Effects of channel wall wettability on gas-liquid dynamics mass transfer under Taylor flow in a serpentine microchannel

The wall wettability of microchannels plays an important role in the gas-liquid mass transfer dynamics under Taylor flow.In this study,we regulated the contact angle of the wall surface through surface chemical grafting polymerization under controlled experimental conditions.The dynamic changes of CO_(2)bubbles flowing along the microchannel were captured by a high-speed video camera mounted on a stereo microscope,whilst a unit cell model was employed to theoretically investigate the gas-liquid mass transfer dynamics.We quantitatively characterized the effects of wall wettability,specifically the contact angle,on the formation mechanism of gas bubbles and mass transfer process experimentally.The results revealed that the gas bubble velocity,the overall volumetric liquid phase mass transfer coefficients(kLa),and the specific interfacial area(a)all increased with the increase of the contact angle.Conversely,gas bubble length and leakage flow decreased.Furthermore,we proposed a new modified model to predict the gas-liquid two-phase mass transfer performance,based on van Baten’s and Yao’s models.Our proposed model was observed to agree reasonably well with experimental observations.

Paclobutrazol induces the concurrent accumulation of chrysolaminarin and lipids in the diatom Phaeodactylum tricornutum

Paclobutrazol is a plant growth regulator and inhibitor of endogenous gibberellin synthesis.It is a powerful inhibitor of vegetative growth by changing the photosynthetic rate and plant hormone levels,thereby affecting plant growth and development.In this study,the effects of paclobutrazol on the model diatom Phaeodactylum tricornutum were investigated.Results show that 2.5-mg/L and 10-mg/L paclobutrazol significantly inhibited the algal growth by inhibiting chlorophyll synthesis,which affects photosynthesis.The antioxidant system,including catalase(CAT)and glutathione peroxidase(GPx)was severely damaged.Chrysolaminarin content was significantly elevated and doubled up to 127 mg/g dry cell weight(DCW)by 10-mg/L paclobutrazol treatment.In combination with transcriptomic analysis,paclobutrazol was demonstrated to play a regulatory role in the accumulation of chrysolaminarin and neutral lipids.

Variability of Prorocentrum donghaiense response to allelopathic action from Alexandrium pacificum in laboratory culture

The dinoflagellates Alexandrium pacificum and Prorocentrum donghaiense are two well-known harmful algal blooms(HABs)-forming species,both were usually found in the same sea areas in form of HABs in China.To date,there is no mechanistic model that can fully explain the occurrence of P.donghaiense blooms with A.pacificum.We found that different strains of P.donghaiense had different intrinsic growth rates of 0.107-0.215/d,and these strains exhibited different responses to the allelopathic action from A.pacificum.Some strains of P.donghaiense could grow well despite some degrees of inhibition in a short period,suggesting the two algal species P.donghaiense and A.pacificum could coexist,even if A.pacificum was allelopathic.Our findings may advance the understanding of phenotypes in P.donghaiense and provide a potential mechanism involved in the coexistence of P.donghaiense and A.pacificum in the same area.

Consensus on the application of negative pressure wound therapy of diabetic foot wounds

Because China is becoming an aging society,the incidence of diabetes and diabetic foot have been increasing.Diabetic foot has become one of the main health-related killers due to its high disability and mortality rates.Negative pressure wound therapy(NPWT)is one of the most effective techniques for the treatment of diabetic foot wounds and great progress,both in terms of research and its clinical application,has been made in the last 20 years of its development.However,due to the complex pathogenesis and management of diabetic foot,irregular application of NPWT often leads to complications,such as infection,bleeding and necrosis,that seriously affect its treatment outcomes.In 2020,under the leadership of Burns,Trauma and Tissue Repair Committee of the Cross-Straits Medicine Exchange Association,the writing group for‘Consensus on the application of negative pressure wound therapy of diabetic foot wounds’was established with the participation of scholars from the specialized areas of burns,endocrinology,vascular surgery,orthopedics and wound repair.Drawing on evidence-based practice suggested by the latest clinical research,this consensus proposes the best clinical practice guidelines for the application and prognostic evaluation of NPWT for diabetic foot.The consensus aims to support the formation of standardized treatment schemes that clinicians can refer to when treating cases of diabetic foot.

关于双绒毛膜双羊膜囊双胎妊娠第二胎儿延迟分娩的临床研究

目的探讨双胎妊娠第2胎儿延迟分娩的临床处理和预后。方法对我院收治的1例双绒毛膜双羊膜囊双胎妊娠第1胎儿流产后第2胎儿继续妊娠至足月分娩,及文献检索的25例双胎妊娠延迟分娩患者(共26例)的临床管理和预后进行分析。结果本例患者第1胎儿21^(+5)周流产后,经抗感染、抑制宫缩、监护等处理,第2胎儿继续妊娠至38^(+6)周阴道分娩,延迟分娩120 d,母儿预后良好;26例患者延迟分娩时间最短5 h,最长157 d,第1胎儿流产或早产孕周为14^(+4)~31^(+1)周,第2胎儿的分娩孕周为24~39^(+5)周,存活率约92.3%,大部分围产结局良好。结论延迟分娩处理得当可明显改善第2胎儿的围产结局,已成为双胎妊娠中一胎流产或早产后处理的重要措施。

Research on the evolutionary characteristics of evaluation policies of Chinese science and technology talents

Science and technology talent evaluation is an important part of the talent development system and mechanism,and the state's emphasis on science and technology talent evaluation is reflect-ed in the national policy.This paper takes 49 policy documents on science and technology tal-ent evaluation issued by the state from 1978 to 2022 as the object,and uses policy text analysis,word frequency analysis and co-word network analysis to interpret the content of the policies.These policy texts are divided into four stages.200 high-frequency words were extracted from the policies in each stage after word segmentation was made,and the co-word matrixes and co-word networks were constructed for each stage.The research draws the following conclu-sions:1)The content of Chinese science and technology talent evaluation policies is gradually becoming concrete,and the concept of science and technology talent evaluation is gradually clear;2)The policies have transitioned from"scientific and technological development"to"sci-entific and technological innovation";3)The distribution of policies with different strengths is uneven;4)The cooperation between all departments involved in policy formulation is not e-nough.

自吸射流搅拌桨液-液非均相混合特性分析

自吸射流搅拌槽作为新型搅拌装置在非均相强化混合过程中具有潜在的工程应用前景。以水为连续相,油为分散相,运用数值模拟和实验研究了自吸射流搅拌槽内液-液非均相混合过程及强化非均相混合过程的影响因素。结果表明,搅拌转速及分散相相含率对液-液非均相自吸射流轴线上无量纲速度影响较小。自吸射流管倾角β对搅拌槽内流场和分散相分布的影响显著,β<0°时,不利于油水非均相在搅拌槽内径向混合;β=0°时,搅拌槽内无自吸和射流现象,不利于轴向混合;β>0°时,搅拌桨上部产生自吸流,下部产生射流,高油相相含率流体被自吸射流管吸入,向下以射流方式进入低油相相含率流体,有效提高了搅拌槽底部湍流动能,强化了油水非均相混合过程。

Diaporthe species occurring on citrus in China

Diaporthe species are important pathogens of a wide range of hosts including many economically important crops.Diaporthe citri is generally accepted to cause melanose of Citrus fruits,leaves and shoots;stem-end rot of fruits and gummosis of perennial branches.In this study,147 strains of Diaporthe were isolated from diseased leaves,twigs,fruits and branches of Citrus from Shaanxi,Zhejiang,Guangxi,Fujian,Guangdong,Jiangxi,Hunan,Chongqing and Shanghai and identified by morphology and molecular analysis of nuclear ribosomal internal transcribed spacer(ITS),partial sequences of translation elongation factor 1-α(EF 1-α),tubulin(TUB)and calmodulin(CAL)genes.All strains from Citrus clustered in three clades.Diaporthe citri was the predominant species and is compared with strains from Florida,USA,where this species was first collected and described.Two new taxa differing from D.citri are described as D.citriasiana and D.citrichinensis in this paper.Inoculation tests indicate that all three species are able to cause stem-end rot of fruits,while only D.citri could cause melanose on leaves.

Phyllosticta species associated with citrus diseases in China

Phyllosticta species associated with diseases of four commercial Citrus species grown in China are reported.Totally,496 Phyllosticta strains were isolated from mandarins(Citrus reticulata),pomeloes(C.maxima),oranges(C.sinensis)and lemons(C.limon)in the main citrus producing regions across China,and 74 strains were selected for phylogenetic analysis.Analyses inferred from the sequences of internal transcribed spacer region(ITS1,5.8S nrDNA and ITS2),partial translation elongation factor 1-alpha(TEF1)and partial actin gene(ACT),showed these representative Phyllosticta isolates clustered in four distinct clades corresponding to three known,and one undescribed species.The newly resolved taxon,Phyllosticta citrichinaensis was isolated from leaves and fruits of all four Citrus species and is introduced in this paper.This taxon caused minor damage,showing irregular spots or freckles.Phyllosticta citriasiana,associated with tan spot of pomeloes,was isolated only from pomeloes,and never from lemons,mandarins and oranges.Phyllosticta citricarpa,the citrus black spot pathogen,which is presently subjected to phytosanitary legislation in the EU and United States,was isolated from lemons,mandarins and oranges,but never from pomeloes.The isolates of P.citricarpa clustered in two subclades,one from mandarins,the other from oranges and lemons.P.capitalensis was isolated from all four Citrus species as an endophyte,causing false melanose,or together with P.citricarpa or P.citriasiana.Morphological,cultural and biochemical characters were consistent with the results of phylogenetic analysis.In addition,a specific primer pair Pca8/ITS4 was designed and selected,and its corresponding PCR procedure was developed for the detection of P.citriasiana in this study.

Fiber oscillator of 5 kW using fiber Bragg gratings inscribed by a visible femtosecond laser

We fabricate a pair of fiber Bragg gratings(FBGs)by a visible femtosecond laser phase mask scanning technique on passive large-mode-area double-cladding fibers for multi-kilowatt fiber oscillators.The bandwidth of high-reflection(HR)and lowreflection(LR)FBG is~1.6 nm and 0.3 nm,respectively.The reflection of the HR-FBG is higher than 99%,and that of the LR-FBG is about 10%.A bidirectional pumped all-fiber oscillator is constructed using this pair of FBGs,a record output power of 5027 W located in the signal core is achieved with a slope efficiency of~82.1%,and the beam quality factor M2is measured to be~1.6 at the maximum power.The FBGs are simply fixed on a water cooling plate without a special package,and the thermal efficiency of the HR-FBG and the LR-FBG is 2.76℃/kW and 1℃/kW,respectively.Our research provides an effective solution for robust high-power all-fiber laser oscillators.

Fabrication of side pump combiners when pumping with a laser diode and a fiber laser

Side pumping combiners are widely used in fiber laser schemes for their high coupling efficiency, low insertion loss, and multi-point pumping capability. However, side pumping combiners perform differently in coupling efficiency when pumping with a laser diode(LD) and a high-brightness 1018 nm Yb-doped fiber laser(YDFL). In this paper, for the first time, to the best of our knowledge, we investigated the different parameters to fabricate the(2 + 1) × 1 combiner with high coupling efficiency when pumping with an LD and a YDFL, respectively. After optimization, the maximum coupled pump power from one single-pump port of the combiner was 1200 W and 2730 W when pumping with a LD and a YDFL, respectively.

Deep learning for position fixing in the micron scale by using convolutional neural networks

We propose here a novel method for position fixing in the micron scale by combining the convolutional neural network(CNN) architecture and speckle patterns generated in a multimode fiber. By varying the splice offset between a single mode fiber and a multimode fiber, speckles with different patterns can be generated at the output of the multimode fiber. The CNN is utilized to learn these specklegrams and then predict the offset coordinate. Simulation results show that predicted positions with the precision of 2 μm account for 98.55%.This work provides a potential high-precision two-dimensional positioning method.

Efficient harvesting of green microalgae cells by magnetic flocculated Fe_(3)O_(4)nanoparticles combined with chitosan

Microalgae harvesting remains a challenging step in microalgae industrialization,thereby provoking the necessity to explore sustainable and economically feasible approaches.This research investigated the use of magnetic flocculated nanoparticles in the harvesting of the common microalgae Chlorella pyrenoidosa and Scenedesmus obliquus.The results showed that magnetic flocculated nanoparticles efficiently adsorbed negatively charged microalgae cells,and a magnetic field could adsorb the magnetic flocculated nanoparticles,thereby harvesting the microalgae cells.Harvesting efficiency was remarkably increased at the optimum magnetic field strength of 0.5 T with the magnetic flocculated nanoparticles at 0.738 g/L,and microalgae broth at pH 9.0,whereas the recovery rates of both C.pyrenoidosa and S.obliquus were around 97%and the sedimentation speed of both was above 2.63 cm/min.This study exemplified the magnetic flocculated nanoparticles-based approach to effectively harvest the microalgae cells.