Synchronized Heterogeneous Viscous Behavior of Soft Materials Upon Macroscopic Loading

Author(s):  
Wenting Gu ◽  
Jiayue Shen ◽  
Xavier-lewis Palmer ◽  
Zhili Hao

This paper presents a preliminary study on characterizing the synchronized heterogeneous viscous behavior of soft materials upon macroscopic sinusoidal loading. Built upon a polymer-based microfluidic device capable of detecting distributed normal loads at a spatial resolution of 1.5mm, a rigid cylinder probe is employed to exert a macroscopic sinusoidal load on a sample placed on the device. Consequently, the synchronized heterogeneous viscous behavior of a sample translates to sinusoidal distributed loads, which are captured by the device. In a measurement, the input and output signals of a sample are the macroscopic sinusoidal load and the DC voltage outputs of the device, respectively, with the latter being representative of the sinusoidal deflections of a sample along its length. A preliminary data analysis is conducted on the recorded input and output signals to obtain their phase shifts at different frequencies, which are representative of the heterogeneous viscosity of a sample along its length. Several agar and polydimethylsiloxane (PDMS) samples and two animal cartilage tissue samples are prepared and measured. Variations among the measured phase shifts in a sample manifest its structural heterogeneity and demonstrate the feasibility of using the device to characterize the synchronized heterogeneous viscous behavior of soft materials upon macroscopic loading.

2017 ◽  
Vol 18 (2) ◽  
pp. 68
Author(s):  
Made Padmika ◽  
I Made Satriya Wibawa ◽  
Ni Luh Putu Trisnawati

A prototype of a wind power plant had been created using a ventilator  as a generator spiner. This power plant utilizes wind speed as its propulsion. Electricity generated in the DC voltage form between 0 volts up to 7.46 volts. The MT3608 module is used to stabilize and raise the voltage installed in the input and output of the charging circuit. For instrument testing, the wind speed on 0 m/s up to 6 m/s interval used. Maximum output of this tool with a wind speed of 6 m/s is 7.46 volts.


Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 489
Author(s):  
Sylwia Prochowska ◽  
Agnieszka Partyka ◽  
Wojciech Niżański

Apoptosis is a crucial process in spermatogenesis, responsible for the elimination of abnormal sperm cells and testicular regression out of breeding season. The aim of this study was to assess if the expression of apoptosis-related genes in testicular tissue of domestic cats differed: (1) between normozoospermic and teratozoospermic donors, and (2) between reproductive and non-reproductive season. The expression of genes: BCL2L1, BCL2, BAX, BAD, FAS, FASLG, and caspases (CASP3, CASP8, CASP9, and CASP10) was analyzed by qRT-PCR in testicular tissue samples. During non-reproductive season significantly higher expression of two anti-apoptotic genes (BCL2L1 and BCL2) was observed. Additionally, there was a significant higher expression of CASP10 in teratozoospermic cats during non-reproductive than during reproductive season. No differences were noted between normozoospermic and teratozoospermic groups. Upregulation of some genes during the non-reproductive season indicates engagement of apoptotic mechanisms in the seasonal changes of semen quality in cats, however further studies on protein levels and analysis of changes on distinct testicular germinal layers are required. At the same time, teratozoospermia in the general population of cats seems to be not connected with dysregulation of apoptosis in the testes.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tadahisa Inoue ◽  
Hiromu Kutsumi ◽  
Mayu Ibusuki ◽  
Masashi Yoneda

AbstractAlthough endobiliary radiofrequency ablation (RFA) has demonstrated considerable potential for the treatment of biliary strictures, conventional catheter RFA has several limitations. This study aimed to evaluate the feasibility of a novel cholangioscopy (CS)-guided balloon-based RFA procedure in vivo using a swine model. CS-guided balloon-RFA was performed under endoscopic retrograde cholangiography guidance at target temperatures of 60 ℃ or 70 ℃, which were maintained for 60 s. We evaluated the technical feasibility, adverse events, and histological effects associated with the procedure. Twelve sites were ablated in seven miniature pigs. The CS-guided balloon-RFA procedure was technically successful in all cases without any hindrance. Mucosal changes could be detected during RFA, and the ablation area was identified on CS. Necropsy was performed in four pigs on the same day as the procedure: the tissue samples showed coagulative necrosis, and the entire internal circumference of the bile duct was uniformly ablated. The mean lengths of the ablation area in the samples ablated at 60 °C and 70 °C were 20.64 and 22.18 mm, respectively, while the mean depths were 3.46 and 5.07 mm, respectively. The other three pigs were reared and euthanized and autopsied 35 days after the procedure. The site to be ablated had replaced the granulation tissue and fibrotic changes. No adverse events were observed in any case. CS-guided balloon-RFA appears to be a promising option for treating biliary strictures. This preliminary study could pave the way for the evaluation of this procedure in future human clinical trials.


2021 ◽  
Author(s):  
Shojiro Katoh ◽  
Hiroshi Yoshioka ◽  
Shoji Suzuki ◽  
Hiroyuki Nakajima ◽  
Masaru Iwasaki ◽  
...  

Chondrocytes are used in cell-based therapies such as autologous chondrocyte implantation (ACI) and matrix-associated cartilage implantation (MACI). To transport the cartilage tissue to the laboratory for in vitro culturing, phosphate-buffered saline (PBS), Euro-Collins solution (ECS) and Dulbecco Modified Eagle Medium (DMEM) are commonly employed at 4-8 deg C. In this study, eight samples of human cartilage biopsy tissues from elderly patients with severe osteoarthritis undergoing arthroscopy, which would otherwise have been discarded, were used. The cartilage tissue samples were compared to assess the cell yield between two transportation groups: i) a thermo-reversible gelation polymer (TGP) based method without cool preservation (~25 deg C) and ii) ECS transport at 4 deg C. These samples were subjected to in vitro culture in a two-dimensional (2D) monolayer for two weeks and subsequently in a three-dimensional (3D) TGP scaffold for six weeks. The cell count obtained from the tissues transported in TGP was higher (0.2 million cells) than those transported in ECS (0.08 million cells) both after initial processing and after in vitro culturing for 2 weeks in 2D (18 million cells compared with 10 million cells). In addition, mRNA quantification demonstrated significantly higher expression of Col2a1 and SOX-9 in 3D-TGP cultured cells and lower expression of COL1a1 in RT-PCR, characteristic of the hyaline cartilage phenotype, than in 2D culture. This study confirms that the TGP cocktail is suitable for both the transport of human cartilage tissue and for in vitro culturing to yield better-quality cells for use in regenerative therapies.


2017 ◽  
Vol 21 (03) ◽  
pp. 276-280 ◽  
Author(s):  
Ezzeddin Elsheikh ◽  
Mohammad El-Anwar ◽  
Hesham Abdel-aziz

Introduction The main histological features of the nasal mucosa in choanal atresia are distorted cilia, marked increase of mucous submucosal glands associated with marked reduction of goblet cell density, and lymphocytic cellular infiltration. Objective To study the nasal mucosal changes in cases of choanal atresia after successful repair compared with pre-repair mucosal histological features. Methods Tissue samples were taken from the inferior turbinate of 3 patients (1 bilateral and 2 unilateral) who were successfully operated. Then, the biopsies were subjected to histopathological, histochemical and immunohistochemical studies. After that, the results were compared with pre-repair findings in the choanal atresia side and in the normal side. Results Four biopsies (4 repaired choanal atresia sides) of the mucosa of the inferior turbinate revealed that 1 patient (who had a bilateral choanal atresia repaired), after achieving a patent choana for 8 months, had not completely recovered a normal nasal mucosa. The other 2 patients, after 18 and 23 months of achieving a patent choana, showed normal nasal cavities. Conclusion The main histological features of the nasal mucosa in choanal atresia could be reversed by surgery, making the patients regain their choanal patency, with their mucosae changing back to normal gradually with time.


2009 ◽  
Vol 15 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Milos Petrovic ◽  
Dragan Mitrakovic ◽  
Branko Bugarski ◽  
Daniel Vonwil ◽  
Ivan Martin ◽  
...  

The provision of mechanical stimulation is believed to be necessary for the functional assembly of skeletal tissues, which are normally exposed to a variety of biomechanical signals in vivo. In this paper, we present a development and validation of a novel bioreactor aimed for skeletal tissue engineering that provides dynamic compression and perfusion of cultivated tissues. Dynamic compression can be applied at frequencies up to 67.5 Hz and displacements down to 5 ?m thus suitable for the simulation of physiological conditions in a native cartilage tissue (0.1-1 Hz, 5-10 % strain). The bioreactor also includes a load sensor that was calibrated so to measure average loads imposed on tissue samples. Regimes of the mechanical stimulation and acquisition of load sensor outputs are directed by an automatic control system using applications developed within the LabView platform. In addition, perfusion of tissue samples at physiological velocities (10-100 ?m/s) provides efficient mass transfer, as well as the possibilities to expose the cells to hydrodynamic shear and simulate the conditions in a native bone tissue. Thus, the novel bioreactor is suited for studies of the effects of different biomechanical signals on in vitro regeneration of skeletal tissues, as well as for the studies of newly formulated biomaterials and cell biomaterial interactions under in vivo-like settings.


2017 ◽  
Vol 17 (2) ◽  
pp. 3-8
Author(s):  
Emils Smitins ◽  
Dace Danberga ◽  
Mara Pilmane ◽  
Ilze Akota

Abstract Introduction. Facial morphogenesis occurs from the fourth to the twelfth gestation week, when the cells from nerve crest migrate to the region of face, forming the primary palate. The cleft palate is an abnormality in embryogenesis period, which is characterized by the absence of fusion of palatal shelves. The incidence of cleft lip and palate is one in 700 live births. In recent years the effect of different genes and signaling molecules, including Runx2, Wnt3 and OPG have been studied in the development of cleft palate, because these substances are considered to be regulators of pathogenesis responsible for formation of bone and cartilage tissue and particularly the bone. Aim of the Study. The aim of the work was to evaluate the expression of Runx2, Wnt3 and OPG in palate bone and nasal cartilage for children with cleft palate. Material and methods.Eleven bone and cartilage samples were obtained from 21 children of the lip, soft and hard palate correction surgery. All the patients were diagnosed with clefts of the lip, alveolar process of maxilla, and palate. In the tissue sections using the immunohistochemistry method (IMH), were determined Runx2 (code: AB192256, 1: 250, Abcam GB, rabbit), Wnt3 (code: AB1992, 1: 800, Abcam GB, rabbit), and OPG (code: A0611, 1: 100, The Orbit USA, rabbit) local expression. We used a semi-quantitative census method for quantifying the positive structures. Results. Runx2 expression was observed in five patient bone tissue samples and six patient cartilage tissue samples. Of the Runx2 positive bone tissue, in one case we observed occasional, in two cases- few, in one case- moderate to numerous and in one case numerous positive osteocytes while in tissue of cartilage in two cases we observed few, in one case- few to moderate, in two casesmoderate, and in one case numerous positive chondrocytes. A significant difference in Wnt3 expiation was observed between bone and cartilage tissues. Wnt3 expressing chondrocytes were observed in all samples, where in one case- occasional, in three cases few, in one case-moderate, and in six cases-numerous positive cartilage cells were observed. The expression of the gene in the bone was observed in nine cases, which contained mostly occasional or few positive structures, except in three cases where in one Wnt3 was marked by few to moderate and in two cases numerous positive osteocytes. OPG expression was observed in all samples, but in the cartilage, the expression was more pronounced. In the cartilage in seven cases, there were numerous positive chondrocytes, in one case- few to moderate, in two cases moderate to numerous and in one case few to moderate number of chondrocytes. OPG showed variable expression. In four cases, we observed occasional to few, in one case few to moderate, in one case- moderate, in one case moderate to numerous and in four cases numerous positive bone cells. Conclusion. Cartilage tissue expresses significantly more Runx2, Wnt3 genes and OPG proteins, indicating a greater compensatory tissue capacity. In the case of palate clefts, the high expression of Wnt3 and OPG and lower expression of Runx2 could indicate a significant tissue proliferation which predominates over mineralization and ossification processes.


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