舌侧活动翼不同翼拉伸长度内收下前牙的生物力学特征

背景:舌侧活动翼矫治技术是一种新型舌侧矫治技术,不同翼的拉伸长度影响前牙转矩控制效果,目前尚无相关的生物力学研究。目的:探讨舌侧活动翼矫治技术内收下前牙时牙列的位移趋势以及不同翼拉伸长度对下颌前牙生物力学效应的影响。方法:利用锥形束CT采集患者下颌骨以及下牙列数据信息,通过Mimics软件进行三维重建,建立舌侧活动翼内收下前牙的三维有限元模型。在ANSYS软件中分别分析工况A(2 mm拉伸长度)、工况B(2.5 mm拉伸长度)、工况C(3 mm拉伸长度)和工况D(3.5 mm拉伸长度)时下颌前牙的初始位移。结果与结论:①下牙列初始位移趋势:中切牙舌向倾斜移动伴有压低,侧切牙、尖牙轻度舌侧移动伴近中舌向扭转,第二前磨牙远中倾斜并伴有明显舌倾,第一磨牙整体表现为近中倾斜并伴有近中牙冠外翻。因此在下颌拔牙内收病例中,对第二前磨牙的舌向移动应给予重视,临床中可以通过相应的技术予以抵消。②前牙各方向位移趋势:从工况A到工况D,矢状方向:中切牙冠根位移差值由-11.891μm变为-5.7574μm,表示中切牙由倾斜移动向整体移动转变;侧切牙冠根位移差值由-11.8281μm变为-6.71145μm,尖牙冠根位移差值由-7.5723μm变为-4.6955μm,表示侧切牙及尖牙的倾斜移动也在向整体移动转变。垂直方向:从工况A到工况D,切牙的压低量逐渐增大,尖牙的压低量逐渐减小。结果表明,翼的拉伸长度会影响前牙的倾斜移动趋势;随着翼的不断拉伸,下前牙的转矩控制效果越好。

醇镁加合物载体在Ziegler-Natta催化剂中的应用进展

基于醇镁加合物载体(简称醇镁载体)的Ziegler-Natta(Z-N)催化剂具有颗粒形貌优良、活性高等特点,醇镁载体的特性对催化剂和聚合物的综合性能有显著影响,是目前聚烯烃领域中的研究热点。介绍了氯化镁载体的发展历程以及醇镁载体的制备方法,分析了不同醇镁比、醇种类对醇镁载体结构的影响,综述了醇镁载体在Z-N催化剂中的应用,并对烯烃聚合用醇镁载体的开发提出了展望。

足前进角对不同年龄膝关节炎患者下肢动力学影响的系统综述和Meta分析

目的:膝关节内收力矩(knee adduction moment,KAM)双峰及膝关节内收角冲量(knee adduction angular impulse,KAAI)增大是膝关节骨性关节炎主要的生物力学危险因素。据调查,调整足前进角可改变膝关节骨性关节炎患者运动模式,然而足内偏、足外偏对青年、老年患者KAM和KAAI的影响未达成共识。因此文章通过Meta分析综合论述足前进角对不同人群膝关节骨性关节炎患者KAM、KAAI的影响,为治疗膝关节骨性关节炎提供借鉴。方法:截至2022年6月,以“足前进角,膝关节内收力矩,膝关节内收角冲量,步态”为中文检索词,以“foot progression angle,knee adduction moment,knee adduction angular impulse,gait”为英文检索词在Web of Science、EBSCO、PubMed和中国知网数据库进行检索。纳入分析足内偏、足外偏对KAM双峰和KAAI影响的自身对照和随机对照试验。运用Cochrane偏倚风险评估工具对纳入文献进行文献质量评价,采用Stata 15.1软件进行亚组分析确定不同足前进角对步行KAM及KAAI的影响,应用Meta回归进一步确定结局指标(KAM及KAAI)随足前进角变化的特征。结果:(1)共15项自身对照试验和2项随机对照试验(455名受试者)纳入Meta分析,所纳入文献均为中、高质量文献。(2)Meta分析结果显示,足内偏可减小青年患者KAM第一峰值(SMD=-0.380,95%CI:-0.710至-0.060,P=0.022)和KAAI(SMD=-1.470,95%CI:-2.160至-0.770,P<0.001),足外偏降低了青年患者KAM第二峰值(SMD=-0.720,95%CI:-1.010至-1.440,P<0.001)。此外,足内偏减了小老年患者KAM第一峰值(SMD=-0.550,95%CI:-0.800至-0.300,P<0.001),但有增高KAM第二峰值的作用(SMD=0.280,95%CI:-0.010-0.560,P=0.047),足外偏可降低该人群KAM第二峰值(SMD=-0.510,95%CI:-0.830至-0.190,P=0.002)。(3)Meta回归显示,老年患者的足外偏程度越大,KAM第二峰值越低。结论:(1)足内偏降低了18-34岁的青年膝关节骨性关节炎患者的KAM第一峰值、KAAI,由于KAM、KAAI与膝关节内侧负荷、膝关节骨性关节炎发病率相关,因此足内偏步态干预可能是青年患者适合的康复策略。(2)足内偏增高了60岁以上老年膝关节骨性关节炎患者的KAM第二峰值,可能会加重这类人群膝关节骨性关节炎的程度,然而,该人群步行时KAM第二峰值会随足外偏程度的增大而减小,有助于降低膝关节内侧负荷,提示老年患者可以考虑在步行时采用足外偏步态。

隐形矫治器远移成年患者上颌磨牙疗效的Meta分析

目的评价无托槽隐形矫治器远中移动成年患者上颌磨牙的临床疗效,以提高正畸医生对疗效的预估性。方法检索Web of Science、The Cochrane Library、Embase、Pubmed、万方数据库、知网数据库、维普数据库公开发表的隐形矫治器远移成年患者上颌磨牙疗效的研究。检索时限为建库以来至2023年8月1日。共3名研究者进行文献筛选及质量评估,将满足质量标准的文献进行Meta分析。结果本研究共纳入13个前后对照试验,总样本量281例。Meta分析结果显示,治疗后颌骨矢状向及垂直向指标与治疗前相比差异无统计学意义(P>0.05);治疗后上颌第一磨牙远中移动量MD=-2.34,95%CI(-2.83,-1.85),压低移动量MD=-0.95,95%CI(-1.34,-0.56),远中倾斜量MD=-2.51,95%CI(-3.56,-1.46),与治疗前相比差异均有统计学意义(P<0.05);治疗后上颌切牙平均内收距离MD=-0.82,95%CI(-1.54,-0.09),唇倾度减小MD=-1.61,95%CI(-2.86,-0.36),与治疗前相比差异均有统计学意义(P<0.05)。结论隐形矫治器能够有效远中移动上颌磨牙并控制磨牙垂直向位置,磨牙远移的同时伴有一定的压低及远中倾斜移动,对高角型患者有利。上颌切牙的矢状向内收有利于患者侧貌的改善。

喉返神经损伤修复的研究进展

检索PubMed、Web of Science、中国知网等数据库中有关喉返神经损伤(RLNI)在甲状腺手术中的研究。关键词包括喉返神经修复、注射喉成形术、Ⅰ型甲状腺成形术、杓状软骨内收术、神经组织工程技术等。总结和比较目前RLNI的常见治疗方法。结果显示,喉返神经直接缝合是目前修复的首选术式,颈袢-喉返神经吻合术最常用于临床,其他修复方式各有其优、缺点。大多数治疗方法可在一定程度上获得不同的效果,但仍存在需进一步克服的缺点。此外神经组织工程技术及中医康复治疗值得进一步探索关注。

分子印迹聚合物对血液中野百合碱-血红蛋白加合物的分析

目的基于分子印迹技术,建立快速检测体内野百合碱和血红蛋白加合物的方法。方法以制备的野百合碱血红蛋白加合物为模板分子,经表面印迹聚合法制备野百合碱-血红蛋白分子印迹聚合物,用作固相萃取介质识别造模大鼠血液中的血红蛋白加合物。结果理化性质表征结果显示聚合层成功接枝在碳纳米管表面,且聚合物具备良好的热稳定性;将聚合物作为固相萃取介质,对造模大鼠血液进行分析,结果显示聚合物血红蛋白加合物具有较强的吸附能力(吸附量达90.86 mg/mg),该结果与肝脏病理检测结果呈正相关性。结论所制备的聚合物可以快速分析体内血红蛋白加合物的含量,与肝脏病理结果相结合,为肝小静脉闭塞症的无创伤诊断提供新的研究思路。

氮芥与DNA体外加合物及其质谱裂解规律

氮芥作为两用物质,不仅是禁止化学武器公约清单物,其衍生物至今仍是临床化疗药物。该文应用高效液相色谱-四极杆静电场轨道阱高分辨质谱法分析并鉴定了3种典型氮芥(HN1、HN2、HN3)分别与4种碱基、4种脱氧核糖核苷、4种脱氧核糖核苷酸和鲑鱼精DNA孵育后形成的加合产物。所有39个孵育体系中的HN-DNA加合产物经色谱分离,采用Full MS/dd-MS2模式进行数据采集获得其质谱特征信息。结果表明,在各孵育体系中均可鉴定到3种氮芥与鸟嘌呤、腺嘌呤和胞嘧啶特定碱基位点形成的单加合产物,并可鉴定到其与鸟嘌呤或腺嘌呤形成的双加合产物。在碱基孵育体系中虽可检测到3种氮芥与胸腺嘧啶形成的单加合产物,但在鲑鱼精DNA中并未检测到,表明其并非DNA的显著加合产物。通过探究各加合物的质谱裂解规律和特征加合离子,优化并给出了鉴定的系列DNA加合物的质谱多反应监测离子对,为氮芥暴露潜在生物标志物的鉴定和定量分析提供了重要的技术支撑,为复杂生物样品中氮芥DNA加合物的结构分析、准确溯源以及快速定量奠定了基础。

富马酸丙酚替诺福韦片中有关物质测定及杂质鉴定

目的建立检测富马酸丙酚替诺福韦片中有关物质含量的高效液相色谱法,以及鉴定制剂中未知湿热降解杂质化学结构的二维液相色谱-三重四极杆串联质谱法。方法有关物质测定中,色谱柱为Waters XTerra MS C_(18)柱(250 mm×4.6 mm,5μm),流动相为0.02 mol/L磷酸盐(1 mol/L氢氧化钾溶液调pH至6.0)-甲醇(95∶5,V/V)-甲醇(梯度洗脱),流速为1.0 mL/min,检测波长为260 nm,柱温为35℃,进样量为20μL。化学结构鉴定中,色谱柱为Agilent Zorbax Eclipse Plus C_(18)柱(50 mm×3.0 mm,1.8μm),流动相为0.1%甲酸水溶液-甲醇(55∶45,V/V),流速为0.4 mL/min,柱温为35℃,采用电喷雾离子源(ESI),正离子模式,质荷比(m/z)扫描范围为100~1000,雾化气体(氮气,N_(2))压力为45 psi,干燥气(N2)流速为6 L/min,温度为350℃,碎裂电压为150 V,二级质谱碰撞裂解能量为30 eV。根据保留时间、分子量及二级碎片识别湿热降解杂质。结果丙酚替诺福韦与5个降解杂质A-E的定量限分别为0.4,0.4,2.0,2.0,0.8,0.8 ng。5个降解杂质A-E的杂质校正因子分别为0.61,0.70,3.16,0.75,0.85;平均加样回收率分别为100.20%,95.23%,102.36%,94.48%,97.26%,RSD分别为0.50%,0.23%,0.89%,1.02%,1.67%(n=9)。未知湿热降解杂质分别为杂质D乳糖加合物及丙酚替诺福韦乳糖加合物。结论该方法专属性强、灵敏度好、准确度高,可用于富马酸丙酚替诺福韦片中有关物质的含量测定,通过特征碎片离子可快速识别丙酚替诺福韦乳糖加合物类杂质。

不同高度种植钉辅助隐形矫治器内收前牙的三维有限元分析

目的研究无托槽隐形矫治器用于拔牙后,单纯内收与辅助不同高度微种植钉到尖牙颈部牵引钩200 g牵引力内收时的前牙生物力学变化。方法选取1名牙列完整、身体健康的年轻志愿者,采用锥形束CT建立上颌牙列-无托槽隐形矫治系统三维有限元模型,根据植入微种植钉高度不同分为空白对照组(仅矫治器加力)、3 mm、4 mm、5 mm、6 mm、7 mm、8 mm及9 mm组,均通过微种植钉与尖牙颈部牵引钩200 g牵引力联合器加力;分析各组的前牙位移及牙周膜应力分布情况。结果微种植钉高度≤4 mm时,前牙最大牙周膜等效应力、矢状向倾斜位移随高度增加而增大,切牙的合向位移随高度增加而增加,尖牙的合向位移随高度增加而减小;微种植钉高度≥5 mm时,以上指标均随高度增加而减小。结论无托槽隐形矫治器整体内收前牙时,主张增加种植钉支抗高度≥5 mm,有利于前牙整体位移及压低。

Significant Positive Correlation of Plasma BPDE-Albumin Adducts to Urinary 1-Hydroxypyrene in Coke Oven Workers

Objective To investigate the application of BPDE-albumin adducts as monitoring biomarkers for coke oven workers exposed to polycyclic aromatic hydrocarbons （PAHs） and to explore possible relationship between BPDE-albumin adducts and urinary 1-hydroxypyrene （1-OHP） levels in them. Methods Thirty-seven coke oven workers from a coke plant and 47 controls without the occupational exposure to PAHs were recruited in this study. The levels of plasma BPDE-albumin adducts and urinary 1-OHP were analyzed using high performance liquid chromatography. Results The median levels of BPDE-albumin adducts （42.10 fmol/mg albumin） and urinary 1-OHP （5.46 μmol/mol creatinine） were significantly higher in coke oven workers than in controls （14.16 fmol/mg albumin, 2.96μmol/mol creatinine, respectively; P〈0.01）. Multiple logistic regression analysis showed that coke oven workers were at higher risk of having BPDE-albumin adduct levels above 25.30 μmol/mg albumin （OR=1.79, P〈0.01） and urinary 1-OHP levels above 4.13 μmol/mol creatinine （OR=2.45, P〈0.05）. There was a positive correlation between the levels of BPDE-albumin adducts and urinary 1-OHP in all subjects （rs=0.349, P〈0.01）. Conclusion BPDE-albumin adduct is a useful biomarker for monitoring long-term exposure to PAHs, and plasma BPDE-albumin adducts level is significantly correlated to urinary 1-OHP levels in coke oven workers.

Chem oprevention of 2-amino-1-methyl-6-phenyli-midazo[4,5-b]pyridine-induced carcinogen-DNA adducts by Chinese cabbage in rats

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Synthesis and Crystal Structure of New Supramolecular Adducts of[PtCl_6]^(2-) with Cucurbit [7] uril:[(H_3O)_2 [PtCl_6]_3 [C_(42)H_(42)N_(28)O_ (14)_2·H_2O

A novel supramolecular adduct 3(C 42H 42N 28O 14) 2·H 2O (1) was synthesized by mixing 2- and cucurbit uril in solution of hydrochloric acid. The crystal structure was determined by single crystal X-ray diffraction analysis. The crystal belongs to orthorhombic system and space group F dd2 with cell dimensions: a=4.705 33 (5) nm, b=7.153 80 (6) nm, c= 1.894 61 (2) nm, Z=16, V=63.7744 (11) nm3, D c= 1.534 g/cm3, μ=3.007 mm -1, F(000)=29 120, R 1= 0.070 7, wR 2=0.169 2. In crystal, the cucurb uril molecules form two zig-zag chains.

GSTM1 and XRCC3 Polymorphisms:Effects on Levels of Aflatoxin B1-DNA Adducts

Objective： Aflatoxin B1 （AFB1）, which can cause the formation of AFB1-DNA adducts, is a known human carcinogen. AFB1-exposure individuals with inherited susceptible carcinogen-metabolizing or repairing genotypes may experience an increased risk of genotoxicity. This study was designed to investigate whether the polymorphisms of two genes, the metabolic gene Glutathione S-transferase M1 （GSTM1） and DNA repair gene x-ray repair cross-complementing group 3 （XRCC3）, can affect the levels of AFB1-DNA adducts in Guangxi Population （n= 966） from an AFB1-exposure area. Methods： AFB1-DNA adducts were measured by ELISA, and GSTM1 and XRCC3 codon 241 genotypes were identified by PCR-RFLP. Results： The GSTM1-null genotype [adjusted odds ratio （OR） = 2.09; 95% confidence interval （CI） = 1.61-2.71] and XRCC3 genotypes with 241 Met alleles [i.e., XRCC3-TM and -MM, adjusted ORs （95% CI） were 1.43 （1.08-1.89） and 2.42 （1.13-5.22）, respectively] were significantly associated with higher levels of AFB1-DNA adducts. Compared with those individuals who did not express any putative risk genotypes as reference （OR = 1）, individuals featuring all of the putative risk genotypes did experience a significantly higher DNA-adduct levels （adjusted ORs were 2.87 for GSTM1-null and XRCC3-TM; 5.83 for GSTM1-null and XRCC3-MM）. Additionally, there was a positive joint effect between XRCC3 genotypes and long-term AFB1 exposure in the formation of AFB1-DNA adducts. Conclusion： These results suggest that individuals with susceptible genotypes GSTM1-null, XRCC3-TM, or XRCC3-MM may experience an increased risk of DNA damage elicited by AFB1 exposure.

A New Diels-Alder Type Adduct and a New Flavone from the Stem and Root Bark of Morus mongolica

A new Diels-Alder type adduct mongolicin G （1） and a new flavone 5＇-（1＂, 1＂-dimethylallyl）-5,7,2＇,4＇-tetrahydroxyflavone （2） were isolated from the stem and root bark of Morus mongolica. Their structures were determined by spectroscopic analysis and chiroptical methods.

CO_(2) Adducts of the Amino and Imino Groups Studied by ~1HNMR and ^(13)CNMR

CO2 adducts of L-(+)-asparaginic acid and some polyhydroxylated alkaloids was studied by 1HNMR and 13CNMR in this paper.

Theoretical Investigation of Detailed Thermodynamic Character of Possible Difunctional Adducts Model

The B3LYP/6-31G^＊ level of theory was used to optimize trans-[Pt（NH3）（Am）G-L], where Am = quinoline or thiazole and L is chosen as the model for functional groups of peptide side chains, and for adenine and guanine sites of DNA as the ultimate target of platinum anticancer drugs. Bond dissociating energy and stability energy of complexes are chosen to study detailedly thermodynamic character of possible difunctional adducts model. In order to investigate the influence of a polarizable environment on the energy of the Pt-L bond formation, we adopt a new bonding energy formula brought forward by Lippard and his coworkers： △H（Sol） = △H（SCF） ＋ △G（Solv）, which is quite appropriate to compare with what is found in experimental studies. Our calculated results demonstrate that N-containing ligands are more favored in view of thermodynamics both in gas phrase and in solution. However, it is worthly to be noted that addition of solvation free energies result in moderate correction of bonding energy in relative ordering, and the largest ones both present in imidazole ligand, not in guanine ligand. Finally, the nature of bond is analyzed in terms of partial charges distribution based on NBO population.

Facile and Stereoselective Synthesis of N-Substituted Benzotriazole with Baylis-Hillman Adducts

A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the present protocol attractive.

2,2'-Bipyridine Adduct of Bis(O,O'-di(2-phenylethyl)dithiophosphato)cadmium(Ⅱ):Synthesis,Spectroscopic Characterization,Crystal Structure and Antibacterial Activity

A new 2,2＂-bipyridine adduct of bis（O,O＇-di（2-phenylethyl）dithiophosphato） cadmium（II）, [Cd{S2P（OCH2CH2Ph）2}2＂bipy] （1, bipy -- 2,2＂-bipyridine）, was synthesized and characterized by elemental analyses, IR, UV-vis, 1H NMR, fluorescence spectroscopy, thermo-gravimetric analysis, and X-ray single-crystal diffraction. The crystal of 1 crystallizes in triclinic, space group P1 with a = 10.4607（19）, b = 11.679（2）, c = 18.480（3） A, a = 98.900（2）, β = 103.321（2）, ）, = 91.779（2）, V= 2165.2（7） A3, Dc = 1.447 g/cm3, Z = 2, C42H4404N2P2S4Cd, Mr = 943.37, F（000） = 968,μ = 0.814 mm-1, the final R = 0.0536 and wR = 0.1206 for 6275 observed reflections with 1 〉 2a（/） and R = 0.0690 and wR = 0.1339 for all data. The result shows that the Cd（1） centre is five-coordinated by two N and three S atoms in a highly distorted square pyramidal configuration. The C-H＇＂S hydrogen bonding interactions and a set of weak intermolecular r-r stacking between adjacent aromatic rings stabilize the structure and make 1 assemble into a 1D zig-zag chain. In addition, the antibacterial activities of 1 against Escherichia coli, Bacillus subtilis and Staphylococcus bacteria were also screened by disc diffusion method.

Active Oxygen Radical Scavenging Ability of Water-Soluble β-Alanine C_(60) Adducts

Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively. It was found thatβ-alanine C60 adducts showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50% inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.15 mg/mL and 0.048 mg/mL, respectively. The difference should be mainly attributed to the different scavenging mechanisms.