Dyakonov waves generation at uniaxial chiral-plasma interface

Numerical analysis of Dyakonov waves generation has been carried out at uniaxial chiral-plasma planar interface. The extended electromagnetic wave theory is utilized, and an impedance boundary conditions approach is employed to obtain characteristics equation. Effective mode index and attenuation under the different values of collisional frequency, plasma frequency and chirality in the THz frequency range for three cases for uniaxial chiral media are discussed. These results can be used in the field of photonics and integrated optics to fabricate nanophotonic devices in the THz frequency range.

Thermally tunable electromagnetic surface waves supported by graphene loaded indium antimonide (InSb) interface

The thermal agitation plays a vital role in tunability of optoelectronic, structural and chemical characteristics of the temperature sensitive materials. Graphene enables the THz optics, due to its unprecedent controlling characteristics over the traditional materials. The influence of temperature on the monolayer graphene is very negligible due to its low free charge carrier density, to enhance the thermal sensitivity of graphene, the graphene loaded temperature sensitive material interface has been proposed. A theoretical analysis has been carried out on temperature dependent propagation characteristics of electromagnetic surface waves supported by the graphene loaded semi-infinite indium antimonide (InSb). The InSb has been taken as temperature sensitive material. The Drude model has been used for the modeling of InSb in the THz region while the modeling of the graphene has been done by random phase approximation-based Kubo's formulism. To realize the graphene loaded indium antimonide interface, the impedance boundary conditions (IBCs) have been employed. The numerical analysis has been conducted to analyze the influence of temperature on the characteristics of electromagnetic surface waves i.e., dispersion curve, effective mode index (Neff), penetration depth (δ), propagation length (Lp), phase speed (Vp) and field profile, propagating along the graphene loaded InSb. In all the numerical results, the temperature variation has been considered from 200 to 350 K. It has been concluded that the graphene-InSb interface provides more temperature assisted tunability to the interfacial surface modes, commonly known as surface waves, as compared to monolayer graphene. Further, the graphene parameters can play a vital role in the dynamical tuning of electromagnetic surface waves in THz to IR frequency range. The numerically computed results have potential applications in designing of thermo-optical waveguides, temperature assisted communication devices, thermo-optical sensors and near field thermal imaging platforms.

A Metasurface-Based LTC Polarization Converter with S-Shaped Split Ring Resonator Structure for Flexible Applications

This paper presents a metasurface-based linear-to-circular polarization converter with a flexible structure for conformal and wearable applications. The converter consists of nested S- and C-shaped split ring resonators in the unit cell and can convert linearly polarized incident waves into left-handed circularly polarized ones at 12.4 GHz. Simulation results show that the proposed design has a high polarization conversion rate and efficiency at the operating frequency. Conformal tests are also conducted to evaluate the performance under curvature circumstances. A minor shift in the operating frequency is observed when the converter is applied on a sinusoidal wavy surface.

Ultra-Wideband Compact Fractal Antenna for WiMAX, WLAN, C and X Band Applications

In this paper, a compact dual-wideband fractal antenna is created for Bluetooth, WiMAX, WLAN, C, and X band applications. The proposed antenna consists of a circularly shaped resonator that contains square slots and a ground plane where a gap line is incorporated to increase the gain and bandwidth with a small volume of 40 × 34 × 1.6 mm³. The patch was supported by the FR4 dielectric, which had a permittivity of 4.4 and tan δ = 0.02. A 50 Ω microstrip line fed this antenna. The antenna was designed by the HFSS program, and after that, the simulated results were validated using the measured results. The measurement results confirm that the suggested antenna achieves dual-band frequencies ranging from 2.30 to 4.10 GHz, and from 6.10 GHz to 10.0 GHz, resonating at 2.8, 3.51, 6.53, and 9.37 GHz, respectively, for various applications including commercial, scholarly, and medical applications. Moreover, the antenna's ability to operate within the frequency range of 3.1-10.6 GHz is in accordance with the FCC guidelines for the use of UWB antennas in breast cancer detection. Over the operational bands, the gain varied between 2 and 9 dB, and an efficiency of 92% was attained. A good agreement between the simulation and the measured results was found.

UWB Circular Fractal Antenna with High Gain for Telecommunication Applications

The present study proposes a new, highly efficient fractal antenna with ultra-wideband (UWB) characteristics. The proposed patch offers a wide simulated operating band that reaches 8.3 GHz, a simulated gain that varies between 2.47 and 7.73 dB throughout the operating range, and a high simulated efficiency that comes to 98% due to the modifications made to the antenna geometry. The modifications carried out on the antenna are composed of several stages, a circular ring extracted from a circular antenna in which four rings are integrated and, in each ring, four other rings are integrated with a reduction factor of 3/8. To further improve the adaptation of the antenna, a modification of the shape of the ground plane is carried out. In order to test the simulation results, the prototype of the suggested patch was built and tested. The measurement results validate the suggested dual ultra-wideband antenna design approach, which demonstrates good compliance with the simulation. From the measured results, the suggested antenna with a compact volume of 40 × 24.5 × 1.6 mm³ asserts ultra-wideband operation with a measured impedance bandwidth of 7.33 GHz. A high measured efficiency of 92% and a measured gain of 6.52 dB is also achieved. The suggested UWB can effectively cover several wireless applications such as WLAN, WiMAX, and C and X bands.

Frequency Switchable Global RFID Tag Antennae with Metal Compatibility for Worldwide Vehicle Transportation

This paper presents an effective way to design an RFID tag antenna to operate at three different frequencies by incorporating a switching technique. PIN diode has been used to switch the RF frequency because of its good efficiency and simplicity. The conventional dipole-based RFID tag has been improvised with added co-planar ground and PIN diode. The layout of the antenna is designed with a size of 0.083 λ0 × 0.094 λ0 at UHF (80-960) MHz, where λ0 is the free-space wavelength corresponding to the mid-point of the targeted UHF range. The RFID microchip is connected to the modified ground and dipole structures. Bending and meandering techniques on the dipole length help to match the complex chip impedance with the dipole impedance. Additionally, it scales down the total structure of the antenna. Two PIN diodes are placed along the dipole length at appropriate distances with proper biasing. The ON-OFF switching states of the PIN diodes enable the RFID tag antenna to switch over the frequency ranges (840-845) MHz (India), 902-928 MHz (North America), and 950-955 MHz (Japan).

Single-fed broadband CPW-fed circularly polarized implantable antenna for sensing medical applications

Biomedical telemetry relies heavily on implantable antennas. Due to this, we have designed and tested a compact, a circularly polarized, a low-profile biomedical implantable antenna that operate in the 2.45 GHz ISM band. In order to keep the antenna compact, modified co-planar waveguide (CPW) technology is used. Slotted rectangular patch with one 45-degree angle slot and truncated little patch on the left end of the ground plane generate a frequency-range antenna with circular polarization. Using a 0.25-millimeter-thick Roger Duroid-RT5880 substrate with a thickness of εr = 2.2, tanδ = 0.0009 provides flexibility. The volume of the antenna is 21 mm x 13.5 mm x 0.254 mm (0.25λg × 0.16λg × 0.003λg). The antenna covers 2.35-2.55 GHz (200 MHz) in free space and 1.63-1.17 GHz (1.17 GHz) in epidermal tissue. With skin tissue that has more bandwidth, the (x and y)-axis bends of the antenna are also simulated via the simulation. Bended antenna simulations and measurements show excellent agreement. At 2.45 GHz, the skin-like gel had -10dB impedance and 3dB axial ratio (AR) bandwidths of 47.7 and 53.8%, respectively. The ultimate result is that the SAR values are 0.78 W/kg in skin over 1 g of bulk tissue, as determined by simulations. The suggested SAR values are lower than the FCC's maximum allowable limit (FCC). This antenna is small enough to be implanted in the body, making it perfect for biomedical applications.

A Low Profile Ultra-Wideband Antenna with Reconfigurable Notch Band Characteristics for Smart Electronic Systems

This study describes the design and implementation of a small printed ultra-wideband (UWB) antenna for smart electronic systems with on-demand adjustable notching properties. A contiguous sub-band between 3-4.1 GHz, 4.45-6.5 GHz, or for both bands concurrently, can be mitigated by the antenna. Numerous technologies and applications, including WiMAX, Wi-Fi, ISMA, WLAN, and sub-6 GHz, primarily utilize these band segments remitted by the UWB. The upper notch band is implemented by inserting an open-ended stub with the partial ground plane; the lower notch band functionality is obtained by etching a U-shaped slot from the radiating structure. The basic UWB mode is then changed to a UWB mode, with a single or dual notch band, using two diodes to achieve reconfigurability. The antenna has a physically compact size of 17 × 23 mm² and a quasi-omnidirectional maximum gain of 4.9 dBi, along with a high efficiency of more than 80%, according to both simulation and measurement data. A significant bandwidth in the UWB region is also demonstrated by the proposed design, with a fractional bandwidth of 180% in relation to the 5.2 GHz center frequency. Regarding compactness, consistent gain, and programmable notch features, the proposed antenna outperforms the antennas described in the literature. In addition to these benefits, the antenna's compact size makes it simple to incorporate into small electronic devices and enables producers to build many antennas without complications.

Design of a Tri-Band Wearable Antenna for Millimeter-Wave 5G Applications

A printed monopole antenna for millimeter-wave applications in the 5G frequency region is described in this research. As a result, the proposed antenna resonates in three frequency bands that are designated for 5G communication systems, including 28 GHz, 38 GHz, and 60 GHz (V band). For the sake of compactness, the coplanar waveguide (CPW) method is used. The overall size of the proposed tri-band antenna is 4 mm × 3 mm × 0.25 mm. Using a watch strap and human tissue, such as skin, the proposed antenna gives steady results. At 28 GHz, 38 GHz, and 60 GHz, the antenna's gain is found to be 5.29 dB, 7.47 dB, and 9 dB, respectively. The overall simulated radiation efficiency is found to be 85% over the watch strap. Wearable devices are a great fit for the proposed tri-band antenna. The antenna prototype was built and tested in order to verify its performance. It can be observed that the simulated and measured results are in close contact. According to our comparative research, the proposed antenna is a good choice for smart 5G devices because of its small size and simple structure, as well as its high gain and radiation efficiency.

Compact Quad Band MIMO Antenna Design with Enhanced Gain for Wireless Communications

In this paper, a novel microstrip line-fed meander-line-based four-elements quad band Multiple Input and Multiple Output (MIMO) antenna is proposed with a gain enhancement technique. The proposed structure resonates at four bands simultaneously, that is, 1.23, 2.45, 3.5 and 4.9 GHz, which resemble GPS L2, Wi-Fi, Wi-MAX and WLAN wireless application bands, respectively. The unit element is extended to four elements MIMO antenna structure exhibiting isolation of more than 22 dB between the adjacent elements without disturbing the resonant frequencies. In order to enhance the gain, two orthogonal microstrip lines are incorporated between the antenna elements which result in significant gain improvement over all the four resonances. Furthermore, the diversity performance of the MIMO structure is analyzed. The Envelope Co-Relation Coefficient (ECC), Diversity Gain (DG), Channel Capacity Loss (CCL), Mean Effective Gain (MEG) and Multiplexing Efficiency are obtained as 0.003, 10 dB, 0.0025 bps/Hz, -3 dB (almost) and 0.64 (min.), respectively, which are competent and compatible with practical wireless applications. The Total Active Reflection Coefficient (TARC) resembles the characteristic of the individual antenna elements. The layout area of the overall MIMO antenna is 0.33 λ × 0.29 λ, where λ is the free-space wavelength corresponding to the lowest resonance. The advantage of the proposed structure has been assessed by comparing it with previously reported MIMO structures based on number of antenna elements, isolation, gain, CCL and compactness. A prototype of the proposed MIMO structure is fabricated, and the measured results are found to be aligned with the simulated results.

A Wideband Circularly Polarized CPW-Fed Substrate Integrated Waveguide Based Antenna Array for ISM Band Applications

This article presents a compact size circularly polarized substrate integrated waveguide (SIW) based wideband antenna array that serves industrial, scientific, and medical (ISM) band applications. A coplanar waveguide (CPW) technique is used to ensure the antenna size compactness. The proposed antenna is fabricated on a low-profile Rogers RT6002 substrate with a dielectric constant of 2.94, tanδ of 0.0012 and an approximate height of 0.76mm. The proposed design covers the frequency range from 2.15 GHz to 3.63 GHz (60.4%) while the axial ratio has a 3 dB bandwidth covering from 2.19 GHz to 2.51 GHz (13%) at the operating band of 2.45 GHz. The antenna is miniaturized and has a size of about 46.50 × 29 × 0.76 mm³. The simulation and experimental results are taken into consideration and there is a good promise between them. Hence, the antenna is a suitable applicant to be utilized for the applications in the ISM band.

A Conformal Frequency Reconfigurable Antenna with Multiband and Wideband Characteristics

A compact flexible multi-frequency antenna for smart portable and flexible devices is presented. The antenna consists of a coplanar waveguide-fed slotted circular patch connected to a rectangular secondary resonator (stub). A thin low-loss substrate is used for flexibility, and a rectangular stub in the feedline is deployed to attain wide operational bandwidth. A rectangular slot is etched in the middle of the circular patch, and a p-i-n diode is placed at its center. The frequency reconfigurability is achieved through switching the diode that distributes the current by changing the antenna’s electrical length. For the ON state, the antenna operates in the UWB region for −10 dB impedance bandwidth from 2.76 to 8.21 GHz. For the OFF state of the diode, the antenna operates at the ISM band (2.45/5.8 GHz), WLAN band (5.2 GHz), and lower X-band (8 GHz) with a minimum gain of 2.49 dBi and a maximum gain of 5.8 dBi at the 8 GHz band. Moreover, the antenna retains its performance in various bending conditions. The proposed antenna is suitable for modern miniaturized wireless electronic devices such as wearables, health monitoring sensors, mobile Internet devices, and laptops that operate at multiple frequency bands.

A cross sectional survey on the effect of COVID-19 related restrictions on undergraduate and postgraduate medical education in Qatar

BACKGROUND

COVID-19 pandemic has affected all dimensions of day to day life across the world and medical education was no exception. With this study, we aimed to understand the effect of nationwide restrictions on medical education in Qatar, the models of education adopted during this period and perceptions of participants to the same.

METHODS

We conducted a cross-sectional study utilizing an online questionnaire distributed via convenience sampling between April-October 2020. Study participants were faculty and trainees in governmental undergraduate and postgraduate medical education institutes. Two sets of questionnaires were designed for each group. They were asked a series of questions to assess pre- and post-COVID pandemic educational practices, their preferred teaching methods, and their familiarity with electronic teaching platforms. Faculty respondents were asked about their perceived barriers to delivery of medical education during the pandemic and their agreement on a 5-point Likert scale on specific elements. Trainees were asked a series of multiple-choice questions to characterize their pre- and post-COVID pandemic educational experiences. Both groups were asked open-ended questions to provide qualitative insights into their answers. Data were analysed using STATA software version 12.0.

RESULTS

Majority of trainees (58.5%) responded that the pandemic has adversely affected medical education at both the undergraduate and postgraduate levels. Trainees (58.5%) and faculty (35.7%) reported an increased reliance on e-learning. Trainees preferred face-to-face education, while faculty preferred a combination of models of education delivery (33.5% versus 37.1%, p = 0.38). Although 52.5% of the faculty had no previous experience of delivering education through e-learning modalities, 58.9% however felt confident in using e-learning software.

CONCLUSIONS

Faculty and trainees agree that the COVID-19 pandemic has had a significant impact on the provision of medical education and training in Qatar, with an increased dependence on e-learning. As trainee's prefer face-to-face models of education, we may have to consider restructuring of medical curricula in order to ensure that optimum learning is achieved via e-learning, while at the same time enhancing our use, knowledge and understanding of the e -learning methods. Further research is warranted to assess if these changes have influenced objective educational outcomes like graduation rates or board scores.

Implementation of a Miniaturized Planar Tri-Band Microstrip Patch Antenna for Wireless Sensors in Mobile Applications

Antennas in wireless sensor networks (WSNs) are characterized by the enhanced capacity of the network, longer range of transmission, better spatial reuse, and lower interference. In this paper, we propose a planar patch antenna for mobile communication applications operating at 1.8, 3.5, and 5.4 GHz. A planar microstrip patch antenna (MPA) consists of two F-shaped resonators that enable operations at 1.8 and 3.5 GHz while operation at 5.4 GHz is achieved when the patch is truncated from the middle. The proposed planar patch is printed on a low-cost FR-4 substrate that is 1.6 mm in thickness. The equivalent circuit model is also designed to validate the reflection coefficient of the proposed antenna with the S₁₁ obtained from the circuit model. It contains three RLC (resistor-inductor-capacitor) circuits for generating three frequency bands for the proposed antenna. Thereby, we obtained a good agreement between simulation and measurement results. The proposed antenna has an elliptically shaped radiation pattern at 1.8 and 3.5 GHz, while the broadside directional pattern is obtained at the 5.4 GHz frequency band. At 1.8, 3.5, and 5.4 GHz, the simulated peak realized gains of 2.34, 5.2, and 1.42 dB are obtained and compared to the experimental peak realized gains of 2.22, 5.18, and 1.38 dB at same frequencies. The results indicate that the proposed planar patch antenna can be utilized for mobile applications such as digital communication systems (DCS), worldwide interoperability for microwave access (WiMAX), and wireless local area networks (WLAN).

Photosynthetic acclamatory response of Panicum antidotale Retz. populations to root zone desiccation stress

Growth of plants is severely reduced due to water stress by affecting photosynthesis including photosystem II (PSII) activity and electron transport. This study emphasised on comparative and priority targeted changes in PSII activity due to progressive drought in seven populations of Panicum antidotale (P. antidotale) collected from Cholistan Desert and non-Cholistan regions. Tillers of equal growth of seven populations of P. antidotale grown in plastic pots filled with soil were subjected progressive drought by withholding water irrigation for three weeks. Progressive drought reduced the soil moisture content, leaf relative water content, photosynthetic pigments and fresh and dry biomass of shoots in all seven populations. Populations from Dingarh Fort, Dingarh Grassland and Haiderwali had higher growth than those of other populations. Cholistani populations especially in Dingarh Grassland and Haiderwali had greater ability of osmotic adjustment as reflected by osmotic potential and greater accumulation of total soluble proteins. Maximum H2O2 under water stress was observed in populations from Muzaffargarh and Khanewal but these were intermediate in MDA content. Under water stress, populations from Muzaffargarh and Dingarh Fort had greater K+ accumulation in their leaves. During progressive drought, non-Cholistani populations showed complete leaf rolling after 23 days of drought, and these populations could not withstand with more water stress condition while Cholistani populations tolerated more water stress condition for 31 days. Moreover, progressive drought caused PSII damages after 19 days and it became severe after 23 days in non-Cholistani populations of P. antidotale than in Cholistani populations.

Compact Dual-Band Antenna with Paired L-Shape Slots for On- and Off-Body Wireless Communication

A simple dual-band patch antenna with paired L-shap slots for on- and off-body communications has been presented in this article. The proposed antenna resonates in the industrial, scientific, and medical (ISM) band at two different frequencies, at 2.45 GHz and 5.8 GHz. At the lower frequency band, the antenna’s radiation pattern is broadsided directional, whereas it is omni-directional at the higher frequency band. The efficiency and performance of the proposed antenna under the influence of the physical body are improved, and the specific absorption rate (SAR) value is significantly reduced by creating a full ground plane behind the substrate. The substrate’s material is FR-4, the thickness of which is 1.6 mm and it has a loss tangent of tanδ = 0.02. The overall size of the proposed design is 40 mm × 30 mm × 1.6 mm. Physical phantoms, such as skin, fat and muscle, are used to evaluate the impact of physical layers at 2.45 GHz and 5.8 GHz. The SAR values are assessed and found to be 0.19 W/kg and 1.18 W/kg at 2.45 GHz and 5.8 GHz, respectively, over 1 gram of mass tissue. The acquired results indicate that this antenna can be used for future on- and off-body communications and wireless services.

Effect of microwave plasma treatment on magnetic and photocatalytic response of manganese ferrite nanoparticles for wastewater treatment

The conventionally synthesized nano-ferrite materials do not possess bulk properties, generally required for their use in mainstream industry. To make ferrite nanoparticles clinically applicable materials, it is important to have good control over morphology and optical properties of these materials. In this study, low-pressure microwave plasma was used to tailor the structural properties and surface chemistry of manganese ferrite nanoparticles. A facile sol-gel method was used to prepare cubic spinal structures of manganese ferrite nanoparticles. These nanoparticles were exposed to oxygen plasma sustained with a microwave source for improving their magnetic and photocatalytic activities. The techniques like XRD, SEM, PL, UV-Vis DRS, transient photocurrent response and EIS were used to characterize the samples. The plasma treated nanoparticles were used to degraded methyl blue (MB) dye in the solution. The photocatalytic activity showed 85% degradation of MB after 100 min of exposure of visible light. The second part of the paper studied the magnetic properties of the nanoparticles. The saturation magnetization decreased from 0.78 emu/g to 0.68 emu/g after plasma treatment of nanoparticles.

Reflectance and transmittance of terahertz waves from graphene embedded into metamaterial structures

In this work, the theoretical study of the interaction of terahertz (THz) waves with graphene embedded into two different semi-infinite metamaterials was carried out. To model the graphene, the effective surface conductivity approach based on the Kubo formalism was used. In addition, two types of metamaterials, i.e., double-positive (DPS) and double-negative (DNG), were studied in the THz regime. The numerical modeling of metamaterials was performed in the framework of causality-principle-based Kramers-Kronig relations. The reflectance and transmittance from the graphene-embedded metamaterial structures are studied for the following four different configurations: DPS-Graphene-DPS, DPS-Graphene-DNG, DNG-Graphene-DPS, and DNG-Graphene-DNG. The influence of the chemical potential and scattering rate on the reflectance and transmittance for each configuration is analyzed. It is concluded that the DPS-Graphene-DPS and DNG-Graphene-DNG configurations behave as anti-reflectors for the THz waves, while the DPS-Graphene-DNG and DNG-Graphene-DPS configurations are suitable for THz reflector applications. Moreover, a parametric study revealed that the relative permittivity of the partnering metamaterial can be used as an additional degree of freedom to control the reflectance and transmittance of THz waves. In conclusion, the transmissive and reflective characteristics of THz waves can be controlled effectively with the appropriate choice of graphene parameters, as well as the configuration of metamaterial structures. The convergence of the analytical and numerical results is found with the published results under special conditions. The present work may have potential applications in the design of THz wave controllers, reflectors, absorbers, and anti-reflectors.

Molecular evidence and hematological alterations associated with the occurrence of coronavirus in domestic dogs in Pakistan

Canine Enteric Coronavirus (CCoV) is one of the major enteric pathogen affecting dogs. This study aims to investigate the molecular prevalence, phylogenetic analysis, associated risk factors, and haemato-biochemical alterations in Canine Coronavirus in dogs in district Lahore, Pakistan. 450 fecal samples were collected from symptomatic dogs originating from various pet-clinics and kennels during 2018-2019. Samples were initially analyzed by sandwich lateral flow immunochromatographic assay and then further processed by RT-PCR (reverse transcriptase polymerase chain reaction) targeting the M gene followed by sequencing. RT-PCR based positive (n=20) and negative (n=20) dogs were samples for their blood for the haemato-biochemical analysis. A questionnaire was used to collect data from pet owners, in order to analyze the data for risk factors analysis by chi square test on SPSS. The prevalence of CCoV was 35.1%, and 23.8 % through Sandwich lateral flow immunochromatographic and RT-PCR respectively. Various risk factors like breed, age, sex, vomiting, diarrhea, sample source, body size, cohabitation with other animals, living environment, food, deworming history, contact with other animals or birds feces, and season were significantly associated with CCoV. The CCoV identified in Pakistan were 98% similar with the isolates from China (KT 192675, 1), South Korea (HM 130573, 1), Brazil (GU 300134, 1), Colombia (MH 717721, 1), United Kingdom (JX 082356, 1) and Tunisia (KX156806). Haematobiochemical alterations in CCoV affected dogs revealed anaemia, leucopenia, lymphopenia, neutrophilia, and decreased packed cell volume, and a significant increase in alkaline phosphate and alanine transaminase. It is concluded that infection with canine coronavirus appears widespread among dog populations in district Lahore, Pakistan. This study is the first report regarding the molecular detection and sequence analysis of CCoV in Pakistan.

Per-Cutaneous Trans-splenic Vein Thrombolysis of Acute Major Portal Vein Thrombosis in Post-Liver Transplant Recipient: A Unique Experience

Portal venous thrombosis (PVT) is an uncommon complication in post-liver transplant recipients. The reported incidence is 1-4%. It may occur within a month, called early or after one month of transplantation, known as late PVT. Early PVT has a poor prognosis, leading to graft failure in most cases. Treatment of such cases is quite challenging because of difficult alternative portal inflow establishment. We performed successful thrombolysis of acute major PVT with a unique technique using ultrasound-guided percutaneous trans-splenic vein access in a post-liver transplant recipient. The per-cutaneous trans- splenic vein approach-based thrombolysis described here in this report might be very helpful in similar cases. This technique minimizes the potential risk of graft loss, avoids re-exploration, has a low risk of bleeding, and is cost-effective.

Identification of degradation products of aflatoxin B1 and B2 resulting after their biodetoxification by aqueous extracts of Acacia nilotica

Contamination of food and feed items with mycotoxins causes extensive economic damage. It is therefore important to explore environmentally friendly approaches to manage these toxins with less drawbacks. Phytochemicals can provide a safe alternative to synthetic chemicals. This study was designed to investigate the detoxification potential of water-based extracts of Acacia nilotica against aflatoxins B1 and B2. First trials were carried out to standardise temperature, pH and incubation time for biodetoxification in spiked maize. A significant percentage of detoxification was observed under all tested conditions, showing an increasing detoxifying potential with an increase in all three parameters. Leaf extract was found to be more effective than shoot extract. Leaf extract resulted in 86-90% detoxification of both aflatoxin B1 and B2 when incubated for 72 h at 60 °C and pH 10. To avoid the detrimental effects of very high temperature and pH, experiments on spiked maize were conducted at 30 °C and pH 8. A significant detoxification of 82-83% was recorded during trials with spiked maize. MS/MS analyses showed conversion of aflatoxins B1 into seven and aflatoxins B2 into two new compounds. Most of the compounds were formed due to the removal of the double bond in the terminal furan ring and modification of the lactone group, indicating less toxicity as compared to the parent compounds. Decontamination and reduction in toxicity of treated aflatoxins was corroborated by a brine shrimps bioassay.

Electromagnetic surface waves supported by a resistive metasurface-covered metamaterial structure

This study examines the analytical and numerical solution of electromagnetic surface waves supported by a resistive metasurface-covered grounded metamaterial structure. To simulate the metamaterial, the Kramers-Kronig relation based on the causality principle is used, while the modeling of the resistive metasurface has been done by implementing the impedance boundary conditions. The analytical expressions for the field phasors of surface waves are developed for the transverse magnetic (TM) polarized mode and transverse electric (TE) polarized mode. The characteristic equations are computed for both modes, and the unknown propagation constant is evaluated numerically in the kernel. After computation, the dispersion curves, electric field profiles, effective mode index ([Formula: see text]), and phase speeds ([Formula: see text]) are presented for both the TM and TE polarized modes. To study the tunability of surface waves, the influence of the thickness of the metamaterial slab ([Formula: see text]), effective permittivity of the metamaterial ([Formula: see text]), thickness of the resistive metasurface ([Formula: see text]), and effective permittivity of the metasurface ([Formula: see text]) on all the numerical results has been studied. However, the geometrical parameters are found to be more sensitive to the effective mode index ([Formula: see text]) and phase speed ([Formula: see text]) of the surface waves. The results are consistent with the published results, which reflects the accuracy of the work. It is concluded that the appropriate choice of parameters can be used to achieve surface waves with the desired characteristics in the GHz range. The present work may have potential applications in surface waveguide design, surface wave speed controllers, surface communication devices, and light trapping configurations.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Bimetallic Ag/Cu incorporated into chemically exfoliated MoS2 nanosheets to enhance its antibacterial potential: in silico molecular docking studies

Bimetallic Ag and Cu (1:1 wt%) nanoparticles (NPs) were synthesized and annealed at temperatures of 400 °C, 600 °C, and 800 °C using chemical reduction techniques. High temperature annealed (at 800 °C) Ag:Cu sample ratios (5 and 10 wt%) were used to dope MoS₂. A wide variety of techniques including X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning, high resolution transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, Raman, photoluminescence, and ultraviolet visible spectrophotometry were used to study the morphology, structure, functional groups, excitons recombination, and thermal and optical properties of both annealed and doped samples. The antimicrobial activity of the prepared products was tested on the MRSA-superbug with ciprofloxacin antibiotic as the reference drug. Statistically significant (P < 0.05) inhibition zones (mm) were recorded for the as-synthesized Ag-Cu, heat-treated samples at 400 °C, 600 °C, and 800 °C, doped Ag-Cu/MoS₂ 5% and Ag-Cu/MoS₂ 10% which ranged from 6.35-9.85 mm and 8.60-11.75 mm at (0.5, 1.0 mg 50 μl^-1) concentrations compared with ciprofloxacin 12.55 mm and DIW 0 mm inhibition zones, respectively. Overall Ag-Cu NPs alone and with different temperature treatments showed less antibacterial efficacy compared with Ag-Cu/MoS₂ 5% and 10%. Furthermore, molecular docking studies were employed to unveil the binding interaction pattern of NPs in the active pocket of β-lactamase enzyme suggested that it could be a potential inhibitor that could be further evaluated for its enzyme inhibition characteristics.

Nitrogen Pollution Impact and Remediation through Low Cost Starch Based Biodegradable polymers

The world does not have too much time to ensure that the fast-growing population has enough land, food, water and energy. The rising food demand has brought a positive surge in fertilizers’ demand and agriculture-based economy. The world is using 170 million tons of fertilizer every year for food, fuel, fiber, and feed. The nitrogenous fertilizers are being used to meet 48% of the total food demand of the world. High fertilizer inputs augment the reactive nitrogen levels in soil, air, and water. The unassimilated reactive nitrogen changes into a pollutant and harms the natural resources. The use of controlled-release fertilizers for slowing down the nutrients’ leaching has recently been practiced by farmers. However, to date, monitoring of the complete discharge time and discharge rate of controlled released fertilizers is not completely understood by the researchers. In this work, corn starch was thermally processed into a week gel-like coating material by reacting with urea and borate. The granular urea was coated with native and processed starch in a fluidized bed reactor having bottom-up fluid delivery system. The processed starch exhibited better thermal and mechanical stability as compared to the native starch. Unlike the pure starch, the storage modulus of the processed starch dominated the loss modulus. The release time of urea, coated with processed starch, remained remarkably larger than the uncoated urea.

Velocimetry and response surface regression analysis of a swirling bed tested with mesh-coupled axial blade distributor

Fluidized bed technology is being used in several industrial processes. The well-controlled fluidization of a bed material is a prerequisite for successful implementation of this technology. Several variants of distributors are being tested for fluidized beds; however, scant information is available on their working regimes. In this study, an annular distributor was constructed by fixing blades between two concentric rings and covering the assembly with a wire mesh. This new distributor design was tested for fluidization of batches of a spherical bed material at different blade angles and superficial air velocities (SAVs). High-speed imaging and MATLAB supported velocimetry techniques were used to generate velocity vector fields of fluidized beds. These fields were analyzed further for bed velocity measurements at different bed zones. A response surface regression model was applied on the data to predict the response of the bed parameters. Statistically, the bed velocity was predicted to be about 0.497 m/s with the confidence interval in the range of 0.4948-0.4999. The experimental bed velocity remained between 0.531 m/s and 0.538 m/s under an optimized blade angle of 60°, SAV of 2.3 m/s, and bed weight of 500 g.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Advancing the science behind human resources for health: highlights from the Health Policy and Systems Research Reader on Human Resources for Health

Health workers are central to people-centred health systems, resilient economies and sustainable development. Given the rising importance of the health workforce, changing human resource for health (HRH) policy and practice and recent health policy and systems research (HPSR) advances, it is critical to reassess and reinvigorate the science behind HRH as part of health systems strengthening and social development more broadly. Building on the recently published Health Policy and Systems Research Reader on Human Resources for Health (the Reader), this commentary reflects on the added value of HPSR underpinning HRH. HPSR does so by strengthening the multi-disciplinary base and rigour of HRH research by (1) valuing diverse research inferences and (2) deepening research enquiry and quality. It also anchors the relevance of HRH research for HRH policy and practice by (3) broadening conceptual boundaries and (4) strengthening policy engagement. Most importantly, HPSR enables us to transform HRH from being faceless numbers or units of health producers to the heart and soul of health systems and vital change agents in our communities and societies. Health workers' identities and motivation, daily routines and negotiations, and training and working environments are at the centre of successes and failures of health interventions, health system functioning and broader social development. Further, in an increasingly complex globalised economy, the expansion of the health sector as an arena for employment and the liberalisation of labour markets has contributed to the unprecedented movement of health workers, many or most of whom are women, not only between public and private health sectors, but also across borders. Yet, these political, human development and labour market realities are often set aside or elided altogether. Health workers' lives and livelihoods, their contributions and commitments, and their individual and collective agency are ignored. The science of HRH, offering new discoveries and deeper understanding of how universal health coverage and the Sustainable Development Goals are dependent on millions of health workers globally, has the potential to overcome this outdated and ineffective orthodoxy.

Advancing the science behind human resources for health: highlights from the Health Policy and Systems Research Reader on Human Resources for Health

Health workers are central to people-centred health systems, resilient economies and sustainable development. Given the rising importance of the health workforce, changing human resource for health (HRH) policy and practice and recent health policy and systems research (HPSR) advances, it is critical to reassess and reinvigorate the science behind HRH as part of health systems strengthening and social development more broadly. Building on the recently published Health Policy and Systems Research Reader on Human Resources for Health (the Reader), this commentary reflects on the added value of HPSR underpinning HRH. HPSR does so by strengthening the multi-disciplinary base and rigour of HRH research by (1) valuing diverse research inferences and (2) deepening research enquiry and quality. It also anchors the relevance of HRH research for HRH policy and practice by (3) broadening conceptual boundaries and (4) strengthening policy engagement. Most importantly, HPSR enables us to transform HRH from being faceless numbers or units of health producers to the heart and soul of health systems and vital change agents in our communities and societies. Health workers' identities and motivation, daily routines and negotiations, and training and working environments are at the centre of successes and failures of health interventions, health system functioning and broader social development. Further, in an increasingly complex globalised economy, the expansion of the health sector as an arena for employment and the liberalisation of labour markets has contributed to the unprecedented movement of health workers, many or most of whom are women, not only between public and private health sectors, but also across borders. Yet, these political, human development and labour market realities are often set aside or elided altogether. Health workers' lives and livelihoods, their contributions and commitments, and their individual and collective agency are ignored. The science of HRH, offering new discoveries and deeper understanding of how universal health coverage and the Sustainable Development Goals are dependent on millions of health workers globally, has the potential to overcome this outdated and ineffective orthodoxy.

Molecular epidemiology, associated risk factors, and phylogenetic analysis of anaplasmosis in camel

Camel Anaplasmosis is caused by members of family Anaplasmatacae, a tick transmitted, obligate intracellular bacteria. The etiological bacteria are transmitted by ixodid tick species. The species have multi host range distribution that is why it is crucial to diagnose it timely. The aim of present study was to investigate the molecular epidemiology i.e. prevalence and risk factors analysis of camel anaplasmosis. Furthermore, variations in hematological standards were also evaluated. The study found an overall 13.33% prevalence in camels. The confirmation of PCR positive samples for Anaplasma spp. was made through sequencing, the study isolatesshowed high homology with Iranian, Chinese, Philippines and South African isolates of Anaplasmatacae (Accession numbers'; KX765882, KP062964, KY242456, LC007100 and U54806) on BLAST queries. The phylogenetic analysis revealedthree study isolates of present study clustered with each other and the cluster was found closer to Chinese isolate of A. phagocytophilum (KY242456), A. marginale (KU586048), and Mongolian isolates of A. ovis (LC194134). Two of the isolates resembled Iranian isolate of Candidatus Anaplasmacamelii (KX765882), while one isolate resembled with Chinese isolates of A. Platys (KX987336) and Croatian isolates of A. Platys (KY114935). The key risk factors odds ratio (OR>1) identified for occurrence of camel anaplasmosis using regression model found sex and age of animal, previous tick history, tick infestation and tick control status, housing type, cracks in walls, rearing system and other species in surrounding as the key risk factors. The hematological parameters like lymphocytes, monocytes, granulocytes and platelets count were significantly decreased (p < 0.05) in diseased camels than healthy. This is the first ever molecular data on camel anaplasmosis in Pakistan. The disease should be monitored unceasingly as the etiologies have multi host distribution. Prompt attention should be offered to animals because neutropenia, lymphopenia and thrombocytopenia can exacerbate the disease by making the animal predisposed to otherdiseases.

Effects of yeast (Saccharomyces cerevisiae) supplementation on intake, digestibility, rumen fermentation and milk yield in Nili-Ravi buffaloes

Rumen Yeast^® (RY; Saccharomyces cerevisiae), a live yeast strain, improves milk yield and composition and nutrients digestibility through balancing rumen ecosystem and increasing ruminal cellulolytic bacteria numbers in cattle. To examine the effects of dietary supplementation of RY in Nili-Ravi buffaloes, 16 buffaloes with 8 L average daily milk production were randomly divided into two groups, and investigated for a 60-day period. Group I (control) was offered maize silage ad libitum as sole forage plus 3 kg of concentrate/head per day (16% crude protein (CP) and 72% total digestible nutrients (TDN)), while group II was given the same diet as control supplemented with RY (14 g/head per day). Feed intake, nutrient digestibility, rumen fermentation and milk production of each animal were recorded. Average dry matter (DM) intake was not affected (P>0.05) in buffaloes with or without RY (14.7 and 14.3 kg/day, respectively). Digestibility of DM, CP, and ruminal pH were similar (P>0.05) between the groups, but the digestibility coefficients of neutral detergent fiber and acid detergent fiber were greater (P<0.05) for the animals that received RY. Milk production (9.60 vs. 9.15 L/day) and 4% fat corrected milk (FCM) (11.32 vs. 11.85 L/day) were significantly (P<0.05) greater in the buffaloes fed with RY than the control group. Milk composition was similar between the experimental groups, however, milk somatic cell count (SCC) was significantly (P<0.01) lower in RY supplemented buffaloes than the control animals. In conclusion, feeding RY had positive effects on milk production, fibre digestibility and SCC in buffaloes fed maize silage-concentrate based diet.

Surgical repairs of the Rotator Cuff Tears

Evaluation of 15 cases who underwent surgical rotator cuff repair is presented. This study extends from 1995 to 2001. Cases operated by senior author have been included in this study. The follow up ranges from 9 months to 4 years. Evaluation includes study as regard to pain relief, range of motion and strength achieved after surgery. In all cases acromion- plasty was done. Rotator cuff problem is a well-know cause of pain and disability in shoulder especially in old age. Good results after surgical repair of rupture rotator cuff have been well documented. To our best knowledge this is the first study in this country about results of surgical rotator cuff repair.

Applying systems thinking to task shifting for mental health using lay providers: a review of the evidence

OBJECTIVE

This paper seeks to review the available evidence to determine whether a systems approach is employed in the implementation and evaluation of task shifting for mental health using lay providers in low- and middle-income countries, and to highlight system-wide effects of task-shifting strategies in order to better inform efforts to strength community mental health systems.

METHODS

Pubmed, CINAHL, and Cochrane Library databases were searched. Articles were screened by two independent reviewers with a third reviewer resolving discrepancies. Two stages of screens were done to ensure sensitivity. Studies were analysed using the World Health Organization's building blocks framework with the addition of a community building block, and systems thinking characteristics to determine the extent to which system-wide effects had been considered.

RESULTS

Thirty studies were included. Almost all studies displayed positive findings on mental health using task shifting. One study showed no effect. No studies explicitly employed systems thinking tools, but some demonstrated systems thinking characteristics, such as exploring various stakeholder perspectives, capturing unintended consequences, and looking across sectors for system-wide impact. Twenty-five of the 30 studies captured elements other than the most directly relevant building blocks of service delivery and health workforce.

CONCLUSIONS

There is a lack of systematic approaches to exploring complexity in the evaluation of task-shifting interventions. Systems thinking tools should support evidence-informed decision making for a more complete understanding of community-based systems strengthening interventions for mental health.

Design of enzyme-immobilized polymer brush-grafted magnetic nanoparticles for efficient nematicidal activity

Parasitic nematodes adversely affect agricultural industry and global health. An efficient and reusable nematicidal platform is developed by immobilization enzyme on the surface of magnetic NPs.

Review on Medicinal Uses, Pharmacological, Phytochemistry and Immunomodulatory Activity of Plants

Since ancient times, plants have been an exemplary source of medicine. Researchers have discovered some important compounds from plants. The present work constitutes a review of the medicinal plants whose immunomodulant activity has been proven. We performed PUBMED, EMBASE, Google scholar searches for research papers of medicinal plants having immunomodulant activity. Medicinal plants used by traditional physicians or reported as having immunomodulant activity include Acacia concocinna, Camellia sinensis, Lawsonia inermis Linn, Piper longum Linn, Gelidium amansii, Petroselinum crispum, Plantago major and Allium sativum. Immunomodulant activities of some of these medicinal plants have been investigated. The medicinal plants documented have immunomodulant activity and should be further investigated via clinical trial.

Geochemical assessment of metal concentrations in sediment core of Korangi Creek along Karachi Coast, Pakistan

Sediment core from Korangi Creek, one of the polluted coastal locations along the Karachi Coast Pakistan, was collected to trace the history of marine pollution and to determine the impact of industrial activity in the area. Down core variation of metals such as Ca, K, Mg, Al, S, Ti, V, Cr, Mn, Fe, Ni, Cu and Zn was studied in the 72.0 cm core. Nuclear analytical techniques, proton induced X-rays emission (PIXE), was employed to ascertain the chemical composition in sediment core. Grain size analysis and sediment composition of cored samples indicated that Korangi creek sediments are clayey in nature. Correlation matrix revealed a strong association of Ni, Cu, Cr and Zn with Fe and Mn. To infer anthropogenic input, enrichment factor (EF), degree of contamination and pollution load index were calculated. EF showed severe enrichment in surface sediment for Ni, Cu, Cr and Zn, indicating increased industrial effluents discharge in recent years. The study suggests that heavy metal discharge in the area should be regulated. If the present trend of enrichment is allowed to continue unabated, it is most likely that the local food web complexes in the creek might be at highest risk.