Parotid gland tissues investigated by picosecond time-gated andoptical spectroscopic imaging techniques

Near-infrared (NIR) time-resolved and spectroscopic transillumination imaging techniques are used to investigate normal tissues and Warthin's tumor of human parotid glands. The time-sliced imaging arrangement uses 120-fs, 1-kHz repetition-rate, 800-nm pulses from a Ti: sapphire laser and amplifier system for sample illumination and an ultrafast gated intensified camera system (UGICS) for recording two-dimensional (2-D) images using transmitted light. Images recorded with earlier temporal slices (approximately first 100 ps) of transmitted light highlight the tumor, while those recorded with later temporal slices (later than 200 ps) accentuate normal tissues. The spectroscopic imaging arrangement uses 1210-1300 nm tunable output of a Cr: forsterite laser for sample illumination, a Fourier space gate to discriminate against multiple-scattered light, and a NIR area camera to record 2-D images. The tumor region in the specimen appears brighter than the normal region in spectroscopic images recorded with light of different wavelengths. A wavelength-dependent variation in the ratio of light transmission through the tumor to that through the normal parotid gland is observed. Differences in scattering and wavelength-dependent absorption characteristics of normal parotid gland and Warthin's tumor provide a consistent explanation of these observed features. Histopathological analysis of the specimen sheds light on the probable origin of the differences in scattering and absorption characteristics     

Evaluation of polycaprolactone − poly‐D,L‐lactide copolymer as biomaterial for breast tissue engineering

The potential of the copolymer polycaprolactone‐co‐ poly‐d ,l ‐lactic acid (PCLLA ) as a biomaterial for scaffold‐based therapy for breast tissue engineering applications was assessed. First, the synthesized PCLLA was evaluated for its processability by means of additive manufacturing (AM ). We found that the synthesized PCLLA could be fabricated into scaffolds with an overall gross morphology and porosity similar to that of polycaprolactone. The PCLLA scaffolds possessed a compressive Young's modulus (ca 46 kPa ) similar to that of native breast (0.5 ? 25 kPa ), but lacked thermal stability and underwent thermal degradation during the fabrication process. The PCLLA scaffolds underwent rapid degradation in vitro which was characterized by loss of the scaffolds' mechanical integrity and a drastic decrease in mass‐average molar mass (M _w) and number‐average molar mass (M _n) after 4 weeks of immersion in phosphate buffer solution maintained at 37 °C. The tin‐catalysed PCLLA scaffold was also found to have cytotoxic effects on cells. Although the initial mechanical properties of the PCLLA scaffolds generally showed potential for applications in breast tissue regeneration, the thermal stability of the copolymer for AM processes, biocompatibility towards cells and degradation rate is not satisfactory at this stage. Therefore, we conclude that research efforts should be geared towards fine‐tuning the copolymer synthesizing methods. © 2016 Society of Chemical Industry     

Electromagnetic energy around Hertzian dipoles

This paper considers the behavior of electromagnetic energy around Hertzian dipoles. The method of “causal surfaces” (surfaces through which there is no net flow of electromagnetic energy) is used to partition and track the energy. A variety of examples, involving both transient and harmonic time dependence, are presented, to illustrate the way in which static and/or reactive energy is converted to outgoing, uncoupled, “radiated” energy around a Hertzian or point dipole. The principal conclusion is that although accelerating charge may be thought of as the source of the radiation fields, the source of the radiated energy lies in the static and/or reactive field energy near an antenna, and not “in” or “on” an antenna itself     

Development and Analysis of Three Diesel Particulate-Related Standard Reference Materials for the Determination of Chemical,Physical, and Biological Characteristics

The National Institute of Standards and Technology (NIST) has recently issued three Standard Reference Materials (SRMs) related to diesel particulate matter: SRM 1650a, Diesel Particulate Matter; SRM 2975, Diesel Particulate Matter (Industrial Forklift); and SRM 1975, Diesel Particulate Extract. These three materials have certified and reference concentrations for selected polycyclic aromatic hydrocarbons (PAHs) including many alkyl-substituted compounds. SRM 1650a is the reissue of an existing material and SRMs 2975 and 1975 represent new materials. The characterization of the PAH content of these three diesel particulate-related SRMs is presented with a discussion of the approach for the certification of PAH concentrations. In addition, the physical and biological characterization of these materials is discussed. A review of customer reported uses of these SRMs in the chemical, physical, and biological sciences is also provided.     

Genetic susceptibility to head and neck cancer: interaction between nutrition and mutagen sensitivity

The development of head and neck cancer may depend not only on exposure to environmental carcinogens but also on a genetically based susceptibility to carcinogen-induced damage. This thesis presents a case-control study that demonstrates the significance of mutagen sensitivity, a measure of an individual's intrinsic DNA repair capacity against free radical damage, as a risk factor for the disease. As part of the case-control analysis, 167 previously untreated patients and 177 age- and sex-matched healthy controls were assessed for various lifestyle factors including tobacco and alcohol habits, occupational exposures, and diet. Mutagen sensitivity expressed by each individual was determined by quantifying bleomycin-induced chromosomal breaks within peripheral blood lymphocytes in vitro. Consistent with our initial observations and those of others, mutagen hypersensitivity was strongly associated with increased risk of head and neck cancer (odds ratio, 4.95; 95% confidence interval, 2.67 to 9.17) after adjusting for age, sex, and race. Low intake of vitamins C and E was also associated with an increased risk of disease and was interactive with mutagen sensitivity in risk estimates. Individuals with both a low intake of various antioxidants and increased chromosomal sensitivity to oxidant-induced DNA damage were at greatest risk. This study supports the concept that the risk of head and neck cancer is determined by a balance of factors that either enhance or protect against free radical oxygen damage, including innate capacities for DNA repair.     

Human coenurosis in North America: case reports and review

To validate the use of mood induction with older adults, 22 older participants receiving a depressed mood induction were compared with 20 controls and 17 older persons with high Center for Epidemiologic Studies-Depression Scale (CES-D) scores. The mood induction procedure, using self-referent statements and music, changed Depressive Adjective Checklist and CES-D scores in each of 2 sessions 1 week apart. Findings indicated that the use of mood induction procedures with older adults can provide experimental control of mood.     

Clinical correlates of circulating immune complexes and antibody reactivity in squamous cell carcinoma of the head and neck. The Department of Veterans Affairs Laryngeal Cancer Study Group

PURPOSE: To evaluate the correlation between the presence and titer of host-derived antibody reactivity, circulating immune complexes, and clinical course and prognosis in patients with squamous cell carcinoma of the head and neck (SCCHN). MATERIALS AND METHODS: Serum samples, obtained from untreated patients with squamous cell carcinoma of the larynx entered onto a multiinstitutional trial, were evaluated for the presence of elevated circulating immune complexes (221 patients) and host-derived antibody directed against two SCCHN cell lines (107 patients). RESULTS: Patients had significantly elevated levels of circulating immune complexes as measured by C1q binding compared with normal controls. Patients with higher levels of circulating immune complexes were less likely to respond to chemotherapy. No correlations were noted between immune complex levels and stage of disease, nodal status, site of disease, recurrence, or survival. Evaluation of native antibody titers for their relationship to clinical correlates showed no statistically significant associations. In sera subjected to immune complex dissociation, patients with moderately or poorly differentiated tumors had significantly higher antibody titers when compared with patients with well-differentiated tumors. Because marked variation in the increase of antibody titers following immune complex dissociation was noted, the ratio of immune complex-dissociated to native antibody titer was examined. Patients with a high ratio had a lower proportion of complete and partial responses to chemotherapy. CONCLUSION: Our results support the conclusion that the formation of tumor-associated immune complexes in patients with SCCHN is associated with a decreased response to chemotherapy.     

Osteogenic differentiation of mesenchymal progenitor cells in computer designed fibrin-polymer-ceramic scaffolds manufactured by fused deposition modeling

Biomimetic scaffolds offer great potentials in the development of bone analogs for tissue engineering. The studies presented in this paper focus specifically on the osteogenic potential of the novel PCL/CaP matrices and its degradation behavior. Biodegradable Polymer-ceramic Scaffolds were fabricated using the solid free form fabrication technology: Fused Deposition Modeling (FDM). The scaffold architecture was characterized by a honeycomb-like design and a complete interconnectivity of the pores. Human mesenchymal stem cells (MSCs) were seeded together with fibrin glue into PCL/CaP scaffolds and cultured in vitro for periods of up to eight weeks. Cellular adhesion, proliferation and osteogenic differentiation were assessed in these constructs using a range of histological and microscopic techniques. In additional experiments, degradation was assessed by measuring mass loss, diameter change, molecular weight change and by scanning electron micrographs. MSCs were able to adhere, migrate, and differentiate along the osteogenic lineage with in these scaffolds. The PCL/CaP scaffolds showed up to 27 fold increased degradation of compared to PCL scaffolds.