Apically guiding electron/mass transfer reaction induced by Ag/FeN_(x)Mott-Schottky effect within a hollow star reactor toward high performance zinc-air batteries

The disparity in the transfer of carriers(electrons/mass)during the reaction in zinc-air batteries(ZABs)results in sluggish kinetics of the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),along with elevated overpotentials,thereby imposing additional constraints on its utilization.Therefore,the pre-design and target-development of inexpensive,high-performance,and long-term stable bifunctional catalysts are urgently needed.In this work,an apically guiding dual-functional electrocatalyst(Ag-FeN_(x)-N-C)was prepared,in which a hierarchical porous nitrogen-doped carbon with three-dimensional(3D)hollow star-shaped structure is used as a substrate and high-conductivity Ag nanoparticles are coupled with iron nitride(FeN_(x))nanoparticles.Theoretical calculations indicate that the Mott-Schottky heterojunction as an inherent electric field comes from the two-phase bound of Ag and FeN_(x),of which electron accumulation in the FeN_(x)phase region and electron depletion in the Ag phase region promote orientated-guiding charge migration.The effective modulation of local electronic structures felicitously reforms the d-band electron-group distribution,and intellectually tunes the masstransfer reaction energy barriers for both ORR/OER.Additionally,the hollow star-s haped hierarchical porous structure provides an apical region for fast mass transfer.Experimental results show that the halfwave potential for ORR is 0.914 V,and the overpotential for OER is only 327 mV at 10 mA cm^(-2).A rechargeable ZAB with Ag-FeN_(x)-N-C as the air cathode demonstrates long-term cycling performance exceeding 1500 cycles(500 h),with a power density of 180 mW cm^(-2).Moreover,when employing AgFeN_(x)-N-C as the air cathode,flexible ZABs demonstrate a notable open-circuit voltage of 1.42 V and achieve a maximum power density of 65.6 mW cm^(-2).Ag-FeN_(x)-N-C shows guiding electron/mass transfer route and apical reaction microenvironment for the electrocatalyst architecture in the exploration prospects of ZABs.

Evaluation of the Effectiveness and Safety of One-Time Endodontics in the Treatment of Chronic Apical Periodontitis with Sinus Tract in Pediatric Deciduous Teeth

Objective:To observe the effectiveness and safety of one-time endodontics in the treatment of chronic apical periodontitis with sinus tract in pediatric deciduous teeth.Methods:109 cases of children with chronic apical periodontitis with sinus tract in the deciduous teeth treated in our hospital from January 2022 to December 2023 were selected and grouped by the randomized numerical table method,with 54 cases in the experimental group and 55 cases in the control group.The experimental group was treated with one-time endodontics and the control group was treated with conventional endodontics.Results:After the treatment,the total effective rate of treatment was higher in the experimental group than in the control group(P<0.05);the incidence of adverse events was lower in the experimental group than in the control group(P<0.05);the satisfaction of the children's family members was higher in the experimental group than in the control group(P<0.05);the pain duration was lower in the experimental group than in the control group(P<0.05).Conclusion:In the experimental group,children with chronic apical periodontitis with sinus tract of the deciduous teeth were given one-time endodontic treatment,and the results of its implementation were relatively good.

Investigation of bubbles escape behavior from low basicity mold flux for high-Mn high-Al steels using 3D X-ray microscope

During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.

Apical bud上皮诱导脂肪间充质干细胞向成牙本质样细胞分化的研究

目的:通过体外及体内实验探讨大鼠切牙Apical bud上皮细胞诱导大鼠脂肪来源间充质干细胞向成牙本质细胞分化的能力。方法:分离培养大鼠脂肪间充质干细胞、Apical bud上皮细胞,制备Apical bud上皮条件诱导液并体外对ADSCs诱导7d,通过实时定量PCR方法检测成牙本质关键基因DMP-1及DSPP的表达。制备ADSCs及Apical bud上皮重组细胞团进行大鼠肾被膜下移植,8W后取材,分别采用HE染色、Masson三色法和免疫组化方法对移植生成物进行组织学检测。结果:Apical bud上皮诱导ADSCs后DMP-1及DSPP m R NA表达水平显著高于对照组。体内移植8W后H E染色可见管样牙本质和骨样牙本质样结构,Masson三色法可以观察到有绿色的牙本质样结构,免疫组化检测中CK14染色阳性,DSPP染色阳性。结论:Apical bud上皮细胞在体外能够诱导ADSCs向成牙本质细胞分化,且细胞重组在体内可以构建出牙本质样结构。

Overexpressed miRNA-155 dysregulates intestinal epithelial apical junctional complex in severe acute pancreatitis

AIM:To investigate whether miRNA-155(miR-155)dysregulates apical junctional complex(AJC)protein expression in experimental severe acute pancreatitis(SAP).METHODS:Twenty-four male BALB/c mice were randomly assigned to two groups:the SAP group(n=12)receiving sequential intraperitoneal injection of 50μg/kg caerulein and 10 mg/kg lipopolysaccharide over 6h,and the control group(n=12)receiving intraperitoneal injection of normal saline.Animals were sacrificed3 h following the last injection for collection of blood samples and pancreas and distal ileal segment specimens.Routine pancreas and intestine histology was used to assess SAP pathology and intestinal epithelial barrier damage.Levels of serum amylase,diamine oxidase(DAO),and tumor necrosis factor(TNF)-αwere determined using commercial kits.Total RNA samples were isolated from intestinal epithelial specimens and reversely transcribed into cDNA.miR-155 and RhoA mRNA expression profiles were determined using quantitative real-time polymerase chain reaction.Target genes for miR-155 were predicted using the miRTarBase database,RNA22 and PicTar computational methods.Western blotting was performed to quantitate the protein expression levels of the target gene RhoA,as well as zonula occludens(ZO)-1 and E-cadherin,two AJC component proteins.RESULTS:Intraperitoneal injection of caerulein and lipopolysaccharide successfully induced experimental acute pancreatic damage(SAP vs control,10.0±2.0vs 3.2±1.2,P<0.01)and intestinal epithelial barrier damage(3.2±0.7 vs 1.4±0.7,P<0.01).Levels of serum amylase(21.6±5.1 U/mL vs 14.3±4.2 U/mL,P<0.01),DAO(21.4±4.1 mg/mL vs 2.6±0.8 mg/mL,P<0.01),and TNF-α(61.0±15.1 ng/mL vs 42.9±13.9 ng/mL,P<0.01)increased significantly in SAP mice compared to those in control mice.miR-155 was significantly overexpressed in SAP intestinal epithelia(1.94±0.50 fold vs 1.03±0.23 fold,P<0.01),and RhoA gene containing three miR-155-specific binding sites in the three prime untranslated regions was one of the target genes for miR-155.RhoA(22.7±5.8 folds vs 59.6±11.6 folds,P<0.01),ZO-1(46±18 folds vs68±19 folds,P<0.01),and E-cadherin proteins(48±15 folds vs 77±18 folds,P<0.01)were underexpressed in SAP intestinal epithelia although RhoA mRNA expression was not significantly changed in SAP(0.97±0.18 folds vs 1.01±0.17 folds,P>0.05).CONCLUSION:TNF-α-regulated miR-155 overexpression inhibits AJC component protein syntheses of ZO-1,and E-cadherin by downregulating post-transcriptional RhoA expression,and disrupts intestinal epithelial barrier in experimental SAP.

Apical hypertrophic cardiomyopathy

We describe a patient with asymptomatic apical hypertrophic cardiomyopathy(AHCM)who later developed cardiac arrhythmias,and briefly discuss the diagnostic modalities,differential diagnosis and treatment option for this condition.AHCM is a rare form of hypertrophic cardiomyopathy which classically involves the apex of the left ventricle.AHCM can be an incidental finding,or patients may present with chest pain,palpitations,dyspnea,syncope,atrial fibrillation,myocardial infarction,embolic events,ventricular fibrillation and congestive heart failure.AHCM is frequently sporadic,but autosomal dominant inheritance has been reported in few families.The most frequent and classic electrocardiogram findings are giant negative T-waves in the precordial leads which are found in the majority of the patients followed by left ventricular(LV)hypertrophy.A transthoracic echocardiogram is the initial diagnostic tool in the evaluation of ACHM and shows hypertrophy of the LV apex.AHCM may mimic other conditions such as LV apical cardiac tumors,LV apical thrombus,isolated ventricular non-compaction,endomyocardial fibrosis and coronary artery disease.Other modalities,including left ventriculography,multislice spiral computed tomography,and cardiac magnetic resonance imagings are also valuable tools and are frequently used to differentiate AHCH from other conditions.Medications used to treat symptomatic patients with AHCM include verapamil,beta-blockers and antiarrhythmic agents such as amiodarone and procainamide.An implantable cardioverter defibrillator is recommended for high risk patients.

microRNA Expression in Rat Apical Periodontitis Bone Lesion

Apical periodontitis, dominated by dense inflammatory infiltrates and increased osteoclast activities, can lead to alveolar bone destruction and tooth loss. It is believed that miRNA participates in regulating various biological processes, osteoclastogenesis included. This study aims to investigate the differential expression of miRNAs in rat apical periodontitis and explore their functional target genes. Microarray analysis was used to identify differentially expressed miRNAs in apical periodontitis. Bioinformatics technique was applied for predicting the target genes of differentially expressed miRNAs and their biological functions. The result provided us with an insight into the potential biological effects of the differentially expressed miRNAs and showed particular enrichment of target genes involved in the MAPK signaling pathways. These findings may highlight the intricate and specific roles of miRNA in inflammation and osteoclastogenesis, both of which are key aspects of apical periodontitis, thus contributing to the future investigation into the etiology, under- lying mechanism and treatment of apical periodontitis.

Relationships of CDXs and apical sodium-dependent bile acid transporter in Barrett's esophagus

Barrett's esophagus (BE) is characterized by intestinal metaplasia with the differentiated epithelium replaced by another type of epithelium morphologically similar to normal intestinal epithelium. The metaplasia is preceded by bile and acid reflux into the esophagus. BE is a premalignant condition associated with increased risk of esophageal cancer, especially esophageal adenocarcinoma. The Caudal-related homeodomain transcription factors Caudal-related homeodomain transcription factor CDX1 and CDX2 are expressed exclusively in the small and large intestine, playing important roles in proliferation and differentiation of intestinal epithelial cells. Ectopic expression of CDX1 and CDX2 occurs in BE. The apical sodium-dependent bile acid transporter (ASBT) is expressed primarily in terminal ileum where it is a key factor for intestinal reabsorption of bile salts. In addition to upregulation of CDX1 and CDX2, ASBT expression is up-regulated in BE. Furthermore, both CDX1/CDX2 and ASBT expressions are down-regulated in high-grade esophageal dysplasia. The alteration of the above-mentioned factors calls for attention: what is the relationship between CDXs and ASBT aberrant expression in BE? In this commentary, we discuss this issue on basis of the recent study done by Ma et al .

Determination of the Photoperiod-Sensitive Inductive Phase in Maize with Leaf Numbers and Morphologies of Stem Apical Meristem

It is vital to determine the effective photoperiods of maize for making full use of tropical germplasm, which is the foundation for determining the effect of latitude and planting date on the development of photoperiod-sensitive maize cultivars. The objective of this study is to determine the photoperiod-sensitive inductive phase using reciprocal transfer between long- day （LD） （15 h d^-1） and short-day conditions （SD） （9 h d^-1）. For Huangzao 4 and CML288, days to tassel and pollen shedding were recorded, and stem apical meristems （SAM） were observed by a laser scanning confocal microscope. The results show that the seedlings are insensitive to photoperiod when they are very young （juvenile）. However, after this period, LD delays flowering and increases the leaf numbers below the inflorescence, and the length of the interval of the photoperiod-sensitive inductive phase is longer under LD conditions than under SD conditions. Transferred from SD to LD, plants show a sudden decrease in leaf numbers once sufficient SD has been received for flower commitment. While transferred from LD to SD, plants have a continuous increase in leaf numbers during the photoperiod sensitive inductive phase under LD conditions. At the same time, when plants are competent to flowers, the obvious morphology is the elongation of maize SAM. There is an obvious variance of the photoperiod sensitive phase under LD and SD conditions in different maize.

Prevalence of Enterococcus faecalis in saliva and filled root canals of teeth associated with apical periodontitis

To investigate the prevalence of Enterococcus faecalis in saliva and filled root canals of patients requiring endodontic retreatment for apical periodontitis.Patients with apical periodontitis who were referred for endodontic retreatment were examined.The type and quality of the restoration,symptoms,quality of obturation were recorded.During retreatment,an oral rinse sample and root canal sample were cultured using brain-heart infusion agar and bile esculinazide agar to select for E.faecalis.The 16S rRNA technique was used to identify E.faecalis.A total of 32 women and 22 men（mean age：38 years;s.d.：11 years） and 58 teeth were studied.The prevalence of E.faecalis was 19% in the saliva and 38% in the root canals.The odds that root canals harbored E.faecalis were increased if the saliva habored this bacterium（odds ratio59.7;95% confidence interval51.8-51.6;P,0.05）.Teeth with unsatisfactory root obturation had more cultivable bacterial species in root canals than teeth with satisfactory root obturation（P,0.05）.E.faecalis is more common in root canals of teeth with apical periodontitis than in saliva.The prevalence of E.faecalis in root canals is associated with the presence of E.faecalis in saliva.

AtCDC5 regulates the G2 to M transition of the cell cycle and is critical for the function of Arabidopsis shoot apical meristem

As a cell cycle regulator, the Myb-related CDC5 protein was reported to be essential for the G2 phase of the cell cycle in yeast and animals, but little is known about its function in plants. Here we report the functional characterization of the CDC5 gene in Arabidopsis thaliana. Arabidopsis CDC5 （AtCDC5） is mainly expressed in tissues with high cell division activity, and is expressed throughout the entire process of embryo formation. The AtCDC5 loss-of-function mutant is embryonic lethal. In order to investigate the function of AtCDC5 in vivo, we generated AtCDC5-RNAi plants in which the expression of AtCDC5 was reduced by RNA interference. We found that the G2 to M （G2/M） phase transition was affected in the AtCDC5-RNAi plants, and that endoreduplication was increased. Additionally, the maintenance of shoot apical meristem （SAM） function was disturbed in the AtCDC5-RNAi plants, in which both the WUSCHEL （WUS）- CLAVATA （CLV） and the SHOOT MERISTEMLESS （STM） pathways were impaired. In situ hybridization analysis showed that the expression of STMwas greatly reduced in the shoot apical cells of the AtCDC5-RNAi plants. Moreover, cyclinB1 or Histone4 was found to be expressed in some of these cells when the transcript of STM was undetectable. These results suggest that AtCDC5 is essential for the G2/M phase transition and may regulate the function of SAM by controlling the expression ofSTMand WUS.

Maxillary first premolars:Ⅰ.Morphology of the apical constriction

Objective： To investigated the apical constriction morphology of maxillary first premolars in the Chinese population. Methods： Eighty recently extracted human maxillary first premolars from a native Chinese population were used. The number and shape of apical constrictions were recorded under a dental operating microscope （DOM） at 12.5 × 2.5 magnification. After access preparation, a new K-file was inserted into the canal until the tip of the file was just seen at the apical constriction under the DOM. The teeth with files in the canals were X-rayed from a mesiodistal direction using a direct digital radiography （DDR） system, and the distance between the file tip and the center of radiographic apex was directly measured from the computer screen using DDR measurement software. Results： The percentage of teeth with an apical constriction was 78.5% （102/130）. The most common apical constriction shapes were oval （55.9%） and round （35.3%）. The mean distance between the apical constriction and the anatomical tip of the root was 0.61 mm, and 84.3% （86/102） were within 1 mm. Conclusion： The most common shape of an apical constriction was oval or round, and the distance to the apex was mostly within 1 mm, indicating that root canal therapy should stop 1 mm from the radiographic apex.

Calcium Hydroxide Removal in Curved Root Canals with Apical Transportation In Vitro

Calcium hydroxide（CH） is applied to improve disinfection of root canals in most root canal retreatment. This study aimed to analyze the CH removal efficacy using 7 different root preparing files（K file, pre-curved K file, EndoActivator, Ultrasonic file, pre-curved ultrasonic file, F file and needle irrigation alone） with apical transportation. Standardized models of curved canal with such apical transportation or not were set up before applying CH to root canal for 7 days. Seven techniques described above were used for its removal. Then the roots were disassembled and digital photos were taken. The ratio of residual CH in the overall canal surface was calculated using the image analyzer image pro plus 6.0. The data were analyzed using one-way ANOVA with post hoc Tukey test. Results revealed that CH was effectively removed（P〈0.05） by using all 6 mechanical methods except irrigation alone. In curved root canals with apical transportation, EndoActivator, pre-curved ultrasonic file and F file were found to be more effective in removing CH than the other four file（P〈0.001）, while there was no significant difference among EndoActivator, pre-curved ultrasonic file and F file groups（P〉0.05）. The percentage of residual CH in the canal with apical transportation was higher than that in the canal without apical transportation（P〈0.05）. In conclusion, CH can be hardly removed completely. Canal with apical transportation will result in insufficient CH removal. EndoActivator, pre-curved ultrasonic file and F file are more effective in the curved root canal with apical transportation.

Speckle tracking echocardiography to assess regional ventricular function in patients with apical hypertrophic cardiomyopathy

AIM To explore regional systolic strain of midwall and endocardial segments using speckle tracking echocardiography in patients with apical hypertrophic cardiomyopathy(HCM).METHODS We prospectively assessed 20 patients(mean age 53 ± 16 years,range:18-81 years,10 were male),with apical HCM. We measured global longitudinal peak systolic strain(GLPSS) in the midwall and endocardium of the left ventricle. RESULTS The diastolic thickness of the 4 apical segments was 16.25 ± 2.75 mm. All patients had a normal global systolicfunction with a fractional shortening of 50% ± 8%. In spite of supernormal left ventricular(LV) systolic function,midwall GLPSS was decreased in all patients,more in the apical(-7.3% ±-8.8%) than in basal segments(-15.5% ±-6.93%),while endocardial GLPPS was significantly greater and reached normal values(apical:-22.8% ±-7.8%,basal:-17.9% ±-7.5%). CONCLUSION This study shows that two-dimensional strain was decreased mainly confined to the mesocardium,while endocardium myocardial deformation was preserved in HCM and allowed to identify subclinical LV dysfunction. This transmural heterogeneity in systolic strain had not been previously described in HCM and could be explained by the distribution of myofibrillar disarray in deep myocardial areas. The clinical application of this novel finding may help further understanding of the pathophysiology of HCM.

Changes of the Unique Odontogenic Properties of Rat Apical Bud Cells under the Developing Apical Complex Microenvironment

Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells （DAC-CM）. Immunocytochemistry, reverse transcriptase polymerase chain reaction （RT-PCR） and scanning electron microscope （SEM） were performed to compare the biolo- gical change of ABC treated with or without DAC-CM. Results First we confirmed the ability of apical bud to form crown-like structure ectopically. Equally important, by using the developing apical complex （DAC） condi- tioned medium, we found the microenvironment created by root could abrogate the ＂crown＂ features of ABCs and promote their proliferation and differentiation. Conclusion ABCs possess odontogenic capability to form crown-like tissues and this property can be affected by root-produced microenvironment.

Multimodality imaging in apical hypertrophic cardiomyopathy

Apical hypertrophic cardiomyopathy(AHCM) is a relatively rare morphologic variant of HCM in which the hypertrophy of myocardium is localized to the left ventricular apex. Symptoms of AHCM might vary from none to others mimic coronary artery disease including acute coronary syndrome, thus resulting in inappropriate hospitalization. Transthoracic echocardiography is the firstline imaging technique for the diagnosis of hypertrophic cardiomyopathies. However, when the hypertrophy of the myocardium is localized in the ventricular apex might results in missed diagnosis. Aim of this paper is to review the different imaging techniques used for the diagnosis of AHCM and their role in the detection and comprehension of this uncommon disease.

Delay enhancement patterns in apical hypertrophic cardiomyopathy by phase-sensitive inversion recovery sequence

Objective:Late gadolinium enhancement(LGE) patterns of cardiovascular magnetic resonance (CMR) relying on PSIR(phase-sensitive inversion recovery sequence) techniques had been used to determine the characteristics of LGE in apical hypertrophic cardiomyopathy(ApHCM). Methods:Forty patients pure ApHCM[age,(60.2±10.4) years,31 men]were enrolled.LGE images were acquired using PSIR,and analyzed using a 17-segment model.Summing the LGE areas in all short axis slices yielded the total volume of late enhancement,which was subsequently presented as a proportion of total LV myocardium(%LGE).Results:Mean maximal apical wall thickness was(17.9±2.3) mm,and mean left ventricular(LV) ejection fraction was(67.7±8.0)%.LGE was detected in 130 segments of 30 patients(75.0%),occupying(4.9±5.5)% of LV myocardium.LGE was mainly detected at the junction between left and right ventricles in 12(30%) and at the apex in 28(70%),although LGE-positive areas were widely distributed,and not limited to the apex.Focal LGE at the non-hypertrophic LV segments was found in some ApHCM patients,even without LGE of hypertrophied apical segments.Conclusions:LGE was frequently observed not only in the thickened apex of the heart but also in other LV segments,irrespective of the presence or absence of hypertrophy.The simple presence of LGE on CMR was not representative of adverse prognosis in this population.

Microscopic removal of type Ⅲ dens invaginatus and preparation of apical barrier with mineral trioxide aggregate in a maxillary lateral incisor:A case report and review of literature

BACKGROUND Invaginated teeth pose greater challenges in clinical management because of their complex configuration.With advancements in equipment and materials,such as the dental operation microscope,cone-beam computed tomography and mineral trioxide aggregate,the preservation rate of type Ⅲ dens invaginatus could be greatly increased.CASE SUMMARY This case report presented a 31-year-old woman with complaints of spontaneous swelling and pain in the right maxillary lateral tooth.With the aid of cone-beam computed tomography,type Ⅲ dens invaginatus with apical periodontitis was diagnosed and confirmed.Three-visit endodontic treatment was performed.In the first visit,the invagination was carefully removed under the dental operation microscope,and chemomechanical preparation was done.In the second visit,mineral trioxide aggregate apical barrier surgery was performed in this tooth.In the third visit,the canal was finally obturated with thermoplastic gutta-percha to recover the crown morphology.A 26-mo follow-up revealed a satisfied outcome both in the radiographic and oral examinations.CONCLUSION In this case,removal of the entire abnormal structure provided great convenience for the follow-up treatment.When confronted with the same clinical case in the future,we can take a similar approach to address it.

Vlouse sperm acquire a new structure on the apical hoo Juring epididymal maturation

Spermatozoa emerging from the testis undergo a maturation process in the epididymis during which they change morphologically, biochemically and physiologically to gain motility and the ability to fertilize ova. We examined mouse epididymal sperm with immunostaining and transmission electron microscopy （EM） and identified a previously unknown structure on the apical hook. The structure has a coiled configuration around 11 nm in thickness and is present at the tip of each corner of the triangular-rod shaped perforatorium. Surveying sperm isolated from various regions of the epididymis indicated that mouse sperm acquire the hook rim （HR） structure during its passage through the proximal two-thirds of the caput epididymidis. The structure withstands vigorous sonication and harsh chemical treatments and remains intact after the acrosome reaction. Its location and sturdiness suggest a function in protecting the apical hook from mechanical wear during fertilization. Our EM images of epididymal sperm also revealed additional novel structures as well as lateral asymmetry of the sperm head, indicating that mouse sperm head has a structure more complex than previously recognized.

Locus TUTOU2 determines the panicle apical abortion phenotype of rice(Oryza sativa L.)in tutou2 mutant

Rice panicle apical abortion(PAA)is a detrimental agronomic trait resulting in spikelet number reduction and yield loss.To understand its underlying molecular mechanism,we identified one recessive PAA mutant tutou2 from the offspring of tissue cultures.The mutation locus was finely mapped to a 75-kb interval on the long arm of chromosome 10.Sequence analysis revealed a single nucleotide substitution of A to T at the 941 position of LOC_Os10g31910 in tutou2,resulting in an amino acid change from isoleucine to phenylalanine.Complementation analysis showed that the degenerated panicle phenotype in tutou2 was rescued in the transgenic lines.A phenotype similar to tutou2 can also be obtained by LOC_Os10g31910 knockout in wild-type rice.These results suggested that LOC_Os10 g31910 is the causative locus TUTOU2 responsible for the tutou2 PAA phenotype and probably also the locus of DEL1,previously documented as a leaf senescence gene.The significant phenotypic differences between del1 and tutou2 suggest that the locus DEL1/TUTOU2 plays roles in both leaf and panicle development which were not considered fully in previous studies.