Truncated Nonlinear Interferometry for Quantum-Enhanced Atomic Force Microscopy.

Nonlinear interferometers that replace beam splitters in Mach-Zehnder interferometers with nonlinear amplifiers for quantum-enhanced phase measurements have drawn increasing interest in recent years, but practical quantum sensors based on nonlinear interferometry remain an outstanding challenge. Here, we demonstrate the first practical application of nonlinear interferometry by measuring the displacement of an atomic force microscope microcantilever with quantum noise reduction of up to 3 dB below the standard quantum limit, corresponding to a quantum-enhanced measurement of beam displacement of 1.7 fm/sqrt[Hz]. Further, we minimize photon backaction noise while taking advantage of quantum noise reduction by transducing the cantilever displacement signal with a weak squeezed state while using dual homodyne detection with a higher power local oscillator. This approach may enable quantum-enhanced broadband, high-speed scanning probe microscopy.

Are the material properties and matrix composition of equine flexor and extensor tendons determined by their functions?

REASONS FOR PERFORMING STUDY: Injury to the superficial digital flexor tendon (SDFT) is common in competition horses. The SDFT contributes to locomotory efficiency by storing energy; such tendons have low safety margins. Tendons which merely position the limb, including the opposing common digital extensor tendon (CDET), are rarely injured. The current failure of strategies to prevent or effectively treat injury to the SDFT indicates the importance of understanding how it differs from tendons which are not injury-prone. HYPOTHESIS: That the structural and material properties and matrix composition of the SDFT and CDET differ, reflecting their specific functional requirements in vivo. METHODS: Forelimb tendons were harvested from 26 mature horses and loaded to failure prior to matrix composition analysis of specimens. RESULTS: The SDFT had a significantly higher cross-sectional area, structural stiffness, failure load and failure strain and a lower elastic modulus than the CDET (P < 0.0001). CONCLUSIONS: The SDFT has conflicting requirements for strength and elasticity; although as a whole it is a stiffer structure than the CDET, differences in the matrix molecular composition including water and total sulphated glycosaminoglycan contents allow it to remain more elastic as a material. POTENTIAL RELEVANCE: Further information on how the two tendons attain these different properties may be of use in the development of prevention and treatment strategies for SDFT rupture.

Phase I trial of intratumoral liposome E1A gene therapy in patients with recurrent breast and head and neck cancer.

PURPOSE: We conducted a Phase 1 study to determine the maximal tolerated dose and maximum biologically active dose of the E1A gene delivered by intratumoral injection as a lipid complex with 3 beta[N-(n',n'-dimethylaminoethane)-carbamoyl] cholesterol/dioleoylphosphatidyl-ethanolamine (tgDCC-E1A). The E1A adenovirus gene functions as a tumor inhibitor gene by repressing oncogene transcription; modulating gene expression, resulting in cellular differentiation; and inducing apoptosis of cancer cells. E1A also sensitizes cancer cells to chemotherapeutic drugs such as etoposide, cisplatin, and taxol. EXPERIMENTAL DESIGN: Nine patients with recurrent and unresectable breast cancer and nine patients with head and neck cancer were enrolled. One tumor nodule in each patient was injected with tgDCC-E1A. Safety, tumor response, E1A gene transfer, and down-regulation of HER-2/neu were evaluated. RESULTS: No dose-limiting toxicity was observed in the four dose groups (15, 30, 60, and 120 microg DNA/cm of tumor). All patients tolerated the injections, although several experienced pain and bleeding at the injection site. A maximally tolerated dose was not reached in this study. E1A gene transfer was demonstrated in 14 of 15 tumor samples tested, and down-regulation of HER-2/neu was demonstrated in two of the five patients who overexpressed HER-2/neu at baseline. HER-2/neu could not be assessed in other posttreatment tumor samples because of extensive necrosis. In one breast cancer patient, no pathological evidence of tumor was found on biopsy of the treated tumor site at week 12. In 16 patients evaluable for tumor response, 2 had minor responses, 8 had stable disease, and 6 had progressive disease. CONCLUSIONS: Gene therapy with an E1A gene:lipid complex appears to be safe and warrants further testing.

Postexercise and positional variation in mechanical properties of the radius in young horses.

The metacarpal of the horse is severely loaded during vigorous exercise. Metacarpal specimens have a greater impact strength in young horses that have been exercised than in those that have only been walked. We did not find a corresponding difference in the radius of the same horses. We show that cranial (anterior) cortical bone from the radius, which is loaded in tension during locomotion, has a greater Young's modulus, and tensile and bending strength, than bone from the caudal (posterior) cortex, which is loaded in compression. Caudal bone is, however, stronger in compression. The differences can be explained by differences in the histological structure developed by the 2 cortices and are presumably adaptive. This work confirms the work of others. Furthermore, we demonstrate that the impact energy absorption of cranial bone is nearly twice as great as that of caudal bone. The caudal cortex has apparently paid a heavy price in its reduction in resistance to accidental impact loading for being stronger than the cranial cortex in compressive loading.

Hyperbaric oxygen therapy.

Hyperbaric oxygen therapy involves intermittent inhalation of 100% oxygen under a pressure greater than 1 atm. Despite over a century of use in medical settings, hyperbaric oxygen remains a controversial therapy. The last 20 years have seen a clarification of the mechanism of action of hyperbaric therapy and a greater understanding of its potential benefit. However, despite the substantial evidence that hyperbaric oxygen may have a therapeutic effect in certain carefully defined disease states, many practitioners remain unaware of these findings or are concerned about using hyperbaric therapy because of the controversy it has engendered. This review examines the indications currently considered appropriate for hyperbaric oxygen and briefly evaluates animal and clinical data substantiating these indications. Areas in which the mechanism of action of hyperbaric oxygen is still not well understood, as well as possible new areas of applications, are discussed.