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1.
J Hazard Mater ; 441: 129928, 2023 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-36113349

RESUMEN

This study investigates the performance of a pilot-scale submerged hollow fiber (HF) ultrafiltration (UF) polytetrafluoroethylene (PTFE) membrane filtration system for the treatment of two different types of oily seawater (i.e., seawater contaminated with light and heavy crude oil). The effects of membrane flux and aeration flow rate on membrane performance and the removal efficiency of different fractions of hydrocarbon, including polycyclic aromatic hydrocarbons (PAHs) were examined. The results for both heavy and light crude oil contaminated wastewater reveal that total petroleum hydrocarbon (TPH) removal efficiency of more than 91% was achieved. This research paper determined the optimal operational parameters for an HF membrane filtration system to obtain a good TPH removal efficiency. This system can easily be upscaled and placed on a barge to treat oily wastewater generated from marine oil spills, which can significantly improve the oil spill response capacity.


Asunto(s)
Contaminación por Petróleo , Petróleo , Hidrocarburos Policíclicos Aromáticos , Hidrocarburos , Aceites , Petróleo/análisis , Contaminación por Petróleo/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Politetrafluoroetileno , Agua de Mar , Aguas Residuales
2.
Digit J Ophthalmol ; 28(3): 51-57, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36405443

RESUMEN

Purpose: Scleral-fixation of intraocular lenses (IOLs) provides an option for eyes that lack sufficient capsular support for in-the-bag IOL placement. The latest techniques for lens fixation include use of a novel suture material, Gore-Tex, and a sutureless method, with flanged intrascleral fixation. The purpose of this pilot study was to compare these methods in terms of anatomic and clinical outcomes. Methods: A total of 35 eyes of patients 18-60 years of age who presented with aphakia, subluxated lens, or ectopia lentis were randomized into two groups. Group A (15 eyes) underwent flanged intrascleral IOL fixation using the Yamane technique; group B (20 eyes) underwent 4-point transscleral fixation of IOL using Gore-Tex suture. The following parameters were compared between groups on day 1, week 3, and month 6 postoperatively: logMAR uncorrected and best-corrected visual acuity, retinoscopy, IOL centration on slit-lamp biomicroscopy, and IOL tilt on ultrasound biomicroscopy. Results: Postoperative visual acuity was better in group B: uncorrected, logMAR 0.89 ± 0.22 versus 0.72 ± 0.24 (P = 0.046); best-corrected, logMAR 0.51 ± 0.18 versus 0.37 ± 0.26 (P = 0.016). No significant difference was found in postoperative retinoscopy and astigmatism between groups. IOL tilt (>100 µm) occurred in 8 cases in group A and in 9 cases in group B; 87% in group A and 100% in group B were well centered. Complications in both groups were minimal. Conclusions: In our small study cohort, both sutureless flanged IOL fixation and Gore-Tex sutured scleral IOL fixation resulted in excellent visual rehabilitation of patients with aphakia and subluxated lenses. Patients who underwent Gore-Tex suture fixation experienced better postoperative visual acuity, IOL centration, and stability.


Asunto(s)
Afaquia Poscatarata , Lentes Intraoculares , Humanos , Afaquia Poscatarata/cirugía , Proyectos Piloto , Implantación de Lentes Intraoculares/métodos , Politetrafluoroetileno , Técnicas de Sutura , Estudios Retrospectivos
3.
Nat Commun ; 13(1): 6808, 2022 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-36357396

RESUMEN

The mechanistic target of rapamycin complex 1 (mTORC1) integrates inputs from growth factors and nutrients, but how mTORC1 autoregulates its activity remains unclear. The MiT/TFE transcription factors are phosphorylated and inactivated by mTORC1 following lysosomal recruitment by RagC/D GTPases in response to amino acid stimulation. We find that starvation-induced lysosomal localization of the RagC/D GAP complex, FLCN:FNIP2, is markedly impaired in a mTORC1-sensitive manner in renal cells with TSC2 loss, resulting in unexpected TFEB hypophosphorylation and activation upon feeding. TFEB phosphorylation in TSC2-null renal cells is partially restored by destabilization of the lysosomal folliculin complex (LFC) induced by FLCN mutants and is fully rescued by forced lysosomal localization of the FLCN:FNIP2 dimer. Our data indicate that a negative feedback loop constrains amino acid-induced, FLCN:FNIP2-mediated RagC activity in renal cells with constitutive mTORC1 signaling, and the resulting MiT/TFE hyperactivation may drive oncogenesis with loss of the TSC2 tumor suppressor.


Asunto(s)
Aminoácidos , Lisosomas , Diana Mecanicista del Complejo 1 de la Rapamicina/genética , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Retroalimentación , Lisosomas/metabolismo , Aminoácidos/metabolismo , Politetrafluoroetileno/metabolismo
4.
ACS Appl Mater Interfaces ; 14(45): 50543-50556, 2022 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-36331290

RESUMEN

The COVID-19 pandemic has revealed the importance of the detection of airborne pathogens. Here, we present composite air filters featuring a bioinspired liquid coating that facilitates the removal of captured aerosolized bacteria and viruses for further analysis. We tested three types of air filters: commercial polytetrafluoroethylene (PTFE), which is well known for creating stable liquid coatings, commercial high-efficiency particulate air (HEPA) filters, which are widely used, and in-house-manufactured cellulose nanofiber mats (CNFMs), which are made from sustainable materials. All filters were coated with omniphobic fluorinated liquid to maximize the release of pathogens. We found that coating both the PTFE and HEPA filters with liquid improved the rate at which Escherichia coli was recovered using a physical removal process compared to uncoated controls. Notably, the coated HEPA filters also increased the total number of recovered cells by 57%. Coating the CNFM filters did not improve either the rate of release or the total number of captured cells. The most promising materials, the liquid-coated HEPA, filters were then evaluated for their ability to facilitate the removal of pathogenic viruses via a chemical removal process. Recovery of infectious JC polyomavirus, a nonenveloped virus that attacks the central nervous system, was increased by 92% over uncoated controls; however, there was no significant difference in the total amount of genomic material recovered compared to that of controls. In contrast, significantly more genomic material was recovered for SARS-CoV-2, the airborne, enveloped virus, which causes COVID-19, from liquid-coated filters. Although the amount of infectious SARS-CoV-2 recovered was 58% higher, these results were not significantly different from uncoated filters due to high variability. These results suggest that the efficient recovery of airborne pathogens from liquid-coated filters could improve air sampling efforts, enhancing biosurveillance and global pathogen early warning.


Asunto(s)
Filtros de Aire , COVID-19 , Virus , Humanos , Pandemias , SARS-CoV-2 , COVID-19/prevención & control , Bacterias , Polvo , Politetrafluoroetileno
5.
BMC Oral Health ; 22(1): 490, 2022 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-36376891

RESUMEN

OBJECTIVES: The aim of this study was to evaluate the effects of membrane exposure during vertical ridge augmentation (VRA) utilizing guided bone regeneration with a dense polytetrafluoroethylene (d-PTFE) membrane and a tent-pole space maintaining approach by registering radiographic volumetric, linear and morphological changes. METHODS: In 8 cases alveolar ridge defects were accessed utilizing a split-thickness flap design. Following flap elevation VRA was performed with tent-pole space maintaining approach utilizing the combination of a non-reinforced d-PTFE membrane and a composite graft (1:1 ratio of autogenous bone chips and bovine derived xenografts). Three-dimensional radiographic evaluation of hard tissue changes was carried out with the sequence of cone-beam computed tomography (CBCT) image segmentation, spatial registration and 3D subtraction analysis. RESULTS: Class I or class II membrane exposure was observed in four cases. Average hard tissue gain was found to be 0.70 cm3 ± 0.31 cm3 and 0.82 cm3 ± 0.40 cm3 with and without membrane exposure resulting in a 17% difference. Vertical hard tissue gain averaged 4.06 mm ± 0.56 mm and 3.55 mm ± 0.43 mm in case of submerged and open healing, respectively. Difference in this regard was 14% between the two groups. Horizontal ridge width at 9-month follow-up was 5.89 mm ± 0.51 mm and 5.61 mm ± 1.21 mm with and without a membrane exposure respectively, resulting in a 5% difference. CONCLUSIONS: With the help of the currently reported 3D radiographic evaluation method, it can be concluded that exposure of the new-generation d-PTFE membrane had less negative impact on clinical results compared to literature data reporting on expanded polytetrafluoroethylene membranes.


Asunto(s)
Pérdida de Hueso Alveolar , Aumento de la Cresta Alveolar , Humanos , Bovinos , Animales , Aumento de la Cresta Alveolar/métodos , Politetrafluoroetileno/uso terapéutico , Regeneración Tisular Guiada Periodontal/métodos , Membranas Artificiales , Pérdida de Hueso Alveolar/diagnóstico por imagen , Pérdida de Hueso Alveolar/cirugía , Pérdida de Hueso Alveolar/tratamiento farmacológico , Proceso Alveolar/cirugía , Trasplante Óseo/métodos , Implantación Dental Endoósea/métodos
6.
United European Gastroenterol J ; 10(8): 874-887, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36217553

RESUMEN

BACKGROUND: Transjugular intrahepatic portosystemic shunt (TIPS) may be used as a salvage treatment in patients with cirrhosis and refractory variceal bleeding. AIM: To synthesize the available evidence on the efficacy of TIPS in patients with cirrhosis and refractory variceal bleeding. METHODS: Meta-analysis of trials evaluating TIPS in patients with cirrhosis and refractory variceal bleeding, including subgroup analysis to assess the impact of recent changes in the management of variceal bleeding (i.e., the use of Polytetrafluoroethylene-covered TIPS and the availability of pre-emptive TIPS as a first-line treatment for acute variceal bleeding). RESULTS: Twenty-three studies with 1430 patients were included. The pooled estimate rates were 0.33 (95% CI = 0.29-0.37) for death at 1 month-6 weeks, 0.46 (95% CI = 0.40-0.52) for death at 1 year, and 0.09 (95% CI = 0.06-0.11) for death due to rebleeding in the follow-up. The pooled estimate rates for death at 1 month or 6 weeks were similar in subgroup analyses including studies that did not use covered TIPS or that did not include patients after the pre-emptive TIPS area compared to the ones that did (pooled estimate rate 0.33 [95% CI = 0.28-0.38] and 0.32 [95% CI = 0.25-0.39], respectively). The pooled estimate rates were 0.16 (95% CI = 0.13-0.18) for rebleeding, 0.25 (95% CI = 0.17-0.36) for occurrence of hepatic encephalopathy, and 0.08 (95% CI = 0.05-0.13) for access to liver transplantation after TIPS insertion. CONCLUSIONS: One third of patients with cirrhosis and refractory variceal bleeding treated with salvage TIPS died within the first 6 weeks. Recent improvements in the management of variceal bleeding did not improve the survival of patients presenting with refractory variceal bleeding.


Asunto(s)
Várices Esofágicas y Gástricas , Derivación Portosistémica Intrahepática Transyugular , Várices Esofágicas y Gástricas/diagnóstico , Várices Esofágicas y Gástricas/etiología , Várices Esofágicas y Gástricas/cirugía , Hemorragia Gastrointestinal/diagnóstico , Hemorragia Gastrointestinal/etiología , Hemorragia Gastrointestinal/cirugía , Humanos , Cirrosis Hepática/complicaciones , Cirrosis Hepática/cirugía , Politetrafluoroetileno , Derivación Portosistémica Intrahepática Transyugular/efectos adversos , Recurrencia , Terapia Recuperativa
7.
Environ Sci Technol ; 56(22): 16453-16461, 2022 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-36316194

RESUMEN

Aerosol iron (Fe) solubility is a key factor for the assessment of atmospheric nutrients input to the ocean but poorly specified in models because the mechanism of determining the solubility is unclear. We develop a deep learning model to project the solubility based on the data that we observed in a coastal city of China. The model has five variables: the size range of particles, relative humidity, and the ratios of sulfate, nitrate and oxalate to total Fe (TFe) contents in aerosol particles. Results show excellent statistical agreements with the solubility in the literature over most worldwide seas and margin areas with the Pearson correlation coefficients (r) as large as 0.73-0.97. The exception is the Atlantic Ocean, where good agreement is obtained with the model trained using local data (r: 0.34-0.66). The model further uncovers that the ratio of oxalate/TFe is the most important variable influencing the solubility. These results indicate the feasibility of treating the solubility as a function of the six factors in deep learning models with careful training and validation. Our model and projected solubility provide innovative options for better quantification of air-to-sea input of aerosol soluble Fe in observational and model studies in the global marine atmosphere.


Asunto(s)
Atmósfera , Hierro , Solubilidad , Aerosoles , Aprendizaje Automático , Oxalatos , Politetrafluoroetileno
8.
J Pak Med Assoc ; 72(8): 1479-1482, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36280905

RESUMEN

Objectives: To evaluate the depth of cure in smart dentin replacement bulkfill composite resins polymerized by constant, pulse and ramped light-emitting diode curing modes. METHODS: The in vitro experimental study was conducted in November and December 2019 at the dental clinics of Aga Khan University Hospital, Karachi, and comprised of cylindrical composite specimens 8x4mm in size which were polymerised in Teflon moulds using light-emitting diode under constant mode in Group 1, pulse mode in Group 2 and ramped mode in Group 3. Once polymerised, each specimen was extruded from the mould and, using the International Organisation for Standardisation-4049 scrapping method, uncured resin was removed. Specimen lengths were measured with a Vernier calliper. Each specimen was measured thrice and the mean was taken as the depth of cure. Data was analysed using SPSS 24. RESULTS: Of the 33 specimens, there were 11(33.3%) in each of the 3 groups. Mean depth of cure in Group 1 was 2.92±0.29mm, in Group 2 it was 2.88±0.27mm, and it was 3.18±0.26mm in Group 3. The difference between Group 2 and Group 3 was statistically significant (p<0.05). Conclusion: Maximum depth of cure of smart dentin replacement bulkfill composite was achieved by ramped cure mode of light-emitting diode unit, followed by constant and pulse modes.


Asunto(s)
Resinas Compuestas , Politetrafluoroetileno , Humanos , Ensayo de Materiales , Polimerizacion , Dureza
9.
Indian J Ophthalmol ; 70(10): 3745, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36190104

RESUMEN

Background: Symblepharon occurs as chronic sequelae of severe chemical injuries. The risk of recurrence is high due to unpredictable wound healing of conjunctiva and tenons following excision in young patients. Gore-tex aids in prevention of the recurrence of pterygium 1. Purpose: To present a surgical video on role of Gore-tex in grade 4 Symblepharon lysis. Synopsis: A 28-year-old male with a previous history of Grade 4 chemical injury presented with symblepharon and total obliteration of both upper and lower fornices after one year in the right eye. He underwent symblepharon lysis, Living related conjunctival allograft, Amniotic membrane graft and Gore-tex. The video explains the surgical steps in detail. A 360-degree complete peritomy was done, Symblepharon was released from the corneal surface, and the fibrotic tissue was extensively dissected away from the corneal surface and released into the fornix. Further, cryopreserved AMG was placed over the entire raw ocular surface and sutured to the episclera with glue. Prepared Gore-tex was placed on the superior and inferior fornix and sutured with 10-0 nylon suture. Again, AMG was placed over the Gore-tex in the fornices and covered with glue. A small 2x2mm biopsy of limbal stem cells from the superior limbus was already excised from the fellow eye (CLAG) and then Lr-CLAL was prepared from the patient's mother. These two grafts were placed on the nasal and temporal bulbar surface over the AMG and sutured to the underlying AMG and the episclera with glue. The entire surface was then covered with the AMG to promote epithelisation. At one month postoperative period, patient had stable ocular surface with intact Limbal conjunctival graft with mild conjunctival recurrence of fibrosis superiorly. Highlights: The video clearly explains the surgical steps of Symblepharon and the benefits of using Gore-tex. Online Video Link: https://youtu.be/aFfq2x9QBwA.


Asunto(s)
Quemaduras Químicas , Enfermedades de los Párpados , Pterigion , Adulto , Cicatriz , Conjuntiva/trasplante , Enfermedades de los Párpados/prevención & control , Enfermedades de los Párpados/cirugía , Humanos , Masculino , Nylons , Politetrafluoroetileno , Pterigion/cirugía
10.
J Vis Exp ; (188)2022 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-36282700

RESUMEN

With the evolution of suture materials, there has been a change in paradigms in primary and secondary tendon repair. Improved mechanical properties allow more aggressive rehabilitation and earlier recovery. However, for the repair to hold against higher mechanical demands, more advanced suturing and knotting techniques must be assessed in combination with those materials. In this protocol, the use of polytetrafluoroethylene (PTFE) as a suture material in combination with different repair techniques was investigated. In the first part of the protocol, both linear tension strength and elongation of knotted against not-knotted strands of three different materials used in flexor tendon repair were evaluated. The three different materials are polypropylene (PPL), ultra-high molecular weight polyethylene with a braided jacket of polyester (UHMWPE), and polytetrafluoroethylene (PTFE). In the next part (ex vivo experiments with cadaveric flexor tendons), the behavior of PTFE using different suture techniques was assessed and compared with PPL and UHMWPE. This experiment is comprised of four steps: harvesting of the flexor tendons from fresh cadaveric hands, transection of the tendons in a standardized manner, tendon repair by four different techniques, mounting, and measurement of the tendon repairs on a standard linear dynamometer. The UHMWPE and PTFE showed comparable mechanical properties and were significantly superior to PPL in terms of linear traction strength. Repairs with four- and six-strand techniques proved stronger than two-strand techniques. Handling and knotting of PTFE are a challenge due to very low surface friction but fastening of the four- or six-strand repair is comparatively easy to achieve. Surgeons routinely use PTFE suture material in cardiovascular surgery and breast surgery. The PTFE strands are suitable for use in tendon surgery, providing a robust tendon repair so that early active motion regimens for rehabilitation can be applied.


Asunto(s)
Politetrafluoroetileno , Traumatismos de los Tendones , Humanos , Traumatismos de los Tendones/cirugía , Polipropilenos , Resistencia a la Tracción , Suturas , Técnicas de Sutura , Tendones , Poliésteres , Cadáver , Fenómenos Biomecánicos
11.
Acta Otorhinolaryngol Ital ; 42(4): 380-387, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36254654

RESUMEN

Objective: Otosclerosis is an osteodystrophic disease of the otic capsule, determining conductive or mixed hearing loss, which can be successfully treated with stapedotomy. The aim of the present multicentric retrospective study was to identify prognostic factors related to better auditory outcomes in stapes surgery. Methods: 581 patients affected by otosclerosis were submitted to stapedotomy under local anaesthesia in two different hospitals. Both Teflon and titanium prostheses were adopted. Results: A statistically significant decrease of postoperative air-conduction thresholds and air-bone gap (ABG) values was seen, whereas the mean bone-conduction threshold did not differ from the preoperative condition. Among the various parameters investigated, the prosthetic material, duration of surgery and intraoperative detection of unexpected anatomical anomalies of the middle ear were found to be related to lower postoperative ABG values. Conclusions: All the previously mentioned parameters played a significant role in determining the postoperative auditory outcomes and can therefore be considered prognostic factors for the success of the stapedotomy.


Asunto(s)
Otosclerosis , Cirugía del Estribo , Conducción Ósea , Humanos , Otosclerosis/cirugía , Politetrafluoroetileno , Pronóstico , Estudios Retrospectivos , Estribo , Titanio , Resultado del Tratamiento
12.
Nagoya J Med Sci ; 84(3): 648-655, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36237890

RESUMEN

Superior vena cava (SVC) syndrome refers to a constellation of symptoms secondary to obstruction of blood flow through the SVC. In this condition, venous blood that usually drains into the SVC is diverted into the inferior vena cava (IVC) via collateral veins. Reconstructive surgery is challenging in such cases owing to the anomalous venous system. In this case report, we describe reconstructive surgery using a pedicled omental flap in a patient with upper thoracic empyema and concomitant SVC syndrome. A 68-year-old man underwent resection of malignant thymoma, the bilateral brachiocephalic veins, and a part of the right upper lobe, followed by polytetrafluoroethylene (PTFE) graft placement for venous system reconstruction, 2 years prior to presentation. He developed postoperative upper thoracic cavity empyema, which necessitated PTFE graft removal. Although the infection was controlled after 2 months, multiple right upper lobe pulmonary fistulas persisted, and the patient was referred to our department for further evaluation. Contrast-enhanced computed tomography revealed SVC syndrome characterized by SVC obstruction and consequent drainage of venous blood from the upper trunk into the IVC via collateral vessels. We debrided necrotic and infected tissues, and a pedicled omental flap was placed for upper lobe fistula coverage. The patient showed an uncomplicated postoperative course, and no recurrent empyema or pulmonary fistulas were observed 3 years postoperatively. Flaps associated with the SVC system show high venous pressures. The use of a pedicled omental flap was deemed feasible because this graft reaches the upper thorax even though it is associated with the IVC system.


Asunto(s)
Empiema Pleural , Procedimientos Quirúrgicos Reconstructivos , Síndrome de la Vena Cava Superior , Anciano , Empiema Pleural/etiología , Empiema Pleural/cirugía , Humanos , Masculino , Politetrafluoroetileno , Síndrome de la Vena Cava Superior/etiología , Síndrome de la Vena Cava Superior/cirugía , Vena Cava Superior/anomalías , Vena Cava Superior/cirugía
13.
J Cardiothorac Surg ; 17(1): 252, 2022 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-36195922

RESUMEN

BACKGROUND: Perigraft seroma is a persistent and sterile fluid confined within a fibrous pseudomembrane surrounding a graft that develops after graft replacement. Development of perigraft seroma is an uncommon complication that occurs after the surgical repair of the thoracic aorta using woven polyester grafts. mechanism underlying perigraft seroma formation remains unclear. CASE PRESENTATION: Herein, we describe the case of 77-year-old man who underwent repeat sternotomy for the treatment of large perigraft seroma 1 year after ascending aorta replacement for acute type A dissection. After removing a cloudy yellow fluid, we covered the prosthetic graft with fibrin glue and wrapped it with a new graft. Bacterial culture and laboratory examination of the fluid confirmed the final diagnosis of perigraft seroma, and there was no evidence of recurrence. The area in which fluid accumulated around the graft shrunk 1 year after surgery. CONCLUSIONS: The cause of a expanding perigraft after repair of the thoracic aorta remains unknown. Physicians should be aware that chronic expanding mediastinal seroma with Dacron grafts is one of the rare postoperative complications of thoracic aortic surgery. Applying fibrin glue to the graft surface might effectively prevent the recurrence of perigraft seroma.


Asunto(s)
Implantación de Prótesis Vascular , Seroma , Anciano , Aorta/cirugía , Aorta Torácica/cirugía , Prótesis Vascular/efectos adversos , Implantación de Prótesis Vascular/efectos adversos , Adhesivo de Tejido de Fibrina/uso terapéutico , Humanos , Masculino , Tereftalatos Polietilenos , Politetrafluoroetileno , Seroma/etiología , Seroma/cirugía
14.
Sci Rep ; 12(1): 16524, 2022 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-36192510

RESUMEN

Stent-grafts composed of expanded polytetrafluoroethylene (e-PTFE), polyethylene terephthalate (PET) and polyurethane (PU) are characterized by poor endothelialization, high modulus, and low compliance, leading to thrombosis and intimal hyperplasia. A composite synthetic/natural matrix is considered a promising alternative to conventional synthetic stent-grafts. This study aimed to investigate the efficacy of thermoplastic polyurethane (TPU) and gelatin (GL) blended nanofibers (NFs) covered stent-graft in the porcine iliac artery. Twelve pigs were randomly sacrificed 7 days (n = 6) and 28 days (n = 6) after stent-graft placement. The thrombogenicity score at 28 days was significantly increased compared at 7 days (p < 0.001). The thickness of neointimal hyperplasia, degree of inflammatory cell infiltration, and degree of collagen deposition were significantly higher at 28 days than at 7 days (all p < 0.001). The TPU and GL blended NFs-covered stent-grafts successfully maintained the patency for 28 days in the porcine iliac artery. Although thrombosis with neointimal tissue were observed, no subsequent occlusion of the stent-graft was noted until the end of the study. Composite synthetic/natural matrix-covered stent-grafts may be promising for prolonging stent-graft patency.


Asunto(s)
Arteria Ilíaca , Nanofibras , Animales , Prótesis Vascular , Gelatina , Hiperplasia/patología , Arteria Ilíaca/patología , Arteria Ilíaca/cirugía , Neointima/patología , Tereftalatos Polietilenos , Politetrafluoroetileno , Poliuretanos , Stents , Porcinos
15.
Phys Chem Chem Phys ; 24(41): 25391-25402, 2022 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-36239696

RESUMEN

Here, we have carried out a proof-of-concept molecular dynamics (MD) simulation with adaptive tempering in a membrane mimetic environment to study the folding of single-pass membrane peptides. We tested the influenza A M2 viroporin, influenza B M2 viroporin, and protein E from coronaviruses MERS-Cov-2 and SARS-CoV-2 peptides with known experimental secondary structures in membrane bilayers. The two influenza-derived peptides are significantly different in the peptide sequence and secondary structure and more polar than the two coronavirus-derived peptides. Through a total of more than 50 µs of simulation time that could be accomplished in trifluoroethanol (TFE), as a membrane model, we characterized comparatively the folding behavior, helical stability, and helical propensity of these transmembrane peptides that match perfectly their experimental secondary structures, and we identified common motifs that reflect their quaternary organization and known (or not) biochemical function. We showed that BM2 is organized into two structurally distinct parts: a significantly more stable N-terminal half, and a fast-converting C-terminal half that continuously folds and unfolds between α-helical structures and non-canonical structures, which are mostly turns. In AM2, both the N-terminal half and C-terminal half are very flexible. In contrast, the two coronavirus-derived transmembrane peptides are much more stable and fast helix-formers when compared with the influenza ones. In particular, the SARS-derived peptide E appears to be the fastest and most stable helix-former of all the four viral peptides studied, with a helical structure that persists almost without disruption for the whole of its 10 µs simulation. By comparing the results with experimental observations, we benchmarked TFE in studying the conformation of membrane and hydrophobic peptides. This work provided accurate results suggesting a methodology to run long MD simulations and predict structural properties of biologically important membrane peptides.


Asunto(s)
COVID-19 , Gripe Humana , Humanos , Simulación de Dinámica Molecular , Péptidos/química , Politetrafluoroetileno , Pliegue de Proteína , Estructura Secundaria de Proteína , SARS-CoV-2 , Solventes , Trifluoroetanol/química , Proteínas Viroporinas , Influenzavirus B , Coronavirus del Síndrome Respiratorio de Oriente Medio
16.
World J Pediatr Congenit Heart Surg ; 13(6): 723-730, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36300265

RESUMEN

BACKGROUND: Use of the expanded polytetrafluoroethylene (ePTFE) valved conduit in the pulmonary position during the correction of congenital heart defects has significantly increased in popularity over the last decade due to its promising conduit longevity. We describe the standardized process to create and implant a trileaflet ePTFE pulmonary conduit along with the early outcomes of such procedures at our institute. METHODS: Records of 100 consecutive patients who underwent ePTFE valved conduit placement using our technique from April 2018 through February 2022 were retrospectively analyzed. The function of the conduit was evaluated by transthoracic echocardiography. RESULTS: The mean age of the patients was 28 ± 13.2 years old at the time of the operation. The conduit diameters ranged from 16 to 24 mm (mean 23.0 ± 1.9 mm). Conduit placement was utilized for pulmonary valve replacement in 68 patients, conduit change in 25 patients, and as a part of total repair in 7 patients. There were 2 in-hospital conduit-unrelated deaths from multi-organ dysfunction and pulmonary hypertensive crisis. From the postoperative echocardiography, the average peak pressure gradient across the conduit was 18.6 ± 9.0 mm Hg, and the conduit regurgitation was graded as none or trace in 81 patients, mild in 17 patients, and moderate in 2 patients. At 589 days of median follow-up, there was no conduit reoperation. Follow-up imaging of 60 available patients at a median time of 511 days did not show a significant change in conduit function. CONCLUSIONS: Our standardized ePTFE valved conduit creation and placement demonstrated satisfactory clinical and echocardiographic outcomes.


Asunto(s)
Cardiopatías Congénitas , Implantación de Prótesis de Válvulas Cardíacas , Prótesis Valvulares Cardíacas , Humanos , Adolescente , Adulto Joven , Adulto , Politetrafluoroetileno , Estudios Retrospectivos , Diseño de Prótesis , Cardiopatías Congénitas/cirugía , Resultado del Tratamiento
17.
PLoS Genet ; 18(10): e1010469, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36251690

RESUMEN

Meiosis in males of higher dipterans is achiasmate. In their spermatocytes, pairing of homologs into bivalent chromosomes does not include synaptonemal complex and crossover formation. While crossovers preserve homolog conjunction until anaphase I during canonical meiosis, an alternative system is used in dipteran males. Mutant screening in Drosophila melanogaster has identified teflon (tef) as being required specifically for alternative homolog conjunction (AHC) of autosomal bivalents. The additional known AHC genes, snm, uno and mnm, are needed for the conjunction of autosomal homologs and of sex chromosomes. Here, we have analyzed the pattern of TEF protein expression. TEF is present in early spermatocytes but cannot be detected on bivalents at the onset of the first meiotic division, in contrast to SNM, UNO and MNM (SUM). TEF binds to polytene chromosomes in larval salivary glands, recruits MNM by direct interaction and thereby, indirectly, also SNM and UNO. However, chromosomal SUM association is not entirely dependent on TEF, and residual autosome conjunction occurs in tef null mutant spermatocytes. The higher tef requirement for autosomal conjunction is likely linked to the quantitative difference in the amount of SUM protein that provides conjunction of autosomes and sex chromosomes, respectively. During normal meiosis, SUM proteins are far more abundant on sex chromosomes compared to autosomes. Beyond promoting SUM recruitment, TEF has a stabilizing effect on SUM proteins. Increased SUM causes excess conjunction and consequential chromosome missegregation during meiosis I after co-overexpression. Similarly, expression of SUM without TEF, and even more potently with TEF, interferes with chromosome segregation during anaphase of mitotic divisions in somatic cells, suggesting that the known AHC proteins are sufficient for establishment of ectopic chromosome conjunction. Overall, our findings suggest that TEF promotes alternative homolog conjunction during male meiosis without being part of the final physical linkage between chromosomes.


Asunto(s)
Proteínas de Drosophila , Drosophila melanogaster , Animales , Masculino , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Drosophila/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Politetrafluoroetileno/metabolismo , Segregación Cromosómica/genética , Meiosis/genética , Cromosomas Sexuales/metabolismo , Emparejamiento Cromosómico
18.
Sensors (Basel) ; 22(20)2022 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-36298300

RESUMEN

SO2F2 and SOF2 are the main components from the decomposition of insulation gas SF6. Photoacoustic spectroscopy (PAS) has been acknowledged as an accurate sensing technique. Polar material adsorption for SO2F2 and SOF2 in the photoacoustic gas cell of PAS may affect detection efficiency. In this paper, the optical gas-cell dynamic adsorptions of four different materials and the detection effects on SO2F2 and SOF2 are theoretically analyzed and experimentally demonstrated. The materials, including grade 304 stainless steel (SUS304), grade 6061 aluminum alloy (Al6061), polyvinylidene difluoride (PVDC), and polytetrafluoroethylene (PTFE), were applied inside the optical gas cell. The results show that, compared with metallic SUS304 and Al6061, plastic PVDC and PTFE would reduce the gas adsorption of SO2F2 and SOF2 by 10 to 20% and shorten the response time during gas exchange. The complete gas defusing period in the experiment was about 30 s. The maximum variations of the 90% rising time between the different adsorption materials were approximately 3 s for SO2F2 and 6 s for SOF2, while the generated photoacoustic magnitudes were identical. This paper explored the material selection for PAS-based gas sensing in practical applications.


Asunto(s)
Aluminio , Acero Inoxidable , Adsorción , Aluminio/química , Análisis Espectral/métodos , Plásticos , Politetrafluoroetileno
19.
Sensors (Basel) ; 22(20)2022 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-36298364

RESUMEN

This work proposes a new compact triple-band triangular patch antenna for RF energy harvesting applications in IoT devices. It is realized on Teflon glass substrate with a thickness of 0.67 mm and a relative permittivity of 2.1. Four versions of this antenna have been designed and realized with inclinations of 0°, 30°, 60° and 90° to study the impact of the tilting on their characteristics (S11 parameter, radiation pattern, gain) and to explore the possibilities of their implementation in the architectures of electronic equipment according to the available space. The antenna is also realized on waterproof paper with a thickness of 0.1 mm and a relative permittivity of 1.4 for biomedical domain. All the antennas (vertical antenna, tilted antennas and antenna realized on waterproof paper) have a size of 39 × 9 mm2 and cover the 2.45 GHz and 5.2 GHz Wi-Fi bands and the 8.2 GHz band. A good agreement is obtained between measured and simulated results. Radiation patterns show that all the antennas are omnidirectional for 2.45 GHz and pseudo-omnidirectional for 5.2 GHz and 8.2 GHz with maximum measured gains of 2.6 dBi, 4.55 dBi and 6 dBi, respectively. The maximum measured radiation efficiencies for the three antenna configurations are, respectively, of 75%, 70% and 72%. The Specific Absorption Rate (SAR) for the antenna bound on the human body is of 1.1 W/kg, 0.71 W/kg and 0.45 W/kg, respectively, for the three frequencies 2.45 GHz, 5.2 GHz and 8.2 GHz. All these antennas are then applied to realize RF energy harvesting systems. These systems are designed, realized and tested for the frequency 2.45 GHz, -20 dBm input power and 2 kΩ resistance load. The maximum measured output DC power is of 7.68 µW with a maximum RF-to-DC conversion efficiency of 77%.


Asunto(s)
Politetrafluoroetileno , Tecnología Inalámbrica , Humanos , Diseño de Equipo , Fenómenos Físicos , Vidrio
20.
Biophys Chem ; 291: 106895, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36182744

RESUMEN

Despite the rich knowledge of the influence of 2,2,2-trifluoroethanol (TFE) on the structure and conformation of peptides and proteins, the mode(s) of TFE-protein interactions and the mechanism by which TFE reversibly denatures a globular protein remain elusive. This study systematically examines TFE-induced equilibrium transition curves for six paradigmatic globular proteins by using basic fluorescence and circular dichroism measurements under neutral pH conditions. The results are remarkably simple. Low TFE invariably unfolds the tertiary structure of all proteins to produce the obligate intermediate (I) which retains nearly all of native-state secondary structure, but enables the formation of extra α-helices as the level of TFE is raised higher. Inspection of the transitions at once reveals that the tertiary structure unfolding is always a distinct process, necessitating the inclusion of at least one obligate intermediate in the TFE-induced protein denaturation. It appears that the intermediate in the minimal unfolding mechanism N⇌I⇌D somehow acquires higher α-helical propensity to generate α-helices in excess of that in the native state to produce the denatured state (D), also called the TFE state. The low TFE-populated intermediate I may be called a universal intermediate by virtue of its α-helical propensity. Contrary to many earlier suggestions, this study dismisses molten globule (MG)-like attribute of I or D.


Asunto(s)
Politetrafluoroetileno , Trifluoroetanol , Trifluoroetanol/farmacología , Desnaturalización Proteica , Naftalenosulfonatos de Anilina/química , Naftalenosulfonatos de Anilina/metabolismo , Estructura Secundaria de Proteína , Dicroismo Circular , Pliegue de Proteína , Conformación Proteica
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