the intrinsic constraints related to conventional architectures, no comparable squeezing factors have been managed yet for the magnetic counterpart of radiation, practically hindering the detection and manipulation of magneto-optical effects at the nanoscale. Here, we observe a strong magnetic field nanofocusing in the infrared, promoted by the induction of a coil-type Fano resonance. By triggering the coil current via a quadrupole-like plasmonic mode, we straightforwardly boost the enhancement of the infrared magnetic field and perform its efficient squeezing in localized nanovolumes.

Fast Fourier transform scanning spreading resistance microscopy: a novel technique to overcome the limitations of classical conductive AFM techniques

A new atomic force microscopy (AFM)-based technique named fast Fourier transform scanning spreading-resistance microscopy (FFT-SSRM) has been developed. FFT-SSRM offers the ability to isolate the local spreading resistance (Sr) from the parasitic series resistance (probe, bulk, and back contact). The parasitic series resistance limits the use of classical SSRM in confined volumes and on very highly doped materials, two increasingly important situations in nanoelectronic components. This is realized via a force modulation at controlled frequency (affecting the SR component) and the extraction of the resistance amplitude at the modulation frequency, performing an FFT-based lock-in deconvolution. A systematic evaluation of the FFT-SSRM performances (i.e., resolution, dynamic range, sensitivity, and repeatability) is presented. The impact of various parameters (i.e., modulation frequency and amplitude or cutoff frequency of the current amplifier) on the performances of FFT-SSRM has been evaluated. We demonstrate the possibility to overcome sensitivity losses due to tip saturation in highly doped material and the utility of the technique in two different structures, presenting isolated and confined volumes.

Using the Taguchi method to investigate the effect of different parameters on mean diameter and variation in PA-6 nanofibres produced by needleless electrospinning

Employing different types of fibre generators, needleless electrospinning gives much higher fibre production rates as compared to needle-based techniques.

Identification and Antimicrobial Susceptibility Pattern of Clinically Significant Coagulase-negative Staphylococci

Aims: This study was undertaken to determine the prevalence and pathogenicity of coagulase-negative staphylococci in clinical samples and to study the antibiotic-sensitivity pattern of the coagulase-negative isolates. Methods: A prospective study was conducted over a period of two years on patients admitted in the Sher-i-Kashmir Institute of Medical Sciences. Blood, urine, pus, catheter tips, cerebrospinal fluid and peritoneal fluid samples of patients who fulfilled the criteria for being labeled as nosocomial were cultured. Results: One hundred and six strains of coagulase negative staphylococci were isolated from the samples and among them 90 isolates were identified as Staphylococcus epidermidis (84.90%). Most of the coagulase-negative staphylococci isolates were resistant to penicillin, cephalosporins and fluoroquinolones. Methicillin resistance was found in a significant number of coagulase-negative isolates. All the isolates were found to be sensitive to vancomycin. Conclusions:  The results of the study emphasized that isolation of coagulase-negative staphylococci should be viewed with serious concern and accurate species identification and antimicrobial susceptibility testing should be performed in all cases. DOI: http://dx.doi.org/10.3126/njog.v9i2.11769

Fano coil-type resonance for magnetic hot-spot generation

The possibility to develop nanosystems with appreciable magnetic response at optical frequencies has been a matter of intense study in the past few years. This aim was strongly hindered by the saturation of the magnetic response of "natural" materials beyond the THz regime. Recently, in order to overcome such limitation, it has been considered to enhance the magnetic fields through the induction of displacement currents triggered by plasmonic resonances. Here we investigate a nanoassembly supporting the hybridization of an electric and magnetic plasmonic mode in Fano resonance conditions. Taking advantage of the enhancement properties owned by such interferential resonance, we have been able to generate an intense and localized magnetic hot-spot in the near-infrared spectral region.

Observation of diameter dependent carrier distribution in nanowire-based transistors

The successful implementation of nanowire (NW) based field-effect transistors (FET) critically depends on quantitative information about the carrier distribution inside such devices. Therefore, we have developed a method based on high-vacuum scanning spreading resistance microscopy (HV-SSRM) which allows two-dimensional (2D) quantitative carrier profiling of fully integrated silicon NW-based tunnel-FETs (TFETs) with 2 nm spatial resolution. The key elements of our characterization procedure are optimized NW cleaving and polishing steps, the use of in-house fabricated ultra-sharp diamond tips, measurements in high vacuum and a dedicated quantification procedure accounting for the Schottky-like tip-sample contact affected by surface states. In the case of the implanted TFET source regions we find a strong NW diameter dependence of conformality, junction abruptness and gate overlap, quantitatively in agreement with process simulations. In contrast, the arsenic doped drain regions reveal an unexpected NW diameter dependent dopant deactivation. The observed lower drain doping for smaller diameters is reflected in the device characteristics by lower TFET off-currents, as measured experimentally and confirmed by device simulations.

Phonon-induced Rabi-frequency renormalization of optically driven single InGaAs/GaAs quantum dots

We study optically driven Rabi rotations of a quantum dot exciton transition between 5 and 50 K, and for pulse areas of up to 14π. In a high driving field regime, the decay of the Rabi rotations is nonmonotonic, and the period decreases with pulse area and increases with temperature. By comparing the experiments to a weak-coupling model of the exciton-phonon interaction, we demonstrate that the observed renormalization of the Rabi frequency is induced by fluctuations in the bath of longitudinal acoustic phonons, an effect that is a phonon analogy of the Lamb shift.

Damping of exciton Rabi rotations by acoustic phonons in optically excited InGaAs/GaAs quantum dots

We report experimental evidence identifying acoustic phonons as the principal source of the excitation-induced-dephasing (EID) responsible for the intensity damping of quantum dot excitonic Rabi rotations. The rate of EID is extracted from temperature dependent Rabi rotation measurements of the ground-state excitonic transition, and is found to be in close quantitative agreement with an acoustic-phonon model.

Role of interleukin 10 in murine postoperative ileus

BACKGROUND AND AIMS

Intestinal manipulation triggers an inflammatory cascade within the muscularis causing postoperative ileus (POI). The aim of this study was to investigate the recovery and therapeutic potential of interleukin 10 (IL10) for POI.

METHODS

POI was induced by bowel surgical manipulation (SM) in wild-type, IL10(-/-) and recombinant murine IL10 (rmIL10)-treated mice. Immunohistochemistry localised IL10 in the muscularis externa, histochemistry quantified neutrophil recruitment, and quantitative PCR quantified alterations in mRNA. Luminex multiplex analysis, Griess reaction and ELISA measured proteins, nitric oxide (NO) and prostanoid release from the muscularis externa, respectively, in 24 h organ culture. Gastrointestinal transit and jejunal circular muscle organ bath techniques assessed gastrointestinal function.

RESULTS

In IL10 knockouts compared with the wild type, the expression of numerous proinflammatory mRNAs (IL6, IL1 beta, chemokine C-C motif ligand 2 (CCL2) and haem oxygenase-1) and proteins (IL6, IL1 alpha, IL12, IL17, interferon gamma, tumour necrosis factor alpha, CCL2, interferon-inducible protein-10 and granulocyte-macrophage colony-stimulating factor (GM-CSF)) were accentuated, and release of muscle inhibitors NO and prostanoids was increased; motility never recovered from manipulation and mortality rate was 87.5%. In wild types, complete functional recovery occurred in 7 days with no mortality. SM delay in transit and suppression in jejunal circular muscle contractions were significantly improved by rmIL10 treatment. Upregulation in IL1 beta, IL6 and CCL2 mRNAs and inflammatory mediators (IL1 alpha, IL6, CCL2, macrophage inflammatory protein-1 alpha, GM-CSF, NO and prostaglandin) after SM were significantly less with rmIL10 treatment, which resulted in a decrease in neutrophil recruitment compared with SM controls.

CONCLUSION

IL10 plays an obligatory role in postoperative intestinal recovery, and exogenous IL10 prevents its development. Pre-emptive exogenous recombinant human IL10 could be a treatment for the prevention of clinical POI.

Alvimopan and COX-2 inhibition reverse opioid and inflammatory components of postoperative ileus

Our objective was to investigate the therapeutic potential of peripheral opioid antagonism with alvimopan and anti-inflammatory cyclooxygenase 2 (COX-2) inhibition in an animal model of postoperative ileus with pain management. Intestinal manipulation was conducted in mice and rats with or without postoperative morphine injection. Rodents were orally fed non-digestible fluorescein (FITC)-labelled dextran and transit measured after a period of 90 min. The immunomodulatory effects of morphine and alvimopan were determined on nitric oxide released from the organ cultured muscularis externa. Surgical manipulation of the intestine resulted in a delay in gastrointestinal transit after 24 h that worsened with exogenous morphine. Alvimopan did not significantly alter transit of control or manipulated animals, but significantly antagonized the transit delaying effects of morphine. However, when the inflammatory component was robust enough to obscure a further opioid induced delay in gastrointestinal transit, alvimopan ceased to be effective in improving postoperative intestinal function. Cyclooxygenase 2 inhibition significantly diminished the inflammatory component of postoperative ileus. Surgical manipulation resulted in an increased release of nitric oxide from the inflamed isolated muscularis externa in 24-h organ culture which was not altered by morphine or alvimopan. Two distinct mechanisms exist which participate in postoperative bowel dysfunction: a local inflammatory response which is antagonized by COX-2 inhibition, and a morphine-induced alteration in neural function which can be blocked with alvimopan.

Selective spin coupling through a single exciton

We present a novel scheme for performing a conditional phase gate between two spin qubits in adjacent semiconductor quantum dots through delocalized single exciton states, formed through the interdot Förster interaction. We consider two resonant quantum dots, each containing a single excess conduction band electron whose spin embodies the qubit. We demonstrate that both the two-qubit gate and arbitrary single-qubit rotations may be realized to a high fidelity with current semiconductor and laser technology.

Toxicity of argemone oil: effect on hsp70 expression and tissue damage in transgenic Drosophila melanogaster (hsp70-lacZ) Bg9

The effect of argemone oil on hsp70 expression and tissue damage was investigated by studying beta-galactosidase activity, Western blotting and hybridization, and trypan blue staining in the larval tissues of transgenic Drosophila melanogaster (hsp70-lacZ)Bg9. Different concentrations of argemone oil were mixed with food and third-instar larvae were allowed to feed on them for different time intervals (2, 4, 24, and 48 h). Argemone oil was found to induce hsp70 even in the lowest concentration of the adulterant while maximum tissue damage was observed in the higher two treatment groups. Malpighian tubules and midgut tissue reflected maximum damage as evidenced by both high beta-galactosidase activity and trypan blue staining in these tissues. A prior temperature shock treatment to the larvae was enough to protect the larvae from argemone oil-induced tissue damage as evidenced by little or no trypan blue staining. The present study suggests the cytotoxic potential of argemone oil and further strengthens the evidence for the use of hsp70 as a biomarker in risk assessment.

Effect of three chlorinated pesticides on hsromega stress gene in transgenic Drosophila melanogaster

Expression of hsromega stress gene in the third-instar larvae of 951-lacZ2 (hsromega-lacZ having-844pb sequence) and 498-lacZ1 (hrsomega-lacZ having -498bp sequence) strains of Drosophila melanogaster at LC(50) and lower dietary concentrations of hexachlorocyclohexane (HCH) pentachlorophenol (PCP), and endosulfan was examined in relation to larval mortality by beta galactosidase activity, vital dye staining, and salivary gland polytene chromosome puffing. Our results showed that both HCH and PCP at lower concentrations evoked strong hsromega stress gene expression in the larval tissues while endosulfan did not. On the other hand, puffing data revealed that endosulfan at lower doses, induced well-developed puff at the resident site (93D) of the hsromega gene but the transgenic sites (30B in 951-lacZ2 and 44B in 498-lacZ1 strain) did not show any well-developed puff. Regression in hsromega stress gene expression in 951-lacZ2 strain at LC(50) concentrations of HCH and PCP after 48 h was concurrent with extensive tissue damage as evident by trypan blue staining. Similarly, strong hsromega expression was accompanied by insignificant trypan blue staining in the larval tissues of this strain after shorter duration of exposure (2-12 h) to these toxicants. Although endosulfan under similar experimental condition did not induce hsromega, strong trypan blue staining indicated extensive tissue damage after 48 h of exposure. The present study suggests that all the three toxicants pose cytotoxic potential to Drosophila. While protective role of this stress gene was evident at the initial stages of exposure, extensive tissue damage in the later stages of intoxication accompanied by autorepression of hsromega led to larval mortality. The study further suggests that -844bp upstream sequence of the gene is adequate for hsromega inducibility against HCH and PCP but not for endosulfan for which responsive elements may be searched further upstream.

Internet: a major resource for toxicologists

Use of the Internet in developing countries is now growing faster. Internet has created a new conduit not only for communication but also in the access, sharing and exchange of information among scientists. The Internet is now viewed as the world's biggest library where retrieval of scientific literature and other information resources are possible within seconds. Large volumes of toxicological information resources are available on the Internet. This review outlines some sites that may be of great importance and useful to the toxicologist.

Chlorpyrifos-induced hsp70 expression and effect on reproductive performance in transgenic Drosophila melanogaster (hsp70-lacZ) Bg9

Expression of hsp70 in the third-instar larval tissues of transgenic Drosophila melanogaster (hsp70-lacZ) following dietary exposure to organophosphate insecticide chlorpyrifos for various time intervals was investigated. Effect of the chemical on different developmental stages of the fly was also evaluated by looking at survivorship, hatchability, emergence, fecundity, fertility, and reproductive performance. Our results showed that the toxicant evokes profound cytotoxic effect as evidenced by dark blue staining in salivary gland, proventriculus, brain ganglia, and midgut in the lowest concentration of the chemical following 24 and 48 h of exposure. On the other hand, a significant increase (61%) in hsp70 expression in the above larval tissues was observed in the next higher concentration of the toxicant after 6 h exposure when compared with that of the lowest dose. A further increase in exposure time caused 100% larval mortality. Similarly, larvae exposed to higher concentrations of the toxicant, exhibited 100% mortality within 1 h of treatment. The insecticide caused a delay in emergence and a severe reduction in survivorship of the flies in a dose-dependent manner with 100% mortality within a day of exposure in the highest dosed group. A delay in emergence by 3 days was evident even in the lowest concentration of the chemical. A drastic effect of the chemical on hatchability was found in the highest dosed group with 100% embryonic mortality at post-16 stage of the embryo. Reproductive performance was significantly affected even in the lowest dosed group. The present study suggests that certain larval tissues of Drosophila, a nontarget organism, are vulnerable to chlorpyrifos as evidenced by hsp70 expression. Further, the adverse effect of the toxicant is reflected on various stages of development of the fly including reproductive performance.