A proposed framework for the implementation of head and neck cancer treatment at a new cancer center from a radiation oncology perspective.

BACKGROUND: Establishing a new head and neck cancer (HNC) treatment center requires multidisciplinary team management and expertise. To our knowledge, there are no clear recommendations or guidelines in the literature for the commencement of HNC radiation therapy (RT) at a new cancer center. We propose a novel framework outlining the necessary components required to set-up a new radiation therapy HNC treatment. METHODS: We reviewed the infrastructure and methodology in the commencement of HNC radiation therapy in our cancer care center and invited several external, experienced metropolitan head and neck radiation oncologists to develop a novel consensus guideline that may be used by new RT centers to treat HNC. Recommendations were presented to our internal and external staff specialists using a survey questionnaire with ratings utilized to determine consensus using pre-defined thresholds as per the American Society of Clinical Oncology Guidelines Methodology Manual. CONCLUSION: This consensus recommendation aims to improve RT utilization whilst advocating for optimal patient outcomes by presenting a framework for new radiation therapy centers ready to step up and manage the treatment of head and neck cancer patients. We propose these evidence-based consensus guidelines endorsed by external HNC radiation oncologists.

Combination of Plant Growth Regulators, Maltose, and Partial Desiccation Treatment Enhance Somatic Embryogenesis in Selected Malaysian Rice Cultivar.

The development of efficient tissue culture protocol for somatic embryo would facilitate the genetic modification breeding program. The callus induction and regeneration were studied by using different parameters i.e., auxins, cytokinins, and desiccation treatment. Scanning electron microscopy and histological analysis were performed to identify the embryogenic callus for regeneration. The callus percentage results showed that MS (Murashige and Skoog) basal medium supplemented with 3 mg/L 2, 4-D and 30g/L maltose were the optimal callus induction medium for MR220 (80%) and MR220-CL2 (95%). The morphology of the embryogenic callus was confirmed by the SEM (Scanning Electron Microscopy) (presence of extracellular matrix surface network) and later by histological analysis. Finally, MS media supplemented with 0.5 mg/L NAA (Naphthalene Acetic Acid), 2 mg/L kin, and 1 mg/L BAP were selected as the optimum regeneration media treatment while callus desiccated for 48 h was proved to produce more plantlets in MR220 (60%) and MR220-CL2 (73.33%) compared to control treatment (without desiccation). The protocol presented here showed the necessity for the inclusion of partial desiccation as an important step in the tissue culture protocol of Malaysian indica rice genotypes in order to enhance their regeneration potential.

Simple and efficient technique for evaluating the optical losses from surface scattering and volume attenuation in a thin film.

We present a simple and efficient technique for evaluating the optical losses of a planar film by use of a quasi-waveguide configuration and a prism film coupler configuration. The technique can separate two contributions to optical loss: that from the surface scattering caused by the roughness of surface and that from volume losses including volume scattering and volume absorption.

Application of matrix-modification in determination of thallium in waste water by graphite-furnace atomic-absorption spectrometry.

A method has been developed for the determination of thallium in waste water at the ng ml level by graphite-furnace atomic-absorption spectrometry. If microgram amounts of palladium or platinum are used as a matrix modifier, the ashing temperature for thallium can be raised to 1000 degrees , and the interference of halides and mineral acids is greatly reduced. The relative standard deviation found was 2% (9 replicate determinations) at the 8-ng ml thallium level, and the detection limit 1 ng ml .

Selective separation and differential determination of antimony(III) and antimony(V) by solvent extraction with N-benzoyl-N-phenylhydroxylamine and graphite-furnace atomic-absorption spectrometry using a matrix-modification technique.

If copper is used as a matrix modifier for the determination of antimony, the ashing temperature for antimony in aqueous solution and a BPHA-CHCl(3) extract can be raised to 1300 degrees and 1100 degrees , respectively. A selective procedure for separating antimony(III) from antimony(V) by extraction with BPHA in chloroform is described, along with the conditions for preserving trace antimony in water samples. The recommended method has been applied satisfactorily to the determination of antimony(III) and antimony(V) in various types of water at sub-ng/ml levels.

Optical properties of inverted opal photonic band gap crystals with stacking disorder.

We present a detailed study of the effect of planar stacking disorder on optical properties of inverted opal photonic crystals. Systems with periodic stacking sequences are first studied that include face centered cubic, hexagonal close-packed, and doubly hexagonal close-packed photonic crystals. For the structures with periodic stacking order, we evaluate the band structure followed by calculation of transmission spectrum along the direction perpendicular to the hexagonal close-packing plane of the structures. Inverted opal photonic crystals with random stacking sequences are then studied by calculating average transmittance of the photonic crystal slabs over various random stacking configurations. The position and width of the lowest stop gap along the direction normal to the hexagonal close-packing plane is found to be invariant, regardless of the stacking sequence in the photonic crystal. We show how the propagation properties at higher frequencies are affected by the stacking configurations (both periodic and disordered stacking sequences), particularly those near the edges of the absolute band gap. The obtained results are directly relevant to transmission/reflection experiments on inverted opal photonic crystals with complete band gap.

Nonlinear Cerenkov radiation in nonlinear photonic crystal waveguides.

We study nonlinear Cerenkov radiation generated from a nonlinear photonic crystal waveguide where the nonlinear susceptibility tensor is modulated by the ferroelectric domain. Nonlinear polarization driven by an incident light field may emit coherently harmonic waves at new frequencies along the direction of Cerenkov angles. Multiple radiation spots with different azimuth angles are simultaneously exhibited from such a hexagonally poled waveguide. A scattering involved nonlinear Cerenkov arc is also observed for the first time. Cerenkov radiation associated with quasi-phase matching leads to these novel nonlinear phenomena.

Transforming spatial entanglement using a domain-engineering technique.

We study the spatial correlation of a two-photon entangled state produced in a multistripe periodically poled LiTaO3 crystal by spontaneous parametric down-conversion. The far-field diffraction-interference experiments reveal that the transverse modulation of domain patterns transforms the spatial mode function of the two-photon state. This result offers an approach to prepare a novel type of two-photon state with a unique spatial entanglement by using a domain-engineering technique.

Persistent median artery as a cause of pronator syndrome.

Pronator syndrome may be caused by a persistent median artery that passes completely through the proximal median nerve and then gives origin to a vascular leash to the flexor muscles that compresses the nerve. A "double crush" compression of the median nerve caused by persistent median artery producing first a carpal tunnel syndrome and then a pronator syndrome is described.

Blue-light generation by frequency doubling of an 810-nm cw GaAlAs diode laser in a quasi-phase-matched LiNbO(3) crystal.

A third-order quasi-phase-matched LiNbO(3) crystal was used to double the output of an 810-nm cw GaAlAs diode laser directly. A blue-light output power of 0.35 mW was measured with a conversion efficiency of 0.13%.

Intrinsic instability of the concentration field in diffusion-limited growth and its effect on crystallization.

The dynamic behavior of the concentration field in crystallization is investigated by considering the coupling of the bulk concentration field and interfacial kinetics. It is shown that the concentration field may become unstable for perturbations with certain wavelength. When instability occurs, the physical environment in front of the growing interface will fluctuate and the interfacial growth mode will be affected accordingly. We suggest that our analysis can be used to interpret some spatial-temporal instabilities observed in crystallization.

Second-harmonic generation in quasi-periodically domain-inverted Sr(0.6) Ba(0.4) Nb(2)O(6) optical superlattices.

One-dimensional Fibonacci-type quasi-periodically domain-inverted structures have been successfully fabricated in a strontium barium niobate crystal by electric field poling. With a single such structure, type I phase-matched second-harmonic generation (SHG) has been demonstrated at several wavelengths from red to near ultraviolet. The spectral positions of the observed SHG peaks are in good agreement with theoretical predictions. The range of measured conversion efficiencies is 2-10%.

[MR imaging of intracerebral hematomas: sequential changes of signal intensities on a 0.2T permanent magnetic system].

We performed 67 examinations in 27 patients with intracerebral hemorrhage on a 0.2T permanent magnet system. MR appearance of the hematomas on T-1 weighted and T-2 weighted images (T1WIs, T2WIs) was carefully evaluated according to the chronological course of the lesions after the ictus. The signal intensity of each hematoma was classified into four stages in terms of the degradation process of hemoglobin. Four hematomas examined within 24 hours after the ictus (ultra-acute stage) appeared slightly hypointense or isointense relative to the normal brain tissue on T1WIs and markedly hyperintense on T2WIs. Three of those lesions became partially or totally hypointense on T2WIs at the acute stage (one to three days after the ictus), though all appeared in general isointense on T1WIs. The hematomas at the subacute stage (four days to two weeks after the ictus) were hyperintense on both T1WIs and T2WIs. At the chronic stage (more than two weeks after the ictus) the signal pattern of hematomas became variable: hyperintense on both T1WIs and T2WIs early at this stage; hypointense on T1WIs but mostly hyperintense on T2WIs latter. The results indicate the clinical feasibility of a low tesla system for MR evaluation of intracerebral hematomas.

Third-harmonic generation in a general two-component quasi-periodic optical superlattice.

The quasi-periodic optical superlattice is a promising material for use in optical frequency conversion. We propose a method for designing a quasi-periodic structure for efficient third-harmonic generation (THG) at any given wavelength. With this method we have made a LiTaO(3) sample in which 27% THG at 0.48microm was achieved, together with a series of highly efficient multiwavelength second-harmonic generation outputs. The result is in good agreement with the theoretical prediction.

Conical second harmonic generation in a two-dimensional chi(2) photonic crystal: a hexagonally poled LiTaO3 crystal.

A new type of conical second-harmonic generation was discovered in a 2D chi((2)) photonic crystal-a hexagonally poled LiTaO3 crystal. It reveals the presence of another type of nonlinear interaction-a scattering involved optical parametric generation in a nonlinear medium. Such a nonlinear interaction can be significantly enlarged in a modulated chi((2)) structure by a quasi-phase-matching process. The conical beam records the spatial distribution of the scattering signal and discloses the structure information and symmetry of the 2D chi((2)) photonic crystal.