Impact of strengthening fluids on roughness of 3D printed models

For some applications, 3D printed parts usually do not have satisfactory mechanical properties, so to broaden their usage, additive technologies should be combined with the well-known metallurgical processes, such as investment and others casting techniques. 3D printing developers persistently introduce new base materials and strengthening fluids which may cause different surface roughness. Therefore, in this paper, the authors have tested the roughness of 3D printed samples strengthened with common, but also with alternative fluids. Measurements proved that fluids do have significant influence on the roughness

Universal properties of correlation transfer in integrate-and-fire neurons

One of the fundamental characteristics of a nonlinear system is how it transfers correlations in its inputs to correlations in its outputs. This is particularly important in the nervous system, where correlations between spiking neurons are prominent. Using linear response and asymptotic methods for pairs of unconnected integrate-and-fire (IF) neurons receiving white noise inputs, we show that this correlation transfer depends on the output spike firing rate in a strong, stereotyped manner, and is, surprisingly, almost independent of the interspike variance. For cells receiving heterogeneous inputs, we further show that correlation increases with the geometric mean spiking rate in the same stereotyped manner, greatly extending the generality of this relationship. We present an immediate consequence of this relationship for population coding via tuning curves

Unusual Interferon Gamma Measurements with QuantiFERON-TB Gold and QuantiFERON-TB Gold In-Tube Tests

INTRODUCTION: Interferon gamma (IFN-γ) release assays, such as QuantiFERON®-TB Gold test (QFT-G) and QuantiFERON®-TB Gold In-Tube test (QFT-GIT) are designed to detect M. tuberculosis (Mtb) infection. Recognition of unusual IFN-γ measurements may help indicate inaccurate results. METHODS: We examined QFT-G and QFT-GIT results from subjects who had two or more tests completed. We classified unusual IFN-γ measurements as: 1) High Nil Concentration (HNC) when IFN-γ concentration in plasma from unstimulated blood exceeded 0.7 IU/mL; 2) Low Mitogen Response (LMR) when Mitogen Response was <0.5 IU/mL; 3) Very Low Mitogen Response (VLMR) when Mitogen Response was ≤-0.5 IU/mL; and 4) Very Low Antigen Response (VLAR) when the response to a Mtb antigen was ≤-0.35 IU/mL and ≤-0.5 times the IFN-γ concentration in plasma from unstimulated blood. RESULTS: Among 5,309 results from 1,728 subjects, HNC occurred in 234 (4.4%) tests for 162 subjects, LMR in 108 (2.0%) tests for 85 subjects, VLMR in 22 (0.4%) tests for 21 subjects, and VLAR in 41 (0.8%) tests for 39 subjects. QFT-GIT had fewer HNC, VLMR, and VLAR (p = 0.042, 0.004, and 0.067 respectively); QFT-G had fewer LMR (p = 0.005). Twenty-four (51.6%) of 47 subjects with positive results and HNC were negative or indeterminate by all other tests. Thirteen (61.9%) of 21 subjects with positive results and LMR were negative or indeterminate by all other tests. CONCLUSION: Unusual IFN-γ measurements including HNC, LMR, VLMR, and VLAR were encountered in small numbers, and in most instances were not seen on simultaneously or subsequently performed tests. To avoid erroneous diagnosis of Mtb infection, IGRAs with unusual IFN-γ measurements should be repeated with another blood sample and interpreted with caution if they recur

Presupernova Evolution with Improved Rates for Weak Interactions

Recent shell-model calculations of weak-interaction rates for nuclei in the mass range A = 45 - 65 have resulted in substantial revisions to the hitherto standard set of Fuller, Fowler, & Newman (FFN). In particular, key electron-capture rates, such as that for Co60 are much smaller. We consider here the effects of these revised rates on the presupernova (post-oxygen burning) evolution of massive stars in the mass range 11 to 40 M_sun. Moreover, we include, for the first time in models by our group, the effects of modern rates for beta-decay in addition to electron capture and positron emission. Values for the central electron mole number at the time of iron core collapse in the new models are typically larger, by delta Y_e = 0.005 to 0.015, than those of Woosley & Weaver 1995, with a tendency for the more massive models to display larger differences. About half of this change is a consequence of including beta-decay; the other half, result of the smaller rates for electron capture. Unlike what might be expected solely on basis of the larger Y_e's, the new iron core masses are systematically smaller owing to a decrease in the entropy in the outer iron core. The changes in iron core mass range from zero to 0.1 M_sun. We also observe, as predicted by Aufderheide et al. (1994), a tendency towards beta-equilibrium just prior to the collapse of the core, and the subsequent loss of that equilibrium as core collapse proceeds. We discuss the key weak reaction rates, both beta-decay and electron-capture, responsible for the evolution of Y_e and make suggestions for future measurements.Comment: 22 pages including 17 PostScript figures, uses emulateapj.sty, submitted to Ap

Strong Deformation Effects in Hot Rotating 46Ti

Exotic-deformation effects in 46Ti nucleus were investigated by analysing the high-energy gamma-ray and the alpha-particle energy spectra. One of the experiments was performed using the charged-particle multi-detector array ICARE together with a large volume (4"x4") BGO detector. The study focused on simultaneous measurement of light charged particles and gamma-rays in coincidence with the evaporation residues. The experimental data show a signature of very large deformations of the compound nucleus in the Jacobi transition region at the highest spins. These results are compared to data from previous experiments performed with the HECTOR array coupled to the EUROBALL array, where it was found that the GDR strength function is highly fragmented, strongly indicating a presence of nuclei with very large deformation.Comment: 10 pages, 6 figures, Proceedings of the Zakopane Conference on Nuclear Physics, to be published in Acta Phys. Pol. B (2007

Comparative anatomical study of standard percutaneous and modified medialised percutaneous Bunnell type repair for artificial Achilles tendon rupture: positive effect of medialisation of the stitches with lower risk of sural nerve injury

Background: Less invasive percutaneous acute Achilles tendon rupture (AATR) repair techniques gain popularity because of lower risk of surgical wound complications. But these approaches have an increased risk of sural nerve iatrogenic injury as this sensory nerve is usually not visualised during minimally invasive operative procedures. We compared standard percutaneous Bunnell type and our proposed modified-medialised percutaneous technique in a cadaver study to evaluate potential advantages. Materials and methods: Ten pairs of fresh frozen specimens were divided into two groups for comparative anatomical study. Tenotomies of Achilles tendons were made and wounds sutured. Ten standard and 10 modified-medialised repairs were applied for artificially performed ruptures. All sutured tendons were dissected meticulously. We carefully looked at repaired Achilles tendon end-to-end contact and adaptation, distance from Achilles insertion in calcaneal tubercle to place where sural nerve crosses lateral border of the Achilles tendon and possible sural nerve and vein entrapment. Groups were compared using Fisher’s exact and Student-T tests. Results: All ends of sharply dissected tendons in both groups were in sufficient contact. No measurable diastasis between tendon ends was found in all cases. No entrapment of sural nerve or vein was found in modified percutaneous Bunnell suture technique group, whereas 7 of 10 sural nerves and 9 small saphenous veins were entrapped when using standard percutaneous Bunnell type technique. Average distance from Achilles tendon insertion in tuber calcanei to sural nerve crossing the lateral border of Achilles was 93 mm. Conclusions: Medialisation of percutaneous suture in AATR repair shows clear advantages compared to standard non medialised technique ensuring a possible lower incidence of sural nerve entrapment injury. Our modified percutaneous Bunnell type technique allows sufficient adaptation of ruptured Achilles tendon.