Electrical measurements on fused quartz under shock compression

The resistivities of specimens of SiO_2 (fused quartz) singly and doubly shocked in the 10–45 and 27–90 GPa ranges, respectively, demonstrate a marked decrease from values of ∼10–0.1 Ω⋅m at a single‐shock pressure of ∼40 and a double‐shock pressure of ∼74 GPa. These states correspond to calculated shock temperatures of ∼3300 and ∼3600 K, respectively. At shock pressures below 36 GPa the measured resistivity versus calculated shock temperature agrees closely with ambient‐pressure and high‐temperature resistivity data. This suggests that the ionic conduction mechanisms inferred to control electrical properties at ambient pressure also act under shock‐induced high temperatures in quartz and the presumed high‐pressure phase, stishovite into which fused quartz appears to transform above 20 GPa. At 36–40 GPa the rapid decrease in resistivity by a factor of 10^2 suggests a further transformation to an unknown phase which may correspond to the onset of melting. The existing pressure‐density Hugoniot data do not demonstrate any anomalous density change associated with this phase change

Shock-induced radiation spectra of fused quartz

An optical multichannel analyzer is applied to observe shock-induced radiation spectra of fused quartz in the 23–31 GPa shock-pressure range. Characteristics of sample-driver interface strongly influence both intensity and profile of the observed spectra. Brightness and color temperature are determined by an integration of spectral radiance and a fit to the greybody radiation spectrum, respectively. The resultant brightness and color temperature are lower and considerably higher than those estimated by the theoretical calculation, respectively. Some broad but strong line spectra are, however, superimposed onto the continuous greybody radiation spectrum even though the influences of the interface are reduced as much as possible. The line spectra are probably caused by electroluminescence and/or triboluminescence

Shock compression of diamond crystal

Two shock wave experiments employing inclined mirrors have been carried out to determine the Hugoniot elastic limit (HEL), final shock state at 191 and 217 GPa, and the post-shock state of diamond crystal, which is shock-compressed along the intermediate direction between the and crystallographic axes. The HEL wave has a velocity of 19.9 ± 0.3 mm/µsec and an amplitude of 63 ± 28 GPa. An alternate interpretation of the inclined wedge mirror streak record suggests a ramp precursor wave and then another HEL value. The maximum post-shock density achieved upon release from the ∼200 GPa shock state is ∼3.95 Mg/m³, which compares to the initial density 3.52 Mg/m³. This result suggests an elastic unloading effect or shock-induced transition to a denser (possibly metallic) phase

Relative Amounts of Keratin 17 Are Higher Than Those of Keratin 16 in Hair-Follicle-Derived Tumors in Comparison with Nonfollicular Epithelial Skin Tumors

Specimens of trichilemmal cyst, malignant trichilemmoma, keratoacanthoma, and epidermal cyst were examined to characterize keratin peptides in hair- follicle-derived tumors, Keratins were extracted front the specimens and analyzed by two-dimensional gel electrophoresis and densitometry, the re- sults were then compared with those for normal epidermis, the outer root sheath of hair follicles, psoriatic epidermis, and various nonfollicular cutaneous epithelial tumors. The specific nonfolilcular tumors examined were squamous cell carcinoma, Bowen disease, actinic keratosis, eccrine porocarcinoma, and sebaceous carcinoma. Immunohistochemistry also was performed with a few anti-keratin monoclonal antibodies. As a general rule, K6 and K16 were expressed in hyperproliferative conditions, such as epidermal tumors, and K17 was coexpressed in the same lesions, The ratio of K16 to K17 in many epithelial skin tumors has been unclear until now. K17 content exceeded K16 content in most follicular tumors, whereas in almost all the nonfollicular tumors and the psoriatic epidermis, K17 levels were less than or about equal to K16 levels. There was a significant difference in the ratio of K16 to K17 between follicular and nonfollicular skin tumors. These results indicate that alterations in the content of these keratins may be associated with follicular differentiation

Programmed cell death 1‐expressing CD56‐negative natural killer (NK) cell expansion is a hallmark of chronic NK cell activation during dasatinib treatment

Dasatinib treatment markedly increases the number of large granular lymphocytes including natural killer (NK) cells in a proportion of Ph+ leukemia patients, which associates with a better prognosis. In-depth immune profiling of NK cells can predict therapeutic response in these patients. In the present study, we showed that CD56-negative (CD56neg) NK cells increased exclusively in cytomegalovirus-seropositive (CMV+) patients treated with dasatinib. The increase longitudinally paralleled with progressive differentiation of CD56dim NK cells during dasatinib therapy driven by CMV reactivation as shown by principal component analysis on 19 NK cell markers. The CD56neg NK cells showed downregulation of NK-activating receptors, upregulation of PD-1, and lower cytotoxicity and cytokine production, indicating that these cells are anergic and dysfunctional as seen in chronic infections with HIV-1 or hepatitis C virus. Moreover, cytolytic activity of CD56dim and CD56neg NK cells against leukemia cells was partially restored by nivolumab in proportion to the frequency of PD-1+ NK cells. The proportion of patients who achieved deep molecular responses at 2 years was significantly higher in dasatinib-treated patients with ≥3% CD56neg NK cells than in those with fewer CD56neg NK cells (54.5% vs 15.8%, P = .0419). These findings suggest that CD56neg NK cells may be an exhausted population induced by chronic activation through CMV reactivation during dasatinib therapy. Expansion of CD56neg NK cells is a hallmark of chronic NK cell activation in patients treated with dasatinib and may predict a better clinical outcome. Furthermore, PD-1 blockade may enhance anti-leukemia responses of such NK cells

Dual-comb spectroscopy for rapid characterization of complex optical properties of solids

We demonstrate rapid characterization of complex optical properties of solids via dual-comb spectroscopy (DCS) in the near-infrared region. The fine spectral structures in the complex refractive index of an Er:YAG are successfully deduced using the developed system and Fourier analysis. Moreover, simultaneous determination of the refractive index and the thickness is demonstrated for a silicon semiconductor wafer through the use of multireflected echo signals. The results indicate the potential of DCS as a powerful measurement tool for the rapid and full characterization of solid materials