Highly efficient active optical interconnect incorporating a partially chlorinated ribbon POF in conjunction with a visible VCSEL.

A low-loss 4-ch active optical interconnect (AOI) enabling passive alignment was proposed and built resorting to a transmitter (Tx) incorporating a red 680-nm VCSEL, which is linked to a receiver (Rx) module via a partially chlorinated ribbon POF. The POF was observed to exhibit an extremely low loss of ~0.24 dB/m at λ = 680 nm, in comparison to ~1.29 dB/m at λ = 850 nm, and a large numerical aperture of ~0.42. Both the Tx and Rx, which taps into a beam router based on collimated beam optics involving a pair of spherical lenses, were meant to be substantially alignment tolerant and compact. The achieved tolerance for the constructed modules was beyond 40 µm in terms of the positioning of VCSEL and photodetector. The proposed AOI was completed by linking the Tx with the Rx via a 3-m long ribbon POF, incurring a transmission loss of as small as 3.2 dB. The AOI was practically assessed in terms of a high-speed data transmission over a wide range of temperatures and then exploited to convey full HD video signals.

CWDM based HDMI interconnect incorporating passively aligned POF linked optical subassembly modules.

A four-channel transmitter OSA (TOSA) and a receiver optical sub-assembly (ROSA) module were presented. They take advantage of a coarse WDM (CWDM) scheme, employing two types of VCSELs at 780 and 850 nm, where no wavelength filters are involved in the TOSA. The ROSA and TOSA were constructed through a fully passive alignment process using components produced by virtue of a cost effective plastic injection molding technique. In order to build a high quality optical HDMI interconnect, four channel optical links between these modules ware established via two graded-index plastic optical fibers (GI-POFs). The HDMI interconnect was thoroughly evaluated in terms of the alignment tolerance, the light beam propagation, and the data transmission capability. For the ROSA, the measured tolerance, as affected by the photodiode alignment, was ~45 µm and over 200 µm for the transverse and longitudinal directions, respectively. For the TOSA, the tolerance, which is mostly dependent upon the VCSEL alignment, was ~20 µm and more than 200 µm for the transverse and longitudinal directions, respectively. The beam profiles for the TOSA and ROSA were monitored to confirm their feasibility from the optical coupling perspective. A digital signal at 2.5 Gb/s was efficiently transmitted through the HDMI interconnect with a bit error ratio of below 10-16. A 1080p HDMI signal from a Blu-ray player was delivered through the interconnect to an LCD monitor and successfully displayed a high quality video.

Ribbon plastic optical fiber linked optical transmitter and receiver modules featuring a high alignment tolerance.

Ribbon plastic optical fiber (POF) linked four-channel optical transmitter (Tx) and receiver (Rx) modules have been proposed and realized featuring an excellent alignment tolerance. The two modules share a common configuration involving an optical sub-assembly (OSA) with vertical cavity surface emitting lasers (VCSELs)/photodetectors (PDs), and their driver ICs, which are integrated onto a single printed circuit board (PCB) substrate. The OSA includes an alignment structure, a beam router and a fiber guide, which were produced by using plastic injection molding. We have accomplished a fully passive alignment between the VCSELs/PDs and the ribbon POF by taking advantage of the alignment structure that serves as a reference during the alignment of the constituent parts of the OSA. The electrical link, which largely determines the operation speed, has been remarkably shortened, due to a direct wire-bonding between the VCSELs/PDs and the driver circuits. The light sources and the detectors can be individually positioned, thereby overcoming the pitch limitations of the ribbon POF, which is made up of perfluorinated graded-index (GI) POF with a 62.5 µm core diameter. The overall alignment tolerance was first assessed by observing the optical coupling efficiency in terms of VCSEL/PD misalignment. The horizontal and vertical 3-dB alignment tolerances were about 20 µm and 150 µm for the Tx and 50 µm and over 200 µm for the Rx, respectively. The VCSEL-to-POF coupling loss for the Tx and the POF-to-PD loss for the Rx were 3.25 dB and 1.35 dB at a wavelength of 850 nm, respectively. Subsequently, a high-speed signal at 3.2 Gb/s was satisfactorily delivered via the Tx and Rx modules over a temperature range of -30 to 70°C with no significant errors; the channel crosstalk was below -30 dB. Finally, the performance of the prepared modules was verified by transmitting a 1080p HDMI video supplied by a Bluelay player to an LCD TV.

Brachytherapy and non-cancer mortality in patients with oral cavity and oropharynx SCCs.

BACKGROUND: Oral cavity and oropharyngeal squamous cell cancers (OC-OPSCC) display high cancer-specific mortality and increased non-cancer mortality. We examined cause of death in patients treated for OC-OPSCC with brachytherapy, chemotherapy, external beam radiation, surgery, or combination of modalities. We hypothesized that brachytherapy does not increase non-cancer mortality comparably with external beam radiation. METHODS: A database was constructed from institutional tumor registry and electronic medical record data from all patients with first OC-OPSCC diagnosis at our institution between 2000 and 2010, excluding patients with a second primary cancer at diagnosis. The primary outcome was association between treatment modality and non-cancer mortality. RESULTS: Of 693 eligible patients, 460 were deceased; 84 from primary malignancy and 96 from a non-primary cancer cause, including 24 with a second primary cancer. 193 patients received brachytherapy. Cox proportional hazards regression was performed on treatment regimen, stratified by AJCC stage, race, and sex. Age, smoking history, and alcohol had HRs for death of 1.05 (p < 0.005), 1.37 (p = 0.106), and 2.24 (p < 0.005), respectively, while brachytherapy had a 0.53 HR (p < 0.005) for death. Non-smoking OPC patients had an 88% 5-year OS, suggesting these were largely HPV-driven cancers. In smoking OPC patients, 5-year OS was 61%. Non-cancer mortality HR of 0.36 for brachytherapy-treated patients. CONCLUSION: We report non-cancer mortality from a cohort of curatively treated OC-OPSCC and show a significant correlation between brachytherapy and non-cancer survival, independent of remission status. The impact of brachytherapy in OPC was strongest in smokers.

Permanent Interstitial Brachytherapy for Previously Irradiated Head and Neck Cancer.

OBJECTIVE: To evaluate our institutional experience using brachytherapy for the re-irradiation of the head and neck. STUDY DESIGN/METHODS: We reviewed the records of patients who received brachytherapy for head and neck cancer in a previously irradiated field between 2007 and 2016. RESULTS: Sixty-nine patients received brachytherapy-based re-irradiation. Forty-nine patients (71%) were treated for recurrent cancers, 15 patients (22%) had second primary cancers, and five patients (7%) were treated for persistent tumors. The median dose was 90 Gy (range 30-180). Median follow-up was 3.0 years for surviving patients and 0.6 years for all patients. Overall survival at one, three, and five years was 58%, 19%, and 12%, respectively. Local control at one, three, and five years was 55%, 38%, and 28%, respectively. A disease-free interval of less than one year was associated with significantly worse local control (p=.04). Patients who received brachytherapy for a neck disease had significantly worse locoregional control than those who received brachytherapy for mucosal disease (heart rate (HR) 2.14, 95% CI 1.00-4.56, p=.05). Patients who had an extranodal extension had significantly worse overall survival than those without an extranodal extension (HR 2.57, 95% CI 1.28-5.37, p=.008). Seventy-four percent of patients who had pain before brachytherapy (with or without surgery) had an improvement of symptoms. Acute and chronic toxicity of at least Common Terminology Criteria for Adverse Events Grade 3 was seen in 27% and 19% of the patients, respectively. CONCLUSIONS: Brachytherapy-based re-irradiation is an effective approach for patients undergoing re-irradiation for head and neck cancer. Brachytherapy may be more effective for mucosal recurrences than neck recurrences.

Pedicle versus free flap reconstruction in patients receiving intraoperative brachytherapy.

Introduction This study compared complication rates between pedicle flaps and free flaps used for resurfacing of intraoperative brachytherapy (IOBT) implants placed following head and neck tumour extirpation to help clarify the ideal reconstructive procedure for this scenario. Patients and methods A retrospective review of reconstructions with IOBT at our institution was conducted. Patient and treatment details were recorded, as were the number and type of flap complications, including re-operations. Logistic regressions compared complications between flap groups. Results Fifty free flaps and 55 pedicle flaps were included. On multivariate analysis, free flap reconstruction with IOBT was significantly associated with both an increased risk of having any flap complication (OR = 2.9, p = 0.037) and with need for operative revision (OR = 3.5, p = 0.048) compared to pedicle flap reconstruction. Conclusions In the setting of IOBT, free flaps are associated with an increased risk of having complications and requiring operative revisions.

Concurrent chemo-radiotherapy with mitomycin C compared with porfiromycin in squamous cell cancer of the head and neck: final results of a randomized clinical trial.

PURPOSE: Previous randomized trials have shown a benefit with concurrent use of the hypoxic cell cytotoxin mitomycin C (MC) and radiation (RT) in the management of squamous cell cancer of the head and neck (SCCHN). We conducted a randomized trial comparing MC with porfiromycin (POR) in combination with RT in the management of SCCHN. METHODS AND MATERIALS: Between 1992 and 1999, 128 patients with SCCHN were enrolled in this prospective randomized trial. Patients were stratified by management intent, and balanced with respect to stage and site of disease. They were randomized to receive MC (15 mg/M(2)) or POR (40 mg/M(2)) on Days 5 and 47 (or last day) of RT. Of 121 evaluable patients, 61 were randomized to MC and 60 to POR. Patients were treated with standard daily RT to a total median dose of 64 Gy over 47 days. Patients were well balanced with respect to management intent, stage, site, age, sex, hemoglobin levels, tumor grade, radiation dose, and days on treatment. RESULTS: There were no significant differences between the two arms with respect to acute hematologic or nonhematologic toxicities. As of January 2003 with a median follow-up of 6.3 years, there have been 19 local relapses (4 MC vs. 15 POR), 21 regional relapses (7 MC vs. 14 POR), 24 distant metastases (11 MC vs. 13 POR), and 66 deaths (33 MC vs. 33 POR). MC was superior to POR with respect to 5-year local relapse-free survival (91.6% vs. 72.7%, p = 0.01), local-regional relapse-free survival (82% vs. 65.3%, p = 0.05), and disease-free survival (72.8% vs. 52.9%, p = 0.026). There were no significant differences between the two arms with respect to overall survival (49.2% vs. 54.4%) or distant metastasis-free rate (79.9% vs. 75.9%). CONCLUSIONS: Despite promising preclinical data, and an acceptable toxicity profile, POR was inferior to MC as an adjunct to RT in the management of SCCHN. This randomized trial emphasizes the need for randomized studies to evaluate new agents in the management of SCCHN.

Prognostic significance of cyclooxygenase-2 in oropharyngeal squamous cell carcinoma.

PURPOSE: To determine the relative prognostic significance of cyclooxygenase (COX)-2 expression in patients with oropharyngeal squamous cell carcinoma (SCC). EXPERIMENTAL DESIGN: This retrospective cohort study included 82 patients with SCC referred to the Department of Therapeutic Radiology at Yale-New Haven Hospital (Connecticut) between 1980 and 1999 who were treated with primary external beam radiotherapy or gross total surgical resection and postoperative radiotherapy. A microarray of archival tumor tissue was constructed and stained with monoclonal antibodies directed against COX-2 and scored for intensity by a pathologist blinded to the clinical outcomes of the patients. COX-2 immunoreactivity and clinicopathological data were analyzed with respect to survival endpoints using bivariate and multivariate techniques. RESULTS: Frequency of COX-2 overexpression was 45%. In multivariate analysis, COX-2 positivity predicted poor 3-year survival (P = 0.02; odds ratio = 0.41; 95% confidence interval, 0.20-0.84). Increasing age was significantly associated with increased 3-year survival (P = 0.03; odds ratio = 1.04; 95% confidence interval, 1.004-1.09). Positive COX-2 status trended toward predicting decreased 3-year disease-free survival. CONCLUSIONS: COX-2 was the most important predictor of poor survival in this patient cohort. In patients with oropharyngeal SCC treated with external-beam radiation therapy, overexpression of COX-2 may affect clinical outcome, and COX-2 may therefore prove valuable both as a prognostic factor and as a therapeutic target.

Microsurgical free flap reconstruction outcomes in head and neck cancer patients after surgical extirpation and intraoperative brachytherapy.

OBJECTIVES: The management of recurrent or persistent head and neck cancer poses a challenging problem. Salvage surgery for these individuals consists of ablative surgery, interstitial brachytherapy, and microsurgical free flap reconstruction. This study reviews complications after such reconstruction. METHODS: We reviewed 139 consecutive head and neck cancer patients undergoing free flap reconstruction from January 1994 to May 2002. These included 66 patients with recurrent head and neck cancer undergoing intraoperative brachytherapy (IOBT) and free flap reconstruction and 73 undergoing free flap reconstructions only. A total of 142 reconstructions were performed, with three patients in IOBT group receiving two free flap reconstructions per patient, giving us a total of 69 reconstructions in the IOBT group versus 73 in the non-IOBT group. Nine patients were excluded from the IOBT group because of nonsynchronous use of brachytherapy and reconstruction, and 10 patients were excluded from the other group because they had prior radiotherapy or surgical treatment, leaving us with a total of 123 reconstructions, 60 in the IOBT group and 63 in the non-IOBT group. The IOBT group patients received iodine Vicryl seed implants, palladium seed implants, or both, to deliver an average dose of 79.3 +/- 31.8 Gy (mean +/- 1SD) to the surgical bed. RESULTS: All patients were followed for evidence of local wound complications. The IOBT group showed multiple complications in 23 (38.33%) of 60 reconstructions, the most common being wound dehiscence in 11. This, when compared with the non-IOBT group complications (15.87%), was found to be statistically significant (chi test, P <.01). CONCLUSION: IOBT increases the rate of complications in patients undergoing microvascular free tissue transfer. This, however, should not deter or alter the aggressiveness of cancer therapy used for managing recurrent head and neck cancer.

Gasification of biodiesel by-product with air or oxygen to make syngas.

In the present study, gasification of biodiesel by-product, crude glycerin, was performed in an entrained flow gasifier. Gasification was conducted in a temperature range of 950-1500 degrees C and excess air ratio of 0.17-0.7 for air or oxygen as a gasification agent. From the results, syngas heating value, carbon conversion and cold gas efficiency of more than 2500 kcal/Nm(3), 92% and 65% were achieved, respectively. The H(2)/CO ratio of the product gas was varied from 1.25 to 0.7 with the excess air ratio and this gas composition was favorable for DME synthesis. The optimum excess air ratio for gasification of biodiesel by-product was evaluated to be an approximately 0.35-0.4. The present results indicate that crude glycerin can be utilized as a feedstock for gasification to make syngas.

Postoperative concurrent chemoradiotherapy with mitomycin in advanced squamous cell carcinoma of the head and neck: results from three prospective randomized trials.

UNLABELLED: Recent prospective randomized trials have shown concurrent chemoradiotherapy improves locoregional control in postoperative patients with squamous cell carcinoma of the head and neck using cisplatin-based regimes. This report presents data pooled from three randomized trials employing mitomycin, selecting those patients treated postoperatively, to evaluate the long-term benefit of mitomycin in the postoperative setting and to compare these results with those of two other recently published randomized trials. METHODS AND MATERIALS: Between 1980 and 1999, a total of 331 patients with squamous cell carcinoma of the head and neck from the three prospective trials were enrolled. Of the 205 postoperative patients in these trials, 103 were randomized to receive mitomycin and radiation, while 102 received radiation alone or radiation with porfiromycin in the third trial. Patients were treated with standard daily radiotherapy to a total median dose of 60 Gy over 47 days. Patients who were randomized to mitomycin C received 15 mg/m2 of the drug on days 5 and 47 (or last day). RESULTS: The 5-year rate of locoregional control was higher in the mitomycin arms. There was no statistically significant difference in the rates of overall survival or distant metastasis. Patients had a lower percentage of high-risk factors in both arms of the study, compared with patients in the large prospective trials, including positive margins, two or more positive lymph nodes, or oropharynx primary tumors. The gains in locoregional control realized with mitomycin were similar to the improvements in the recently published randomized trials using platinum. CONCLUSIONS: These results confirm significant gains in locoregional control using concurrent chemoradiotherapy in the postoperative setting for patients with squamous cell carcinoma of the head and neck. The lack of consensus over a benefit in the rates of overall survival and distant metastasis emphasizes the need for further prospective trials in the postoperative management of squamous cell carcinoma of the head and neck.