Elastic fiber degradation in the development of pediatric granuloma annulare:Report of 39 cases

BACKGROUND Granuloma annulare(GA)has diverse clinical manifestations,multiple subtypes,and unknown etiology and pathogenesis.Existing studies regarding GA in children are scarce.AIM To examine the correlation between clinical manifestation and histopathology of pediatric GA.METHODS A total of 39 patients under 18 years of age with both a clinical and pathological diagnosis of GA at Kunming Children's Hospital from 2017 to 2022 were retrieved.Their medical records were consulted,and clinical data of the children were recorded and summarized,including gender,age,disease site,etc.Existing wax blocks of skin lesion specimens of children and pathological films were retrieved for further study and relevant histology,including hematoxylin-eosin,Alcian blue,elastic fiber(Victoria blue-Lichon red method),and antacid staining.Finally,the children’s clinical manifestations,histopathological results,and special staining characteristics were analyzed.RESULTS The clinical manifestations of granuloma annulare in children were diverse:11 cases presented with a single lesion,25 with multiple lesions,and 3 with generalized lesions.The pathological typing comprised histiocytic infiltration,palisading granuloma,epithelioid nodular,and mixed types in 4,11,9,and 15 cases,respectively.Thirty-nine cases were negative for antacid staining.The positive rate of Alcian blue staining was 92.3%,and that of elastic fiber staining was 100%.The degree of elastic fiber dissolution and granuloma annulare histopathological typing were positively correlated(r=0.432,P<0.05).No correlation was found between clinical presentation and histopathological typing of the granuloma annulare in children.In the pathological diagnosis of granuloma annulare,the positive elastic fiber staining rate was higher than that of Alcian blue staining.A correlation was found between elastic fiber dissolution degree and histopathological staging.However,the differences in pathological staging may have been related to the pathological manifestation of granuloma annulare at different periods.CONCLUSION Elastic fiber degradation may be a critical step in the pathogenesis of pediatric granuloma annulare.This is also one of the first studies focused on granuloma annulare in children.

The role of elastic fibers in pathogenesis of conjunctivochalasis

The Pub Med,MEDLINE databases and China National Knowledge Infrastructure（CNKI）were searched for information regarding the etiology and pathogenesis of conjunctivochalasis（CCh）and the synthesis and degradation of elastic fibers.After analysis of the literature,we found elastic fibers was a complex protein molecule from the structure and composition;the degradation of elastic fibers was one of the histopathological features of the disease;the vast majority of the factors related to the pathogenesis of CCh ultimately pointed to abnormal elastic fibers.By reasonably speculating,we considered that abnormal elastic fibers cause the conjunctival relaxation.In conclusion,we hypothesize that elastic fibers play an important role in the pathogenesis of CCh.Studies on the mechanism of synthesis,degradation of elastic fibers are helpful to clarify the pathogenesis of the disease and to find effective treatment methods.

Stabilize and Reinforce Hydrogen-Bonded Polymer Complex Elastic Fiber by Catechol Chemistry and Coordination

Hydrogen-bonded polymer complex fiber of poly(ethylene oxide)(PEO)and poly(acrylic acid)(PAA)shows rubber elasticity in ambient environment,but the fiber has relatively low strength and weak stability.We apply the catechol chemistry and metal coordination to stabilize and strengthen the PEO/PAA fiber.PAA is grafted with dopamine(Dopa),and then combines with PEO to prepare fiber.PAA-Dopa in the fiber is crosslinked through oxidation induced dismutation and the metal ions are introduced through coordination.The cross-linking and coordination greatly improve the stability of the fiber against the erosion of alkaline water.Among four different metal coordination fibers,PEO/PAA-Dopa/Cu fiber keeps the excellent extensibility(~1000%)and presents much higher initial modulus(~7 MPa),ultimate strength(~20 MPa),and toughness(~60 MJ/m^(3))than its precursor PEO/PAA fiber.In addition,PEO/PAA-Dopa/Cu fiber shows quick recovery and large energy dissipation ratio compared with the PEO/PAA fiber.The distinct mechanical properties enhancement of the hydrogen-bonded complex fiber is attributed to the synergy of hydrogen bonds,coordination and covalent bond cross-linking.

Liquid Metal-Based Self-Healable and Elastic Conductive Fiber in Complex Operating Conditions

Flexible conductive fibers are essential for wearable electronics and smart electronic textiles.However,in complex operating conditions,conductive fibers will inevitably fracture or damage.Herein,we have developed an elastic conductive self-healable fiber(C-SHF),of which the electrical and mechanical properties can efficiently heal in a wide operating range,including room temperature,underwater,and low temperature.This advantage can be owed to the combination of reversible covalent imine bond and disulfide bond,as well as the instantaneous self-healing ability of liquid metal.The C-SHF,with stretchability,conductivity stability,and universal self-healing properties,can be used as an electrical signal transmission line at high strain and under different operating conditions.Besides,C-SHF was assembled into a double-layer capacitor structure to construct a self-healable sensor,which can effectively respond to pressure as a wearable motion detector.

Elastic fiber regeneration in vitro and in vivo for treatment of experimental abdominal aortic aneurysm

Background The pathological characteristics of abdominal aortic aneurysm （AAA） involved the regression of extracellular matrix （ECM） in aortic walls, especially elastic structure in medial layer. As the major structural protein of aorta, elastin contributes to the extensibility and elastic recoil of the vessels. We hypothesized that overexpression of elastin in vessel walls might regenerate the elastic structure of ECM, restore the elastic structure of the aneurysmal wall, and eventually lead to a reduction of aortic diameters （ADs） in an experimental model of AAA. Methods Tropoelastin （TE） of Sprague Dawley （SD） rat was synthesized by reverse transcription polymerase chain reaction and used to construct adneviral vectors containing elastin precursor protein （AdTE-GFP）. Cultured vascular smooth muscle cells （VSMCs） from aortas of male SD rats were transfected with AdTE-GFP, AdGFP, adenoviral vector （AdNull）, and phosphate buffered saline （PBS）. Immunofluorescence staining was performed to determine the expression of elastin in transfected cells. The expression of elastic fibers in ECM of VSMCs transfected with AdTE-GFP were detected by fluorescence microscopy and transmission electron microscopy （TEM） at 1, 3, and 5 days following gene transfer. The AAA vessel walls were infused with AdTE-GFP or an empty AdNull, or PBS directly into the aneurysmal lumen. ADs of the aneurysms were compared in infused aortas. Formation of new elastic fibers in vivo was assessed by hematoxylin and eosin, and elastic von-Giesson staining. Recombinant elastin-GFP in vivo was identified by immunohistochemical staining. Results Elastic fibers were increased both in ECM of VSMC and in vessel walls after gene transfer. Histological studies revealed that the AdTE-GFP-transduced aortas had elastic fiber regeneration in the aneurysmal walls. The AdTE-GFP-transduced aortas showed a decreased AD （23.04%±14.49%, P 〈0.01） in AAA vessel walls. Conclusions Elastic fibers have been successfully overexpressed both in vitro and in a rat model of AAA by a technique of gene transfer. The overexpression of elastic fibers within the aneurysmal tissue appeared to reverse the aneurysm dilatation in this model.

Facile and Large-scale Fabrication of Self-crimping Elastic Fibers for Large Strain Sensors

Stretchable conductive fibers offer unparalleled advantages in the development of wearable strain sensors for smart textiles due to their excellent flexibility and weaveability.However,the practical applications of these fibers in wearable devices are hindered by either contradictory properties of conductive fibers(high stretchability versus high sensing stability),or lack of manufacturing scalability.Herein,we present a facile approach for highly stretchable self-crimping fiber strain sensors based on a polyether-ester(TPEE)elastomer matrix using a side-by-side bicomponent melt-spinning process involving two parallel but attached components with different shrinkage properties.The TPEE component serves as a highly elastic mechanical support layer within the bicomponent fibers,while the conductive component(E-TPEE)of carbon black(CB),multiwalled carbon nanotubes(MWCNTs)and TPEE works as a strain-sensitive layer.In addition to the intrinsic elasticity of the matrix,theTPEE/E-TPEE bicomponent fibers present an excellent form of elasticity due to self-crimping.The self-crimping elongation of the fibers can provide a large deformation,and after the crimp disappears,the intrinsic elastic deformation is responsible for monitoring the strain sensing.The reliable strain sensing range of theTPEE/E-TPEE composite fibers was 160%-270%and could be regulated by adjusting the crimp structure.More importantly,the TPEE/E-TPEE fibers had a diameter of 30-40 pm and tenacity of 40-50 MPa,showing the necessary practicality.This work introduces new possibilities for fiber strain sensors produced in standard industrial spinning machines.

Elastic and Stretchable Functional Fibers: A Review of Materials, Fabrication Methods, and Applications

Elastic and stretchable functional fibers have drawn attentions from wide research field because of their unique advantages including high dynamic bending elasticity,stretchability and high mechanic strength.Lots of efforts have been made to find promising soft materials and improve the processing methods to fabricate the elastomer fibers with controllable fiber geometries and designable functionalities.Significant progress has been made and various interdisciplinary applications have been demonstrated based on their unique mechanical performance.A series of remarkable applications,involving biomedicine,optics,electronics,human machine interfaces etc.,have been successfully achieved.Here,we summarize main processing methods to fabricate soft and stretchable functional fibers using different types of elastic materials,which are either widely used or specifically developed.We also introduce some representative applications of multifunctional elastic fibers to reveal this promising research area.All these reported applications indicate that the fast innovated interdisciplinary area is of great potential and inspire more remarkable ideas in fiber sensing,soft electronics,functional fiber integration and other related research fields.

Effects of aging on the architecture of the ileocecal junction in rats

AIM: To evaluate the structural organization of the elastic and collagen fibers in the region of the ileocecal transition in 30 young and old male Wistar rats. METHODS: Histology, immunohistochemistry(IHC), transmission electron microscopy and scanning electron microscopy were employed in this study. The results demonstrated that there was a demarcation of the ileocecal region between the ileum and the cecum in both groups. RESULTS: The connective tissue fibers had different distribution patterns in the two groups. IHC revealed the presence of nitric oxide synthase, enteric neurons and smooth muscle fibers in the ileocecal junctions(ICJs) of both groups. Compared to the young group, the elderly group exhibited an increase in collagen type Ⅰ?fibers, a decrease in collagen type Ⅲ fibers, a decreased linear density of oxytalan elastic fibers, and a greater linear density of elaunin and mature elastic fibers. CONCLUSION: The results revealed changes in the patterns of distribution of collagen and elastic fibers that may lead to a possible decrease in ICJ functionality.

钢纤维增强混凝土的机理及断裂模型

以钢纤维对混凝土基体的增强、增韧效果以及钢纤维混凝土材料在单向拉伸条件下的本构行为为研究对象,总结了钢纤维对于混凝土材料中宏微观裂纹扩展阻滞效果的力学模型以及钢纤维增韧混凝土的力学模型。