Terahertz toroidal dipole metamaterial sensors for detection of aflatoxin B1

Terahertz metamaterial biosensors have attracted significant attention in the biological field due to their advantages of label-free,real-time and in situ detection.In this paper,a highly sensitive metamaterial sensor with semi-ring mirror symmetry based on toroidal dipole resonance is designed for a new metamaterial biosensor.It is shown that a refractive index sensitivity of 337.5 GHz per refractive index unit can be achieved under an analyte of saturated thickness near a 1.33 THz transmission dip.For biosensor samples where aflatoxin B1 is dropped on the metamaterial surface in our experiment,dip amplitudes of transmission varying from 0.1904 to 0.203 and 0.2093 are observed as aflatoxin B1 concentrations are altered from 0 to 0.001μg·ml-1 and to 0.01μg·ml-1,respectively.Furthermore,when aflatoxin B1 concentrations are 0.1μg·ml-1,1μg·ml-1,10μg·ml-1 and 100μg·ml-1,dip amplitudes of 0.2179,0.226,0.2384 and 0.2527 and dip redshifts of 10.1 GHz,20.1 GHz,27.7 GHz and 37.6 GHz are respectively observed.These results illustrate high-sensitivity,label-free detection of aflatoxin B1,enriching the applications of sensors in the terahertz domain.

Thermal and Electrical Properties of Liquid Metal Gallium During Phase Transition

Liquid metal gallium has been widely used in numerous fields, from nuclear engineering, catalysts, and energy storage to electronics owing to its remarkable thermal and electrical properties along with low viscosity and nontoxicity. Compared with high-temperature liquid metals, room-temperature liquid metals, such as gallium(Ga), are emerging as promising alternatives for fabricating advanced energy storage devices, such as phase change materials, by harvesting the advantageous properties of their liquid state maintained without external energy input. However, the thermal and electrical properties of liquid metals at the phase transition are rather poorly studied, limiting their practical applications. In this study, we reported on the physical properties of the solid–liquid phase transition of Ga using a custom-designed, solid–liquid electrical and thermal measurement system. We observed that the electrical conductivity of Ga progressively decreases with an increase in temperature. However, the Seebeck coefficient of Ga increases from 0.2 to 2.1 μV/K, and thermal conductivity from 7.6 to 33 W/(K·m). These electrical and thermal properties of Ga at solid–liquid phase transition would be useful for practical applications.

Bottom-Up Engineering Strategies for High-Performance Thermoelectric Materials

The recent advancements in thermoelectric materials are largely credited to two factors,namely established physical theories and advanced materials engineering methods.The developments in the physical theories have come a long way from the“phonon glass electron crystal”paradigm to the more recent band convergence and nanostructuring,which consequently results in drastic improvement in the thermoelectric figure of merit value.On the other hand,the progresses in materials fabrication methods and processing technologies have enabled the discovery of new physical mechanisms,hence further facilitating the emergence of high-performance thermoelectric materials.In recent years,many comprehensive review articles are focused on various aspects of thermoelectrics ranging from thermoelectric materials,physical mechanisms and materials process techniques in particular with emphasis on solid state reactions.While bottom-up approaches to obtain thermoelectric materials have widely been employed in thermoelectrics,comprehensive reviews on summarizing such methods are still rare.In this review,we will outline a variety of bottom-up strategies for preparing high-performance thermoelectric materials.In addition,state-of-art,challenges and future opportunities in this domain will be commented.

Optical strong coupling in hybrid metal-graphene metamaterial for terahertz sensing

We propose a terahertz hybrid metamaterial composed of subwavelength metallic slits and graphene plasmonic ribbons for sensing application.This special design can cause the interaction between the plasmon resonances of the metallic slits and graphene ribbons,giving rise to a strong coupling effect and Rabi splitting.Intricate balancing in the strong coupling region can be perturbed by the carrier concentration of graphene,which is subject to the analyte on its surface.Thereby,the detection of analyte can be reflected as a frequency shift of resonance in terahertz transmission spectra.The result shows that this sensor can achieve a theoretical detection limit of 325 electrons or holes per square micrometer.Meanwhile,it also works well as a refractive index sensor with the frequency sensitivity of 485 GHz/RIU.Our results may contribute to design of ultra-micro terahertz sensors.

Surgical treatment of pancreatic head cancer: concept revolutions and arguments

As we have a deeper and more thorough understanding of the biological behavior of pancreatic head cancer, surgical treatment concepts of this lethal disease are changing all the time. Meanwhile, numerous arguments emerge. Thus, we will probe into the focuses and arguments in the surgical treatment of pancreatic head cancer in this article, including the scope of lymphadenectomy, total mesopancreas excision（TMp E）, vascular resection, minimally invasive pancreaticoduodenectomy（PD）, palliative resection, surgery for recurrent disease and surgery for primary pancreatic cancer and liver metastasis.

Polymer electrolytes for flexible zinc-air batteries:Recent progress and future directions

This review article delves into the development of electrolytes for flexible zinc-air batteries(FZABs),a critical component driving the advancement of flexible electronics.We started by surveying the current advancements in electrolyte technologies,including solid-state and gel-based types,and their contributions to enhance the flexibility,efficiency,and durability of FZABs.Secondly,we explored the challenges in this domain,focusing on maintaining electrolyte stability under mechanical stress,ensuring compatibility with flexible substrates,optimizing ion conductivity,and under harsh environmental conditions.Furthermore,the key issues regarding interface details between electrolyte and the electrodes are covered as well.We then discussed the future of electrolyte development in FZABs,highlighting potential avenues such as materials development,sustainability,in-situ studies,and battery integration.This review offers an in-depth overview of the advancements,challenges,and potential breakthroughs in creating electrolytes for FZABs over the past five years.It serves as a guide for both researchers and industry professionals in this dynamic area.

Coal-based activated carbon prepared by H2O activation process for supercapacitors using response surface optimization method

The scalable production of high grade activated carbon from abundant coal for supercapacitors application is an efficient way to achieve high value-added utilization of coal sources.However,this technology is challenging due to lack of comprehensive understanding on the mechanism of activation process and effect of external factors.In this paper,the effect of activating temperature and time on the specific capacitance of coal-based activated carbon prepared by H2O steam activation was studied using the response surface method.Under optimal conditions,coal-based activated carbon exhibits the largest specific capacitance of 194.35 F·g^(−1),thanks to the appropriate pore/surface structure and defect degree.Density functional theory calculations explain in detail the mechanism of contraction of aromatic rings and overflow of H2 and CO during the activation.Meanwhile,oxygen-containing functional groups are introduced,contributing to the pseudocapacitance property of coal-based activated carbon.This mechanism of reactions between aromatic carbon and H2O vapor provides understanding on the role of water during coal processing at the molecular level,offering great potential to regulate product distribution and predict rate of pore generation.This insight would contribute to the advancement of other coal processing technology such as gasification.

Polyethylene glycol/polylactic acid block co‐polymers as solid–solid phase change materials

Phase change materials(PCMs)are promising thermal energy storage materials due to their high specific latent heat.Conventional PCMs typically exploit the solid–liquid(s–l)transition.However,leakage and leaching are common issues for solid–liquid PCMs,which have to be addressed before usage in practical applications.In contrast,solid–solid(s–s)PCMs would naturally overcome these issues due to their inherent form stability and homogeneity.In this study,we report a new type of s–s PCM based on chemically linked polyethylene glycol(PEG,the PCM portion)with polylactic acid(PLA,the support portion)in the form of a block co‐polymer.Solid‐solid latent heat of up to 56 J/g could be achieved,with melting points of between 44°C and 55°C.For comparison,PEG was physically mixed into a PLA matrix to form a PEG:PLA composite.However,the composite material saw leakage of up to 9%upon heating,with a corresponding loss in thermal storage capacity.In contrast,the mPEG/PLA block co‐polymers were found to be completely homogeneous and thermally stable even when heated above its phase transition temperature,with no observable leakage,demonstrating the superiority of chemical linking strategies in ensuring form stability.

KCNH2 regulates the growth and metastasis of pancreatic cancer

Objective:Due to the characteristics of insidious onset and early metastasis of pancreatic cancer(PC),patients are often diag-nosed at an advanced stage and often delayed in completing surgical resection timely,resulting in poor prognosis.Therefore,this study aims to explore the expression of potassium voltage-gated channel subfamily H member 2(KCNH2)in PC and its relation-ship with clinicopathological parameters and the related mechanisms.Methods:GEPIA database and immunohistochemical staining were used to analyze the difference in KCNH2 expression be-tween PC and adjacent tissue in RNA and protein levels.Chi-squared test was used to evaluate the relationship between KCNH2 expression and clinicopathological features.The Cox regression model was used for multivariate analysis and univariate analysis.Histological diagnosis was performed according to World Health Organization(WHO)criteria to evaluate the relationship between KCNH2 expression and clinicopathological features.Results:KCNH2 expression was upregulated in PC compared with normal pancreatic tissue.In addition,the knockdown of KCNH2 inhibits PC cell proliferation,migration,invasion,and epithelial-mesenchymal transformation and promotes their apopto-sis.In addition,clinical data showed that the abnormal expression of KCNH2 in PC was related to the tumor stage.Patients with high expression of KCNH2 had a poor prognosis.Conclusions:KCNH2 is expected to be a novel targeted molecule in treating PC.

A composite disturbance observer and H_∞ control scheme for flexible spacecraft with measurement delay and input delay

In this paper, the attitude control algorithm of flexible spacecraft with unknown measurement delay and input delay based on disturbance observer is designed. The influence of measurement delay and input delay on the attitude control system and disturbance observer is analyzed. The disturbance estimation error equation is transformed into a differential system with a pure delay. Then, the observer gain is chosen based on the 3/2 stability theorem to ensure the stability and disturbance attenuation performance of the pure delay system. Next, the controller gain is designed based on the Linear Matrix Inequality(LMI) approach to guarantee the stability of the composite system and achieve H_∞ performance with two additive delays. The simulation results show that the proposed method can improve the anti-disturbance ability of the attitude control system.

Analysis of 100 consecutive cases of resectable pancreatic neuroendocrine neoplasms： clinicopathological characteristics and long-term outcomes

The incidence rate of pancreatic neuroendocrine neoplasms （pNENs） has increased rapidly in recent years. However, the clinicopathological characteristics of pNENs are poorly understood. Medical records of patients who underwent surgery and were confirmed as pNENs by pathological examination from January 2003 to February 2015 in Qilu Hospital were reviewed retrospectively. A total of 100 patients, 36 males and 64 females, were included with a mean operation age of 46.26 ± 13.41 years. Among the 100 cases, 76 had insulinomas and 24 had non-functional pNENs. Tumor size ranged from 0.5 cm to 9 cm, and the mean size was 2.20 ± 1.40 cm. The percentages of TNM stages I, II, III, and IV tumors were 89.0%, 8.0%, 0.0%, and 3.0%, respectively. Based on the WHO classification, pNENs were classified into three grades： G1, G2, and G3. G1, G2, and G3 tumors were confirmed in 72.9%, 23.7%, and 3.4% patients, respectively. The positive rates of CgA and Syn immunohisto- chemical staining were 94.5% （69/73） and 100% （74/74）, respectively. Compared with insulinoma, non-functional pNENs have larger tumor sizes, more advanced TNM staging, a higher Ki-67 index, and a higher rate of liver metastasis （P 〈 0.05）. In conclusion, pNENs are heterogeneous tumors with varying clinical manifestations, diverse tumor biological characteristics, and different prognoses. Non-functional pNENs present a more aggressive behavioral model and have poorer prognosis than functional pNENs.

Corrosion mechanism of H_2O on Sm_2Fe_(17) and nitrogenation process of corroded Sm_2Fe_(17)

Sm_2 Fe_(17) prepared by reduction-diffusion method needs to be washed with water to remove calcium oxide. Electrochemical corrosion occurs when Sm_2 Fe_(17) powder is in contact with liquid water. Corrosion mechanism of H_2 O on Sm_2 Fe_(17) powder and nitrogenation process of corroded Sm_2 Fe_(17) were studied by analyzing the structure and morphology. It is indicated that the metallic hydroxide forms and deposits on the Sm_2 Fe_(17) powder surfaces during water corrosion. At the same time, oxygen and hydrogen enter the unit cell of Sm2 Fe_(17), causing a slight increase in Curie temperature. In the subsequent nitriding process,the hydroxide is dehydrated and hydrogen is desorbed. The resulting oxide reacts with Sm_2 Fe_(17)N_x to form a-Fe and Sm_2 O_3. Thermodynamic calculations using the HSC Chemistry 6.0 software indicate that the reaction can occur spontaneously. The effect of water corrosion on the magnetic properties of the nitride can be eliminated by hydrogen reduction prior to nitriding.

Analysis of crystallographic orientation and morphology of microstructure during hot working for an alpha/beta titanium alloy

This work focuses on analysis of microstructure morphology and crystallographic orientation for Ti-17 alloy during hot working.The results show that alpha phase and beta phase influence each other and there is a coordinate deformation between them.The non-uniform deformation is observed under small deformation conditions.The observing area can be divided into small deformation zone(area L)and large deformation zone(area H).Both alpha and beta phases remain the initial morphology,and they have better capability of coordinate deformation in area L,while coordinate capability is weak in area H in which alpha phase is globularized.Correspondingly,the Burgers orientation relations are well preserved in area L,but the orientation relations are more or less destroyed in area H.Dynamic recovery is the main mechanism of beta phase evolution when height reduction is lower.By contrast,the continuous dynamic recrystallization(CDRX)of beta phase gradually dominates the deformation pattern as the deformation increases.An uniformly globularized alpha structure is obtained under large deformation condition.The unsynchronized rotation of alpha phase around<11-20>pole occurs during deformation,which leads to the uniform crystal structure inside the same alpha lamellae.This process is an important step of globularization of the lamellar structure.

Malaria from hyperendemicity to elimination along international borders in Yunnan, China during 2003‒2020: a case study

Background: Border malaria is one of the most intractable problems hindering malaria elimination worldwide.Movement of both the human population and anopheline mosquitoes infected with Plasmodium spp.can cause cross-border malaria transmission.The Yunnan border area was still hyperendemic for malaria in the early part of this century.The objective of this case study was to analyze the strategies,interventions and impacts of malaria control and elimination in the Yunnan border area.Main text: A total of 10,349 malaria cases and 17.1 per 10,000 person-years of annual parasite incidence(API)were reported in the border area in 2003.Based on natural village-based stratification,integrated interventions,including mass drug administration for radical cures and preventive treatment,clinically presumptive treatment of all febrile patients for malaria and indoor residual spraying or dipping bed nets with insecticides were successfully carried out from 2003 to 2013.The overall API was reduced to 0.6 per 10,000 person-years by 2013,while effective cross-border collaboration interventions dramatically reduced the malaria burden in the neighbouring border areas of Myanmar.From 2014 forward,the comprehensive strategy,including universal coverage of surveillance to detect malaria cases,a rapid response to possible malaria cases and effective border collaboration with neighbouring areas,successfully eliminated malaria and prevented reintroduction of malaria transmission in the Yunnan border area.Conclusions: In Yunnan malaria burden has successfully reduced by dynamically accurate stratification and comprehensive interventions;and then the region achieved elimination and prevented reintroduction of malaria transmission through intensive surveillance,rapid response and border collaboration.Other border areas should perform their own intervention trials to develop their own effective strategy.

Labor Market Dynamics and Structural Change： Evidence from China

Structural change theories usually assume agents are homogeneous. However, because of demand-side or supply-side heterogeneities, the probability of switching among sectors differs across people. This paper reveals these differences through restoring a long-period, individual-level panel dataset from China＇s Urban Household Survey for 1986-2009. We find that both for people who started working for the first time and those who switched jobs, the sector choice depends on personal characteristics. In particular, women and people with higher educational attainment or a previous white- collar job are more likely to join the tertiary sector and less likely to join the primary sector. These effects are substantial even if the macroeconomic variables used in conventional structural change theories are controlled. They are also robust in various periods and at more detailed industry levels. Our research suggests that it is important to pay greater attention to the labor composition when mal^ng policy related to economic structural change.

Why Has China's Current Account Balance Converged after the Global Financial Crisis?

China's current account surplus declined significantly from its peak of nearly 10 percentof GDP in 2007 to less than 1 percent in 2018.The new pattern offered fresh evidencefor our understanding of China's current account dynamics.In this paper,we used flowof funds data to gauge its underlying driving forces.Specifically,by employing indexdecomposition analysis,we decomposed the current account from the perspective ofsavings and investment into three sectors:the household,corporate,and governmentsectors.We found that the decline in China's current account ratio was first driven bycyclical factors,i.e.weak corporate saving growth induced by the economic slump in2009 as well as the following massive corporate investment bolstered by the governmentstimulus plan.However,such cyclical factors quickly subsided,and the subsequentcurrent account balance reduction was later supported by structural factors,i.e.household savings declined enduringly and the Chinese government switched to a moreexpansionary fiscal policy.There are three possible explanations for the structuralmovement:reduced precautionary saving due to higher social security coverage ratio,lower corporate profits as a result of economic slowdown,and a twin deficit due to thegovernment's more relaxed fiscal stance.The new facts,however,were not consistent withother current account theories focusing on long-term aspects of the saving-investmentaccount puzzle,especially those relating to China's special demographic characteristics.

Trends in Stroke Mortality Rate--China,2004-2019

Introduction:Stroke has been the leading cause of death in China for decades.This study described the trends in stroke mortality in China from 2004 to 2019.Methods:Data was obtained from the National Disease Surveillance Point(DSP)system.A descriptive analysis was conducted.The adjusted mortality rate(AMR)and age-standardized mortality rate(ASMR)of stroke were calculated.Results:From 2004 to 2019,the ASMR substantially decreased,with a reduction of 39.8%,but the AMR stayed relatively stable.The mortality rate of stroke in rural areas was consistently higher than in urban areas.A geographical gradient in mortality of stroke was also apparent,with an increased rate in the western part of China and a decreased rate in the eastern part of China.In central China,the rate remained relatively stable.Conclusions:Although the ASMR of stroke continued to decline in China,the stagnant crude mortality rates suggested that China had not achieved sufficient decline to offset the demographic forces of population growth and ageing.More vigorous and effective prevention and treatment strategies are urgently needed to mitigate the disease burden of stroke in China,especially in areas with high stroke burden and limited resources.

Current Research Trends and Perspectives on Solid-State Nanomaterials in Hydrogen Storage

Hydrogen energy,with environment amicable,renewable,efficiency,and cost-effective advantages,is the future mainstream substitution of fossil-based fuel.However,the extremely low volumetric density gives rise to the main challenge in hydrogen storage,and therefore,exploring effective storage techniques is key hurdles that need to be crossed to accomplish the sustainable hydrogen economy.Hydrogen physically or chemically stored into nanomaterials in the solid-state is a desirable prospect for effective large-scale hydrogen storage,which has exhibited great potentials for applications in both reversible onboard storage and regenerable off-board storage applications.Its attractive points include safe,compact,light,reversibility,and efficiently produce sufficient pure hydrogen fuel under the mild condition.This review comprehensively gathers the state-of-art solid-state hydrogen storage technologies using nanostructured materials,involving nanoporous carbon materials,metal-organic frameworks,covalent organic frameworks,porous aromatic frameworks,nanoporous organic polymers,and nanoscale hydrides.It describes significant advances achieved so far,and main barriers need to be surmounted to approach practical applications,as well as offers a perspective for sustainable energy research.

Enhanced maximum energy product of(SmY)FeN caused by abundant yttrium doping

Replacement of samarium(Sm) with abundant yttrium(Y) can help solve the potential shortage of Sm in the preparation of promising Sm2 Fe17 Nx magnets.In this article,phase composition,microstructure and magnetic properties of(Sm1-yYy)2 Fe17Nx(y=0,0.2,0.4,0.6,0.8,1.0) were investigated.Maximum energy product(BH)max is improved when less than 40 at% Y is doped in(Sm1-yYy)2 Fe17Nx powder.In particular,when 20 at% Y replaces Sm,(BH)max of(Sm1-yYy)2 Fe17Nx powder increases by 15.1% from 131.7 to151.6 kJ/m3.The effect of annealing temperature on the structural properties of high Y doping(Sm0.6Y0.4)2 Fe17 and the magnetic properties of the corresponding nitrides were subsequently investigated.In the RE2 Fe17 phase grain combination process,the interlaced structure of the rhombohedral Th2 Zn17-type structural phase and the hexagonal Th2 Ni17-type structural phase is formed.Due to shortrange exchange coupling,the nitride with the highest content of two interlaced RE2 Fe17 phases has the highest magnetic properties:Br=1.23 T,HcJ=443.9 kA/m and(BH)max=197.6 kJ/m3.