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2.
Polymers (Basel) ; 15(6)2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36987254

RESUMO

We investigate mode coupling in a multimode graded-index microstructured polymer optical fiber (GI mPOF) with a solid core by solving the time-independent power flow equation (TI PFE). Using launch beams with various radial offsets, it is possible to calculate for such an optical fiber the transients of the modal power distribution, the length Lc at which an equilibrium mode distribution (EMD) is reached, and the length zs for establishing a steady-state distribution (SSD). In contrast to the conventional GI POF, the GI mPOF explored in this study achieves the EMD at a shorter length Lc. The earlier shift to the phase of slower bandwidth decrease would result from the shorter Lc. These results are helpful for the implementation of multimode GI mPOFs as a part of communications and optical fiber sensory systems.

3.
Opt Express ; 30(14): 24667-24675, 2022 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-36237015

RESUMO

By solving the time-independent power flow equation (TI PFE), we study mode coupling in a multimode W-type microstructured polymer optical fiber (mPOF) with a solid-core. The multimode W-type mPOF is created by modifying the cladding layer and reducing the core of a multimode singly clad (SC) mPOF. For such optical fiber, the angular power distributions, the length Lc at which an equilibrium mode distribution (EMD) is achieved, and the length zs for establishing a steady state distribution (SSD) are determined for various arrangements of the inner cladding's air-holes and different launch excitations. This information is useful for the implement of multimode W-type mPOFs in telecommunications and optical fiber sensors.

4.
Polymers (Basel) ; 13(23)2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34883721

RESUMO

By solving the time-dependent power flow equation, we present a novel approach for evaluating the bandwidth in a multimode step-index polymer photonic crystal fiber (SI PPCF) with a solid core. The bandwidth of such fiber is determined for various layouts of air holes and widths of Gaussian launch beam distribution. We found that the lower the NA of SI PPCF, the larger the bandwidth. The smaller launch beam leads to a higher bandwidth for short fibers. The influence of the width of the launch beam distribution on bandwidth lessens as the fiber length increases. The bandwidth tends to its launch independent value at a particular fiber length. This length denotes the onset of the steady state distribution (SSD). This information is useful for multimode SI PPCF applications in telecommunications and optical fiber sensing applications.

5.
Cancers (Basel) ; 13(19)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34638373

RESUMO

Improvements in the clinical outcome of osteosarcoma have plateaued in recent decades with poor translation between preclinical testing and clinical efficacy. Organotypic cultures retain key features of patient tumours, such as a myriad of cell types organized within an extracellular matrix, thereby presenting a more realistic and personalised screening of chemotherapeutic agents ex vivo. To test this concept for the first time in osteosarcoma, murine and canine osteosarcoma organotypic models were maintained for up to 21 days and in-depth analysis identified proportions of immune and stromal cells present at levels comparable to that reported in vivo in the literature. Cytotoxicity testing of a range of chemotherapeutic drugs (mafosfamide, cisplatin, methotrexate, etoposide, and doxorubicin) on murine organotypic culture ex vivo found limited response to treatment, with immune and stromal cells demonstrating enhanced survival over the global tumour cell population. Furthermore, significantly decreased sensitivity to a range of chemotherapeutics in 3D organotypic culture relative to 2D monolayer was observed, with subsequent investigation confirming reduced sensitivity in 3D than in 2D, even at equivalent levels of drug uptake. Finally, as proof of concept for the application of this model to personalised drug screening, chemotherapy testing with doxorubicin was performed on biopsies obtained from canine osteosarcoma patients. Together, this study highlights the importance of recapitulating the 3D tumour multicellular microenvironment to better predict drug response and provides evidence for the utility and possibilities of organotypic culture for enhanced preclinical selection and evaluation of chemotherapeutics targeting osteosarcoma.

6.
Open Forum Infect Dis ; 6(1): ofy331, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30648126

RESUMO

BACKGROUND: Osteomyelitis is a challenging infection that can involve 4-6 weeks of intravenous (IV) antibiotics. Dalbavancin, approved for acute bacterial skin and skin structure infections, has potent activity against gram-positive pathogens. This study assessed the efficacy and safety of dalbavancin as a 2-dose regimen for osteomyelitis. METHODS: This study was a randomized, open-label, comparator-controlled trial in adults with a first episode of osteomyelitis defined by clinical symptoms, radiologic findings, and elevated C-reactive protein. Patients were randomized 7:1 to dalbavancin (1500 mg IV on days 1 and 8) or standard of care (SOC) for osteomyelitis (oral or IV) per investigator judgment for 4-6 weeks. The primary endpoint was clinical response at day 42, defined as recovery without need for additional antibiotics in the clinically evaluable (CE) population. Clinical response was also assessed at day 21, 6 months, and 1 year. RESULTS: Eighty patients were randomized to dalbavancin (n = 70) or SOC (n = 10). All had baseline debridement; Staphylococcus aureus was the most common pathogen (60% of patients). Clinical cure at day 42 was seen in 65/67 (97%) and 7/8 (88%) patients in the dalbavancin group and SOC group in the CE population, respectively. Clinical response was similar in the dalbavancin group at day 21 (94%), 6 months, and 1 year (96%). Treatment-emergent adverse events occurred in 10 patients in the dalbavancin group; no patient discontinued treatment due to an adverse event. CONCLUSIONS: A 2-dose regimen of weekly dalbavancin is effective and well tolerated for the treatment of osteomyelitis in adults. CLINICAL TRIALS REGISTRATION: NCT02685033.

7.
Appl Opt ; 53(30): 6999-7003, 2014 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-25402786

RESUMO

By experimental measurement and from a numerical solution to the time-dependent power flow equation, the frequency response, bandwidth, mode coupling, and mode-dependent attenuation are determined for a low-numerical-aperture (NA) plastic optical fiber. Frequency response and bandwidth are specified as a function of fiber length. Numerical results are verified against experimental measurements. Mode coupling and modal attenuation are found to differ substantially between two fiber varieties of the same type (both low-NA, step-index, and plastic), implying their preferential suitability that is application-specific.

8.
Gastrointest Endosc ; 75(2): 332-8, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22248601

RESUMO

BACKGROUND: TNFeradeBiologic (AdGVEGR.TNF.11D) is a replication-deficient adenoviral vector that expresses tumor necrosis factor-α (TNF-α) under the control of the Egr-1 promoter, which is inducible by chemotherapy and radiation. OBJECTIVE: This study was conducted to determine the maximal tolerated dose of TNFeradeBiologic with standard chemoradiotherapy and preliminary activity and safety of the combination in the treatment of locally advanced pancreatic cancer (LAPC). DESIGN: TNFeradeBiologic was injected into locally advanced pancreatic carcinomas by using EUS or percutaneous administration once a week for 5 weeks together with 50.4 Gy radiation and 5-fluorouracil (5-FU) 200 mg/m(2) daily over 5.5 weeks. Dose levels from 4 × 10(9) to 1 × 10(12) particle units (PU) were studied. SETTING: Multicentered, academic institutions. PATIENTS: Fifty patients with LAPC were treated. INTERVENTIONS: Doses of TNFerade Biologic were administered to patients. MAIN OUTCOME MEASUREMENTS: Toleration of TNFerade Biologic was measured through toxicity and tumor response, by using the criteria of the Response Evaluation Criteria in Solid Tumors and the World Health Organization, and was reviewed by a central radiology facility. Overall survival and progression-free survival were also measured. RESULTS: Dose-limiting toxicities of pancreatitis and cholangitis were observed in 3 patients at the 1 × 10(12) PU dose, making 4 × 10(11) PU the maximum tolerated dose. One complete response, 3 partial responses, and 12 patients with stable disease were noted. Seven patients eventually went to surgery, 6 had clear margins, and 3 survived >24 months. LIMITATIONS: This is a Phase 1/2 non-randomized study. CONCLUSIONS: Intratumoral delivery of TNFerade Biologic by EUS with fine-needle viral injection or percutaneously, combined with chemoradiation, shows promise in the treatment of LAPC. There appeared to be better clinical outcome at the maximal tolerated dose than at lower doses. The dose of 4 ×10(11) PU TNFerade Biologic was generally well tolerated, with encouraging indications of activity, and will be tested in the randomized phase of this study. Delivery of TNFerade Biologic did not interfere with subsequent surgical resection.


Assuntos
Carcinoma/terapia , DNA/uso terapêutico , Vetores Genéticos/administração & dosagem , Dose Máxima Tolerável , Neoplasias Pancreáticas/terapia , Fator de Necrose Tumoral alfa/administração & dosagem , Adenovírus Humanos/genética , Adulto , Idoso , Antimetabólitos Antineoplásicos/uso terapêutico , Carcinoma/patologia , Quimiorradioterapia/efeitos adversos , Colangite/etiologia , DNA/administração & dosagem , DNA/efeitos adversos , Intervalo Livre de Doença , Fracionamento da Dose de Radiação , Feminino , Fluoruracila/uso terapêutico , Vetores Genéticos/efeitos adversos , Vetores Genéticos/uso terapêutico , Humanos , Injeções Intralesionais , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/patologia , Pancreatite/etiologia , Resultado do Tratamento , Fator de Necrose Tumoral alfa/efeitos adversos , Fator de Necrose Tumoral alfa/uso terapêutico
9.
Appl Opt ; 44(19): 3898-903, 2005 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-16004034

RESUMO

The core-cladding boundary in step-index plastic optical fibers is imperfect. Surface irregularities locked in during the manufacturing process couple the guided modes by reflecting them in directions that deviate unpredictably from the expected directions. This causes an additional loss as the multiple reflections from surface elements with directions randomized around the nominal for the cylinder transfer the power to the radiation modes that are carried away from the core into the cladding. We model such loss and mode coupling by ray tracing. The irregular core-cladding interface is represented by nominally cylindrical surface elements with orientations randomly perturbed around two geometric axes. The results show mode coupling and relative loss per unit fiber length caused by the core-cladding interface irregularities. The loss is high close to the input fiber end where mode coupling is intense. It drops farther along the fiber as mode coupling slows down and stabilizes where the equilibrium mode distribution is reached.

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