A Compact Dual-Band Notched UWB Antenna for Wireless Applications

This article presents the design and analysis of a V-shaped ultrawideband (UWB) antenna and dual-band UWB notch antenna. A rectangular slot is cut into a semicircular partial ground plane of the antenna to achieve ultrawide bandwidth. A U-shape slot is etched on a V-shaped patch that radiates, and an inverted U-shape parasitic resonator is placed beside the feedline to generate dual-band notch characteristics. The overall dimension of the proposed antenna is 28×23 mm2. The proposed UWB antenna has a gain of 9.8 dB, S11 < −10 dB, impedance bandwidth in the range of 3.4 to 12.3 GHz, response with a linear phase, group delay <1 ns, and stable radiation pattern. The UWB notch antenna shows strong rejection in the WLAN band from 5.15 to 5.8 GHz with a notch at 5.6 GHz and X band from 9.1 to 10.5 GHz with a sharp notch at 9.6 GHz, having a S11 < −10 dB impedance bandwidth ranging from 3.2 to 11.7 GHz. This antenna also exhibits a stable radiation pattern, group delay <1 ns, and linear phase response throughout the bandwidth except at the rejection frequencies.

Medical students positions regarding resource allocation in times of crisis

Objective To compare the perspectives of medical students in the preclinical and clinical phases of medical training on the issue of rationing scarce medical resources in times of crisis. Methods Questionnaire-based cross-sectional study. Results A total of 201 participants took part in the study, with 100 participants in the preclinical phase group, and 101 in the clinical phase group. A multivariable analysis found that just 14.9% (n = 34) of the clinical phase students were willing to give a short-supplied blood unit to the first-arrived patient to the emergency department when more patients are expected compared to 63.9% in the preclinical group (n = 62) ( p < 0.001, OR = 0.75 95% CI: 0.029−0.192). Seventy-four percent (n = 74) of the clinical phase students were found to be willing to remove a patient from a respirator to allocate it to an ill child compared to 35.7% (n = 35) in the preclinical phase group ( p < 0.001, OR = 4.168 95% CI: 1.931−8.998). Of the clinical phase group, 46.6% (n = 41) were willing to allocate a short supplied flu medicine to a patient with poor prognosis compared to 57.7% (n = 56) in the preclinical phase group ( p = 0.04, OR = 0.457 95% CI: 0.216−0.966). Conclusion Clinical exposure during training may affect the way medical students make ethical decisions, independent of age, sex, as well as marital and parental status.

P-OGC81 The learning curve for robotic assisted abdominal phase in two stage oesophagectomy

Background Robotic assisted oesophagectomy (RAO) is increasingly being utilised in the management of oesophageal cancer. RAO implementation into practice has an inevitable learning curve. As oesophagectomy usually involves at least 2 stages, a staggered approach to training and introduction of RAO can be done. A major advantage of this is that the surgeon can concentrate on overcoming the learning curve in one phase of the procedure at a time, whilst the remaining phase can be completed by an established technique. This study looks at the learning curve of a robotic assisted abdominal phase for two-stage oesophagectomy compared to an open abdominal phase to achieve parity. Methods This study uses a prospectively maintained database to retrospectively analyse the abdominal phase of the first 17 RAO compared to the previous 20 open abdominal phase procedures. The cases are sequential, done by a single surgeon at a large UK oesophagogastric referral centre. Operating time, nodal count, and R0 rate were reviewed to determine the number of cases on the learning curve to reach parity with the open procedure. Results The open abdominal phase group had a similar age (65.6 vs 65.7), pre-op anaerobic threshold (13.9 vs 14.6 p = 0.3) but a higher BMI (mean 30.6 vs 24.6 p &lt; 0.05) then the RAO group. All cases were T3 adenocarcinoma except for 2 cases in the robotic group (one HGD and one T2 adenocarcinoma). No RAO cases were converted to open. The mean time for the abdominal phase in the open group was 175.4 minutes with an average nodal count of 32.9. After 8 robotic assisted cases the mean operating time decreased from 267 minutes to 197 minutes, which was when a non-significant difference to the open group (p = 0.094) became apparent. The mean nodal count in the first 8 robotic assisted cases was 29.5 and increased to 38.4 in the subsequent cases. All patients had a R0 resection. Conclusions The multi-phase nature of oesophagectomy allows for modular implementation of a robotic programme. We have found that the learning curve for robotic assisted abdominal is around 8 cases. This allows for parity to open abdominal phase to be achieved regarding operative time, nodal count and R0 resection.

Optimal Timing for Intermittent Administration of Parathyroid Hormone (1-34) for Distraction Osteogenesis in Rabbits

BackgroundTo date, the usefulness of parathyroid hormone (PTH (1-34)) in distraction osteogenesis has been reported in several studies. We aimed to determine the optimal timing of PTH (1-34) administration in a rabbit distraction osteogenesis model.MethodsThe lower hind leg of a Japanese white rabbit was externally fixed, and tibial osteotomy was performed. One week after the osteotomy, bone lengthening was carried out at 0.375 mm/12 h for two weeks. After five weeks, the lower leg bone was collected. Bone mineral density (BMD), peripheral quantitative computed tomography (pQCT), micro-computed tomography (micro-CT), and mechanical tests were performed on the distracted callus. The rabbits were divided into three groups according to the timing of PTH administration: four weeks during the distraction and consolidation phases (group D+C), two weeks of the distraction phase (group D), and the first two weeks of the consolidation phase (group C). A control group (group N) was administered saline for four weeks during the distraction and consolidation phases. Furthermore, to obtain histological findings, lower leg bones were collected from each rabbit at two, three, and four weeks after osteotomy, and tissue sections of the distracted callus were examined histologically.ResultsThe BMD was highest in group C and was significantly higher than group D. In pQCT, the total cross-sectional area was significantly higher in groups D+C, D, and C than group N, and the cortical bone area was highest in group C and was significantly higher than group D. In micro-CT, group C had the highest bone mass and number of trabeculae. Regarding the mechanical test, group C had the highest callus failure strength, and this value was significantly higher compared to group N. There was no significant difference between groups D and N. The histological findings revealed that the distracted callus mainly consisted of endochondral ossification in the distraction phase. In the consolidation phase, the chondrocytes were almost absent, and intramembranous ossification was the main type of ossification.ConclusionWe found that the optimal timing of PTH (1-34) administration is during the consolidation phase, which is mainly characterized by intramembranous ossification.

Vernal keratoconjunctivitis activity induces decrease of ocular surface CD14, TLR-4 and TLR-9 expression

Purpose: CD14 is involved in the modulation of immune reaction via toll-like receptors (TLR) and may influence the development of allergic diseases. The role of CD14 in vernal keratoconjunctivitis (VKC) has not yet been investigated. The aim of this study is to evaluate changes of tear soluble sCD14 and conjunctival CD14, TLR-4 and 9 expression in patients with VKC in the active and quiescent phases. Methods: Eighteen patients with VKC during active inflammation (group A, N = 9), in the quiescent phase (group Q, N = 5) and after recovery (group R, N = 4) and 10 healthy subjects were included. Expression of sCD14 in tears and of CD14, TLR-4, and TLR-9 by conjunctival epithelium were evaluated by Western Blot in all groups. Results: Expression of tear sCD14 and of conjunctival CD14, TLR-4, and TLR-9 was significantly decreased in group A when compared with healthy subjects and with VKC group Q and R. Lower expression of sCD14, CD14, TLR-4, and TLR-9 were significantly correlated with the severity of papillary reaction, while the lower sCD14 was correlated with severity of conjunctival hyperemia. Conclusions: Tear sCD14, and conjunctival CD14, TLR4, and TLR-9 decreased during ocular surface inflammatory reaction in patients with VKC. CD14 and TLRs ocular surface evaluation may represent biomarkers of VKC activity and novel therapeutic target.

The Effect of Topical Corticosteroid Time of Application on Fibroblast and Type III Collagen Expression in Oryctolagus cuniculus with Deep Dermal Burn Wound (As an Indicator for the Best Time to Start Topical Corticosteroid Application in Preventing Hypertrophic Scar)

Background: Hypertrophic scar is an abnormal scar that causes physical deteriorations, psychological problems, and aesthetic issues. An excessive number of fibroblasts and collagen III expressions are histopathology indicators for the hypertrophic scar. The role of topical corticosteroids in suppressing inflammation and hypergranulation had widely demonstrated in previous studies. However, there is no study related to the application of topical corticosteroids as prevention of hypertrophic scars from burn wound found. Hence, this study aimed to examine the evidence of the effects of corticosteroid topical in decreasing the number of fibroblasts and type III collagen expression and the best time to start its application in preventing hypertrophic scars. Methods: This randomized experimental post-test only study involved 54 deep dermal burn wounds on the ventral ear of female Oryctolagus cuniculus that distributed into three groups based on the healing phases. Each group consisted of treatments and controls. Corticosteroid topical application on the first treatment group (inflammatory phase group), the second group (proliferation phase group), and the third group (remodelling phase group) was started on day 3, on day 10, and day 21, respectively. Specimens taken on day 35. Haematoxylin-Eosin and Immunohistochemically staining performed to measure the number of fibroblasts and type III collagen and to observe the epithelization and inflammation process. Results: The number of fibroblasts significantly decreased in the second treatment group (p =0.001) and followed by the first group (p = 0.016), but no significant decrease found in the third group (p = 0.430). The type III collagen decreased significantly in the second treatment group (p = 0.000) and followed by the third group (p = 0.019), but no significant decrease found in the first group. There was no statistically different number of fibroblast and type III collagen discovered between the controls. Complete epithelization found in all groups. Also, no ongoing inflammation found in all groups. Conclusion : Topical corticosteroids on deep dermal burn wound revealed to be effective in reducing the number of fibroblasts and type III collagen with no healing disruption. The proliferation phase found to be the best time to start the application of topical corticosteroids.

Comparative study on clinical efficacy of different methods for the treatment of intramural aortic hematoma

To explore the difference of curative effect between different treatment modalities, in order to provide reference for the treatment of aortic intramural hematoma (IMH). 168 patients with aortic intramural hematoma diagnosed and treated from January 2010 to July 2020 were selected in the Second Affiliated Hospital of Nanchang University. Among them, 48 patients were diagnosed with Stanford A aortic intramural hematoma and 120 were diagnosed with Stanford B aortic intramural hematoma. According to the therapeutic methods, patients were divided into conservative treatment group and endovascular treatment group (TEVAR). For endovascular treatment group, according to the different timing of surgery, can be divided into acute phase group (onset within 72 h) and non-acute phase group (time of onset > 72 h).The clinical data and follow-up data were collected and analyzed by variance analysis and χ2 test. There were 168 patients diagnosed with aortic intramural hematoma 39 of them were (81.25%) Stanford A aortic intramural hematoma patients with pleural or pericardial effusion. For patient with Stanford A aortic intramural hematoma, endovascular treatment was performed in 15 patients (31.2%), and 33 cases (68.8%) for conservative treatment. The average follow-up (24.9 ± 13.9) was months. There were 120 patients with Stanford type B aortic intramural hematoma (71.4%), 60 patients received endovascular treatment (50%), and 60 patients (50%) received conservative treatment, with an average follow-up of (27.8 ± 14.6) months. For Stanford A type aortic intramural hematoma patients when the maximum aortic diameter ≥ 50 mm or hematoma thickness ≥ 11 mm, with high morbidity and mortality, positive endovascular treatment can reduce complications and death. For patients with Stanford type B aortic intramural hematoma, when the maximum aortic diameter ≥ 40 mm or hematoma thickness ≥ 10 mm, with high morbidity and mortality, positive endovascular treatment can reduce complications and death. Both Stanford type A and B aortic intramural hematoma patients could benefit from the endovascular treatment when the initial maximum aortic diameter is ≥ 50 mm or the hematoma thickness is ≥ 11 mm.

Method of nonlinear code multiplexing of a multiphase group sequence.

This paper presents the generalization of the method of nonlinear code multiplexing of a binary group sequence is considered for the r – phase group sequences. A transition to a complex space, as well as using definite integrals, and conversion of the Cartesian chart while turning at a set angle are used to form the r – phase group sequence with a constant power from the multiphase summary group sequence, which consist of the sum of the r – phase information orthogonal sequences. As a result, the multiphase summary group sequences are mapped to the r-phase group sequences with constant power, which contain the information orthogonal r-phase sequences which are a part of these summary group sequences. Analytical expressions of the r – phase group sequences with constant power are obtained for even values of r. If the r is 4 the final formulas of group sequences with the constant power at the odd quantity of the information orthogonal sequences in the summary group sequences is obtained. The method of nonlinear code multiplexing of a multiphase group sequence considered in this paper, can be applied to increase capacity of communication channels with nonlinear code multiplexing.

USING ANALOGY IN SOLVING PROBLEMS: A CASE STUDY OF TEACHING THE RADICAL INEQUALITIES

In mathematics education, teachers can use several reasoning methods to find solutions such as inductive, deductive and analogy. This study was intended to guide students to find solutions to problems of radical inequalities through analogical reasoning. The experiment was conducted on 36 grade 10 students at a high school in Can Tho city of Vietnam. The instrument used was a problem of radical inequalities. A three-phase teaching process had been organized with this class comprising individual work phase, group work phase and institutionalization phase. The data collected included student worksheets and was qualitatively analyzed. As a result, many students discovered how to solve the above inequality by using the analogy, and they had a considerable improvement in their problem-solving skills. Additionally, a few ideas were discussed about the use of analogy in mathematics education. <p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/edu_01/0769/a.php" alt="Hit counter" /></p>