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The Varian Trilogy linear accelerator’s multi-leaf collimator moves on a carriage with a maximum leaf span of 15 cm. The traditional open and limited X-jaw technique of volumetric-modulated arc radiotherapy (VMAT) yields a relatively compromised dose distribution within the planning target volume (PTV) region. This study aimed to determine whether the split X-jaw planning technique for VMAT improves plan quality regarding target dose coverage and organs at risk (OAR) sparing for PTVs that require a field size of more than 15 cm in the X-jaw direction in prostate cancer patients.
Computed tomography data sets from 15 patients with prostate cancer were enrolled in the study. Only the PTVs requiring a field size larger than 18 cm in the X-jaw position were considered, and a dose of 4500 cGy in 25 fractions was prescribed. For each case, three separate treatment plans were generated: open, limited and split X-jaw planning techniques with similar planning objectives
The split X-jaw technique resulted in statistically significant superior coverage of PTV when compared with the open (P < 0·0001) and limited methods (P < 0·001). The split technique delivered a lower dose to the OARs, although statistical significance could not be achieved. D2% (cGy) was lowest for the PTV in the split technique (4684·8 ± 18·16) and highest for the open technique (4710 ± 18·75), P < 0·001.
The x-split jaw technique can replace the traditional open X-jaw practice of VMAT for PTVs requiring an X-jaw width of more than 15 cm in the Varian linear accelerator.
The Endangered Kashmir musk deer Moschus cupreus occurs in the western Himalayan region from Nepal to Afghanistan, but there is a lack of comprehensive and reliable information on its range. The region also harbours the Endangered Himalayan musk deer Moschus leucogaster, and this range overlap may have led to misidentification of the two musk deer species and errors in the delimitation of their ranges. Here, using genetic analysis of the mitochondrial DNA control region, we examined the phylogenetic relationship among musk deer samples from three regions in India: Ganderbal District in Jammu and Kashmir, and Kedarnath Wildlife Sanctuary and Nanda Devi Biosphere Reserve, both in Uttarakhand. The Bayesian phylogenetic analysis indicated a close genetic relationship between samples from Jammu and Kashmir, Kedarnath Wildlife Sanctuary and Nanda Devi Biosphere Reserve, validated by previously published sequences of Kashmir musk deer from Nepal. Our analyses confirmed the samples from Uttarakhand to be from the Kashmir musk deer, which was not previously known from this region. Therefore, we recommend further research in this area, to validate species identification and confirm the geographical distribution of the various species of musk deer. In addition, we recommend revision of the range of M. cupreus in the IUCN Red List assessment, to facilitate effective conservation and management of this Endangered species.
Remnants of some of the planet’s most ancient life forms, stromatolites in the late Mesoproterozoic sea of the Chattisgarh Basin, India, preserve a conspicuous sinuous pattern. They occur as successive biostromes, 10–30 cm thick, separated by 2–5-cm-thick marly layers and discrete bioherms up to several metres thick and 20 m across. Stromatolite columns in the Chandi Formation are 5–10 cm high, sinuous, inclined and straight, with both branched and non-branched types. These stromatolites are composed of calcite micrite and show well defined light and dark laminae with evidence of erosion between lamina sets. The column sinuosity probably originated as a response to changes in direction and strength of currents. Successive flat beds of stromatolite (biostromes), separated by marl/clay horizons, impart a rhythmic pattern to the succession. The Chandi sinuous stromatolite columns resemble those occurring in China, North America and Siberia, of a comparable age, suggesting that similar marine conditions of stromatolite formation might have been operating in the late Mesoproterozoic seas worldwide. However, the petrographic and sedimentological analyses of these stromatolites indicate their development through in situ production of carbonate with some trapping and binding of detrital sediment. As a result of the presence of terrigenous material within the stromatolites, whole-rock geochemical analyses for trace elements and rare earth elements cannot be used for interpretation of seawater chemistry and the redox conditions at the time.
This study illustrates the dynamical reconfiguration of a concentric hexagonal antenna array radiation to generate a pencil beam and flat-top beam simultaneously by electronic control in two principle vertical planes under consideration. Both the beams share a common normalized optimal current excitation amplitude distribution while the optimal sets of phase excitation coefficients are varied radically across the hexagons to generate a flat-top beam. The proposed approach is able to solve the underlying multi-objective problem and flexible enough to the efficient implementation of additional design constraints in the considered φ-planes. In this paper, a set of simulation-based examples are presented in an integrated way. The outcomes validate the effectiveness of the stated optimization using meta-heuristic optimization algorithms (teaching–learning-based optimization, symbiotic organism search, multi-verse optimization) to reach the solution globally and prove actual relevance to the concerned applications.
This study aims to compare the dosimetric parameters among four different external beam radiotherapy techniques used for the treatment of retinoblastoma.
Materials and methods:
Computed tomography (CT) sets of five retinoblastoma patients who required radiotherapy to one globe were included. Four different plans were generated for each patient using three dimensional conformal radiotherapy (3DCRT), intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT) and VMAT using flattening filter free (VMAT-FFF) beam techniques. Plans were compared for target coverage and organs at risk (OARs) sparing.
The target coverage of planning target volume (PTV) for all the four modalities were clinically acceptable with a V95 of 95 ± 0%, 97·6 ± 1·87%, 99·3 ± 0·5% and 99·17 ± 0·45% for 3DCRT, IMRT, VMAT and VMAT-FFF respectively. The VMAT and IMRT plans had better target coverage than the 3DCRT plans (p = 0·001 and p = 0·07 respectively). IMRT and VMAT plans were also found superior to 3DCRT plans in terms of OAR sparing like brainstem, optic chiasm, brain (p < 0·05). VMAT delivered significantly lower dose to the brainstem and contralateral optic nerve in comparison to IMRT. Use of VMAT-FFF beams did not show any benefit over VMAT in target coverage and OAR sparing.
VMAT should be preferred over 3DCRT and IMRT for treatment of retinoblastoma owing to better target coverage and less dose to most of the OARs. However, IMRT and VMAT should be used with caution because of the increased low dose volumes to the OARs like contralateral lens and eyeball.
To depict various temporal bone abnormalities on high-resolution computed tomography in congenital aural atresia patients, and correlate these findings with auditory function test results and microtia subgroup.
Forty patients (56 ears) with congenital malformation of the auricle and/or external auditory canal were evaluated. Auricles were graded according to Marx's classification, divided into subgroups of minor (grades I and II) and major (III and IV) microtia. Other associated anomalies of the external auditory canal, tympanic cavity, ossicular status, oval and round windows, facial nerve, and inner ear were evaluated.
Minor and major microtia were observed in 53.6 and 46.4 per cent of ears respectively. Mean hearing levels were 62.47 and 62.37 dB respectively (p = 0.98). The malleus was the most commonly dysplastic ossicle (73.3 vs 80.8 per cent of ears respectively, p = 0.53). Facial nerve (mastoid segment) abnormalities were associated (p = 0.04) with microtia subgroup (80 vs 100 per cent in minor vs major subgroups).
Microtia grade was not significantly associated with mean hearing levels or other ear malformations, except for external auditory canal and facial nerve (mastoid segment) anomalies. High-resolution computed tomography is essential in congenital aural atresia, before management strategy is decided.
Genetic improvement along with widened crop base necessitates for the detailed understanding of the genetic diversity and population structure in wheat. The present investigation reports the discovery of a total of 182 alleles by assaying 52 simple sequence repeats (SSRs) on 40 genotypes of bread wheat. Unweighted neighbour-joining method grouped these genotypes into two main clusters. Highly heat tolerant and intermediate tolerant cultivars were grouped in the same cluster, whereas remaining genotypes, particularly sensitive ones, were assigned different cluster. Similarly, the entire population was structured into two sub-populations (K = 2), closely corresponding with the other distance-based clustering patterns. The marker-trait association was discovered for four important physiological parameters, viz. canopy temperature depression, membrane thermostability index (MSI), normalized difference vegetation index and heat susceptibility index, indicating for heat stress (HS) tolerance in wheat. Both general and mixed linear models of association studies during 2017 and 2018, revealed the association of SSR markers, wmc222 (17.60%, PV) and gwm34 (20.70%, PV) with the mean phenotypic value of MSI. Likewise, SSR markers barc183, gwm75, gwm11 and cfd7 revealed a unique relationship with four selected physiological traits. Candidate genes discovered using in silico tools had nine SSR markers within the genic regions reported to play a role in heat and drought stress responses in plants. The information generated about these genic regions may be explored further in expression studies in-vivo to impart HS tolerance in bread wheat.
The implementation of stable, accurate, and wideband second-order microwave integrators (SOMIs) is presented in this paper. These designs of SOMIs are obtained by using different combinations of transmission line sections and shunt stubs in cascading. Particle swarm optimization (PSO), cuckoo search algorithm (CSA), and gravitational search algorithm (GSA) are applied to obtain the optimal values of the characteristic impedances of these line elements to approximate the magnitude response of ideal second-order integrator (SOI). The performance measure criteria for the proposed SOMIs are carried out based on magnitude response, absolute magnitude error, phase response, convergence rate, pole-zero plot, and improvement graph. The simulation results and statistical analysis demonstrate that GSA surpasses the PSO and CSA to approximate the ideal SOI in all state-of-the-art, that is eligible for wide-band microwave integrator. The designed SOMI is compact in size and suitable to cover microwave applications. The magnitude errors for the proposed SOMIs GSA based are as low as 4.9954 and 3.6573, respectively. The structure of the designed SOMI is implemented in the form of microstrip line on RT/Duroid substrate with dielectric constant 2.2 and having height 0.762 mm. The simulated and measured magnitude result agrees well with the ideal one in the frequency range of 3–15 GHz.
In this paper, an experimental study is carried out while charging the sealed lead acid battery bank using a series-parallel (SP) compensated contactless power transfer (CPT) system. Constant current (CC) and constant voltage (CV) modes are used for charging the battery bank. An expression of optimum operating frequency is derived to maintain the maximum compensated coil efficiency throughout the load variation in charging process. An experimental setup of SP compensated CPT system is built for charging the battery bank. The variation of compensated coil efficiency and the load phase angle with respect to different operating frequencies in CC and CV modes is verified with the measurement. Based on the analysis, the control parameters are identified.
Weed management is the major challenge to the success of boro rice (rice grown during Dec–Jan to May–Jun, also known as summer rice) in Southern Asia. Herbicide seems to be a cost effective and strategic tool from an agronomic view point to control weeds; however, herbicide application can potentially interfere with soil enzyme activity and microbial biomass carbon (MBC). A field study was conducted in 2012/13 and 2013/14 to evaluate the performance of sole and combined application of different pre-emergence herbicides in comparison to manual weeding in boro rice. Lowest weed density, biomass and highest weed control efficiency (~83%) were recorded with the pyrazosulfuron ethyl, causing higher grain yield (6.7 Mg ha−1 in 2012/13 and 4.5 Mg ha−1 in 2013/14) than treatments with chlorimuron + metsulfuron-methyl, bensulfuron methyl + pretilachlor, butachlor fb 2,4D, butachlor and cono-weeder. Among, the herbicidal treatments butachlor caused lower grain yield and higher weed density and biomass when compared to the others. Although grain yield was highest in weed-free treatments but net returns and (B:C) benefit cost ratio was highest for pyrazosulfuron ethyl due to high cost of hand weeding. After 15 days of herbicide application, lowest microbial biomass carbon was recorded with bensulfuron methyl + pretilachlor, whereas lower values of dehydrogenase and fluorescein diacetate activities were observed with the application of chlorimuron + metsulfuron-methyl at 15 days after herbicide application. Our results suggest that pyrazosulfuron ethyl is one broad-spectrum and economically effective herbicide for controlling weeds as an alternative to labour consuming hand weeding in boro rice cultivation.
Balance between adipocyte and osteoblast differentiation is the key link of disease progression in obesity and osteoporosis. We have previously reported that formononetin (FNT), an isoflavone extracted from Butea monosperma, stimulates osteoblast formation and protects against postmenopausal bone loss. The inverse relationship between osteoblasts and adipocytes prompted us to analyse the effect of FNT on adipogenesis and in vivo bone loss, triggered by high-fat diet (HFD)-induced obesity. The anti-obesity effect and mechanism of action of FNT was determined in 3T3-L1 cells and HFD-induced obese male mice. Our findings show that FNT suppresses the adipogenic differentiation of 3T3-L1 fibroblasts, through down-regulation of key adipogenic markers such as PPARγ, CCAAT/enhancer-binding protein alpha (C/EBPα) and sterol regulatory element-binding protein (SREBP) and inhibits intracellular TAG accumulation. Increased intracellular reactive oxygen species levels and AMP-activated protein kinase (AMPK) activation accompanied by stabilisation of β-catenin were attributed to the anti-adipogenic action of FNT. In vivo, 12 weeks of FNT treatment inhibited the development of obesity in mice by attenuating HFD-induced body weight gain and visceral fat accumulation. The anti-obesity effect of FNT results from increased energy expenditure. FNT also protects against HFD-induced dyslipidaemia and rescues deterioration of trabecular bone volume by increasing bone formation and decreasing bone resorbtion caused by HFD. FNT’s rescuing action against obesity-induced osteoporosis commenced at the level of progenitors, as bone marrow progenitor cells, obtained from the HFD mice group supplemented with FNT, showed increased osteogenic and decreased adipogenic potentials. Our findings suggest that FNT inhibits adipogenesis through AMPK/β-catenin signal transduction pathways and protects against HFD-induced obesity and bone loss.
A microstrip transmission line fed fork-shaped planar antenna is proposed for Bluetooth, WLAN, and WiMAX applications. The antenna made of a microstrip feed line, fork-shape patch on one side and defected ground plane on the other side of dielectric substrate. A fork-shape is formed by two side circular arms and a rectangular central arm. The inverted T-shaped ground plane with a rectangular slot in the center arm is used to increase the bandwidth with better impedance matching of the lower band. The antenna is practically fabricated to validate the design. The antenna resonate dual band to cover an entire the WLAN and WiMAX bands. The antenna shows the measured bandwidth of 410 MHz (2.26–2.67) and 3.78 GHz (3.0–6.78 GHz) at lower and upper bands, respectively.
In this paper, a novel design and experimental study of microstrip-line-fed rhombus-shaped slot antenna is presented. The proposed antenna shows an ultra-wide band (UWB) operation with good impedance matching by choosing appropriate rhombus-shaped slot and feeding structure. The proposed antenna has a simple structure and compact size as compared with many reported antennas. The measured results validate the design and the impedance bandwidth can operate from 2.78 to 12.92 GHz (10.14 GHz), which evidently covers entire UWB (3.1–10.6 GHz). Furthermore, the key parameters of the antenna are also discussed to study their persuade on the antenna performance.
To restrict electromagnetic interference at WiMAX (3.3–3.7 GHz) and wireless local area network (WLAN) (5.15–5.825 GHz) bands operating within ultra wide bandwidth (UWB) band, a novel design of lamp-shaped UWB microstrip antenna with dual band-notched characteristics is presented. The proposed antenna is composed of a lamp-shaped radiating patch with two rectangular ground planes on both the sides of the radiator with the gap of 0.57 mm. To improve impedance mismatch at middle frequencies, two triangular strips one at each of the ground plane are added; whereas a rectangular slot is etched in the radiating patch to remove impedance mismatch at higher frequencies of the UWB band. Furthermore, an L-shaped slot in the radiator and two L-shaped slots in the ground plane are used to restrict electromagnetic interference (EMI) at WiMAX and WLAN bands, respectively, without affecting the electrical performance of the UWB antenna. Effects of the key parameters on the frequency range of the notched bands are also investigated. The proposed design shows a measured impedance bandwidth of 12.5 GHz (2.7–14.4 GHz), with the two band-notched bands of 3.0–3.9 and 4.9–5.8 GHz. The antenna is suitable to be integrated within the portable UWB devices without EMI interference at WiMAX and WLAN bands.
To incorporate two different communication standards in a single device, a compact triple-band antenna is proposed in this paper. The proposed antenna is formed by etching an inverted L-shaped slot on the patch with defected ground structure. The antenna is targeted to excite three separate bands first from 2.39–2.51, second from 3.15–3.91, and third from 4.91–6.08 GHz that covers entire Wireless Local Area Network (WLAN) (2.4/5.2/5.8 GHz) and Worldwide Interoperability for Microwave Access (WiMAX) (2.5/3.5/5.5) bands. Thus, the proposed antenna provides feasibility to integrate WLAN and WiMAX communication standards in a single device with good radiation pattern quality. Furthermore, a prototype of the proposed antenna fabricated and measured to validate the design, shows a good agreement between simulated and measured results. The simulation and measurement results show that the designed antenna is capable of operating over the 2.39–2.51 GHz, 3.15–3.91 GHz, and 4.91–6.08 GHz frequency bands while rejecting frequency ranges between these three bands. The proposed antenna offers a compact size of 20 × 30 mm2 as compared with earlier reported papers.
In this paper, a novel circularly polarized square slot microstrip antenna is proposed for radio frequency identification (RFID) applications. The circular polarization is achieved by incorporating an arc-shaped strip in the square slot antenna. This antenna is fed by deformed bent feeding line to achieve a broad bandwidth (BW). The key parameters of the antenna are used for parametric study to understand the influence on the antenna performance. To validate simulation results of the design, a prototype is fabricated on the commercially available FR4 material. Measured results show a good agreement with the simulated results. It is found that the antenna shows an impedance BW of 170 MHz (844–1014 MHz) and axial-ratio BW of 170 MHz (834–1004 MHz), which shows that the proposed antenna is a good candidate to be used as a RFID antenna.
A single-feed dual-band circularly polarized stacked microstrip patch antenna with a small-frequency ratio is presented. Two pair of orthogonal slits is cut on the lower circular patch for achieving circular polarization and truncated corner square patch is used as the upper parasitic element. The frequency ratio of the dual-band is 1.03. The 3 dB axial ratio bandwidth is 1.3% for the upper band and 1.1% for the lower band. Proposed structure is fabricated on the FR-4 epoxy substrate and fed by SMA connector. The measured results are in good agreement with the theoretical and simulated results. The antenna shows stable radiation characteristics in both bands of operation.
A single-fed circularly polarized microstrip antenna is proposed where the antenna structure exhibits truncated corners in the radiating square patch. The truncated corners square patch structure is loaded with a circular slot and is resonating at 2.25 GHz with circular polarization. Furthermore, the proposed antenna is stacked using an upper circular patch thus achieving a dual-band circularly polarized pattern. The dual-band antenna resonates at 2.25 GHz in the first band and with impedance bandwidth ranging from 4.4 to 5.5 GHz in the second band. The size of the proposed stacked structure is compact compared with the conventional circularly polarized stacked antenna designs. Proposed structures are fabricated and fed using Subminiature version A (SMA) connector. The measured results are in good agreement with the simulated. The antenna shows stable radiation characteristics for the entire band of operation.
A novel design of a compact ultra wideband antenna with triple band-notched characteristics is proposed. Much wider impedance bandwidth (from 2.63 to 13.02 GHz) is obtained by using a star like-shaped radiator and a defected rectangular ground plane and band-notched functions are obtained by attaching L- and I-shaped structure on the ground and a capacitive-loaded loop (CLL) resonator on the patch. The triple band-notch rejection at WiMAX, WLAN, and ITU bands are obtained by attaching I-shape strip, CLL resonator, and flip L-shape, respectively. The parametric study is carried out to study the influence of varying dimensions on the antenna performance. To validate simulation results of the design a prototype is fabricated on the commercially available FR4 material. The measured results reveal that the presented triple band-notch antenna offers a very wide bandwidth of 10.41 GHz (2.63–13.04 GHz) with triple band-notched characteristics at WiMAX (2.94–3.7 GHz), WLAN (5.1–5.9 GHz), and ITU (7.4–8.7 GHz).