Single Spin Process Research Articles

Behavior Analysis of Si Etching Process with HF/HNO<sub>3</sub> Mixture in Single-Spin Wafer Process

The HF/HNO3mixture Si etching process is widely used to remove stress and damaged layers after Si wafer back grinding. Although there have been many reports on the dip process, there have been few detailed reports on the single-spin process. In a single spin process, Si etch rate distributions largely differ with different HF/HNO3concentrations. On the other hand, thermal SiO2etch rate distributions are similar even with different HF/HNO3concentrations. In this work, we analyzed Si surfaces with XPS (X-ray Photoelectron Spectroscopy) after processing various HF/HNO3mixture concentrations. SiOxstays steady in any wafer position and HNO3concentration, whereas SiO2thickens depending on HNO3concentration at the center. We assumed that Si etch rate distributions were caused by HF or HNO3consumption and confirmed this assumption was correct in a wafer center SiN cover experiment.

Platelet-rich Plasma by Single-spin Process in Male Pattern Androgenetic Alopecia: Is it an Effective Treatment?

Platelet-rich Plasma by Single-spin Process in Male Pattern Androgenetic Alopecia: Is it an Effective Treatment?

Effects of repetitive platelet-rich plasma application on human tenocyte proliferation.

Current clinical application of platelet-rich plasma is showing a trend toward multiple treatments. The goal of this study was to show the benefit of interval platelet-rich plasma application in the healing and recovery of human tenocytes using an in vitro cell model. Eight volunteers (6 men and 2 women) were included in this study (mean±SD age, 31.6±10.9 years). Venous blood was collected from new blood draws at 3 different times. Two blood products were prepared on each day of treatment: platelet-rich plasma derived from a single-spin process (PRPSS) and platelet-rich plasma derived from a double-spin process (PRPDS). The study had 2 limbs: 2-day and 4-day intervals. Cell proliferation, measured as disintegrations per minute, was then examined via a radioactive thymidine assay. In the 2-day-interval group, the difference in disintegrations per minute between days 0 and 2 in the PRPSS group reached statistical significance (P =.006). In the PRPDS group, statistical difference was seen between days 0 and 4 (P=.001) and between days 2 and 4 (P=.030). In the 4-day-interval group, the difference in disintegrations per minute between days 4 and 8 in the PRPSS group reached statistical significance, showing a decrease in cell proliferation (P =.013). In the PRPDS group, a statistical difference was seen between days 0 and 8 (P=.021), also showing a decrease in cell proliferation. The greatest effect of platelet-rich plasma, which has a positive effect on tenocyte proliferation and recovery, is seen on initial application. Its effect is diminished with repetitive application, and this finding leads to questioning of the efficacy of interval platelet-rich plasma dosing.

In vitro evaluation of the anti-bacterial effect of two preparations of platelet rich plasma compared with cefazolin and whole blood

This study investigates the antibacterial properties of two different platelet-rich plasma (PRP) platelet concentration preparations (PRPLP and PRPHP) through a time-kill assay. Two different PRP preparations - a single spin process yielding lower white blood cells and platelet concentration (PRPLP) and one yielding high platelet and white blood cell concentration (PRPHP) - were obtained from 2 individuals. PRPLP, PRPHP, phosphate buffered saline (PBS), whole blood and Cefazolin were added to experimental reaction tubes, each containing a single bacterial inoculum of Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epi), methicillin-resistant Staphylococcus aureus (MRSA) or Propionibacterium acnes (P. acnes). Two dilutions (1:1,000, and 1:10,000) were plated in duplicate tubes, along with positive (blood and PBS) and negative (Cefazolin) controls and assessed at five time points (0, 1, 4, 8 and 24 hours). After centrifugation, platelet count of PRPLP was 386 ± 65.5 × 103/?L and PRPHP was 867 ± 234.4 × 103/?L. Both PRP products showed a significant decrease (p<0.05) in bacterial growth at 8 hours compared to whole blood. The application of PRPLP and PRPHP showed a significant decrease in bacterial growth after 8 hours for S. aureus, S. epi, MRSA and P. acnes compared to the whole blood control group. S.epi, MRSA, and P. acnes also showed a significant decrease in bacterial growth after 24 hours. Despite differences in platelet concentration and WBC concentration, no difference in antibacterial activity was seen between the two preparations.

The Positive Effects of Different Platelet-Rich Plasma Methods on Human Muscle, Bone, and Tendon Cells

Background: Clinical application of platelet-rich plasma (PRP) in the realm of orthopaedic sports medicine has yielded variable results. Differences in separation methods and variability of the individual may contribute to these variable results. Purpose: To compare the effects of different PRP separation methods on human bone, muscle, and tendon cells in an in vitro model. Study Design: Controlled laboratory study. Methods: Blood collected from 8 participants (mean ± SD age 31.6 ± 10.9 years) was used to obtain PRP preparations. Three different PRP separation methods were used: a single-spin process yielding a lower platelet concentration (PRPLP), a single-spin process yielding high platelet and white blood cell concentrations (PRPHP), and a double-spin that produces a higher platelet concentration and lower white blood cell concentration (PRPDS). Human bone, muscle, and tendon cells obtained from discarded tissue samples during shoulder surgery were placed into culture and treated with the 3 PRP preparations, control media (2% fetal bovine serum [FBS] and 10% FBS), and native blood. Radioactive thymidine assays were obtained to examine cell proliferation, and testing with enzyme-linked immunosorbent assay was used to determine growth factor concentrations. Results: Addition of PRPLP to osteocytes, myocytes, and tenocytes significantly increased cell proliferation (P ≤ .05) compared with the controls. Adding PRPDS to osteoblasts and tenocytes increased cell proliferation significantly (P ≤ .05), but no significance was shown for its addition to myocytes. The addition of PRPHP significantly increased cell proliferation compared with the controls only when added to tenocytes (P ≤ .05). Osteoblasts: Proliferation was significantly increased by addition of PRPLP compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRPDS led to significantly increased proliferation compared with all controls, native blood, and PRPHP (P ≤ .05). Proliferation was significantly less when PRPHP was added compared with PRPDS (P ≤ .05). Myocytes: Proliferation was significantly increased by addition of PRPLP compared with native blood (P ≤ .05). Adding PRPHP or PRPDS to myocytes showed no significant increase in proliferation compared with the controls or the other separations. Tenocytes: Proliferation was significantly increased by addition of PRPLP compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRPDS showed a significant increase compared with the controls and native blood. For tenocytes, there was a significant increase (P ≤ .05) seen when PRPHP was added compared with the controls and native blood but not compared with the other separations. Conclusion: The primary findings of this study suggest the application of different PRP separations may result in a potential beneficial effect on the clinically relevant target cells in vitro. However, it is unclear which platelet concentration or PRP preparation may be optimal for the treatment of various cell types. In addition, a “more is better” theory for the use of higher platelet concentrations cannot be supported. This study was not intended to prove efficacy but to provide a platform for future research to be built upon. Clinical Relevance: The utilization of different PRP separations may result in a potentially beneficial effect on the clinically relevant target cells in vitro, but it is unclear which platelet concentration or PRP preparation may be optimal for the treatment of various cell types.

Quantum and thermal spin relaxation in the diluted spin iceDy2−xMxTi2O7(M=Lu,Y)

We have studied the low temperature a.c. magnetic susceptibility of the diluted spin ice compound Dy(2-x)MxTi2O7, where the magnetic Dy ions on the frustrated pyrochlore lattice have been replaced with non-magnetic ions, M = Y or Lu. We examine a broad range of dilutions, 0 <= x <= 1.98, and we find that the T ~ 16 K freezing is suppressed for low levels of dilution but re-emerges for x > 0.4 and persists to x = 1.98. This behavior can be understood as a non-monotonic dependence of the quantum spin relaxation time with dilution. The results suggest that the observed spin freezing is fundamentally a single spin process which is affected by the local environment, rather than the development of spin-spin correlations as earlier data suggested.

Lambda polarization and single-spin left-right asymmetry in diffractive hadron-hadron collisions

We discuss Lambda polarization and single-spin left-right asymmetry in diffractive hadron-hadron scattering at high energies. We show that the physical picture proposed in a recent Letter is consistent with the experimental observation that $\Lambda$ polarization in the diffractive process, $pp\to \Lambda K^+p$, is much higher than that in the inclusive reaction, $pp\to \Lambda X$. We make predictions for the left-right asymmetry, A_N, and for the spin transfer, $D_{NN}^\Lambda$, in the single-spin process $p(\uparrow)p\to \Lambda K^+p$ and suggest further experimental tests of the proposed picture.

Mechanical characterization of a new high-aspect-ratio near UV-photoresist

Characterization of the mechanical and thermal properties of the high-aspect-ratio, negative, UV resist, SU-8 has been carried out. This resist allows for a broad range of thicknesses to be obtained with a single spin process. Standard exposure with a UV aligner has produced outstanding aspect ratios, 15 for lines and trenches. This type of performance lends itself well to MEMS applications, packaging, micromolds, spacers, etc. Because of the simplicity of use of the resist in addition to the large range of possible applications, the process dependent mechanical and thermal properties must be understood in order to completely exploit the potential of the resist.