Frequency stabilization of a terahertz quantum-cascade laser to the Lamb dip of a molecular absorption line.

We demonstrate the frequency stabilization of a terahertz quantum-cascade laser (QCL) to the Lamb dip of the absorption line of a D2O rotational transition at 3.3809309 THz. To assess the quality of the frequency stabilization, a Schottky diode harmonic mixer is used to generate a downconverted QCL signal by mixing the laser emission with a multiplied microwave reference signal. This downconverted signal is directly measured by a spectrum analyzer showing a full width at half maximum of 350 kHz, which is eventually limited by high-frequency noise beyond the bandwidth of the stabilization loop.

Low noise 874 GHz receivers for the International Submillimetre Airborne Radiometer (ISMAR).

We report on the development of two 874 GHz receiver channels with orthogonal polarizations for the International Submillimetre Airborne Radiometer. A spline horn antenna and dielectric lens, a Schottky diode mixer circuit, and an intermediate frequency (IF) low noise amplifier circuit were integrated in the same metallic split block housing. This resulted in a receiver mean double sideband (DSB) noise temperature of 3300 K (minimum 2770 K, maximum 3400 K), achieved at an operation temperature of 40 °C and across a 10 GHz wide IF band. A minimum DSB noise temperature of 2260 K at 20 °C was measured without the lens. Three different dielectric lens materials were tested and compared with respect to the radiation pattern and noise temperature. All three lenses were compliant in terms of radiation pattern, but one of the materials led to a reduction in noise temperature of approximately 200 K compared to the others. The loss in this lens was estimated to be 0.42 dB. The local oscillator chains have a power consumption of 24 W and consist of custom-designed Schottky diode quadruplers (5% power efficiency in operation, 8%-9% peak), commercial heterostructure barrier varactor (HBV) triplers, and power amplifiers that are pumped by using a common dielectric resonator oscillator at 36.43 GHz. Measurements of the radiation pattern showed a symmetric main beam lobe with full width half maximum <5° and side lobe levels below -20 dB. Return loss of a prototype of the spline horn and lens was measured using a network analyzer and frequency extenders to 750-1100 GHz. Time-domain analysis of the reflection coefficients shows that the reflections are below -25 dB and are dominated by the external waveguide interface.

Millimeter-wave sensor based on a λ/2-line resonator for identification and dielectric characterization of non-ionic surfactants.

Studies of biological and artificial membrane systems, such as niosomes, currently rely on the use of fluorescent tags, which can influence the system under investigation. For this reason, the development of label-free, non-invasive detection techniques is of great interest. We demonstrate an open-volume label-free millimeter-wave sensing platform based on a coplanar waveguide, developed for identification and characterization of niosome constituents. A design based on a λ/2-line resonator was used and on-wafer measurements of transmission and reflection parameters were performed up to 110 GHz. Our sensor was able to clearly distinguish between common niosome constituents, non-ionic surfactants Tween 20 and Span 80, measuring a resonance shift of 3 GHz between them. The complex permittivities of the molecular compounds have been extracted. Our results indicate insignificant frequency dependence in the investigated frequency range (3 GHz - 110 GHz). Values of permittivity around 3.0 + 0.7i and 2.2 + 0.4i were obtained for Tween 20 and Span 80, respectively.

Blockade of nerve sprouting and neuroma formation markedly attenuates the development of late stage cancer pain.

For many patients, pain is the first sign of cancer and, while pain can be present at any time, the frequency and intensity of pain tend to increase with advancing stages of the disease. Thus, between 75 and 90% of patients with metastatic or advanced-stage cancer will experience significant cancer-induced pain. One major unanswered question is why cancer pain increases and frequently becomes more difficult to fully control with disease progression. To gain insight into this question we used a mouse model of bone cancer pain to demonstrate that as tumor growth progresses within bone, tropomyosin receptor kinase A (TrkA)-expressing sensory and sympathetic nerve fibers undergo profuse sprouting and form neuroma-like structures. To address what is driving the pathological nerve reorganization we administered an antibody to nerve growth factor (anti-NGF). Early sustained administration of anti-NGF, whose cognate receptor is TrkA, blocks the pathological sprouting of sensory and sympathetic nerve fibers, the formation of neuroma-like structures, and inhibits the development of cancer pain. These results suggest that cancer cells and their associated stromal cells release nerve growth factor (NGF), which induces a pathological remodeling of sensory and sympathetic nerve fibers. This pathological remodeling of the peripheral nervous system then participates in driving cancer pain. Similar to therapies that target the cancer itself, the data presented here suggest that, the earlier therapies blocking this pathological nerve remodeling are initiated, the more effective the control of cancer pain.

The current state of sexual ethics training in clinical psychology: issues of quantity, quality, and effectiveness.

Given the harm caused to clients and the psychology profession by therapist sexual misconduct, sexual ethics training should be given high priority in graduate training programs. The present study surveyed sexual ethics training and student understanding of sexual ethics in clinical psychology doctoral programs from the perspectives of training directors (n=84) and students (n=451). Ninety-four percent of the students had received sexual ethics training; programs provided an average of 6 hr of training. Still, students showed significant deficits in knowledge of sexual ethics principles. Students who had discussed a client attraction with a supervisor showed the best understanding of sexual ethics. Suggestions for ensuring adequate sexual ethics training are discussed.

Bipolarity in Jungian type theory and the Myers-Briggs Type Indicator.

The standard form of the Myers-Briggs Type Indicator (MBTI; Myers & McCaulley, 1985) was constructed to measure introversion/extroversion, sensing/intuiting, and thinking/feeling as single, bipolar dimensions. We tested this assumption of bipolarity with a Likert form of the MBTI that allowed for the independent assessment of each attitude and function. A total of 106 female and 59 male undergraduate and graduate students completed the standard and Likert MBTI forms approximately 3 weeks apart. Evidence for the bipolarity of the introversion/extroversion dimension was weak, and findings did not support the bipolarity of the sensing/intuiting or thinking/feeling dimensions. Results provide evidence that high negative correlations within MBTI dimensions are an artifact of its forced-choice format. Implications of the findings for typology measurement are discussed.

Optimal timing for stent replacement in malignant biliary tract obstruction.

Endoscopic stent placement has become accepted palliative therapy for malignant biliary tract obstruction. Because stent occlusion remains a significant late complication, prophylactic replacement has been suggested, although the appropriate time interval remains unclear. Patients with malignant biliary strictures who received 10F or 11.5F stents were analyzed with respect to clinical response, occlusion rates at 3 and 6 months, and survival rates. Seventy stents were placed in 50 patients. Pancreatic carcinoma was the most common underlying malignancy. Overall, obstructive symptoms resolved in 94% of cases. Occlusion rates at 3 months (4.2%) and 6 months (10.8%) were not significantly different. Median overall survival averaged 22 weeks. Results were also stratified by underlying diagnosis, with the worst clinical response and survival being seen in the group of patients with metastatic cancer. Findings suggest that the time interval for stent replacement can be extended safely from 3 to 6 months, resulting in decreased patient discomfort and cost and obviating any replacement in that significant percentage of patients who expire before 6 months.

The effects of assertive training on the performance self-esteem of adolescent girls.

Assertiveness training was provided for 148 girls in 10 high school business and homemaking classes in six senior high schools. Training sessions were co-led by an experienced leader and the students' own high school teacher. Significant changes in performance self-esteem scores were found between pretesting and a three-month follow-up (p<0.001) for the 103 subjects available at follow-up; low self-esteem subjects showed greater increases than high self-esteem subjects (p<0.001). Changes in self-esteem were related to the girls' perceptions of teacher reactions to their assertive behavior (p<0.01).