Ultraintense few-cycle infrared laser generation by fast-extending plasma grating

Ultraintense short-period infrared laser pulses play an important role in frontier scientific research,but their power is quite low when generated using current technology.This paper demonstrates a scheme for generating an ultraintense few-cycle infrared pulse by directly compressing a long infrared pulse.In this scheme,an infrared picosecond-to-nanosecond laser pulse counterpropagates with a rapidly extending plasma grating that is created by ionizing an undulated gas by a short laser pulse,and the infrared laser pulse is reflected by the rapidly extending plasma grating.Because of the high expansion velocity of the latter,the infrared laser pulse is compressed in the reflection process.One-and two-dimensional particle-in-cell simulations show that by this method,a pulse with a duration of tens of picoseconds in the mid-to far-infrared range can be compressed to a few cycles with an efficiency exceeding 60%,thereby making ultraintense few-cycle infrared pulses possible.

Self-powered stimuli responsive material for dual stimulation of heat and guest molecules

Stimuli-responsive smart materials exhibit reverse chemical/physical changes in response to external stimuli and research on stimuli-responsive smart materials with self-powered properties is still uncultivated ground.Here,we report perovskite crystalline self-powered multiple stimuli-responsive materials triggered by chemical and thermal stimuli.[HMEP]PbI_(3)·(H_(2)O)(1;HMEP is a hydroxytris(1-methylethyl)phosphorus cation)crystallizes in a chiral space group P 21 at 293 K and has the piezoelectric reaction(d_(33)=10 pC/N and output voltage=1 V)of self-powered modes,this value is larger than the value of 3 pC/N for the classical piezoelectric material ZnO.Piezoelectric materials can generate energy due to mechanical deformation,and using thermal heating to lose water,[HMEP]PbI_(3)(2)can be obtained.2 crystallizes in the non-centrosymmetric space group,undergoes two reversible phase transitions at 243/255 K and 315/348 K,and shows second harmonic generation switching.Interestingly,2 can return to the hydrated form 1 after absorbing water.This work will lay the foundation for self-powered stimuli-responsive compounds and contribute to the construction of novel organic-inorganic hybrid materials with second harmonic generation switching.

胰腺神经内分泌肿瘤肝转移的超声特征及危险因素分析

目的:探讨胰腺神经内分泌肿瘤肝转移的超声特点及术后超声复查的意义。方法:收集2011年1月至2020年12月于天津医科大学肿瘤医院收治的经病理证实且影像资料完整的胰腺神经内分泌肿瘤(pancreatic neuroendocrine neoplasms,pNEN)患者225例,分析胰腺原发肿瘤及肝转移瘤的超声声像图特征。结果:225例pNEN患者中81例发生肝转移,超声显示胰腺肿瘤边缘、肝转移在不同病理分类pNEN间具有统计学差异(P<0.000)。胰腺肿瘤最大径、边缘、肿瘤内钙化、区域淋巴结转移等超声特征及患者性别、梗阻性黄疸在肝转移和无肝转移组间具有统计学差异(P<0.05)。经Logistic分析,梗阻性黄疸、病理分类、胰腺病灶最大径及胰腺肿瘤内钙化是影响pNEN患者肝转移的独立危险因素(P<0.05)。与同时性肝转移相比,异时性肝转移患者均完整切除原发灶,年龄相对年轻,肝转移瘤常单发,多位于右叶,以I型多见,最大径<3 cm,边缘常较清晰,pNEN相关死亡较少,差异具有统计学意义(P<0.05)。结论:pNEN患者肝转移的发生与病理分类有关,梗阻性黄疸、胰腺病灶最大径、病理类型及胰腺病灶内钙化是影响pNEN患者肝转移的独立危险因素。根据声像图特点,异时性肝转移灶更适于手术治疗,且预后优于同时性肝转移。掌握pNEN原发肿瘤及肝转移瘤的超声声像图特征,对pNEN伴肝转移的诊断、治疗及随访均具有重要的临床意义。

Molecular mechanism of non-alcoholic fatty liver disease induced and aggravated by chronic stress through HSL/ATGL-FFA which promotes fat mobilization

Objective:To study the effects of social stress(CS)and social stress combined with high-fat diet on fat mobilization as a candidate mechanism for the induction or aggravation of non-alcoholic fatty liver disease(NAFLD).Methods:Thirty-two male Wistar rats(250±10 g)were randomly allocated to a blank control group(BC),a high-fat diet group(HFD),a CS group,and a combined CS and high-fat diet group(CS t HFD).Rats were sacrificed and tissues were collected after 8 weeks.Liver and body mass were measured and used to calculate the liver index.Serum aspartate aminotransferase(AST),alanine aminotransferase(ALT),and free fatty acids(FFAs)were measured.Liver sections were examined microscopically after oil red O and hematoxylin and eosin staining.The relative mRNA expression of acetyl-CoA carboxylase(ACCase),hydroxymethylglutaryl coenzyme A(HMG-CoA)reductase in liver,and hormone-sensitive lipase(HSL),and adipose triglyceride lipase(ATGL)in subcutaneous adipose tissue,were measured by real-time PCR.The liver concentrations of triglyceride,reactive oxygen species,and ACCase were measured by ELISA and HSL activity was determined using turbidimetry.Results:NAFLD developed in the CS,HFD,and CS t HFD groups,with the most severe NAFLD being in the CS t HFD group.Serum AST,ALT,and FFA,liver index,and hepatic triglyceride,FFA,and tumor necrosis factor-a were significantly higher in both the CS and CS t HFD groups.However,food intake and ACCase mRNA expression were lower.The mRNA expression of HSL and ATGL in adipose tissue was much higher,and HSL activity was higher in the CS group than in the BC group,and in the CS t HFD group than in the HFD group.Conclusion:We have successfully established two models of stress-induced NAFLD,suggesting stress can induce and aggravate NAFLD by promoting fat mobilization through upregulation of HSL and ATGL.

Laser compression via fast-extending plasma gratings

A method is proposed for compressing laser pulses by fast-extending plasma gratings(FEPGs),which are created by ionizing a hypersonic wave generated by stimulated Brillouin scattering in a background gas.Ionized by a short laser pulse,the phonon forms a light-velocity FEPG to fully reflect a resonant pump laser.As the reflecting surface moves with the velocity of light,the reflected pulse is temporally overlapped and compressed.One-and two-dimensional fully kinetic particle-in-cell simulations with a laser wavelength of 1μm show that in this regime,a pump pulse is compressed from 10–40 ps to 7–10 fs(i.e.,a few optical cycles),with a two-dimensional transfer efficiency up to 60%.This method is a promising way to produce critical laser powers while avoiding several significant problems that arise in plasma-based compressors,including an unwanted linear stage,major plasma instabilities,and the need for seed preparation.

A cylindricalÖffner stretcher based on ternary reflector for femtosecond petawatt-level laser system

A cylindricalÖffner stretcher based on ternary reflector(COSTER)is proposed and analyzed.Compared with the traditionalÖffner stretcher,the COSTER has no off-axis aberration in the multipass configuration,and the output laser of COSTER has lower spectral phase noise and higher temporal contrast in the far field.The COSTER is quite suitable to be used in multipetawatt laser facilities,and it might be the preferred stretcher configuration for ultrafast and ultra-intense lasers.

压缩聚焦过程中的波前畸变对远场时空分布影响

针对超高峰值功率激光系统中脉冲的压缩及聚焦过程进行建模,基于光线追迹法和夫琅禾费衍射方法对平行光栅对压缩器的色散过程和抛物面镜的聚焦过程进行了模拟分析,同时采用Square-Radial多项式对方形口径的波前畸变进行描述,分析了近场存在4种不同波前畸变情况时对远场时空分布的影响,定量给出了不同情况下波前畸变误差的允许范围。

Differentiation of a Miniature Inverted Transposable Element （MITE） System in Asian Rice Cultivars and Its Inference for a Diphyletic Origin of Two Subspecies of Asian Cultivated Rice

In the present study, we report a survey on a Miniature Inverted Transposable Element （MITE） system known as mPing in 102 varieties of Asian cultivated rice （Oryza sativa L.）. We found that mPing populations could be generalized Into two families, mPing-1 and mPing-2, according to their sequence structures. Further analysis showed that these two families of mPing had significant bias in their distribution pattern in two subspecies of rice, namely O. sativa ssp. japonica and indica. 0. sativa japonica has a higher proportion of mPing-1 as a general trait, whereas 0. sativa indica has a higher proportion of roPing-2. We also examined the mPing system In a doubled haploid （DH） cross-breeding population of jingxi 17 （japonica） and zhaiyeqing 8 （indica） varieties and observed that the mPing system was not tightly linked to major subspecies-determining genes. Furthermore, we checked the mPing system in 28 accessions of Asian common wild rice O. rufipogon and found the roPing system in 0. rufipogon. The distribution pattern of the roPing system in O. rufipogon indicated a diphyletlc origin of the Asian cultivated rice O. sativa species. We did not find the mPing system in another 20 Oryza species. These results substantiated a previous hypothesis that O. ruflpogon and O. nivara species were the closest relatives of O. sativa and that the two extant subspecies of O. sativa were evolved independently from corresponding ecotypes of O. ruflpogon.

Current epidemiological and etiological characteristics and treatment of seizures or epilepsy in patients with HIV infection

Seizures or epilepsy is one of the common serious complications in patients with advanced human immunodeficiency virus(HIV)infection or diagnosed with immune deficiency syndrome,with higher incidence and prevalence than in the general population.Generalized seizures are the most common type in the patients.Opportunistic infections are a stereotypical predisposing factor for seizures in HIV patients,but a variety of pathogenic factors can also be found in these patients,such as metabolic perturbation and drug-drug interactions.The diagnostic criteria for seizures in these patients are the same as those in the general population.As HIV patients with seizures need to take both antivirals and antiepileptic drugs,the risk of drug-drug interactions is greatly increased,and the side effects of drugs may also become more prominent.At present,most experience in antiepileptic drug usage has come from the general population,and there is still a lack of guidance of antiepileptic drug use in special groups such as the HIV-infected people.Unlike the old-generation drugs that involve metabolisms through CYP450,the first-line antiepileptic drugs usually bypass CYP450,thus having less drug-drug interactions.In this review,we summarize the recent research progress on the above-mentioned widely discussed topics and make a prospect on future research direction.

The role of picornavirus infection in epileptogenesis

Picornaviridae are a family of small positive-strand RNA viruses,and transmitted via the respiratory or fecal-oral route.The neurotropic picornaviruses can induce acute or late recurrent seizures following central nervous system infection,by infecting the peripheral nerve,crossing the blood-brain barrier and migrating in the Trojan-horse method.Theiler’s murine encephalomyelitis virus(TMEV),as a member of Picornaviridae family,can cause encephalitis,leading to chronic spontaneous seizures.TMEV-infected C57BL/6 mice have been used as an animal model for exploring the mechanism of epileptogenesis and assessing new antiepileptic drugs.Astrogliosis,neuronal death and microglial recruitment have been detected in the hippocampus following the picornaviruse-induced encephalitis.The macrophages,monocytes,neutrophils,as well as IL-6 and TNF-αreleased by them,play an important role in the epileptogenesis.In this review,we summarize the clinical characteristics of picornavirus infection,and the immunopathology involved in the TMEV-induced epilepsy.

Ketogenic diet therapy for epilepsy:past 100 years of practice

Ketogenic diet(KD)is a classic therapy for epilepsy,in addition to the therapeutic medicines and surgeries.KD as the treatment for epilepsy entered the 100th year.The classic KD was proposed in the 1920s as a formula diet with a high proportion of fat(90%),a low proportion of carbohydrate,and appropriate proportions of protein and other nutrients,which does not affect normal growth and development,but is effective in treating some nervous system diseases,cancer and other diseases[1].

Calculation and management of ketogenic diet parenteral nutrition in super-refractory status epilepticus

Super-refractory status epilepticus(SRSE)is an important neurological emergency associated with high mortality and morbidity and poses a heavy economic burden on patients.Ketogenic diet parenteral nutrition(KD-PN)is ketogenic diet therapy provided through parenteral administration and may be an adjuvant treatment for these who cannot accept enteral diet.However,the calculation and management of KD-PN presents a challenge for clinicians.This review focuses on the practical aspects of KD-PN therapy for treatment of SRSE,including the dietary composition,potential drug-diet interactions,and monitoring during KD-PN treatment.As with all SRSE treatments,KD-PN has many adverse effects,like hyperlipemia,hepatotoxicity,metabolic acidosis,insufficient ketosis or hyper-ketosis,and propofol infusion syndrome.We summarize monitoring and treatment methods in our review.This review provides some practical aspects for treatment of SRSE.

Special issue on the battle against complex virus world in the human brain:seizure as a result of viral infection

Viruses are the smallest living things known to science,yet they hold the entire planet in their way.-from A Planet of Viruses,Carl Zimmer The corona virus disease 2019(COVID-19)pandemic,caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has become a big threat to human health.Studies have shown that SARS-CoV-2 can also invade the central nervous system(CNS)[1].Currently.