Activities of the Deriviatives of Chitin on the Osbeoblast Proliferation and the Effect on Bone Strength in Ovariectomized Rats

This study intends to examine the effects of different concentrations of four kinds of degradations of chitin： glucosamine （GLC）, N-acetyl-D-glucosamine （NAG）, chitooligosaccharide（COS）, CM-chitooligosaccharide （CM-COS）—on the proliferation of MC3T3-E1 cell line cultured in vitro. Results suggest that all of the glucoses mentioned above promoted the proliferation of osteoblast, and various concentrations have different effects： the proliferation was remarkable when the concentration of GLC, NAG, COS, CM-COS was 100 , 100, 500, 500 μg/mL ,respectively. Furthermore we choose the glucosamine as the material and study the effect on the bone strength in ovariectomized rats. The results showed that the middle does of glucosamine can significantly increase the hone strength of femur in ovariectomized rats.

Diabetes-related impairment in bone strength is established early in the life course

AIM: To evaluate properties of bone quantity/quality using young non-obese Type 1(T1D)-diabetic(NOD) prone and syngenic non-diabetic(NOD.scid) mice.METHODS: Quantitative bone assessment of tibia was conducted using dual-energy X-ray absorptiometry(DXA) for the evaluation of body mass,bone mineral content,body fat mass and lean mass.Qualitative assessment was accomplished by three-point breakage for assessment of force to failure and micro-computed tomography for evaluation of trabecular and cortical properties of bone.In addition,fasting blood was evaluated prior to sacrifice at week eleven and fifteen to evaluate and compare glucose homeostasis between the strains of mice.RESULTS: Our findings support a perturbation in the relationship between bone quantity,quality,and subsequently,the association between structure and strength.There were no differences in DXA-assessed body composition(body fat,% fat mass and lean mass) and bone composition(bone mineral content and bone mineral density) between strains.However,relative to NOD.scid,NOD mice had lower trabecular bone volume,relative trabecular bone volume,trabecular number and trabecular total material density(P < 0.05).Conversely,NOD mice had greater cortical total mean volume(P < 0.05).General linear models analysis adjusted for body weight revealed a significant contribution of T1D to bone health as early as 5 wk.CONCLUSION: It is well-established that diabetes is a significant risk factor for increased fractures,although the underlying mechanisms are not fully understood.Investigation of bone parameters encompassing strength and structure early in the life course will facilitate the elucidation of the pathogenesis of impaired bone integrity.

The relationship between orthopedic clinical imaging and bone strength prediction

Pathologic fracture is caused by bone diseases,which is common in middle-aged and elderly adults.Compromised bone strength is the leading contributor to this type of fracture.Therefore,accurately quantifying bone strength could help clinicians assess individualized fracture risk and develop therapeutic interventions.Orthopedic clinical imaging including dual X-ray absorptiometry(DXA),computed tomography(CT),and magnetic resonance imaging(MRI)has been an important tool to obtain radiology images of bone,which could be further used for noninvasive assessment of bone strength and related fracture risk.With the development of biomechanics and computer technology,the combination of finite element analysis with orthopedic imaging is the most advanced method for noninvasive prediction of bone strength in clinics.In this review,an overview is provided for the commonly noninvasive methods based on the radiology images(i.e.,DXA,CT,and MRI)to predict bone strength,which may improve the understanding of the relationship between orthopedic clinical imaging and biomechanics.

Bone loss in chronic liver diseases:Could healthy liver be a requirement for good bone health?

Given that the liver is involved in many metabolic mechanisms,it is not surprising that chronic liver disease(CLD)could have numerous complications.Secondary osteoporosis and increased bone fragility are frequently overlooked complications in CLD patients.Previous studies implied that up to one-third of these individuals meet diagnostic criteria for osteopenia or osteoporosis.Recent publications indicated that CLD-induced bone fragility depends on the etiology,duration,and stage of liver disease.Therefore,the increased fracture risk in CLD patients puts a severe socioeconomic burden on the health system and urgently requires more effective prevention,diagnosis,and treatment measures.The pathogenesis of CLD-induced bone loss is multifactorial and still insufficiently understood,especially considering the relative impact of increased bone resorption and reduced bone formation in these individuals.It is essential to note that inconsistent findings regarding bone mineral density measurement were previously reported in these individuals.Bone mineral density is widely used as the“golden standard”in the clinical assessment of bone fragility although it is not adequate to predict individual fracture risk.Therefore,microscale bone alterations(bone microstructure,mechanical properties,and cellular indices)were analyzed in CLD individuals.These studies further support the thesis that bone strength could be compromised in CLD individuals,implying that an individualized approach to fracture risk assessment and subsequent therapy is necessary for CLD patients.However,more well-designed studies are required to solve the bone fragility puzzle in CLD patients.

Experimental repetitive mild traumatic brain injury induces deficits in trabecular bone microarchitecture and strength in mice

To evaluate the long-term consequence of repetitive mild traumatic brain injury （mTBI） on bone, mTBI was induced in 10-week-old female C57BL/6J mice using a weight drop model, once per day for 4 consecutive days at different drop heights （0.5, 1 and 1.5 m） and the skeletal phenotype was evaluated at different time points after the impact. In vivo micro-CT （μ-CT） analysis of the tibial metaphysis at 2, 8 and 12 weeks after the impact revealed a 5%-32% reduction in trabecular bone mass. Histomorphometric analyses showed a reduced bone formation rate in the secondary spongiosa ofl.5 m impacted mice at 12 weeks post impact. Apparent modulus （bone strength）, was reduced by 30% （P 〈 0.05） at the proximal tibial metaphysis in the 1.5 m drop height group at 2 and 8 weeks post impact. Ex vivo μ-CT analysis of the fifth lumbar vertebra revealed a significant reduction in trabecular bone mass at 12 weeks of age in all three drop height groups. Serum levels of osteocalcin were decreased by 22%, 15%, and 19% in the 0.5, 1.0 and 1.5 m drop height groups, respectively, at 2 weeks post impact. Serum IGF-I levels were reduced by 18%-32% in mTBI mice compared to control mice at 2 weeks post impact. Serum osteocalcin and IGF-I levels correlated with trabecular BV/TV （r2 = 0.14 and 0.16, P 〈 0.05）. In conclusion, repetitive mTBI exerts significant negative effects on the trabecular bone microarchitecture and bone mechanical properties by influencing osteoblast function via reduced endocrine IGF-I actions.

“筋揉骨正”中医特色疗法在股骨粗隆间骨折术后康复中的应用

目的:基于“筋揉骨正”理论观察中医特色康复疗法在股骨粗隆间骨折患者术后康复中的应用效果。方法:回顾性分析天津中医药大学第二附属医院2021年6月至2022年6月收治的股骨粗隆间骨折住院患者84例,按照治疗方法不同分为对照组和观察组,每组42例。对照组采用Intertan或PFNA髓内钉固定手术治疗,观察组在其基础上结合中医特色三期辨证治疗。比较2组疗效、中医证候积分、髋关节功能、骨强度及并发症。结果:观察组治疗总有效率高于对照组,观察组治疗后的各项中医证候积分均低于对照组,差异有统计学意义(P<0.05)。观察组治疗后的Harris髋关节评分和骨密度值高于对照组,差异有统计学意义(P<0.05)。2组感染、下肢深静脉血栓、关节僵硬、压疮等并发症发生率差异无统计学意义(P>0.05)。结论:基于“筋揉骨正”理论采用中医特色康复疗法治疗股骨粗隆间骨折术后康复效果显著,可以提高患者髋关节功能和骨密度,安全性良好。

鸡爪跗跖骨的剥离特性及其影响因素

目前鸡爪在脱骨加工过程中存在骨肉剥离特性不明确,几何形貌不规整,机械化脱骨难的问题。本文首先建立具有统计学意义的鸡爪及其跗跖骨的数字模型以及参考坐标系。在此坐标系下,以剥离强度为衡量指标,通过各向剥离法对鸡爪的各向剥离强度及相应的剥离残留率进行测定,分析影响剥离强度的因素。结果表明,轴向剥离强度曲线整体趋势呈U型,最大剥离强度为3.23 kN/m。周向剥离强度曲线大多呈锯齿状,最大剥离强度出现的位置在跗跖骨顶部,为5.12 kN/m。在剥离过程中跗跖骨的骨外组织呈层性的特征,肉质内部存在脱层现象。在跗跖骨不同界面处的生物结构及组成对界面结合强度的影响不同,跖骨槽处界面结合强度最低,滑车凹口处骨外组织的呈层性特征并未影响界面的结合强度,且其正交方向上表现为各向同性,韧带脊和杯状凹处的界面结合存在着比较明显的各向异性。轴向剥离强度在峰值大小及数量上远小于周向剥离强度,剥离残留率结果也表明,轴向剥离残留率远小于周向的剥离残留率,这表明采用轴向剥离的方式在实际脱骨中是最优的选择。

1562例绝经后女性人群骨密度与握力相关性研究

目的分析1562例绝经后女性人群骨密度与握力之间的相关性。方法收集2022年5月~2023年8月于解放军总医院第一医学中心放射诊断科行骨密度检查与握力测试的1562例绝经后女性人群的骨密度检查结果与握力测试数据。按照年龄分成3组,分别是A组(<60岁,n=663)、B组(60~74岁,n=749)、C组(≥75岁,n=150)。对1562例绝经后女性进行腰椎与股骨近端骨密度检查及优势侧手握力测试。比较3组的骨密度和握力,分析骨密度与握力之间的相关性。结果腰椎骨密度T≤-2.5 SD的患者501例(32.07%);股骨颈骨密度T≤-2.5 SD的患者383例(24.52%);髋部骨密度T≤-2.5 SD的患者186例(11.91%)。A组患者的握力为(22.35±4.64)kg,B组患者的握力为(19.81±4.94)kg,C组患者的握力为(16.57±4.27)kg。握力、骨密度均随着年龄的增长逐渐降低(P<0.05)。共125例患者既往发生过骨折(8.00%),其中A组28例(4.22%),B组66例(8.81%),C组31例(20.67%)。随着患者年龄的增长,骨折的发生率升高(P<0.05)。相关性分析结果显示,绝经后女性人群的握力与股骨颈、髋部、腰椎骨的骨密度均呈正相关(r=0.936、0.938、0.935,P<0.05);握力、股骨颈骨密度、髋部骨密度、腰椎骨密度均与年龄呈负相关(r=-0.928、-0.967、-0.971、-0.970,P<0.05)。握力与腰椎、股骨颈、髋部骨密度均呈正相关(r=0.935、0.936、0.938,P<0.05);握力、股骨颈骨密度、髋部骨密度、腰椎骨密度均与BMI呈正相关(r=0.932、0.982、0.985、0.982,P<0.05)。结论绝经后女性人群的握力与骨密度相互依存,相互影响,呈正相关;握力、骨密度与绝经后女性人群的年龄呈负相关。

《强健、平衡和敏捷:英国关于体育运动和锻炼治疗骨质疏松症的共识声明》解读

骨质疏松症(osteoporosis,OP)是一种中老年常见的全身性、代谢性骨骼疾病,主要表现为骨量丢失、骨微结构退变、骨强度受损,导致骨脆性增加,易发生骨折。为提高骨质疏松症患者和卫生专业人员的锻炼信心,与英国联合发布了关于体育运动和锻炼治疗OP的共识声明(以下简称“共识声明”)。进一步确定优化骨强度、减少跌倒和骨折风险、改善姿势和管理椎体骨折症状等所需的体育运动和锻炼,同时将OP患者的潜在风险降至最低,使每位OP患者都可以从适应姿势和动作的指导中受益,并恢复运动能力和提高生活质量。总的来说,好处大于风险。

汉中市儿童超声骨密度检测结果分析

目的了解汉中市儿童骨密度情况,为临床防治儿童骨强度不足提供依据。方法选取2020年6月到2022年7月间在汉中市中心医院儿童保健科做超声骨密度检查的32855例儿童为研究对象,比较不同性别、年龄、季节间骨密度检测结果的差异。结果本次超声传导速度(SOS)平均值为(3297.90±212.77)m/s,男童组的SOS均值高于女童,差异有统计学意义(t=3.99,P<0.001);SOS值整体上随年龄组增长(F=3956.21,P<0.001);不同季节组间SOS值差异有统计学意义,组间比较显示夏季SOS值最高,春季最低(F=39.97,P<0.001)。整体骨强度正常检出率为45.90%,偏低25.59%,轻度不足15.35%,不足13.16%;男童组的骨强度不足检出率低于女童组(Z=-21.50,P<0.001);0岁组的骨强度不足检出率高于其他年龄组(H=8214.68,P<0.001);春、冬季组骨强度不足检出率高于夏、秋季组(H=71.35,P<0.001)。结论汉中市儿童的骨密度有明显的性别、年龄、季节特征,有相当大的一部分群体存在骨强度不足的情况,应当引起重视。在儿童保健工作中,应持续跟踪监测骨强度不足儿童的骨密度情况,针对性采取防治措施,保证儿童骨骼健康发育。

定量磁共振评估骨质疏松症研究进展

骨质疏松症是骨折的主要危险因素,除了骨矿化成分之外,骨微结构及微环境的变化对骨的完整性同样重要。常规MRI测得的信号强度比可用于脊柱手术患者的骨质疏松筛查,使用超短回波时间磁共振成像可以定量评估骨孔隙度、胶原基质、骨的矿化成分等,利用水脂分离技术能测量骨髓脂肪含量、组成以及T2^(*)值,体素内不相干运动技术反映骨髓灌注情况,人工智能技术如纹理分析及深度学习进一步发展了MRI技术,本文总结了近期使用磁共振方法评估骨质疏松症的研究进展。

亚胺培南西司他丁抗生素骨水泥的体外药物释放试验和力学测试

目的探讨不同浓度亚胺培南西司他丁抗生素骨水泥缓释载体的体外释放速率和抑菌效果,以及对骨水泥力学性能的影响,为慢性骨髓炎的临床治疗提供实验依据。方法先制备不同浓度的亚胺培南西司他丁梯度溶液,采用三重四级杆液质联用仪(Liquid Chromatograph Mass Spectrometer,LC-MS)进行检测,分别得出亚胺培南和西司他丁2条标准曲线方程。用亚胺培南西司他丁与骨水泥按质量1∶40、4∶40、8∶40(g∶g),制备低、中、高浓度组的亚胺培南西司他丁骨水泥,进行体外释放试验,检测1、3、7、14、21、28、35 d的释放速率。采用低、中、高浓度组的亚胺培南西司他丁骨水泥分别对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌进行抑菌试验,记录1、2、3、4、5、6 d的抑菌环直径。另外检测不同浓度的亚胺培南西司他丁骨水泥抗压力学性能。结果亚胺培南标准曲线方程Y=0.001X-0.0088(R2=0.9989),西司他丁标准曲线方程Y=0.0026X+0.0281(R^(2)=0.9999)。在不同时间点,亚胺培南西司他丁骨水泥的释放速率,低浓度组<中浓度组<高浓度组,差异具有统计学意义(P<0.001)。对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌的抑菌环直径,低浓度组<中浓度组<高浓度组,差异具有统计学意义(P<0.05)。随着添加亚胺培南西司他丁的质量越多,骨水泥的抗压强度越低(P<0.05)。结论制备的亚胺培南西司他丁抗生素骨水泥,随着亚胺培南西司他丁浓度的增加,释放速率更快,抗菌效果更好,但抗压能力降低。

营养状况、骨代谢及股骨颈强度指数和骨髓脂质分数与老年髋部骨折术后关节功能恢复的关系研究

目的探究营养状况、骨代谢及股骨颈强度指数(FSI)和骨髓脂质分数(LF)与老年髋部骨折术后关节功能恢复的关系。方法选取2021年6月至2023年6月于原阳县中心医院接受治疗的髋部骨折手术老年患者160例为研究对象。根据患者髋关节功能恢复情况进行分组,恢复良好患者87例纳入良好组,恢复不良患者73例纳入不良组。对比两组患者一般资料、营养状况、骨代谢及FSI和LF。结果良好组年龄≥75岁比例、体重、体质量指数(BMI)、股骨粗隆间骨折比例、Ⅰ型胶原蛋白N端肽(NTX)、抗酒石酸酸性磷酸酶5b(TPACP-5b)水平表达均低于不良组,差异均有统计学意义(P<0.05);良好组微型营养评定(MNA)评分、FSI、LF、骨钙蛋白(BGP)水平表达均高于不良组,差异均有统计学意义(P<0.05);经Logistic回归分析,MNA评分、LF、FSI、NTX、TPACP-5b、BGP水平表达均为影响老年髋部骨折术后关节功能恢复情况的独立危险因素,差异有统计学意义(P<0.05);经受试者工作特征(ROC)曲线分析,MNA评分、FSI、LF、NTX、TPACP-5b水平表达均对老年髋部骨折术后关节功能恢复情况有较高的预测价值,曲线下面积(AUC)值分别为0.936、0.874、0.866、0.884、0.825;BGP水平表达的AUC值为0.634,可作为次要参考。结论观察行髋部骨折手术的老年患者术后营养状况、骨代谢及股骨颈强度指数和骨髓脂质分数的变化情况,有利于早期预测患者术后髋关节功能恢复情况,从而制定相应防控措施,帮助患者早日康复。

腰椎椎体骨强度综合指数预测骨质疏松性椎体的压缩骨折

背景:骨质疏松性椎体压缩骨折是继发于骨质疏松症的常见骨折,目前尚缺乏有效的骨质疏松性椎体压缩骨折预测指标及方法。目的:探讨腰椎椎体骨强度综合指数对骨质疏松性椎体压缩骨折的预测作用。方法:纳入骨质疏松患者233例,根据是否发生椎体骨折分为骨折组和非骨折组。收集患者人口统计学、体质量指数、椎体骨密度等详细信息,拍摄腰椎X射线侧位片,测量并计算椎体宽度、椎体长度、骶骨倾斜角、骨盆倾斜角、骨盆入射角、腰椎抗压强度指数及腰椎抗冲击强度指数,对以上参数进行单因素及多因素分析,并进行受试者操作特征曲线(ROC)分析,根据截断值进行生存分析。结果与结论:①所有患者皆获得随访,随访时间2-4年,平均3.1年。随访期间,99例(L1椎体38例,L2椎体61例)患者发生骨折(骨折组),134例(L1椎体52例,L2椎体82例)患者未发生骨折(非骨折组);单因素分析显示两组年龄、性别、身高、体质量、体质量指数、骨折节段比较均无统计学意义(P>0.05)。②骨折组腰椎抗压强度指数、腰椎抗冲击强度指数均低于非骨折组(P<0.05)。骨折组骨盆入射角、骨盆倾斜角大于非骨折组(P<0.05)。③多因素分析显示,腰椎抗压强度指数、腰椎抗冲击强度指数及骨盆倾斜角是患者发生骨质疏松性椎体压缩骨折的危险因素(P<0.05)。④ROC曲线分析显示椎体骨密度、腰椎抗压强度指数、腰椎抗冲击强度指数、骨盆倾斜角和骨盆入射角的截断值分别为0.9135 g/cm2,1.932,0.903,21.5°,55°;曲线下面积(AUC)分别为0.630,0.800,0.911,0.633,0.568。⑤根据生存分析(以骨质疏松性椎体压缩骨折为终点),腰椎抗冲击强度指数≥0.903椎体平均生存时间显著大于腰椎抗冲击强度指数<0.903者(P<0.05)。⑥结果说明,腰椎椎体骨强度综合指数比椎体骨密度和脊柱-骨盆矢状位参数对骨质疏松性椎体压缩骨折预测更加精准,有助于早期防治骨质疏松性椎体压缩骨折。

老年住院患者握力及躯体活动能力与骨密度的相关性研究

目的 探究老年住院患者握力及躯体活动能力与骨密度(BMD)之间的关系。方法 选取2020年10月—2021年10月在大连医科大学附属第二医院老年医学科治疗的235例老年患者(≥60岁),评估其握力及躯体活动能力(步速、5次起坐试验时间、起立-行走试验时间),分析其与BMD的相关性。结果 单因素分析显示握力、步速与BMD呈正相关,起立-行走试验时间、5次起坐试验时间与BMD呈负相关,这种相关性在不同性别的患者中均存在(P<0.001)。偏相关分析显示握力、步速与BMD呈正相关(P<0.001);5次起坐试验时间、起立-行走试验时间与BMD呈负相关(P<0.001)。多元线性回归分析结果显示BMI、握力、起立-行走试验时间、5次起坐试验时间为BMD的主要影响因素(R^(2)=0.449,P<0.05)。结论 增加BMI、肌肉力量并改善躯体活动能力有利于维持老年患者的BMD。

基于CT有限元分析预测椎体撞击骨折的研究

目的本研究旨在通过基于CT定量有限元分析(finite element analysis,FEA)来确定椎体强度与椎体骨折(vertebral fracture,VF)、骨密度(bone mineral density,BMD)之间的关系,以期为临床诊治提供参考。方法回顾性分析本院于2020年1月至2020年12月期间收治的26例椎体骨折患者和62例匹配的对照组。腰椎CT扫描评估椎体压缩强度、积分vBMD、骨小梁vBMD、基于CT的BMC和基于CT的aBMD。结果调整年龄、BMI和椎体骨折状态后,基线时脊柱强度较低与新发或恶化的椎体骨折风险增加相关(OR=5.2,95%CI:1.3-19.8)。ROC曲线下面积显示,椎体强度比基于CT的aBMD更好地预测椎体骨折的发生(AUC=0.804比0.715,P=0.05),但不如积分vBMD(AUC=0.815)或基于CT的BMC(AUC=0.794)。此外,脆性骨强度阈值在识别椎体骨折方面倾向于比骨密度分类的骨质疏松症有更好的敏感性(0.46 vs.0.23,P=0.09)。结论椎体强度测量与椎体骨折事件之间存在关联,基于CT的有限元分析估计的骨强度提供了同等或更好的预测椎体骨折事件的能力,基于CT的有限元分析估计椎体强度对于识别脊柱骨折的高危患者是有用的。

Effects of Source of Inorganic Phosphorus and Phytase Supplementation on Performance,Physiological Parameters and Bone Mineralization in Broilers

The objective of this study was to eval- uate the effects of inorganic phosphorus source and phytase addition on performance, nutrient digestibility and bone mineralization in broiler chickens. In Exp. 1,150 two-day old, male broiler chicks were fed a corn-soybean meal basal diet supplemented with phos- phorus provided by dicalcium phosphate, tricalcium phosphate or defluorinated rock phosphate. Five cages containing 10 birds were allotted to each of the three treatments. In Exp. 2,120 three-day old, male broiler chicks were fed the basal diet from Exp. 1 supplemen- ted with 0,250,500 ,or 1,000 P-＇rU phytase per kg of diet. Six cages containing five chicks were allotted to each of the four treatments. In Exp. 1, there was no difference in weight gain, feed intake or feed conver- sion as a result of feeding the different sources of in- organic phosphorus. The digestibility of phosphorus was significantly lower （P =0.01 ） for chicks fed di- ets supplemented with tricalcium phosphate than for chicks fed the other two diets. However, despite the lower digestibility, serum phosphorus levels did not differ among the three treatments. For Exp. 2, feedconversion showed a linear improvement （P = 0.03 ） with increasing levels of phytase inclusion （ days 0 to 33 ）. Phytase supplementation resulted in linear increa- ses in the digestibility of dry matter （P = 0.02 ）, crude protein （ P --- 0.04 ） and energy （ P 〈 0.01 ）. Chicks fed 1,000 FTU/kg phytase had significantly higher bone calcium （ P = 0.05 ） and bone breaking strength （P = 0.04 ） than chicks fed the basal diet on day 33. In conclusion, the results of the current study indicated that the performance of birds fed diets sup- plemented with dicalcium phosphate, tricalcium phos- phate or defluorinated phosphate was similar and therefore production costs could be lowered by choo- sing the cheapest inorganic phosphorus source when formulating diets for poultry. When diets were formu- lated to meet dietary phosphorus requirements, the growth of broilers was not enhanced with phytase sup- plementation. However, increases in feed conversion and bone breaking strength and its potential to impact culling and mortality in broiler operations may be suf- ficient justification for the routine inclusion of phytase in diets fed to broilers.

矿山尾砂胶结充填体抗拉强度测试方法研究进展

矿山尾砂胶结充填是实现金属矿绿色开采的重要技术载体,尾砂胶结充填体抗拉力学性能是影响矿山采场充填体整体稳定性以及确保相邻采场安全高效充填采矿的关键要素。科学、准确测量尾砂胶结充填体抗拉强度是确保矿山充填材料强度合理设计的重要环节。尾砂胶结充填材料属于低强度材料,我国尚无针对尾砂胶结充填材料抗拉性能的统一试验方法或测试标准。系统回顾了矿山充填材料抗拉强度测试方法的应用情况,并指出了当前借鉴混凝土、岩土工程等领域抗拉强度测试方法存在的问题。从抗拉强度直接拉伸测试方法、抗拉强度间接拉伸测试方法和适用于尾砂胶结充填材料的抗拉强度测试方法创新3个方面介绍了最新的测试方法研究应用进展。首先系统梳理总结了4种直接拉伸测试方法及其应用场景,然后研究分析了3种间接拉伸测试方法及其应用条件,并对比分析了两大类不同测试方法的优缺点。在研究分析上述测试方法的基础上,并考虑尾砂胶结充填材料的力学特性,创新发明了一种“工字型”尾砂胶结充填体抗拉强度测试法,研发了相应的压-拉转换装置,实现了用单轴压缩的方式开展胶结充填体试样直接拉伸测试。经中国和加拿大相关矿山和研究机构验证,该方法是适用于矿山尾砂胶结充填材料抗拉性能测试的科学方法,目前已被国际矿业咨询机构—Paterson&Cooke公司、加拿大2家矿业公司、中国3家矿业公司采用,可为国内外金属矿山充填采矿研究与设计提供参考与技术支撑。

益生菌治疗老年骨质疏松患者的效果

目的探索益生菌治疗老年骨质疏松患者的效果,从而为益生菌临床干预骨质疏松提供数据支持。方法选取2021年9月至2022年9月赣州市第三人民医院老年科收治的88例老年骨质疏松患者作为研究对象,按照随机数字表法分为观察组(44例)和对照组(44例)。对照组患者给予常规口服药物治疗(碳酸钙D3及阿法骨化醇),观察组患者在对照组基础上采用益生菌治疗。比较两组患者治疗前及治疗6个月后的血清骨代谢标志物[血清钙(Ca)、维生素D(VD)、总Ⅰ型胶原氨基端延长肽(PINP),β-胶原降解产物(β-CTX)]、炎症指标[降钙素原(PCT)、白介素-6(IL-6)]、骨密度、疼痛程度、肌力等。结果治疗后观察组的Ca、VD、PINP、骨密度、肌力均高于对照组(P<0.05),PCT、IL-6、疼痛程度均低于对照组(P<0.05),两组的β-CTX比较,差异无统计学意义(P>0.05)。结论益生菌治疗老年骨质疏松,可显著改善骨骼质量,缓解慢性疼痛,提高肌力,值得临床推广应用。

术中塑形与锁钉分布及术后愈合状态对接骨板生物力学的影响

目的分析塑形对接骨板弯曲强度以及不同锁钉分布情况对接骨板受力的影响,为临床上对接骨板进行塑形与选择不同的锁钉分布方式提供生物力学依据。方法根据YY/T 0342—2020标准对接骨板四点弯曲强度进行有限元仿真分析,并应用理论分析及有限元仿真方法对不同锁钉分布的假体模型进行受力分析。结果在30°折弯时,3.7 mm厚接骨板比2.7 mm厚接骨板的等效塑性应变高28%;3.7、2.7 mm厚接骨板的极限折弯角度分别为55°、67°。折痕对接骨板受力影响较小,未塑形结构四点弯曲强度为2.64 N·m,等效弯曲刚度为1.12 N·m^(2);带折痕四点弯曲强度为2.63 N·m,等效弯曲刚度为1.10 N·m^(2);正反折弯后接骨板四点弯曲强度由2.64 N·m降低至2.45 N·m,降低约7.72%,等效弯曲刚度由1.12 N·m^(2)降低至0.98 N·m^(2),降低了12%,影响较为明显。植入填塞螺钉后单孔接骨板四点弯曲强度改善较为明显,由2.64 N·m提升至3.15 N·m,提升约19.32%,等效弯曲刚度由1.12 N·m^(2)提升至1.14 N·m^(2),提升幅度为2.1%。骨折线两侧至少各留出两个锁定孔不植入锁钉比打满锁钉应力降低约50%。在未形成骨痂的情况下,术后16周下地行走,TC4材质应力达到852.7 MPa,出现屈服。结论在需要进行较大塑形的临床场景下,不适合厚度过大的接骨板,厚度大塑形后更易出现接骨板断裂问题,可指导临床基于塑形角度选择合适厚度接骨板,极端情况可选择植入填塞螺钉。建议临床固定锁钉时,避免打满螺钉的固定锁钉方式;骨折线两端各保留两个锁定孔不固定锁钉,生物力学效果最好。