Pull-in control in microswitches using acoustic Casimir forces

In this paper we present a theoretical calculation of the acoustic Casimir pressure in a model micro system. Unlike the quantum case, the acoustic Casimir pressure can be made attractive or repulsive depending on the frequency bandwidth of the acoustic noise. As a case study, a one degree of freedom simple-lumped system in an acoustic resonant cavity is considered. We show that the frequency bandwidth of the acoustic field can be tuned to increase the stability in existing microswitch systems by selecting the sign of the force. The acoustic intensity and frequency bandwidth are introduced as two additional control parameters of the microswitch

Hamartomas, teratomas and teratocarcinosarcomas of the head and neck: Report of 3 new cases with clinico-pathologic correlation, cytogenetic analysis, and review of the literature

<p>Abstract</p> <p>Background</p> <p>Germ-cell tumors (GCT) are a histologically and biologically diverse group of neoplasms which primarily occur in the gonads but also develop at different extragonadal sites in the midline of the body. The head and neck region including the upper respiratory tract is a very rare location for such tumors in both children and adults, which can cause diagnostic and therapeutic difficulties.</p> <p>Methods</p> <p>We describe here two new cases of multilineage tumors including sinonasal teratocarcinosarcoma [SNTCS], and congenital oronasopharyngeal teratoma (epignathus) and compare their features with those of a new case of a rare salivary gland anlage tumor [SGAT], an entity for which the pathogenesis is unclear (i.e. hamartoma versus neoplasm). We correlate their presenting clinico-pathological features and compare histologic and cytogenetic features in an attempt to elucidate their pathogenesis and biologic potentials.</p> <p>Results and discussion</p> <p>Cytogenetic analysis revealed chromosomal abnormalities only in the case of SNTCS that showed trisomy 12 and 1p deletion. Both cytogenetic abnormalities are characteristically present in malignant germ cell tumors providing for the first time evidence that this rare tumor type indeed might represent a variant of a germ cell neoplasm. The SGAT and epignathus carried no such cytogenetic abnormalities, in keeping with their limited and benign biologic potential.</p> <p>Conclusion</p> <p>The comparison of these three cases should serve to emphasize the diversity of multilineage tumors (hamartomas and GCT) of the upper respiratory tract in regards to their biology, age of presentation and clinical outcomes. Malignant tumors of germ cell origins are more likely to affect adults with insidious symptom development, while benign tumors can nevertheless cause dramatic clinical symptoms which, under certain circumstances, can be fatal.</p

β-cyclodextrin columns for separation of fluorous and non-fluorous compounds: How to use β-cyclodextrin columns in fluorous mixture synthesis and racemic synthesis

Guidelines for the use of β-cyclodextrin columns in fluorous and non-fluorous mixture synthesis, and racemic synthesis are suggested. Fluorous compounds can be separated more efficiently with SUMICHIRAL OA-7000 and -7100, while non-fluorous compounds can be separated better with SUMICHIRAL OA-7500. When the ratio of water in the mobile phase is large (>20%), the guard column (GL cart) can improve the separability of the fluorinated mixture

Incorporation of N-acetylgalactosamine into consecutive threonine residues in MUC2 tandem repeat by recombinant human H-acetyl-D-galactosamine transferase-T1, T2 and T3

AbstractAn oligopeptide containing three consecutive Thr residues mimicking the tandem repeat portion of MUC2 (PTTTPLK) was investigated for the acceptor specificity to UDP-N-acetyl-D-galactosamine:peptide N-acetylgalactosaminyltransferase isozymes, UDP-N-acetyl-D-galactosamine:peptide N-acetylgalactosaminyltransferase-T1, T2 and T3. The enzymatic reaction products were fractionated by the reversed-phase high performance liquid chromatography, then characterized by matrix-assisted laser desorption ionization time of flight mass spectrometry and by a peptide sequencing analysis. A maximum of two, one or three N-acetyl-D-galactosamine residues was transferred by UDP-N-acetyl-D-galactosamine:peptide N-acetylgalactosaminyltransferase-T1, T2 or T3, respectively. The preferential orders of N-acetyl-D-galactosamine incorporation were Thr-2, then Thr-4 for UDP-N-acetyl-D-galactosamine:peptide N-acetylgalactosaminyltransferase-T1, Thr-2 for UDP-N-acetyl-D-galactosamine:peptide N-acetylgalactosaminyltransferase-T2 and Thr-4, Thr-3, then Thr-2 for UDP-N-acetyl-D-galactosamine:peptide N-acetylgalactosaminyltransferase-T3

Divalent, trivalent, and heavy fermion states in Eu compounds

International audienc