Pulmonary Arterial Hypertension in Congenital Heart Disease with Left-to-Right Shunt: According to a Retrospective Study at Albert Royer’s National Children’s Hospital Center

Pulmonary arterial hypertension PAH is a progressive disease characterized by an increase in pulmonary arterial pressure and resistance. It often complicates congenital heart disease with a left-to-right shunt. The objective of this study is to evaluate the evolutionary profile of the pulmonary pressures of children with congenital heart disease with left-to-right shunt and to identify the factors favoring an evolution towards PAH. This is a retrospective, descriptive and analytical study over a period of four years and six months (from January 1, 2016 to June 30, 2020) at the Center National d’Enfant Albert Royer in Dakar on a series of 87 cases. The hospital frequency was 3.98 per thousand, and the incidence of PAH was 9.44%. The sex ratio of 0.74. The average age was 44.76 months. The average time between the onset of symptoms and the diagnosis of heart disease is 78.81 days. Dyspnea was found in 70.11% of cases, the burst of pulmonary B2 was found in 55%. Global heart failure was noted in 39.08% of cases. Cardiomegaly was found in 89.66% and pulmonary hypervascularization was found in 57.72% of cases. CIV was present in 54.02% of cases, followed by PCA in 21.14% and CAVc in 18.39% of cases. furosemide was used in 97.70% of cases and Captopril in 74.71% of cases. Sildenafil was used in 10.34% of patients, and 12.64% of patients benefited from surgical management. Eisenmenger syndrome was found in 12.64% of patients. PAH in these heart diseases is a formidable and frequent complication, due to an increase in precapillary flow. The major improvement in mortality and morbidity is early surgical management, in the first months of life, to prevent pulmonary vascular disease.

Left-definite boundary conditions of Sturm-Liouville problems when the interval shrinks to a point

On the condition that the interval of the problem shrinks to a point, we investigated the separated boundary conditions Sα,β of left-definite Sturm-Liouville problem, and answered the following question： Is there a co ∈ J such that Sα,β is always left-definite or semi-left-definite for the Sturm-Liouville equation for each c ∈ （a, co）？

A Study on Left-behind Junior Students'Foreign Language Learning Anxiety

Since the 1960s, foreign language educators and researchers home and abroad have started to pay attention to the influence of the affective variables including language learning anxiety on foreign language learning. This thesis tried to find out the factors that may influence the foreign language learning anxiety level of left-behind students and put forward ways to help lower down the foreign language learning anxiety level of the left-behind junior middle school students.

Left-sided appendicitis:Review of 95 published cases and a case report

AIM:To give an overview of the literature on left-sided acute appendicitis (LSAA) associated with situs inversus totalis (SIT) and midgut malrotation (MM).METHODS:We present a new case of LSAA with SIT and a literature review of studies published in the English language on LSAA,accessed via PubMed and Google Scholar databases.RESULTS:Ninety-five published cases of LSAA were evaluated and a 25-year-old female,who presented to our clinic with left lower abdominal pain caused by LSAA,is reported.In the reviewed literature,fiftyseven patients were male and 38 were female with an age range of 8 to 82 years and a median age of 29.1 ± 15.9 years.Sixty-six patients had SIT,23 had MM,three had cecal malrotation,and two had a previously unnoted congenital abnormality.Fifty-nine patients had presentedto the hospital with left lower,14 with right lower and seven with bilateral lower quadrant pain,and seven subjects complained of left upper quadrant pain.The diagnosis was established preoperatively in 49 patients,intraoperatively in 19,and during the postoperative period in five;14 patients were aware of having this anomaly.The data of eight patients were not unavailable.Eleven patients underwent laparoscopic appendectomy,which was combined with cholecystectomy in two cases.Histopathological examination of the appendix specimens revealed adenocarcinoma in only two of 95 patients.CONCLUSION:The diagnosis of left lower quadrant pain is based on well-established clinical symptoms,physical examination and physician's experience.

The impact of migration on the food consumption and nutrition of left-behind family members: Evidence from a minority mountainous region of southwestern China

While migration is widely recognized as a valid option for improving farmers’ income, the welfare effects of migration on left-behind family members are ambiguous. This study examines the impacts of migration on left-behind family members’ food consumption and nutrient intake, particularly in remote rural areas in China. Based on household survey data collected from 611 smallholder rubber farmers in Xishuangbanna Dai Autonomous Prefecture of southwestern China, the empirical results suggest that the migration of family members contributes to improving household net income, whereas it negatively affects left-behind family members’ consumption of grain and pork. Migration also leads to a decrease in left-behind family members’ nutrient intake. Surprisingly, the economic returns of farmers’ migration not only do not foster the transformation of household food consumption from a staple food-dominated dietary structure to one including more meat and dairy products but also reduce left-behind family members’ nutrient intake. This study adds to the literature on the impact of farmers’ migration. The findings have important implications for better understanding the impacts of migration on farmers’ livelihood and human capital development in rural China.

Propagation of Airy beams from right-handed material to left-handed material

Based on the ABCD matrix formalism,the propagation property of an Airy beam from right-handed material（RHM） to left-handed material（LHM） is investigated.The result shows that when the Airy beam propagates in the LHM,the intensity self-bending due to its propagation in the RHM can be compensated.In particular,if the propagation distance in the RHM is equal to that in the LHM and the refractive index of the LHM is n L =-1,the transverse intensity distribution of the Airy beam can return to its original state.

Subwavelength rectangular cavity partially filled with left-handed materials

In this paper, we present the electromagnetic analysis of a rectangular cavity partially filled with a left-handed material slab. Our theoretical investigation shows that there exist novel resonant modes in the cavity, and such a cavity becomes a subwavelength cavity. The eigenvalue equation of the cavity is derived and the resonant frequencies of the novel modes are calculated by using numerical simulation. We also discuss the stability of the novel resonant modes and show the best condition under which a useful rectangular cavity of subwavelength dimensions with tolerable stability is obtained.

Right-and left-sided colorectal cancers respond differently to traditional Chinese medicine

AIM To explore the differences in the responses of left-sided colorectal cancer(LSCRC) and right-sided colon cancer(RSCC) to traditional Chinese medicine(TCM).METHODS Patients with postoperative stage I-III colorectal cancer(CRC) were enrolled and divided into the LSCRC with or without TCM and RSCC with or without TCM groups depending on the primary tumor side and TCM administration. Patients in the TCM group were given TCM for at least 6 mo. Our research adopted diseasefree survival(DFS) as the primary endpoint. We applied a Cox proportional hazards regression model for the multivariate factor analysis using Stata 12.0 and SPSS 22.0 software for data analysis.RESULTS Of the 817 patients included in our study, 617 had LSCRC(TCM group, n = 404; Non-TCM group, n = 213), and 200 had RSCC(TCM group, n = 132; NonTCM group, n = 68). The 6-year DFS for patients with LSCRC was 56.95% in the TCM group and 41.50% in the Non-TCM group(P = 0.000). For patients with RSCC, the 6-year DFS was 52.92% in the TCM group and 37.19% in the Non-TCM group(P = 0.003). Differences between LSCRC and RSCC were not statistically significant regardless of TCM ingestion.CONCLUSION Patients with either LSCRC or RSCC and who took TCM experienced longer DFS; furthermore, patients with RSCC benefited more from TCM in DFS.

Primary colon resection or Hartmann's procedure in malignant left-sided large bowel obstruction? The use of stents as a bridge to surgery

There is still significant debate regarding the best surgical treatment for malignant left-sided large bowel obstruction.Primary resection and anastomosis offers the advantages of a definite procedure without need for further surgery.Its main disadvantages are related to the increased technical challenge and to the potential higher risk of anastomotic leakage that occurs in the emergency setting.Primary resection with end colostomy(Hartmann's procedure) is considered the safer option.Tan et al compared in a systematic review and meta-analysis the use of self-expanding metallic stents(SEMS) as a bridge to surgery vs emergency surgery in the management of acute malignant left-sided large bowel obstruction.The authors concluded that the technical and clinical success rates for stenting were lower than expected.SEMS was associated with a high incidence of clinical and silent perforation.Stenting instead of loop colostomy can be recommended only if the appropriate expertise is available in the hospital.The goal of stenting,a decrease of the stoma rate,may be advocated only if the complication rates of stenting are lower than those of stoma creation in the emergency situation.Until now,this was not demonstrated in a prospective randomized trial.

Design of Structural Left-handed Material based on Topology Optimization

An effective method to design structural Left-handed material（LHM） was proposed. A commercial finite element software HFSS and S-parameter retrieval method were used to determine the effective constitutive parameters of the metamaterials, and topology optimization technique was introduced to design the microstructure configurations of the materials with desired electromagnetic characteristics. The material considered was a periodic array of dielectric substrates attached with metal film pieces. By controlling the arrangements of the metal film pieces in the design domain, the potential microstructure with desired electromagnetic characteristics can be obtained finally. Two different LHMs were obtained with maximum bandwidth of negative refraction, and the experimental results show that negative refractive indices appear while the metamaterials have simultaneously negative permittivity and negative permeability. Topology optimization technique is found to be an effective tool for configuration design of LHMs.

The Correlation between Social Anxiety and Loneliness of Left-Behind Children in Rural China: Effect of Coping Style

In this study, the relationship between social anxiety, coping style and loneliness amongst left-behind children was investigated. The participants were 773 left-behind children recruited from 8 junior middle schools in rural areas of Zhejiang Province in China who completed the Social Anxiety Scale for Children, Simplified Coping Style Questionnaire and Children’s Loneliness Scale. Results show that there was a moderate correlation between social anxiety and loneliness, and these variables had a significant negative relationship with positive coping style and a significant positive relationship with negative coping style. Furthermore, the left-behind children’s social anxiety, coping style and loneliness were different within specific demographic groups, such as gender, only child status and different type of parental work. Also negative coping style moderated the association between loneliness and social anxiety, so that children who were more likely to use negative coping strategies showed a stronger relationship between social anxiety and loneliness. Finally, the left-behind children’s social anxiety not only directly predicted their loneliness, but also had an indirect effect mediated by their copying style.

THE GLOBAL APPROXIMATION BY LEFT-BERNSTEIN-DURRMEYER QUASI-INTERPOLANTS IN Lp[0,1]

In this paper, we will use the 2r-th Ditzian-Totik modulus of smoothness wψ2r(f,t)p to discuss the direct and inverse theorem of approximation by Left-Bernstein-Durrmeyer quasi-interpolants Mn[2r-1]f for functions of the space Lp[0,1] (1≤ p≤ +∞).

Microwave left-handed composite material made of slim ferrite rods and metallic wires

This paper reports on experimental study of the microwave properties of a composite material consisting of ferrite and copper wires. It finds that the slim ferrite rods can modify the magnetic field distribution through their anisotropy, so that the ferrite＇s negative influence on the copper wires＇ plasma will be reduced. Left-handed properties are observed even in the specimen with close stuck ferrite rods and copper wires.

Spectrum of a class of fourth order left-definite differential operators

The spectrum of a class of fourth order left-definite differential operators is studied. By using the theory of indefinite differential operators in Krein space and the relationship between left-definite and right-definite operators, the following conclusions are obtained： if a fourth order differential operator with a self-adjoint boundary condition that is left-definite and right-indefinite, then all its eigenvalues are real, and there exist countably infinitely many positive and negative eigenvalues which are unbounded from below and above, have no finite cluster point and can be indexed to satisfy the inequality …≤λ-2≤λ-1≤λ-0〈0〈λ0≤λ1≤λ2≤…

Left-handed properties of a composite structure with metallic wires in a homogeneous Lorentz medium

The electromagnetic properties of a composite structure with metallic wires in a Lorentz medium were studied. The results show that the electromagnetic properties of the medium host influence the plasma resonance of metallic wires and the left-handed character of the composite. The plasma frequency of metallic wires reduces with the rise of permittivity or permeability of the medium host. Also, the negative permeability of the medium can destroy the wires’ plasma resonance and prevent the realization of left-handed properties. The high loss of medium permittivity or permeability also inhibits the metallic plasma resonance. The negative influence of the media host on the left-handed properties of the composite structure can be effectively reduced by proper structure design, such as introducing a nonmagnetic medium in the host or using an anisotropic medium.

Dual-band left-handed metamaterials fabricated by using tree-shaped fractal

A method of fabricating dual-band left-handed metematerials （LHMs） is investigated numerically and experimen- tally by single-sided tree-like fractals. The resulting structure features multiband magnetic resonances and two electric resonances. By appropriately adjusting the dimensions, two left-handed （LH） bands with simultaneous negative per- mittivity and permeability are engineered and are validated by full-wave eigenmode analysis and measurement as well in the microwave frequency range. To study the multi-resonant mechanism in depth, the LHM is analysed from three different perspectives of field distribution analysis, circuit model analysis, and geometrical parameters evaluation. The derived formulae are consistent with all simulated results and resulting electromagnetic phenomena, indicating the ef- fectiveness of the established theory. The method provides an alternative to the design of multi-band LHM and has the advantage of not requiring two individual resonant particles and electrically continuous wires, which in turn facilitates planar design and considerably simplifies the fabrication.

Super energy flows in a waveguide filled with air and left-handed materials

The phenomena of super energy flows are studied theoretically and numerically in a parallel-plate waveguide which is filled with two layered equally-thick different media, i.e. air and specific left-handed materials （LHM） with εr1 = -1/（1 ＋δ） ＋iγ and μr1 = -（1 ＋ δ） ＋ iγ. In this special waveguide, two-directional super-energy flows are excited by a three-dimensional horizontal electric dipole at the same time, which has transmission patterns different from those of two-dimensional source and three-dimensional vertical electric dipole. We also show that the retardation and loss in LHM are sensitive to the amplitude of super power densities, and the dimensions of waveguide determine the propagating modes, which makes super energy flows more practical.

A planar left-handed metamaterial based on electric resonators

A planar left-handed metamaterial（LHM） composed of electric resonator pairs is presented in this paper. Theoretical analysis, an equivalent circuit model and simulated results of a wedge sample show that this material exhibits a negative refraction pass-band around 9.6GHz under normal-incidence and is insensitive to a change in incidence angle. Furthermore, as the angle between the arm of the electric resonators and the strip connecting the arms increases, the frequency range of the pass-band shifts downwards. Consequently, this LHM guarantees a relatively stable torlerence of errors when it is practically fabricated. Moreover, it is a candidate for designing multi-band LHM through combining the resonator pairs with different angles.

Analysis of opposing left-turn conflicts based on traffic conflict technology

The relationship between the opposing left-turn conflict and the traffic participants was analyzed in this study. Based on the traffic conflict technology, the image data were collected in a real traffic situation. The relationship was investigated under two different conditions. The number of opposing left-turn conflicts was positively correlated with the number of left-turn vehicles while the ratio of left-turn vehicles to opposing vehicles was less than 1, and showed a positive correlation with the number of opposing-through vehicles when the ratio of left-turn vehicles to opposing vehi- cles was more than 1. In other words, the opposing left-turn risk was positively correlated with the number of the minor traffic participants, which had a negative effect on the whole traffic system op- eration.

（3＋1）-dimensional nonlinear propagation equation for ultrashort pulsed beam in left-handed material

In this paper a comprehensive framework for treating the nonlinear propagation of ultrashort pulse in metamaterial with dispersive dielectric susceptibility and magnetic permeability is presented. Under the slowly-evolving-wave approximation, a generalized （3＋1）-dimensional wave equation first order in the propagation coordinate and suitable for both right-handed material （I^HM） and left-handed material （LHM） is derived. By the commonly used Drude dispersive model for LHM, a （3＋1）-dimensional nonlinear Schrodinger equation describing ultrashort pulsed beam propagation in LHM is obtained, and its difference from that for conventional RHM is discussed. Particularly, the self-steeping effect of ultrashort pulse is found to be anomalous in LHM.