Design and raytrace simulations of a multilayer-coated Wolter x-ray optic for the Z machine at Sandia National Laboratories.

Recent breakthroughs in the fabrication of small-radii Wolter optics for astrophysics allow high energy density facilities to consider such optics as novel x-ray diagnostics at photon energies of 15-50 keV. Recently, the Lawrence Livermore National Laboratory, Sandia National Laboratories (SNL), the Smithsonian Astrophysical Observatory, and the NASA Marshall Space Flight Center jointly developed and fabricated the first custom Wolter microscope for implementation in SNL's Z machine with optimized sensitivity at 17.5 keV. To achieve spatial resolution of order 100-200 microns over a field of view of 5 × 5 × 5 mm3 with high throughput and narrow energy bandpass, the geometry of the optic and its multilayer required careful design and optimization. While the geometry mainly influences resolution and the field of view of the diagnostic, the mirror coating determines the spectral response and throughput. Here we outline the details of the design and fabrication process for the first multilayer-coated Wolter I optic for SNL's Z machine (Z Wolter), including its W/Si multilayer, and present results of raytrace simulations completed to predict and verify the performance of the optic.

An x-ray optic calibration facility for high energy density diagnostics.

A facility to calibrate x-ray imaging optics was built at Lawrence Livermore National Laboratory to support high energy density (HED) and inertial confinement fusion (ICF) diagnostics such as those at the National Ignition Facility and the Sandia Z-Machine. Calibration of the spectral reflectivity and resolution of these x-ray diagnostics enable absolute determination of the x-ray flux and wavelengths generated in the HED and ICF experiments. Measurement of the optic point spread function is used to determine spatial resolution of the optic. This facility was constructed to measure (1) the x-ray reflectivity to ±5% over a spectral range from 5 to 60 keV; (2) point spread functions with a resolution of 50 µm (currently) and 13 µm (future) in the image plane; and (3) optic distance relative to the x-ray source and detector to within ±100 µm in each dimension. This article describes the capabilities of the calibration facility, concept of operations, and initial data from selected x-ray optics.

A Wolter imager on the Z machine to diagnose warm x-ray sources.

A new Wolter x-ray imager has been developed for the Z machine to study the emission of warm (>15 keV) x-ray sources. A Wolter optic has been adapted from observational astronomy and medical imaging, which uses curved x-ray mirrors to form a 2D image of a source with 5 × 5 × 5 mm3 field-of-view and measured 60-300-µm resolution on-axis. The mirrors consist of a multilayer that create a narrow bandpass around the Mo Kα lines at 17.5 keV. We provide an overview of the instrument design and measured imaging performance. In addition, we present the first data from the instrument of a Mo wire array z-pinch on the Z machine, demonstrating improvements in spatial resolution and a 350-4100× increase in the signal over previous pinhole imaging techniques.

The AP-1 transcription factor JunB is essential for multiple myeloma cell proliferation and drug resistance in the bone marrow microenvironment.

Despite therapeutic advances, multiple myeloma (MM) remains an incurable disease, predominantly because of the development of drug resistance. The activator protein-1 (AP-1) transcription factor family has been implicated in a multitude of physiologic processes and tumorigenesis; however, its role in MM is largely unknown. Here we demonstrate specific and rapid induction of the AP-1 family member JunB in MM cells when co-cultured with bone marrow stromal cells. Supporting a functional key role of JunB in MM pathogenesis, knockdown of JUNB significantly inhibited in vitro MM cell proliferation and survival. Consistently, induced silencing of JUNB markedly decreased tumor growth in a murine MM model of the microenvironment. Subsequent gene expression profiling revealed a role for genes associated with apoptosis, DNA replication and metabolism in driving the JunB-mediated phenotype in MM cells. Importantly, knockdown of JUNB restored the response to dexamethasone in dexamethasone-resistant MM cells. Moreover, 4-hydroxytamoxifen-induced activation of a JunB-ER fusion protein protected dexamethasone-sensitive MM cells against dexamethasone- and bortezomib-induced cytotoxicity. In summary, our results demonstrate for the first time a specific role for AP-1/JunB in MM cell proliferation, survival and drug resistance, thereby strongly supporting that this transcription factor is a promising new therapeutic target in MM.

A methodology for calibrating wavelength dependent spectral resolution for crystal spectrometers.

High quality absorption spectroscopy measurements were recently achieved at the Sandia National Laboratories Z facility in the soft x-ray range. Detailed spectral resolution knowledge is a key requirement for their interpretation. We present a methodology for measuring the wavelength dependent crystal spectral resolution, with a particular focus on the 7-17 Å range. We apply this procedure to the case of 1st order resolution of a potassium acid phthalate (KAP) convex crystal spectrometer. One calibration issue is that inferring the crystal resolution requires that the x-ray source emission feature widths and spectral profiles are known. To this aim, we resolve Manson x-ray source Si, Al, and Mg Kα line profiles using a KAP crystal spectrometer in 2nd order to achieve relatively high resolution. This information is exploited to measure 1st order KAP resolving powers λ∕Δλ∼1100-1300 in the 7-10 Å wavelength range.

10-year stability of clinical-grade serum-free γ-retroviral vector-containing medium.

More than 10 years ago, we developed an efficient protocol for serum-free retroviral transduction of human hematopoietic stem cells derived from mobilized peripheral blood. After upscaling of the methodology, serum-free retroviral gibbon-ape leukemia virus (GALV) pseudotype PG13/LN vector supernatant produced under strict good manufacturing practice (GMP) conditions was used in the first clinical gene-marking trial in Germany. In this study, we analyzed the titer and transduction efficiency of this serum-free clinical-grade retroviral supernatant 10 years after production to evaluate the long-term stability. Long-term storage and transport on dry ice resulted in modestly decreased titers and levels of transduction efficiency in CD34+ cells ranging from 38.4 to 49.1%. We conclude that the stability of retroviral vectors in serum-free medium allows extended storage and distribution of approved clinical-grade retroviral vector stocks to distant sites in multicenter clinical trials.

Insulin reversal of diabetes-induced inhibition of vascular contractility in the rat.

Contractures induced by 10(-9)-10(-4) M phenylephrine (PE) or 10-70 mM KCl were observed in aortas isolated from untreated and insulin-treated streptozotocin-diabetic rats. The experiments were conducted at 2-wk intervals for a 12-wk period after the induction of diabetes. Diabetes caused an average decrease of 58 and 60% in the K and PE contractures, respectively. Although the PE contractures in aortas from the insulin-treated diabetic animals (81%) were significantly greater than those in aortas from the untreated diabetic animals (60%), they were significantly less than those in control tissues (100%). Insulin treatment completely reversed the diabetes-induced decrease in the K contracture (102%). It appears that the diabetes-induced decreases in tension may result from an altered sensitivity of the tissues to KCl but not PE. Histological examination of the tissues revealed that the diminished contractions were not due to any detectable change in mural structure. The data indicate that diabetes-induced inhibition of the mechanisms involved in mediating the K contracture are completely reversible by insulin treatment, whereas those mediating the PE contracture are only partially reversible.

Diet-induced atrial endothelial damage--a scanning electron-microscopic study.

A semipurified diet containing 28% fat (as lard), but no known atherogenic substances such as cholesterol, was fed to a group of Swiss stock mice. A group of similar mice was fed laboratory chow as controls. Within six weeks of diet feeding, experimental mice developed atrial thrombosis. In scattered areas of atria where thrombi were not present, the scanning electron microscope showed an endothelial response to the high-fat diet in the form of holes and crater-like lesions. In extreme cases, a whole endothelial cell might be almost totally destroyed. Clusters of leucocytes mixed with platelets and fibrin attached to the larger holes, suggesting the initiating mechanism of thrombogenesis, were also observed.

Observations on the results of specific histochemical techniques and empirical staining methods on several tissue/organ types using a variety of fixing fluids.

Several histotechniques (Harris hematoxylin and alcoholic eosin, Gomori's reticulum method, Verhoeff's elastic stain; Gomori's trichrome, Mallory's aniline blue collagen stain and the Cameron and Steele method) were each used with a number of fixatives (Lavdowsky's chromic acid, Karnovsky's glutaraldehyde/paraformaldehyde, neutral buffered formalin, Lavdowsky's formalinacetic acid-alcohol, Zenker's and Helley's). Lavdowsky's chromic acid fixative provided superior results as compared to the other fixing fluids and its use was critical with respect to the trichrome or connective tissue staining procedures. The Cameron and Steele modification used with Lavdowsky's chromic acid fixative gave the best differentiation of tissue types and was also the most reproducible.

Transplantable colon tumors as chemotherapy screening models.

A series of transplantable murine colon tumors have been developed from primary tumors induced by dimethylhydrazine. They are moderately- to well-differentiated adenocarcinomas which retain their histologic appearance and growth characteristics through successive transplant generations. The sensitivity of two tumor lines to 11 standard drugs is reported and some correlation shown with the sensitivity of human colorectal tumors to the same drugs. Therapeutic indices are low and each tumor has an individual pattern of sensitivity. The models have potential as secondary drug screening systems and for investigation of factors affecting drug sensitivity.

Chemotherapy of transplanted adenocarcinomas of the colon in mice.

Transplantable adenocarcinomas of the colon in mice have been developed from primary tumors induced by 1,2-dimethylhydrazine. Two such transplant lines, MAC-13 and MAC-15, have been used to assess the possible value of this type of tumor in chemotherapy screening. A protocol has been established and 11 standard drugs were tested against the two lines. Both tumors show sensitivity which is remarkably similar to that of human large bowel cancer, and MAC-13 would have correctly predicted the activity in man for ten of the 11 drugs. Quantitatively, CCNU, methyl-CCNU, and cyclophamide were the most effective drugs. A comparison of the predictive efficiencies of L1210 leukemia, B16 melanoma, and these new tumors as screening systems for colorectal cancer is made and discussed.

Transplantation of adenocarcinomas of the colon in mice.

1, 2-Dimethylhydrazine treatment induced multiple colon tumors in 100% of NMRI mice. Many of these tumors were transplanted and yielded five serially transplantable tumor lines. These subcutaneously transplanted neoplasms were all adenocarcinomas varying in degree of differentiation and mucin production. No evidence of dedifferentiation or change in growth rate has been seen in up to six transplant generations. These tumor lines appeared to provide relatively stable, well-differentiated models for colorectal cancer.