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A headspace-GC (HSGC) method with multiple extractions from a single vial was developed for the measurement of desorption isotherms with any volatile organic component at any reasonable temperature. The geometric parameters of porous silica and chemically modified silica have been determined by this method. The methodology and instrumentation for the determination of porosity and surface areas of solids at various temperatures are described. This methodology is based on the periodic withdrawal and gas chromatographic analysis of aliquots of vapors from a headspace vial containing the adsorbent spiked with a chemical of interest (adsorbate). The instrumentation is calibrated using the same chemical in a vial without adsorbent. The desorption isotherm of the adsorbate on mesoporous silica was measured by headspace GC at 363°K up to p/po = 1.00 and by low-temperature nitrogen adsorption at 77 K. On the basis of the desorption isotherms, the pore size distribution was calculated by the Barrett, Joyner, and Hallender¹ method where the pore shape was assumed to be cylindrical. The measurement of the total surface area was performed according to Brunauer−Emmett−Teller (BET) theory.² The isotherm obtained using benzene as the adsorbate was then used for the determination of the geometrical properties of the mesoporous silica. The surface area, pore volume, and average pore radius were determined to be 325 m²/g, 1.1 mL/g, and 77 Å for Prodigy-Si (Phenomenex, Torrance, CA) using benzene with the headspace-GC method. The surface area, pore volume, and average pore radius determined by low-temperature nitrogen adsorption were 326 m²/g, 1.2 mL/g, and 75 Å, respectively. In addition to geometrical characterization of surfaces, the methodology and instrumentation proposed provide information about specific interactions between the adsorbate and the surface of the adsorbent or catalyst under study. It also permits the determination of the energies involved in these interactions as well as the evaluation of the competitive sorption of mixtures.

Various methods of detecting cancer with fluorescence have been developed. One type of fluorescence is based on the tumor-localizing properties of certain dyes. However, the phototoxicity of most known tumor-localizing dyes hinders the safe use of such diagnostic methods. The authors have developed a fluorescence imaging system to detect the distribution of a nontoxic dye, fluorescein, and they have evaluated the feasibility of the system by using it to detect oral dysplastic lesions in hamsters. Dysplasia was induced in the cheek pouches of hamsters by application of the carcinogen 9,10-dimethyl-1,2-benzantracene. Fluorescein was administered to the hamsters either intravenously or orally before the fluorescence examination. The endoscopic fluorescence system produced dye-distribution images of both treated and control pouches. Two fluorescence images in different spectral regions were processed for each dye image. Biopsy material from both pouches was examined histopathologically. The accumulation of fluorescein was detected in 22 of 23 specimens containing dysplastic lesions. These results demonstrate the utility of this fluorescein accumulation method in the detection of dysplasia. The accumulation of fluorescein in dysplastic lesions may point to acidification of interstitial medium in such lesions. Cancer 1999;85:1421–9. © 1999 American Cancer Society.

The radiation defect production and annealing processes in dislocated silicon are analysed. The character of the effect of dislocations on the radiation defect parameters is shown to depend on their nature. Taking into account the dependence determined a scheme is suggested in accordance with which the electrically active defects in Si are divided into four groups. This is useful when identifying defects of unknown nature.

Radiation-induced accumulation and annealing processes of radiation defects with level Ec-0,22 eV in silicon of various perfection are analysed and it is concluded that they consist of oxygen and two vacancies (oxygen-divacancy complex).

The influence of the irradiation kind and dislocation density on the rearrangement processes at annealing of radiation defects of different types has been studied.

The effect of dislocations on nonequilibrium charge carrier recombination in irradiated Si has been studied and the model providing satisfactory explanation of the experimental results has been proposed.

Reconstruction processes proceeding during annealing of radiation defects in60Co γ-ray-irradiated (Tin≲50°C) n-type silicon (ρ=20 to 250 Ω cm) grown by the vacuum float-zone technique were investigated. The temperature dependences (80 to 400 K) of charge carrier concentration and life time were measured at various stages of annealing (Tann= 100 to 600°C). It has been established that during annealing theE-centres interact with carbon-containing complexes of interstitial type or are transformated into more complicated complexes of phosphorus-divacancy. Phosphorus electrical activity is completely restored after annealing of phosphorus-divacancy complexes atTann = 400 to 500°C. The energy level of phosphorus-divacancy complexes was found to be in lower half of forbidden gap (ΔEr= 0.34 eV). The cross-section s`p of hole capture by these complexes was determined to be equal to 4 × 10-15 cm2. It was concluded that the phosphorus-divacancy complexes are singly charged acceptors.

Radiation defect accumulation in 60Co γ-ray-irradiated n-type Si single crystals (ρ=150ωcm) with various densities of dislocations (ND= 1 × 104 to 1 × 107 cm -2) introduced at plastic deformation was studied. The temperature dependences of the Hall coefficient were measured. The probabilities of interaction of vacancies with oxygen, phosphorus atoms, and dislocation line elements were determined. It has been established that with the increase of ND they can increase at the expense of complication of dislocation structure, decrease during formation of impurity atmosphere near dislocations and compensation of deformation fields, and they do not change if complex formation of vacancies with impurities occurs far from dislocations. Kinetics of A- and E-centre accumulation in the crystals containing dislocations with different impurity atmosphere was described.

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The recent successful use of electrospray gas-phase electrophoretic mobility molecular analysis (GEMMA) to separate globular proteins (mass 6 to 670 kDa) and the excellent correlation found between the electrophoretic mobility diameter (EMD), or Millikan diameter, and the protein mass (S. L. Kaufmanet al.,1996,Anal. Chem.68, 1895–1904; 1996,Anal. Chem.68, 3703), prompted the examination of a large protein complex, the 3.6-MDa, heteromultimeric, hexagonal bilayer hemoglobin (Hb) and its subunits from the earthwormLumbricus terrestris.The native Hb had an EMD of 25.7 nm and the products of its dissociation at pH >8 and <5 were resolved into peaks with EMDs of 10.5, 6.3, 5.0, and 4.2 nm, identified as a dodecamer of globin chains ([a+b+c]3d3, 213 kDa), the disulfide-bonded trimer of globin chains ([a+b+c], 52.7 kDa), all the linker chains (L1, 27.5 kDa; L2, 32.1 kDa; L3, 24.9 kDa; L4, 24.1 kDa), and the monomer subunit (chain d, 17 kDa), respectively. Reassembly of the Hb complex was observed on restoring the pH from >8 to 7. The EMDs and the masses of the Hb and its subunits are in excellent agreement with the correlation found earlier, under the assumption of nearly spherical shape with an effective density around 0.7 g/cm3. GEMMA also provided a profile of the Hb completely dissociated in 0.1% SDS; its deconvolution permitted a quantitative determination of the subunit stoichiometry, providing a globin to linker ratio of 3 to 1.

The accumulation processes of the compensating and recombination centres during 60Co γ-ray irradiation of n-type Si (ρ = 50-250 Ωcm, τ = 50-100 μs) with a high dislocation density (ND= 1 ˙ 104-˙-1 ˙ 107 cm-2) introduced by plastic deformation are studied. The results are obtained from measurements of the minority charge-carrier lifetime by the method of conductivity modulation at a point contact and the Hall coefficient temperature dependences. Radiation defect introduction efficiency is found to depend significantly on the content of the dislocation impurity atomosphere whose change is achieved by varying the deformation conditions (fast and slow cooling) and subsequent radiation-heat treatments (γ-ray irradiation and annealing). The experimental results are interpreted taking into account the conception of compensation of elastic stress fields by impurity atoms and participation of impurities in complexing with primary radiation defects near dislocations.

BACKGROUND Odontogenic keratocysts of the jaw are a central feature of basal cell nevus syndrome (BCNS) and arise from the basal cell layer of the surface epithelium. Although they are benign, they tend to be aggressive, with local invasion of bony structures, extensive growth, and potential for substantial disfigurement and speech dysfunction. Complete surgical resection is the current standard of care; however, the procedures are often technically challenging and are followed by high recurrence rates. OBSERVATIONS We report the case of a 55-year-old man with a long-standing history of BCNS. Over a 25-year period, this patient had been treated for many basal cell carcinomas (BCCs). He also had multiple large odontogenic keratocysts in the mandible that had previously been treated using surgical, chemotherapeutic, and radiation treatment techniques. He had also undergone a right inguinal lymph node dissection after BCC metastasis was diagnosed within a lymph node. Owing to the recalcitrant nature of his condition and his history of BCC metastasis, the patient was started on a daily regimen of a new oral drug, GDC-0449, which inhibits the hedgehog signaling pathway, a key genetic contributor in the oncogenesis of BCCs. In addition to complete resolution of all his BCCs at 12-week follow-up, nearly complete resolution of 3 odontogenic keratocysts was documented by serial dental radiographs after 2 years of therapy. CONCLUSIONS We report the nearly complete regression of multiple BCNS-associated odontogenic keratocysts following nonsurgical treatment with GDC-0449. This novel drug, useful for the treatment of BCC, also appears to be effective for treatment of odontogenic keratocysts.

Perforated cystic mediastinal teratoma is rare. The diagnosis of this condition and a clear demonstration of its associated complications are important for defining the surgical approach. We report the clinical manifestation, computed tomography (CT) and ultrasound findings of a case of mediastinal mature cystic teratoma perforating into the lung. Ultrasound features of teratoma-lung fistula have not been previously described. The pathological examination confirmed perforation of mediastinal teratoma into the lung without evidence of pulmonary invasion.

It is shown that the temporal modulation of a pulse from an electron-beam-controlled CO laser can be caused by the periodic modulation of losses caused by the monotonic heating of the active medium.

A relief spatial optical modulator converts an input electrical (or optical) signal into a deformed, light-reflecting surface whose deformation at each point corresponds to the two-dimensional power distribution of the supplied signal. This paper describes a prototype of an optically controllable seven-channel relief optical modulator, with a large deformation amplitude, up to 10 µm, of the light-reflecting surface. The main characteristics of the electromechanical and optical elements of the modulator are presented, and the prospects of the practical use of relief optical modulators are briefly considered. © 2003 Optical Society of America

The first investigation was made of the emission spectrum of a pulsed electron-beam-controlled (EBC) CO laser with the main discharge pumped by a pulse-forming LC line. This line made it possible to increase considerably the number of the vibrational — rotational lines in the emission spectrum of this laser, compared with an EBC-CO laser with a capacitor bank.

A study was made of the operation of an electron-beam-controlled CO laser based on two-quantum transitions in the carbon monoxide molecule and pumped by a discharge from a pulse-forming LC line. The use of this line made it possible to increase considerably the efficiency of two-quantum lasing transitions.

The excess adsorption isotherms of methanol-water and acetonitrile-water mixtures are compared for C4, C8, and C18 types of reversed-phase adsorbents with the same type of silica support (Hypersil). Adsorption behavior of the organic modifier is also measured for three different types of C8 adsorbents (Bakerbond, Supelcosil, and Hypersil) and on the Ultracarb-ODS at different temperatures. It is shown that the adsorption behavior of acetonitrile for all types of bonded phases is similar, but that of methanol shows an obvious dependence on the alkyl chain length of the bonded phase.

The definition of dead volume in high-performance liquid chromatography and its determination on the basis of the thermodynamic Gibbs theory is discussed. The suggested thermodynamic approach can be applied to the description of any liquid chromatographic method such as normal phase, reversed phase, ion exchange, and even size exclusion. A method is suggested for the accurate calculation of the dead volume from mobile phase component disturbance peaks through the whole concentration range. The existence of negative values of capacity factors for some compounds is also explained.