Temperature characteristics of surface micromachined MEMS-VCSEL with large tuning range.

Several Applications for tunable laser diodes have strict constraints in terms of overall power consumption. Furthermore, the implementation in harsh environments with large temperature fluctuations is necessary. Due to the constraint in power consumption, the application of active cooling might not be an option. For this reason we investigate the temperature characteristics of an electrically pumped MEMS-VCSEL with wide continuous wavelength tuning. For the first time, a mode hop free single mode (side mode suppression ratio (SMSR) > 40dB) tuning range of 45nm at 70°C is demonstrated with a MEMS-VCSEL. An increase of the tuning range from 85nm at 20°C to 92nm at 40°C is measured and explained. In contrast to fixed wavelength VCSEL, the investigated device shows a negative temperature induced wavelength shift of -4.5nmK(-1), which is caused by the MEMS-mirror. At 1560nm, the fibre-coupled optical output power is above 0.6mW over the entire temperature range between 20°C to 70°C and shows a maximum of > 3mW at 20°C.

Surface micromachined tunable 1.55 µm-VCSEL with 102 nm continuous single-mode tuning.

For the first time a vertical-cavity surface-emitting laser (VCSEL) with a single-mode wavelength-tuning over 102 nm in the range of 1550 nm is demonstrated. The fiber-coupled optical output power has a maximum of 3.5 mW and is > 2 mW over the entire tuning range. The sidemode suppression ratios are > 45 dB. The wavelength tuning is achieved with the micro-electro mechanical actuation of a mirror membrane fabricated with surface micro-machining for on-wafer mass production. The mirror membrane consists of low cost dielectric materials (SiOx/SiNy) deposited with low temperature (< 100°C) Plasma Enhanced Chemical Vapor Deposition (PECVD).

Retroperitoneal mature teratoma 15 years after initial treatment of testicular mixed germ cell tumor.

We present a patient with a retroperitoneal tumor noted 15 years after treatment of a testicular mixed germ cell cancer. The patient initially underwent right-sided orchiectomy and retroperitoneal lymph node dissection for clinical stage I disease. An early relapse indicated by increasing tumor markers shortly after retroperitoneal lymph node dissection was successfully treated with five cycles of combined chemotherapy. However, 187 months after completion of chemotherapy, a symptomatic right-sided iliac mass was diagnosed. Radical surgical excision of the mass was performed and histologic examination revealed differentiated mature teratoma. This represents the longest time interval reported in the literature for a mature teratoma following treatment of a testicular germ cell tumor.

[Improvement of transrectal ultrasound. Artificial neural network analysis (ANNA) in detection and staging of prostatic carcinoma]. / Weiterentwicklung des transrektalen Ultraschalls. Artifizielle neuronale Netzwerkanalyse (ANNA) in der Erkennung und Stadieneinteilung des Prostatakarzinoms.

As a result of the enhanced clinical application of prostate specific antigen (PSA), an increasing number of men are becoming candidates for prostate cancer work-up. A high PSA value over 20 ng/ml is a good indicator of the presence of prostate cancer, but within the range of 4-10 ng/ml, it is rather unreliable. Even more alarming is the fact that prostate cancer has been found in 12-37% of patients with a "normal" PSA value of under 4 ng/ml (Hybritech). While PSA is capable of indicating a statistical risk of prostate cancer in a defined patient population, it is not able to localize cancer within the prostate gland or guide a biopsy needle to a suspicious area. This necessitates an additional effective diagnostic technique that is able to localize or rule out a malignant growth within the prostate. The methods available for the detection of these prostate cancers are digital rectal examination (DRE) and Transrectal ultrasound (TRUS). DRE is not suitable for early detection, as about 70% of the palpable malignancies have already spread beyond the prostate. The classic problem of visual interpretation of TRUS images is that hypoechoic areas suspicious for cancer may be either normal or cancerous histologically. Moreover, about 25% of all cancers have been found to be isoechoic and therefore not distinguishable from normal-appearing areas. None of the current biopsy or imaging techniques are able to cope with this dilemma. Artificial neural networks (ANN) are complex nonlinear computational models, designed much like the neuronal organization of a brain. These networks are able to model complicated biologic relationships without making assumptions based on conventional statistical distributions. Applications in Medicine and Urology have been promising. One example of such an application will be discussed in detail: A new method of Artificial Neural Network Analysis (ANNA) was employed in an attempt to obtain existing subvisual information, other than the gray scale, from conventional TRUS and to improve the accuracy of prostate cancer identification.

Keratoacanthoma in the differential diagnosis of anal carcinoma: difficult diagnosis, easy therapy. Report of three cases.

Three male patients who had an anal keratoacanthoma are described. Anal keratoacanthoma is a rapidly growing skin tumor that invades the dermis but remains locally and can mimic clinically and histologically a squamous-cell carcinoma.

Direct amifostine effect on renal tubule cells in rats.

Clinical trials indicate that amifostine offers protection against cisplatin-induced nephrotoxicity. It is unclear whether a direct pharmacological t on renal tubular cells is involved. We investigated the effect of amifostine pretreatment on the tubular apparatus and evaluated its nephroprotective potential. A total of 32 rats were treated by i.p. administration of 0.9% saline solution (group 1), 5 mg/kg cisplatin (group 2), 25 mg/kg amifostine (group 3), and 25 mg/kg amifostine followed by 5 mg/kg cisplatin (group 4) after 30 min. We recorded elevation of N-acetyl-beta-D-glucosaminidase (NAG) in 24 h pooled urine as a specific marker for tubular lesions, renal leakage of magnesium as an unspecific nephrotoxicity marker, and survival over a 10-day observation period. A significant (P < 0.002) increase in urinary NAG after treatment was documented only in cisplatin-treated group 2 [day 2 (mean+/-SE), 93+/-2.1 units/gram creatinine; day 4, 70.6+/-16 units/gram creatinine; normalization at day 8]. Treatment with amifostine before cisplatin administration resulted in a slight urinary NAG leakage (day 2, 2.8+/-1.8 units/gram creatinine; day 4, 13.8+/-13 units/gram creatinine; normalization at day 6). No increase in urinary enzyme levels was seen in the other groups, and there were no significant differences in urinary magnesium between all groups. Four of eight rats in the cisplatin-treated group and one of eight rats in the amifostine plus cisplatin-treated group died.

Artificial neural network analysis (ANNA) of prostatic transrectal ultrasound.

BACKGROUND: Our purpose was to determine the diagnostic potential of a new, computerized method of interpreting transrectal ultrasound (TRUS) information by artificial neural network analysis (ANNA). This method was developed to resolve the current dilemma of visual differentiation between benign and malignant tissue on TRUS. To train and objectively evaluate ANNA, a new precise method of computerized virtual correlation of preoperative ultrasound findings and radical prostatectomy histopathology was devised. After training with this pathologically confirmed digitized TRUS information, ANNA was tested in a blinded study. METHODS: Following radical prostatectomy, 289 pathology whole-mount sections of 61 patients were correlated digitally with the corresponding TRUS slices. Specific selection of TRUS areas unequivocally identified on the correlated digitized pathohistology resulted in 553 pathology-confirmed representations (samples). Of these, 53 were used for training and 500 were subjected to blind analysis by ANNA. RESULTS: ANNA classified 378 (99%) of the 381 benign pathology-confirmed samples correctly as benign. The false-positive rate was 1% (n = 3). Of the 119 pathology-confirmed malignant samples, 94 (79%) were classified correctly; 25 (21%) were falsely classified as normal. Out of all 119 cancers, ANNA classified 60 (71%) of the hypoechoic cancers as malignant and 24 (29%) as benign. Surprisingly, 34 (97%) of the isoechoic cancers were correctly classified by ANNA, missing only one sample. CONCLUSIONS: The introduction of ANNA enhanced the accuracy of TRUS prostate cancer identification. Although not all malignant areas were detected, cancer was detected in each patient. The ability to detect isoechoic cancerous lesions appears to be the essential innovation over conventional TRUS interpretation.

Symmetrical dispersion compensation for standard monomode-fiber-based communication systems with large amplifier spacing.

Optical 10-Gbit / s return-to-zero pulse transmission in cascaded communication systems using dispersion compensation of the standard monomode fiber with large amplifier spacing is examined. It is shown that pulse distortions that are due to Kerr nonlinearity are significantly diminished by symmetrical ordering of the compensation sections when the total number of precompensation and postcompensation sections is equal. Repositioning of these sections is not critical.

Reverse-phase liquid chromatographic determination of benzoic and sorbic acids in fresh cheese.

The sorbate and benzoate contents of commercial fresh cheese (quarg) samples are determined by reverse-phase liquid chromatography following extraction with a methanol-acetate buffer pH 4.5 mixture (37 + 63). The mobile phase is acetonitrile-acetate buffer pH 4.5 (20 + 80), the effluent flow rate is maintained at 1.0 mL/min, and the detector is set at 232 nm. Recoveries from quarg spiked at the 5-50 mg/kg level ranged from 95 to 99%, which compares favorably with methods previously published. Precision averaged 2-5% RSD, whereas the limit of detection was 0.3 mg/kg (sorbic acid) and 1.0 mg/kg (benzoic acid).

High performance liquid chromatography of furfural and hydroxymethylfurfural in spirits and honey.

Furfural (2-furaldehyde) and hydroxymethylfurfural (5-hydroxy-2-furaldehyde, HMF) are determined in brandy and honey by reverse phase high performance liquid chromatography. Brandies and other spirits are injected without sample preparation; honey is diluted with water and the solution is filtered before injection onto a reverse phase column with detection at 285 nm. The mobile phase is methanol--water (10 + 90) and the effluent flow rate is maintained at 1.0 mL/min. External standardization is used for quantitative determination. Recoveries from cognac and honey spiked at different levels ranged from 95 to 99% (furfural) and 95 to 100% (HMF). The furfural content of the brandies was also determined by the existing colorimetric method of the Bureau National Interprofessionel du Cognac. The HMF content of the honey was correlated to the results of the classic method of Winkler.

Papaver bracteatum Lindl.: quantitative extraction and determination of thebaine.

An interlaboratory procedure for the quantitative extraction and analysis of thebaine from different tissues of Papaver bracteatum Lindl. is presented. Each step was evalutated for the yield of thebaine by use of 1-3H-thebaine and GLC. The method of drying and milling of tissue and the size of resultant particles were important factors in the quantitative recovery of thebaine.