Molybdenum Target Research Articles

Relationships of ductal carcinoma in situ calcification feature and ER, PR and HER2 expression

Objective To discuss the relationships of ductal carcinoma in situ calcification feature and estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) expression. Methods The mammary gland molybdenum target X-ray results of 226 patients with ductal carcinoma in situ were retrospectively analyzed in our hospital during January 2013 to December 2016. All patients were divided into calcification group (n=110) and no calcium group (n=116). Immunohistochemical method was used to detect the expressions of ER, PR and HER2, and their relationships with calcification feature were analyzed. Results The positive expression rates of ER and PR in calcification group were 72.73% and 54.55%, significantly higher than those in no calcium group (39.66% and 38.79%; χ2=25.033, P 30, with mass were the independent prediction factors of ER, PR and HER2 expressions (all P<0.001). Conclusion The mammary gland molybdenum target calcification features of ductal carcinoma in situ are associated with ER, PR and HER2 expressions, the small polymorphic form, cluster distribution, number>30, with mass can be used as important reference indexes to preliminarily predict biological therapy and expressions of prognostic factors. Key words: Carcinoma, intraductal, noninfiltrating; Calcinosis; Receptors, estrogen; Receptors, progesterone; Receptor, epidermal growth factor

Imaging the human placental microcirculation with micro-focus computed tomography: Optimisation of tissue preparation and image acquisition

Micro-CT provides 3D volume imaging with spatial resolution at the micrometre scale. We investigated the optimal human placenta tissue preparation (contrast agent, perfusion pressure, perfusion location and perfusion vessel) and imaging (energy, target material, exposure time and frames) parameters.Microfil (Flow Tech, Carver, MA) produced better fill than Barium sulphate (84.1%(±11.5%)vs70.4%(±18.02%) p = 0.01). Perfusion via umbilical artery produced better fill than via chorionic vessels (83.8%(±17.7%)vs78.0%(±21.9%), p < 0.05), or via umbilical vein (83.8%(±16.4%)vs69.8%(±20.3%), p < 0.01). Imaging at 50 keV with a molybdenum target produced the best contrast to noise ratio. We propose this method to enable quantification and comparison of the human fetoplacental vascular tree.

Correlation of target properties and plasma parameters in DC magnetron sputtering with Langmuir probe measurements

Utilizing different manufacturing methods for producing sputtering targets leads to significant variations in target microstructure with the latter showing a pronounced impact on the performance of the target in direct current magnetron sputtering (DCMS) in terms of varying sputtering yields. This study aims at correlating measured plasma parameters on the one hand with varying microstructure of molybdenum targets on the other hand. To this end, the sputtering performance of targets manufactured by means of selected powder metallurgy as well as melting metallurgy processes in DCMS is experimentally investigated. Ranging over two orders of magnitude, the mean grain size is identified as the major varying microstructural parameter of the investigated targets. Measurements of spatially varying plasma parameters under steady state sputtering conditions are carried out by means of a Langmuir probe moved over the target at several distances perpendicular to the target top surface. The largest differences in the measured parameters are found in the vicinity of the target surface. In particular, the electron density is found to decrease with increasing mean grain size.

Structural and mechanical properties of Zr1−x Mox thin films: From the nano-crystalline to the amorphous state

Zr1−xMox thin films were synthesized on glass substrates by co-sputtering molybdenum and zirconium targets in the presence of argon with x in the 0.32–0.95 range. From X-ray diffraction analyses and transmission electron microscopy images it was possible to observe an evolution of the samples structure from a nano-crystalline solid solution of Zr in the bcc lattice of Mo to clusters of Zr(Mo) nano-crystalline in an amorphous matrix. The coherence length deduced from X-ray diffractograms was around 1 nm–8 nm depending on the composition. Mechanical measurements show that the films exhibited high hardness H, low Young's modulus E and therefore high H∕E ratio compared with the bulk of Zr and Mo. We also found a low friction coefficient values for all the samples. Finally, an inverse Hall-Petch effect was observed for coherence length lower than 6 nm.

Production of 99Mo/99mTc via photoneutron reaction using natural molybdenum and enriched 100Mo: part 1, theoretical analysis

A theoretical analysis was performed for the production of 99Mo via the 100Mo(γ,n)99Mo reaction using natural (natMo) and enriched (100Mo) molybdenum targets in a modified NIRTA® Targetry system. High energy electrons from a linear accelerator were simulated on a tungsten converter to produce bremsstrahlung incident on molybdenum targets using the TALYS computer code. All open channels and decay schemes were used to assess the production rates and final amounts of radioactive and stable components at end-of-bombardment (3-day irradiation), and after 2 h of cooling. Computations were performed at an accelerator energy of 40 MeV, correlating to a maximized photon fluence at 14 MeV. Impurities of Zr and Nb were found when utilizing enriched 100Mo (excluding Mo isotopes). Targets utilizing natMo added substantial stable and radioactive impurities of Mo, Nb, Zr, Y, and Sr; however, all but the Mo impurities can be readily separated. This study confirms the potential of producing 99Mo via 100Mo(γ,n)99Mo using natMo with manageable impurities.

X-Ray Dosimetry During Low-Intensity Femtosecond Laser Ablation of Molybdenum in Ambient Conditions

The absorbed X-ray dose was measured during 35 fs pulsed laser ablation of a high purity molybdenum target in ambient conditions for optical intensities from $1.8 \times 10^{14}$ to $1.6 \times 10^{15}$ W/cm2 (0.5–4.5 mJ per pulse) at a repetition rate of 1 kHz. During 1 s of ablation, at a distance of 6 cm from the source, appreciable X-ray dose was observed at all optical intensities, ranging from $0.08~\mu $ Gy, at the minimum intensity, to $0.97~\mu $ Gy at the maximum intensity, corresponding to equivalent dose rates of 0.3–3.5 mSv/h. At the highest optical intensity, an absorbed dose of $0.29~\mu $ Gy was measured at a distance of 12 cm from the source, corresponding to an equivalent dose rate of 1.1 mSv/h. Characterization of the laser plasma emissions showed X-rays with energies approaching 20 keV at higher laser pulse energies. In Canada, the annual equivalent dose limit for nonradiation workers is 1 mSv. Our findings suggest that under certain conditions it is possible to exceed this dosage in as little as an hour of fs-laser material processing in ambient conditions. As such, workers in these environments may need to be trained in radiation safety, equipped with personal dosimeters, and provided proper radiation shielding.

A rare mixed breast cancer of intraductal and solid papillary with tubular carcinoma histotypes in a young woman

Mixed breast cancer, especially of uncommon breast cancer histotypes, is rare, limiting our understanding of the disease and influencing diagnostic and management outcomes. We report a case of mixed breast cancer, with features of intraductal and solid papillary and tubular carcinomas, which appeared in a young patient. Physical examination, ultrasonography, molybdenum target mammography, and histopathology were performed for a definitive diagnosis. Tumor resection followed by radiotherapy and adjuvant chemotherapy was selected as the therapeutic strategy, and the patient was followed up thrice post treatment. We discuss the detailed diagnosis, treatment, and follow-up, together with a literature review of mixed breast cancer, to help optimize clinical management of mixed breast cancer.

The evolution of the Mo5+ oxidation state in the thermochromic effect of MoO3 thin films deposited by rf magnetron sputtering

Molybdenum trioxide (MoO3) thin films were deposited on glass substrates by rf reactive magnetron sputtering using a metallic molybdenum target. The thermochromic effect was induced by exposing the samples to either argon or air at specific temperatures within the range 25–300 °C. Optical absorption spectra indicated that the samples annealed in argon show a higher thermochromic response than the samples annealed in air. Moreover, the average luminous transmittance T∗lum was investigated as a function of the annealing temperature, Ta. The highest change of T∗lum was found in samples treated in argon, where T∗lum shifted from 71.69% at room temperature (RT) to 44.58% at 300 °C. For samples treated in air, T∗lum decreased from 71.69% at RT down to 67.47% at 200 °C, but increased up to 79.08% at 300 °C. In addition, the annealing in argon at 300 °C revealed the formation of two coloration bands around 550 nm and 900 nm, which are associated with an oxygen vacancy defect state (Mo5+O5) and an intervalence charge transfer transition of a hexa-coordinated defect state (Mo5+O6), respectively. Raman spectra, HR-TEM images, and X-ray diffraction measurements showed that the samples treated in air displayed mainly the orthorhombic α–MoO3 phase with small indications of the monoclinic β–MoO3 phase, whereas the treatment in argon led to a mixture of β–MoO3 and the Magneli phase Mo9O26. The dependence of the Mo5+ oxidation state on Ta, was analyzed by X-ray photoemission spectroscopy (XPS) using deconvolution methods. For the annealing in air, it was found that the Mo5+ signal of the Mo 3d3/2 peak increased slightly from 25 to 200 °C but exhibited a steep decrease at 300 °C; on the contrary, this signal showed a slight increase in the whole range for the anoxic atmosphere. These results show that the Mo5+ oxidation state and the optical density display a similar dependence on Ta for both types of annealing atmosphere.

Laser-plasma sources of ionizing radiation for simulation of radiation effects in microelectronic materials and components

The characteristics of the X-ray and gamma pulses as well as pulsed proton fluxes induced by the action of femotsecond laser pulses (800 nm, 1018 W/cm2) on the surface of liquid gallium and solid molybdenum targets are measured. Estimated calculations show the possibility in principle of availability of these ionizing radiation sources for experimental simulation of single-event effects in advanced microelectronic components with a high degree of integration.

In situ plasma sputtering and angular distribution measurements for structured molybdenum surfaces

We present in situ sputtering yield measurements of the time-dependent erosion of flat and micro-architectured molybdenum samples in a plasma environment. The measurements are performed using the plasma interactions (Pi) Facility at UCLA, which focuses a magnetized hollow cathode plasma to a material target with an exposure diameter of approximately 1.5 cm. During plasma exposure, a scanning quartz crystal microbalance (QCM) provides angular sputtering profiles that are integrated to estimate the total sputtering yield. This technique is validated to within the scatter of previous experimental data for a planar molybdenum target exposed to argon ion energies from 100 to 300 eV. The QCM is then used to obtain in situ measurements during a 17 h exposure of a micro-architectured-surface molybdenum sample to 300 eV incident argon ions. The time-dependent angular sputtering profile is shown to deviate from classical planar profiles, demonstrating the unique temporal and spatial sputtering effects of micro-architectured materials. Notably, the sputtering yield for the micro-architectured sample is initially much less than that for planar molybdenum, but then gradually asymptotes to the value for planar molybdenum after approximately 10 h as the surface features are eroded away.

Application of three-dimensional wire localization and orientation in the resection of non-palpable breast lesions.

The aim of the present study was to compare the application value of the 3D stereo wire localization technique guided by a full digital breast X-ray machine, and general location technique in the resection of breast non-palpable lesions. A retrospective analysis of the clinical data of 80 patients with abnormal findings for non-palpable breast molybdenum target X-ray was conducted between June, 2011 and July, 2014. The patients were divided into two groups: 40 cases with a general location of lesions identified by perturbation axial + standard lateral radiograph to guide the clinical operation biopsy (group A); and 40 cases with a general location of lesions identified by the 3D stereo wire localization method to guide the clinical operation biopsy (group B). The one-time success rate of the resection of breast lesions of the two groups of patients was compared. Both groups of patients completed the operation. Of the 40 cases in group A, 33 cases had one-time complete resection of lesions, 5 cases had incomplete resection with the second resection, and the lesions of 2 cases were not excised and the one-time success rate of the breast lesion resection was 82.5%. Of the 40 cases in group B, lesions of 38 cases were one-time complete resection and 2 had vagal reaction; thus, the one-time success rate of breast lesion resection being 95%. Compared to group A, the one-time success rate of breast lesion resection of group B was statistically and significantly higher (χ2=3.638, P<0.05). In conclusion, the 3D stereo wire localization technique guided by the full digital breast X-ray machine for the excision of non-palpable breast lesions has high positioning accuracy with small operation excision scope. It is therefore an effective method that can be utilized for the qualitative diagnosis of non-palpable breast lesions.

Computer simulation and experimental investigation of Mo-99 yield in thick targets as a Tc-99m generator

The most important requirement for the production technology of radionuclides is to provide a high specific activity of the target nuclide as well as the full activity of the target. This problem can be solved by using a large volume of photonuclear targets, and then by the target nuclide radiochemical separation. Computer simulation and experimental study of the spatial distribution of the activity is carried out in this work for the molybdenum target. Optimal parameters of irradiation to achieve the maximum yield of isotopes Mo-99 (Tc-99m) from the molybdenum target have been found.

Industrial-scale sputter deposition of molybdenum oxide thin films: Microstructure evolution and properties

The current work investigates the microstructure and property relations of molybdenum oxide thin films synthesized by reactive dc magnetron sputtering in an industrial-scale sputter deposition plant using a rotatable molybdenum target with varying oxygen/argon gas flow ratio. The evolution of microstructure and chemical bonds as a function of oxygen partial pressure was studied by x-ray diffraction, Raman spectroscopy, and x-ray photoelectron spectroscopy. With oxygen partial pressure raising from 0% to 100%, the film growth rate decreased from 350 to 50 nm/min, while the oxygen content within the films increased up to 75 at. %. The films were dominated by MoO2, polymorphs of Mo4O11 and Mo9O26, and MoO3 phases. The electrical properties changed from electrically conductive to insulating with increasing oxygen partial pressure. The optical properties are versatile, e.g., transmittance values up to 80%, absorbance values between 50% and 80% and reflectance values up to 55%, depending on the oxygen content. In general, it can be concluded that microstructure and properties of molybdenum oxide thin films can be adjusted by varying the oxygen/argon gas flow ratio and might thus enable their use in a wide range of optical and electronic applications.

Surface Microstructure of Mo(C)N Coatings Investigated by AFM

MoCN coatings have been formed by cathodic arc evaporation using the mixture of acetylene and nitrogen and pure molybdenum target. The surface structure, in conjunction with x-ray data, was analyzed by atomic force microscopy (AFM). The AFM results show differently shaped grain forms on the surface of coatings investigated. The increase in carbon in chemical coatings composition results in the reduction in surface grain size and the increase in roughness of the coatings.

Measurements of hot-electron temperature in laser-irradiated plasmas

In a recently published work [Yaakobi et al., Phys. Plasmas 19, 012704 (2012)] we reported on measuring the total energy of hot electrons produced by the interaction of a nanosecond laser with planar CH-coated molybdenum targets, using the Mo Kα emission. The temperature of the hot electrons in that work was determined by the high-energy bremsstrahlung [hard X-ray (HXR)] spectrum measured by a three-channel fluorescence-photomultiplier HXR detector (HXRD). In the present work, we replaced the HXRD with a nine-channel image-plate (IP)–based detector (HXIP). For the same conditions (irradiance of the order of 1014 W/cm2; 2–ns pulses), the measured temperatures are consistently lower than those measured by the HXRD (by a factor ∼1.5 to 1.7). We supplemented this measurement with three experiments that measure the hot-electron temperature using Kα line-intensity ratios from high-Z target layers, independent of the HXR emission. These experiments yielded temperatures that were consistent with those measured by the HXIP. We showed that the thermal X-ray radiation must be included in the derivation of total energy in hot electrons (Ehot), and that this makes Ehot only weakly dependent on hot-electron temperature. For a given X-ray emission in the inertial confinement fusion compression experiments, this result would lead to a higher total energy in hot electrons, but preheating of the compressed fuel may be lower because of the reduced hot-electron range.

MOMAC: a SAXS/WAXS laboratory instrument dedicated to nanomaterials

This article presents the technical characteristics of a newly built small- and wide-angle X-ray scattering (SAXS/WAXS) apparatus dedicated to structural characterization of a wide range of nanomaterials in the powder or dispersion form. The instrument is based on a high-flux rotating anode generator with a molybdenum target, enabling the assessment of highly absorbing samples containing heavy elements. The SAXS part is composed of a collimation system including a multilayer optic and scatterless slits, a motorized sample holder, a vacuum chamber, and a two-dimensional image-plate detector. All the control command is done through a TANGO interface. Normalization and data correction yield scattering patterns at the absolute scale automatically with a q range from 0.03 to 3.2 Å−1. The WAXS part features a multilayer collimating optic and a two-dimensional image-plate detector with variable sample-to-detector distances. The accessible q range is 0.4–9 Å−1, ensuring a large overlap in q range between the two instruments. A few examples of applications are also presented, namely coupled SAXS/WAXS structure and symmetry determination of gold nanocrystals in solution and characterization of imogolite nanotubes and iron-filled carbon nanotube samples.

Process Engineering of Dimensional Fused Silica Etching

The process of dimensional fused silica etching was offered. The production process of molycoat by magnetron sputtering of molybdenum target in inert gas (Argon) on vacuum distillation unit (NIKA-2012 TN) was examined. The coat quality (delamination, discontinuity) was analyzed; the influence of the first kind internal strains on the type of the observed defects was determined. The research was conducted by means of microscopic and X-ray diffraction analysis. It has been established that the internal strain value in the coat depends on the sputtering gas (Argon) flow rate, and, consequently, its pressure in the magnetron system for molybdenum sputtering. Zero stresses are registered under Argon's flow rate, which is 7.5 L/h. Influence of internal stresses level in the barrier coating on the quality of etching dimple.

Ablation study of laser micromachining process with molecular dynamics simulation

A three-dimensional molecular dynamics model is presented for the simulation of the creation of a micro-hole on a thin film metal substrate via laser ablation. For the presented analysis, molybdenum and aluminium specimens are selected and short pulses are assumed. The laser fluence takes several values between 0.5 and 20 J/cm2. The proposed models include significant laser ablation phenomena such as plasma shielding. However, they are not computationally intense. In this study, the Morse potential is used for the interactions of the atoms of the specimens. The analysis is carried out in order to investigate the ablation rate, the ablation depth and the mean temperature of molybdenum and aluminium targets under their heating by the laser beam, for several different values of fluence. Results for molybdenum indicate that as fluence increases, it takes less time for the atoms to be ablated. For low-fluence pulses, more than one pulse may be required for the ablation of all atoms. For high-fluence pulses, the ablation is not uniform across the entire duration of the pulse and the specimen is overheated. A fluence value around 2–3 J/cm2 is suggested for uniform ablation. From the analysis, it is evident that the evolution of ablation and system temperature is different for molybdenum and aluminium, for the same laser fluence. This is attributed to different crystalline structures and absorptivity of each material. It may be said that molecular dynamics prove to be a powerful tool for the simulation of nanomanufacturing processes and useful conclusions are drawn from the analysis.

Structure evolution in reactively sputtered molybdenum oxide thin films

The current work investigates structure and property relations of molybdenum oxide thin films deposited by reactive dc magnetron sputtering from a molybdenum target with varying oxygen/argon gas flow ratio during deposition. With increasing oxygen partial pressure, the film growth rate decreased from 90 to 7 nm/min, whereas the oxygen content in the films increased up to 75 at.%. The dominating phases found by X-ray diffraction and Raman spectroscopy were MoO2, different polymorphs of Mo4O11, and MoO3. The optical appearance changed from metallic to yellowish transparent with increasing oxygen content in the thin film, while the electrical properties varied from electrically conductive to insulating. In general, structure and properties of the deposited molybdenum oxide thin films are tuneable by adjusting the oxygen/argon gas flow ratio during deposition, which enables the use of these films in a wide range of optical and electronic applications.

The use of sequential X-ray, CT and MRI in the preoperative evaluation of breast-conserving surgery.

The aim of the study was to investigate the value of sequential application of molybdenum target X-ray, multi-slice spiral computed tomography (MSCT) and magnetic resonance imaging (MRI) in the preoperative evaluation of breast-conserving surgeries. In total, 76 patients with indications for breast-conserving surgery due to complicated breast cancer participated in the study and were assigned to either control or observation group (n=38 per group). The patients in the control group were evaluated with two sets of random combinations of molybdenum target X-ray, MSCT or MRI with ultrasound inspection, whereas the patients in the observation group were evaluated by sequential inspection methods of molybdenum target X-ray, MSCT and MRI. A comparison of surgery outcomes, incidence of complications, rate of positive surgical margins, and recurrence and survival rates in the groups during a follow-up period of 24 months was made. Comparisons of the preoperative evaluation results for tumor number, average maximum diameter, number of lymphatic metastatic groups and number of metastatic lymph nodes in the observation group showed the numbers to be significantly higher than those in the control group (P<0.05). Conversely, the comparisons of age, tumor distribution and T-staging yielded no significant differences, validating the analysis. The percentage of successful breast-conserving surgeries in the observation group was significantly higher than that in the control group, while the incidence of complications in the observation group was lower (P<0.05). The rate of positive surgical margins and the recurrence rate of cancer in the observation group were lower than those in the control group, and the survival rate in the observation group was higher, with differences having statistical significance (P<0.05). In conclusion, the sequential application of molybdenum target X-ray, MSCT and MRI during the preoperative evaluation for breast-conserving surgery positively affects the success rate of the procedure improving the diagnostic accuracy and therapeutic effects.