MORPHOLOGY AND MECHANICAL PROPERTIES OF POLYPROPYLENE WITH in situ FORMED POLYAMIDE-6 FIBRILS

in situ Fibril formation of polyamide-6 （PA6） in isotropic polypropylene （iPP） was first fabricated using a slit die extrusion and hot stretching process. Then the prepared materials were subjected to injection molding in the temperature range higher than the melting temperature of iPP but lower than that of PA6. The obtained injection-molded samples were characterized via scanning electron microscopy （SEM）, differential scanning calorimetry （DSC） and two-dimensional wide- angle X-ray scattering （2D-WAXS）. Mechanical properties were also investigated. The SEM result shows that the optimum fibril formation could be only achieved in the range of 20 wt% to 30 wt% of PA6 content for the studied system. The fibril morphology changes along the sample thickness in the injection-molded bars. The fibril morphology in the skin layer was better than that in the core layer. 2D-WAXS results showed that the orientation of PP decreased with the increase of PA6 content, which indicated that the orientation of PP was confined by PA6 fibrils. Combined consideration of mechanical properties and morphology indicates that only PP/PA6 composites with 20 wt% of PA6 content show better properties because of the better fibril morphology and PP chain orientation.

Quantitative analysis of collagen morphology in breast cancer from millimeter scale using multiphoton microscopy

The tumor microenvironment(TME)is now recognized as an important participant of tumor progression.As the most abundant extracellular matrix component in TME,collagen plays an important role in tumor development.The imaging study of collagen morphological feature in TME is of great significance for understanding the state of tumor.Multiphoton microscopy(MPM),based on second harmonic generation(SHG)and two-photon excitation fluorescence(TPEF),can be used to monitor the morphological changes of biological tissues without labeling.In this study,we used MPM for large-scale imaging of early invasive breast cancer from the tumor center to normal tissues far from the tumor.We found that there were signi¯cant di®erences in collagen morphology between breast cancer tumor boundary,near tumor transition region and normal tissues far from the tumor.Furthermore,the morphological feature of eight collagen¯bers was extracted to quantify the variation trend of collagen in three regions.These results may provide a new perspective for the optimal negative margin width of breast-conserving surgery and the understanding of tumor metastasis.

Role of corneal collagen fibrils in corneal disorders and related pathological conditions

The cornea is a soft tissue located at the front of the eye with the principal function of transmitting and refracting light rays to precisely sense visual information. Corneal shape, refraction, and stromal stiffness are to a large part determined by corneal fibrils, the arrangements of which define the corneal cells and their functional behaviour. However, the modality and alignment of native corneal collagen lamellae are altered in various corneal pathological states such as infection, injury, keratoconus, corneal scar formation, and keratoprosthesis. Furthermore, corneal recuperation after corneal pathological change is dependent on the balance of corneal collagen degradation and contraction. A thorough understanding of the characteristics of corneal collagen is thus necessary to develop viable therapies using the outcome of strategies using engineered corneas. In this review, we discuss the composition and distribution of corneal collagens as well as their degradation and contraction, and address the current status of corneal tissue engineering and the progress of corneal cross-linking.

Studies on morphology and biomechanics of the coronary arteries

Morphology and biomechanics of the coronary arteries have been studied in the human and common experimental animals since 1979. The types of the coronary distribution, the artery-vein relationship,and the intramural vascular changes and the coronary colla

Different architectures of collagen fibrils enforce different fibrillogenesis mechanisms

According to current knowledge on collagen fibril-logenesis, collagen fibrils are formed by a cooperative process involving lateral fusion of small protofibrils. Almost all the experimental research, however, was carried out on tendon collagen, whose fibrils are characterized by approximately straight subfibrils. By contrast, in most tissues the collagen fibril sub-units follow a helical course in which geometrical constraints prevent lateral fusions, thereby implying a different mechanism where collagen fibrils grow by addition of individual microfibrils rather than by lateral fusion of pre-assembled subfibrils. The proc-ess at the origin of these fibrils may provide a simple, automatic explanation for the remarkable uniformity in fibrils size observed in most tissues without re-quiring the intervention of unknown mechanisms of diameter control. Other mechanisms of growth con-trol remain indispensable to terminate the fibril-logenesis process in tendons and ligaments.

<i>In Situ</i>Hydroxyapatite Synthesis: Influence of Collagen on Its Structural and Morphological Characteristic

Hydroxyapatite (HA) was synthesized in situ by the precipitation method, with and without the presence of collagen (COLL), to study its influence on HA’s structural and morphological characteristics. The material was characterized by energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The Ca/P molar ratio was influenced by collagen addition—1.89 and 2.38 for samples without and with collagen, respectively. The WAXD pattern revealed better resolution and intensity besides higher crystallinity degree of the HA in the presence of collagen. The photomicrographs showed a strong influence of collagen on the HA morphology.

抗菌肽聚赖氨酸对胶原自组装的影响

将抗菌肽聚赖氨酸(ε-PL)引入胶原溶液,旨在探究生理条件下ε-PL对胶原(Col)自组装的影响。结果显示,阳离子性的ε-PL减缓了Col的自组装进程,组装产物网络结构趋于松散,胶原原纤维直径减小。当Col/ε-PL比例<1∶0.5时,仍可清晰地观察到Col自组装形成具有D周期的纤维,Col/ε-PL组装产物热稳定性与纯Col组装产物接近。并且,由于ε-PL的引入,Col/ε-PL组装产物表现出出色的抗菌活性。因此,适量引入抗菌肽ε-PL参与Col的自组装是一种构建抗菌性仿生胶原原纤维的有效策略。

An Unprecedented Efficiency with Approaching 21%Enabled by Additive‑Assisted Layer‑by‑Layer Processing in Organic Solar Cells

Recently published in Joule,Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8%power conversion efficiency in organic solar cells(OSCs)with an interpenetrating fibril network active layer morphology,featuring a bulk p-in structure and proper vertical segregation achieved through additive-assisted layer-by-layer deposition.This optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion,reduces recombination losses,and enhances light capture capability.This approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.

Relationship between Atrial Tissue Remodeling and ECG Features in Atrial Fibrillation

The difference in the atrial organizational structure between patients with atrial fibrillation (AF) and those with sinus rhythm was investigated.In order to analyze the rationality in explaining the electrocardiogram (ECG) characteristics of AF with statistics data or tissue remodeling model,and the logical relationship between the hypothesis of pulmonary veins (PV) muscle sleeves and that of multi wavelets in mechanism of AF,we examined the expression of collagen volume fraction of type I (CVF-I ) with picrosirius red staining,connexin 40 (Cx40) by immunohistochemistry,and intercalated disc (ID) using transmission electron microscope in atrial tissue.The results showed that there was significant difference in the expression of CVF-I (t=3.827,P<0.01),Cx40 (t=4.21,P<0.01),and groups of the ID that keeping the electrical transmission and atrial electrical coupling synchronization (t=15.116,P<0.001),but no significant difference was found in total IDs (t=0.611,P=0.543) between patients with AF and those with sinus rhythm.The quantitative differences in the tissue remodeling could not explain the ECG characteristics of AF.The number of normal IDs and abnormal distribution are the structural basis to trigger and maintain atrial electrical remodeling,and induce and maintain AF.Such histological reconstruction supports the hypothesis of multi wavelets and can also explain ECG features.

Platelet-Derived Growth Factor-A Overexpression Correlates with Atrial Fibrosis in the Patients with Atrial Fibrillation Secondary to Rheumatic Valvular Disease

Objective: To investigate the relationship between platelet-derived growth factor-A (PDGF-A) and atrial fibrosis in patients who have developed atrial fibrillation (AF) secondary to rheumatic valvular disease. Methods: 84 selected patients participated in the current study who have developed rheumatic heart disease and were going to have a cardiac surgical operation. In the current study, whole subjects were divided into two group, they were atrial fibrillation (AF) group (the quantity is thirty-nine) and sinus rhythm (SR) group (the quantity is forty-five). Before the operation, complete clinical data was available for the whole patients. During the operation, the right atrial tissue (0.3 - 0.5 mm3) was disserted from every patient. Right atrial fibrosis was observed by Masson staining and the distribution of PDGF-A in right atrium specimen was observed by immunohistochemistry. RT-PCR techniques were applied to admeasure the mRNA expressions of PDGF-A in patients’ atrial tissue. At the same time, western-Blot techniques were employed to admeasure the protein expressions of PDGF-A. Results: In baseline clinical characteristics, in both AF group and SR group, there was no apparently difference between them (P > 0.05);compared with SR group, the diameters of left atrium and right atrium in AF group were apparently increased (P Conclusion: Atrial remodeling plays an important role in patients with valvular atrial fibrillation;PDGF-A in patients with AF was highly expressed in the right atrial, and was closely related with atrial fibrosis.

Left atrial appendage morphology in patients with atrial fibrillation in China： implications for stroke risk assessment from a single center study

Background The left atrial appendage （LAA） is thought to be the main source of thrombi in patients with atrial fibrillation （AF）. The purpose of this study was to describe the LAA orifice diameter, LAA length, and morphologic type of the LAA in Chinese patients with AF as well as to evaluate whether these LAA parameters are associated with a history of stroke in patients with AF from a single center in China. Methods The study population consisted of 219 consecutive patients with drug-refractory, symptomatic paroxysmal, or persistent AF scheduled to undergo radiofrequency catheter ablation in our single center. All patients underwent extensive clinical assessment and multidetector computed tomography to fully explore the anatomy of the LAA. Results Of the 219 patients who underwent catheter ablation procedures, chicken wing LAA morphology was found in 114 patients （52.2%）, windsock in 52 （23.9%）, cauliflower in 29 （13.0%）, and cactus in 24 （10.9%）. Compared with the windsock LAA morphology, cactus had a larger left atrial diameter （（42.40±3.68） and （37.91±4.32） mm, P=-0.005） and LAA orifice diameter （（27.38±3.70） and （24.14±3.58） mm, P=0.048）. The LAA length was significantly larger in the chicken wing morphology than in the windsock （（37.50±6.74） and （31.33±3.92） ram, P=0.015） and cauliflower morphologies （（37.50±6.74） and （31.33±3.92） mm, P=-0.015）. According to their medical records, 26 patients （11.9%） had suffered a prior stroke. Compared with patients who had no history of stroke, the prior-stroke patients were older （62.04±8.07 and 58.24±9,24, P=-0.047） and there were fewer patients with chicken wing （23.1% and 59.1%, P=-0.001） and more patients with cauliflower （26.9% and 9.8%, P=-0.046）. Multivariate Logistic regression analysis demonstrated that age （odds ratio （OR） 1.26; 95% confidence interval （CI） 1.08-1.47; P=0.003）, non-chicken wing morphology （OR 5.82; 95% CI 1.61- 21.03; P=-0.007）, and LAA orifice diameter （OR 1.25; 95% CI 1.05-1.49; P=0.014） were independent predictors of stroke after adjusting for all parameters that emerged as potential confounders with univariate analysis. Conclusion LAA analysis can potentially be used to inform guidance on the implication for stroke risk assessment.

Optimal bulk-heterojunction morphology enabled by fibril network strategy for high-performance organic solar cells

A bicontinuous network formed spontaneously upon film preparation is highly desirable for bulk-heterojunction(BHJ) organic solar cells(OSCs). Many donor-acceptor(D-A) type conjugated polymers can self-assemble into polymer fibrils in the solid state and such fibril-assembly can construct the morphological framework by forming a network structure, inducing the formation of ideal BHJ morphology. Our recent works have revealed that the fibril network strategy(FNS) can control the blend morphology in fullerene, non-fullerene and ternary OSCs. It has been shown that the formation of fibril network can optimize phase separation scale and ensure efficient exciton dissociation and charge carriers transport, thus leading to impressive power conversion efficiencies(PCEs) and high fill factor(FF) values. We believe that FNS will provide a promising approach for the optimization of active layer morphology and the improvement of photovoltaic performance, and further promote the commercialization of OSCs.

Effect of hydrophilic or hydrophobic interactions on the self-assembly behavior and micro-morphology of a collagen mimetic peptide

Peptide self-assembles with bionic properties have been widely utilized for bioactive drugs and biomedical materials.Collagen mimetic peptide(CMP)gains more attention due to its unique advantages in biosecurity and function.Unfortunately,the self-assembly mechanism of CMP,particularly the effect of intermolecular forces on its self-assembly behavior and morphology,is still unrecognized.Herein,the hydrophilic glycidol(GCD)and hydrophobic Y-glycidyl ether oxypropyl trimethoxysilane(GLH)were grafted onto the side chains of CMP through the ring-opening reaction(GCD/CMP,GLH/CMP).Subsequently,the effects of hydrophilic and hydrophobic interactions on the self-assembly behavior and morphology of CMP were further studied.The results substantiated that the GCD/CMP and GLH/CMP self-assembly followed“nucleation-growth”mechanism,and the supererogatory hydrophilic and hydrophobic groups prolonged the nucleation and growth time of CMP self-assembly.Noted that the hydrophilic interaction had stronger driving effects than hydrophobic interaction on the self-assembly of CMP.The GCD/CMP and GLH/CMP self-assembles exhibited fibrous 3D network and microsphere morphology,respectively.Furthermore,the GLH/CMP self-assembles had better resistance to degradation.Consequently,the microtopography and degradation properties of CMP self-assembles could be controlled by the hydrophilic and hydrophobic interactions between CMP,which would further provide a way for subsequent purposeful design of biomedical materials.

心电图MVP积分在阵发性心房颤动射频导管消融术后随访中的临床价值

目的探讨心电图P波形态、电压及时间(MVP)积分在阵发性心房颤动(下称房颤)射频导管消融术(下称消融)后随访中的临床价值。方法选择2018年2月至2022年1月嘉兴市第一医院(嘉兴大学附属医院)收治的心房颤动消融患者84例,随访1年,依据房颤是否复发分为未复发组60例、复发组24例。比较两组患者消融前、消融后1年心电图P波参数(MVP)积分、超声心动图检查指标。结果未复发组消融前患者P波时间、MVP积分小于复发组,P波面积大于复发组,未复发组消融后1年患者P波时间、V_(1)P波负向部分振幅和时间的乘积(PtfV_(1))、P波面积、MVP积分小于复发组,差异均有统计学意义(均P<0.05)。复发组消融后1年PtfV_(1)大于消融前,差异有统计学意义(P<0.05)。心电图P波时间、P波面积、MVP积分是房颤消融后房颤复发的影响因素(均P<0.05)。ROC曲线分析发现,MVP积分诊断房颤复发的AUC较大(P=0.001)。未复发组消融前后左心房前后径(LAD)小于复发组,消融后左心室短轴缩短率、左心室射血分数大于复发组,差异均有统计学意义(均P<0.05)。复发组消融前后MVP积分与LAD均呈正相关(r=0.312、0.381,均P<0.05)。结论心电图MVP积分有助于预测房颤消融后复发。

人发角蛋白人工腱诱导自体腱形成中胶原原纤维的形态学变化

目的观察人发角蛋白(HHK)人工腱诱导自体腱形成过程中胶原原纤维形成的形态学变化。方法制备肌腱损伤动物模型,植入HHK人工腱,于术后3、6、9、12、16周取出,进行光镜及电镜观察。结果自体腱形成过程中,先后有一级、二级和三级胶原原纤维形成。结论HHK人工腱诱导自体腱形成过程中,人工腱植入区肌腱断端和腱膜下的腱细胞去分化,分泌大量的胶原蛋白,并在细胞外生成一级胶原原纤维,再逐级融合形成二级和三级胶原原纤维,最终多数腱细胞胶原化而消失。

心房颤动患者心房组织醛固酮水平与心房结构重构的相关性研究

目的探讨心房颤动患者心房组织醛固酮水平和心房结构重构的相关性。方法入选进行人工心脏瓣膜置换术的风湿性心脏病患者25例,其中窦性心律者12例,慢性心房颤动者13例(房颤时间≥6个月)。上述患者均于手术时取左右心房侧壁组织(窦性心律右房标本=12,左房标本=7;房颤心律右房标本=13,左房标本=8),用放射免疫法测定心房组织醛固酮水平;用免疫组织化学法对Ⅰ型胶原和Ⅲ型胶原容量分数(CVF-Ⅰ,CVF-Ⅲ)进行半定量分析;用VG染色法对总胶原容量分数(CVF)进行半定量分析。结果与窦性心律组比较,心房颤动组左房内径显著扩大(P<0.01);心房肌组织醛固酮、CVF-Ⅰ、CVF-Ⅰ/CVF-Ⅲ比值及CVF均明显增加(P<0.01);两组CVF-Ⅲ无差异;上述指标在左右心房之间无差异;CVF-Ⅰ与左心房直径(r=0.856,P<0.001)、CVF-Ⅰ/CVF-Ⅲ比值与心房颤动时间(r=0.766,P<0.01)、CVF与左心房直径(r=0.845,P<0.001)均显著正相关;心房组织醛固酮水平与左心房内径(r=0.814,P<0.001)和CVF(r=0.885,P<0.001)呈明显正相关。结论心房组织醛固酮水平在心房颤动心房结构重构中起重要作用,并可能参与了心房颤动的发生和维持。

胶原纤维溶胀液的流变特性研究

采用酸酶法制备牛肌腱胶原纤维,采用旋转粘度仪研究了不同浓度胶原纤维溶胀液的流变性能,并采用幂律方程对流变性能数据进行非线性回归拟合,得到胶原纤维在不同温度下的流变模型。研究结果表明,在实验范围内,浓度分别为0.5%,1.0%和1.5%的胶原纤维溶胀液的剪切应力均随着剪切速率与胶原纤维含量的增加而增大;随着温度的升高,胶原纤维溶胀液的表观粘度呈下降趋势,当体系温度达到36℃时,胶原纤维溶胀液的表观粘度下降急剧,胶原纤维发生热变性;胶原纤维溶胀液流体出现"剪切稀化"现象,表现出假塑性流体的特征,流变模型的拟合相关系数r2≥0.991,说明幂律模型能有效地表征胶原纤维溶胀液的流变性能。胶原纤维溶胀液的流变学特性研究为天然胶原纤维的进一步开发及利用提供了理论和实验依据。

兔耳增生性瘢痕的形态学观察与羟脯氨酸含量变化

目的 建立动物增生性瘢痕实验模型 ,并探讨其胶原代谢特点与形态学变化规律。方法 用圆形钻刀在兔耳腹面产生直径 6mm的全层皮肤缺损创面 6 4个 ,分别在术后 1 4、2 1、35、70和 98d进行形态学观察与羟脯氨酸含量测定。结果 术后 2 1d ,76 %的创面 ( 4 5 /5 9)有突出瘢痕形成 ,术后 35d ,瘢痕增生达高峰 ,厚度平均为 2 .0 5mm ,术后 70d ,瘢痕变薄 ,术后 98d ,46 %的突出瘢痕 ( 1 1 /2 4)消失 ;组织学观察示术后 2 1、35d有大量增殖成纤维细胞和旋涡状排列胶原纤维 ,术后 70、98d突出瘢痕内成纤维细胞减少 ,但不规则排列纤维仍存在 ;术后 2 1d ,瘢痕组织内羟脯氨酸含量增加 ,显著高于正常兔耳皮肤 (P <0 .0 5 ) ,35d时羟脯氨酸含量约为正常皮肤的 3倍 ,术后 98d的羟脯氨酸含量亦显著高于正常皮肤 (P <0 .0 5 )。结论 胶原大量沉积是动物增生性瘢痕的胶原代谢特征 ;动物正常愈合瘢痕转化为增生性瘢痕发生在术后 1 4～ 2 1d ;动物增生性瘢痕形成快 。

龙血竭对肺纤维化大鼠肺组织TGF-β/Smads信号通路分子mRNA表达的影响

目的观察龙血竭对肺纤维化大鼠肺组织TGF-β信号通路分子TGFβR及Smad4 mRNA表达的影响,探讨其防治肺纤维化的作用及机制。方法将30只SD大鼠随机分为3组:肺纤维化模型组,龙血竭治疗组和正常对照组,每组10只,雌雄各半。模型组和治疗组大鼠均以博来霉素(5 mg/kg)气管内滴入诱导肺纤维化;对照组以等量生理盐水气管内滴入。从第2 d起,治疗组大鼠给予龙血竭(180 mg/kg,溶于2 mL生理盐水中)灌胃,对照组和模型组大鼠则以等量生理盐水灌胃。所有大鼠于第29 d早晨处死。HE染色检测肺组织病理改变;原位杂交检测肺组织TGFβR及Smad4 mRNA表达;免疫组化法(S-P法)检测型胶原纤维。结果模型组肺组织内炎性细胞计数为22243.60±5011.55,治疗组为12913.78±5640.12,两组比较差异有统计学意义(P<0.01)。经龙血竭治疗后大鼠肺内TGFβR mRNA表达较模型组降低(P<0.01)。治疗组Smad4 mRNA表达与模型组比较差异无统计学意义。治疗组和模型组比较,型胶原纤维表达减弱(P<0.01)。结论龙血竭能有效地减轻肺纤维化大鼠的纤维化程度,其机制可能与抑制肺内TGFβR mRNA的表达,从而阻止型胶原过度沉积有关。

应用原子力显微镜对不同种属Ⅰ型胶原纤维微观结构的研究

目的 :利用原子力显微镜 (AFM)对猪和牛的Ⅰ型胶原蛋白在溶液中的聚集行为进行微观结构的形态学研究。方法 :将Ⅰ型胶原蛋白溶液 ,滴至新鲜剥离的云母片上 ,空气中干燥后 ,用原子力显微镜观察。结果 :发现来自猪和牛的I型胶原蛋白在浓度为 3 2 μg ml时以单体形式和聚集体形式混合存在 ,在浓度为 4mg ml时两种I型胶原蛋白自发装配成胶原纤维 ,形成多孔网状结构 ,孔隙大小为 :牛 ,10 0～ 15 0nm ;猪 ,170～ 2 0 0nm。孔隙率 :牛 ,5 75个 μm2 ;猪 ,193个 μm2 。平均粗糙度为 :牛 ,3 1nm ;猪 ,8 7nm。均方根粗糙度为 :牛 ,4 0nm ;猪 ,11 4nm。平均高度 :牛 ,5 0 9nm ;猪 ,5 2 3nm。Rp v :牛 ,72 1nm ;猪 ,10 2 7nm。结论 :利用原子力显微镜能够准确直观地观察到Ⅰ型胶原蛋白形成的胶原纤维的种属差异性 。