The construction of P-expansive maps of regular continua: A geometric approach

AbstractIn this paper, we prove the following: Let G be a graph, f:G→G a continuous map and P a finite subset of G such that f(P)⊂P. Then there exist a regular continuum Z, a continuous map g:Z→Z and a semi-conjugacy π:G→Z such that(1) g is π(P)-expansive, and(2) if p,q∈P and Q is a subset of P with A∩Q≠∅ for any arc A in G between p and q, then A′∩π(Q)≠∅ for any arc A′ in Z between π(p) and π(q).In addition, f is point-wise P-expansive if and only if π|P is one-to-one.In this paper we are especially interested in the geometrical structure of Z. Actually we can see the complicated construction of Z

Bone apatite anisotropic structure control: Via designing fibrous scaffolds

Bone tissue has an anisotropic structure, associated with the collagen fibrils' orientation and the c-axis direction of the bone apatite crystal. The bone regeneration process comprises two main phases: bone mineral density restoration (bone quantity), and subsequent recovery of bone apatite c-axis orientation (bone quality). Bone quality is the determinant factor for mechanical properties of bone. Control of osteoblast alignment is one of the strategies for reconstructing bone quality since the collagen/apatite matrix orientation in calcified tissues is dependent on the osteoblast orientation. In this work, fibrous scaffolds designed for reconstruction of bone quality via cell alignment control was investigated. The fibrous scaffolds were fabricated using the electrospinning method with poly(lactic acid) at various fiber collecting speeds. The degree of fiber alignment in the prepared fibrous scaffolds increased with increasing fiber collecting speed, indicating that the fibers were oriented in a single direction. The alignment of osteoblasts on the fibrous scaffolds as well as the subsequent apatite c-axis orientation increased with increasing fiber collecting speed. We successfully controlled cell alignment and apatite c-axis orientation using the designed morphology of fibrous scaffolds. To the best of our knowledge, this is the first report demonstrating that adjusting the degree of fiber orientation for fibrous scaffolds can manipulate the regeneration of bone quality.Lee S., Nagata F., Kato K., et al. Bone apatite anisotropic structure control: Via designing fibrous scaffolds. RSC Advances, 10, 23, 13500. https://doi.org/10.1039/d0ra01295e

The repeating dislodgement of an ASO device

Transcatheter closure with an Amplatzer Septal Occluder (ASO) has become the standard treatment for secundum atrial septal defect (ASD). However, this procedure is associated with complications, such as device dislodgement. A 52-year-old woman was admitted with exertional dyspnea. Transesophageal echocardiography showed an ASD involving a 29 mm defect. Calculated Qp/Qs was 5.6 and all the rims were > 5 mm, with the exception of the posterior rim, which was 3 mm. Transcatheter ASD closure with an ASO was performed under general anesthesia. During emergence from anesthesia, tachycardia developed and the ASO device became dislodged. Hemodynamic changes associated with the end of anesthetic administration were believed to have led to device dislodgement. In a second transcatheter ASD closure, a low dose of propofol and remifentanil was maintained during emergence from anesthesia to reduce hemodynamic changes. However, device dislodgement occurred with nonsustained ventricular tachycardia. Finally, surgical ASD closure was performed. The large defect size, high Qp/Qs, and rim deficiency may have predisposed to device dislodgement after transcatheter ASD closure with ASO. The risk of device dislodgement should be considered in advance of surgery and, in high-risk cases, the patient's cardiovascular status should be closely monitored

Development of orthophosphosilicate glass/poly(lactic acid) composite anisotropic scaffolds for simultaneous reconstruction of bone quality and quantity

Reconstruction of organ-specific architecture is necessary to recover the original organ function. The anisotropic structure of bone tissue is strongly related to the collagen fibril alignment and bone apatite crystal direction. Bone regeneration indicates following two main process; first, restoration of bone mineral density (BMD; bone quantity), and second, restoring bone apatite c-axis orientation (bone quality). In addition to BMD, bone quality is the most important factor among bone mechanical properties. Recovery of the original bone function requires development of novel scaffolds with simultaneous reconstruction of bone quality and quantity. Herein, novel orthophosphosilicate glass (PSG)/poly(lactic acid) composite anisotropic scaffolds were developed to control cell alignment and enhance bone formation, which are important for the simultaneous reconstruction of bone quality and quantity. The strategy to control cell alignment and bone formation involved designing anisotropic scaffolds in combination with the release of therapeutic ions by PSGs. The morphology of fibrous scaffolds containing PSGs was quantitatively designed using electrospinning. This successfully modulated cell alignment and subsequent bone apatite c-axis orientation along the fiber-oriented direction. The released silicate and Mg2+ ions from PSGs in scaffolds improved cell adhesion, proliferation, and calcification. To best of our knowledge, this is the first report demonstrating that the anisotropic scaffolds containing bioactive glasses regenerate bone tissues with simultaneous reconstruction of bone quality and quantity via stimulating osteoblasts by inorganic ions and designing morphology of scaffolds.Lee S., Nagata F., Kato K., et al. Development of orthophosphosilicate glass/poly(lactic acid) composite anisotropic scaffolds for simultaneous reconstruction of bone quality and quantity. Journal of Biomedical Materials Research - Part A, 109, 5, 788. https://doi.org/10.1002/jbm.a.37067

Structures and dissolution behaviors of quaternary CaO-SrO-P₂O₅-TiO₂ glasses

Calcium phosphate glasses have a high potential for use as biomaterials because their composition is similar to that of the mineral phase of bone. Phosphate glasses can dissolve completely in aqueous solution and can contain various elements owing to their acidity. Thus, the glass can be a candidate for therapeutic ion carriers. Recently, we focused on the effect of strontium ions for bone formation, which exhibited dual effects of stimulating bone formation and inhibiting bone resorption. However, large amounts of strontium ions may induce a cytotoxic effect, and there is a need to control their releasing amount. This work reports fundamental data for designing quaternary CaO-SrO-P₂O₅-TiO₂ glasses with pyro- and meta-phosphate compositions to control strontium ion-releasing behavior. The glasses were prepared by substituting CaO by SrO using the melt-quenching method. The SrO/CaO mixed composition exhibited a mixed cation effect on the glassification degree and ion-releasing behavior, which showed non-linear properties with mixed cation compositions of the glasses. Sr²⁺ ions have smaller field strength than Ca²⁺ ions, and the glass network structure may be weakened by the substitution of CaO by SrO. However, glassification degree and chemical durability of pyro- and meta-phosphate glasses increased with substituted all CaO by SrO. This is because titanium groups in the glasses are closely related to their glass network structure by SrO substitution. The P-O-Ti bonds in pyrophosphate glass series and TiO₄ tetrahedra in metaphosphate glass series increased with substitution by SrO. The titanium groups in the glasses were crosslink and/or coordinate phosphate groups to improve glassification degree and chemical durability. Sr²⁺ ion releasing amount of pyrophosphate glasses with >83% SrO substitution was larger than 0.1 mM at day seven, an amount that reported enhanced bone formation by stimulation of osteogenic markers.Lee S., Nagata F., Kato K., et al. Structures and dissolution behaviors of quaternary CaO-SrO-P₂O₅-TiO₂ glasses. Materials, 14, 7, 1736. https://doi.org/10.3390/ma14071736

MRI and CT features of a malignant myoepithelioma of the scrotum : A case report and literature review

Malignant myoepithelioma of the scrotum is extremely rare. We report the case of a 51-year-old man with malignant myoepithelioma of the scrotum, wherein computed tomography and magnetic resonance imaging revealed a lobulated soft tissue mass with calcification, cystic component, and solid component with gradual contrast enhancement on dynamic contrast-enhanced scans. The patient presented with scrotal induration, and there was no elevation of tumor markers and no evidence of a metastatic lesion on computed tomography and magnetic resonance imaging. Histopathological examination of the resected scrotal specimen confirmed a well-circumscribed solid tumor with septa, a small area of hemorrhage, and necrosis. The subsequent diagnosis was malignant myoepithelioma of the scrotum. This case shows that scrotal malignant myoepithelioma might appear as a well-defined lobulated mass with cystic regions. We conjecture that the enhancement pattern and apparent diffusion coefficient values can be potential markers for scrotal myoepithelial tumors

Pilot Analysis of Asbestos-induced Diffuse Pleural Thickening with Respiratory Compromise

We investigated the clinical features of asbestos-induced diffuse pleural thickening (DPT) with severe respiratory compromise. We conducted a retrospective study of consecutive subjects with asbestos-induced DPT. Medical data such as initial symptoms, radiological findings, respiratory function test results, and clinical course were collected and analyzed. There were 24 patients between 2003 and 2012. All were men, and the median age at the development of DPT was 74 years. The top occupational category associated with asbestos exposure was dockyard workers. The median duration of asbestos exposure was 35.0 years, and the median latency from first exposure to the onset of DPT was 49.0 years. There were no significant differences in respiratory function test results between the higher and lower Brinkman index groups or between unilateral and bilateral DPT. Thirteen patients had a history of benign asbestos pleural effusion (BAPE), and the median duration from pleural fluid accumulation to DPT with severe respiratory compromise was 28.4 months. DPT with severe respiratory compromise can develop after a long latency following occupational asbestos exposure and a history of BAPE

Computer aided diagnosis for severity assessment of pneumoconiosis using CT images

240,000 participants have a screening for diagnosis of pneumoconiosis every year in Japan. Radiograph is used for staging of severity in pneumoconiosis worldwide. This paper presents a method for quantitative assessment of severity in pneumoconiosis using both size and frequency of lung nodules that detected by thin-section CT images. This method consists of three steps. First, thoracic organs (body, ribs, spine, trachea, bronchi, lungs, heart, and pulmonary blood vessels) are segmented. Second, lung nodules that have radius over 1.5mm are detected. These steps used functions of our developed computer aided detection system of chest CT images. Third, severity in pneumoconiosis is quantified using size and frequency of lung nodules. This method was applied to nine pneumoconiosis patients. The initial results showed that proposed method can assess severity in pneumoconiosis quantitatively. This paper demonstrates effectiveness of our method in diagnosis and prognosis of pneumoconiosis in CT screening