The porous silicon (PSI) process is a wafering method to fabricate high quality kerfless crystalline Si wafers by epitaxial wafer growth on porous Si and subsequent detachment from a reusable ...substrate wafer. The process yield is a key parameter for the economic viability of the PSI process. We experimentally demonstrate the detachment of 59 out of 62 PSI wafers with a size of 10 × 10 cm2, and separation layer etch current densities of 105–120 mA/cm2 for electrochemically etching the porous Si, and for substrate wafers with a resistivity of 15.7–16.9 mΩcm. We discuss the statistics of how to deduce a detachment probability from this. From our experiments, we determine a detachment yield of at least 88% with an error probability of 5%. The demonstration of a 99% detachment yield with an error probability of 5% would require at least 300 successfully detached wafers with no failed detachment. Samples have a minority carrier density ranging from 1 to 1.7 ms before any external gettering, which demonstrates the high electric quality of the PSI wafers.
Choledocholithiasis is a common disease in the West. Lithotripsy by mechanical methods using baskets and by laser or electrohydraulic methods varies in effectiveness. With argon plasma coagulation ...(APC), high temperatures are used for devitalization and fragmentation; cryogenic techniques use the selective controlled application of freeze-thaw cycles to devitalize pathological tissue; and the dissecting water jet exploits the high pressure action of a thin laminar jet. We aimed to assess the feasibility and effectiveness of APC, cryotechnology, and the dissecting water jet as options for the fragmentation of bile duct stones.
In an in vitro feasibility study, we evaluated the fragmentation of 120 bile duct stones treated with the three methods. Primary measures were assessment of the fragmentation rate, fragmentation effect, and energy application for each technology.
Fragmentation was seen in only 10 % of stones treated cryogenically using liquid nitrogen. APC at a power setting of 30 - 50 W fragmented all the cholesterol stones, but results with hard pigment stones were unsatisfactory even at high energies of a 100 W setting and long application time. Using the water jet, all 40 stones (100 %) were cracked effectively and completely with a pressure of 10 - 50 bar.
In this feasibility study, the first of its kind, only the water-jet device demonstrated efficient fragmentation of large bile duct stones in vitro. APC and cryotechnology are not suitable for the treatment of bile duct stones; the fragmentation rate with these methods was inadequate.
We discuss the influence of selenization time during the preparation of low-cost CuInSe 2 (CIS) solar cells using commercially available elemental Cu and In nanoparticles. A simple non-vacuum ink ...deposition method is used where the nanoparticles are dispersed in alcohol and deposited onto a Mo-coated substrate in ambient atmosphere. Furthermore we investigate in this work a simple non-vacuum selenization reaction based on elemental selenium instead of the rather complex selenization processes normally used in the sequential process. SIMS/SNMS, XRD and XRF measurements of the CIS layers are carried out for various selenization durations. We observed that longer selenization times lead to less oxygen and carbon residues, an increase of selenium at the back contact and higher power conversion efficiencies.
We discuss the design and performance of a very sensitive low-field magnetometer based on the detection of free spin precession of gaseous, nuclear polarized
3
He or
129
Xe samples with a SQUID as ...magnetic flux detector. The device will be employed to control fluctuating magnetic fields and gradients in a new experiment searching for a permanent electric dipole moment of the neutron. Furthermore, with the detection of the free precession of co-located
3
He/
129
Xe nuclear spins it can be used as ultra-sensitive probe for non-magnetic spin interactions, since the magnetic dipole interaction (Zeeman-term) drops out. Characteristic spin precession times T
2
*
of up to 60 h were measured. The achieved signal-to-noise ratio of more than 5000:1 leads to an expected sensitivity level (Cramer-Rao lower bound) of δB≈1 fT after an integration time of 220 s and of δB≈10
-4
fT after one day. By means of a co-located
3
He/
129
Xe magnetometer, noise sources inherent in the magnetometer could be investigated, showing that CRLB is fulfilled, at least down to δB≈10
-2
fT. The reason for such a high sensitivity is that free precessing
3
He (
129
Xe) nuclear spins are almost completely decoupled from the environment. Therefore, this type of magnetometer is particularly attractive for precision field measurements where long-term stability is required.
In multiple myeloma (MM), circulating malignant B cells are proposed as the proliferative compartment of the disease. In view of the close relationship between multiple myeloma and primary plasma ...cell leukemia (PCL), an anti-CD20 antibody treatment might also be considered as consolidation for patients with PCL. A 55-year-old patient diagnosed with PCL achieved complete remission after autologous transplantation. A total of four weekly courses of rituximab (375 mg/m(2)) were administered. Prior to antibody therapy, CD20+ cells comprised 22.6% of the mononuclear cells in peripheral blood (PB) assessed by flow cytometry and were enriched by magnetic activated cell sorting (MACS). In the enriched CD20+ fraction, 0.093% clonotypic cells were detected using a quantitative polymerase chain reaction (PCR) assay based on limiting dilutions. The proportion of clonotypic cells was 0.034% in PB and 0.032% in bone marrow (BM). Rituximab depleted CD20+ cells completely in PB and BM. Tumor load in PB and BM at day 40 and in PB at day 70 did not change in comparison to prior to therapy (0.037% in PB, 0.026% in BM). At day 90, the tumor load increased to 0.066% in PB. At day 120, the patient relapsed with 0.65% CD38++/CD138+/CD20- plasma cells and furthermore no CD20+ B cells in PB. The expansion of plasma cells was accompanied by an increase in the tumor load in both compartments (PB: 0.65%, BM: 1.8%). The accumulation of plasma cells during disease progression without the reappearance of CD20+ cells did not sustain the role of circulating clonotypic B cells as proliferative compartment in our patient. However, it cannot be excluded that rituximab was not able to eradicate malignant B cells, which subsequently contributed to relapse.
Polarization of {sup 3}He gas by means of optical pumping is well known since the early 1960s with first applications in fundamental physics. Some thirty years later it was discovered, that one can ...use hyperpolarized {sup 3}He as contrast agent for magnetic resonance imaging of the lung. The wide interest in this new method made it necessary to find ways of polarizing {sup 3}He in large quantities with high polarization degrees. A high performance polarizing facility has been developed at the University of Mainz, designed for centralized production of hyperpolarized {sup 3}He gas. We present the Mainz concept as well as some examples of numerous applications of spin polarized {sup 3}He in fundamental research and medical applications.
Polarization of
3
He gas by means of optical pumping is well known since the early 1960s with first applications in fundamental physics. Some thirty years later it was discovered, that one can use ...hyperpolarized
3
He as contrast agent for magnetic resonance imaging of the lung. The wide interest in this new method made it necessary to find ways of polarizing
3
He in large quantities with high polarization degrees. A high performance polarizing facility has been developed at the University of Mainz, designed for centralized production of hyperpolarized
3
He gas. We present the Mainz concept as well as some examples of numerous applications of spin polarized
3
He in fundamental research and medical applications.
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