Oscillatory tunneling magnetoresistance in magnetic tunnel junctions with inserted nonmagnetic layer

Oscillatory tunneling magnetoresistance (TMR) as a function of spacer thickness is investigated theoretically for a magnetic tunnel junction with a nonmagnetic layer inserted between the tunnel barrier and the ferromagnetic layer. TMR is characterized in an analytical form, that is expressed with the transmission and reflection amplitudes of single interfaces at the Fermi level, and by the extremal wavevectors. Electronic structures with multiple bands are taken into account in the derivation characterizing the TMR, and the proposed analytical expression can be directly applied to real junctions. Based on our model, the features of TMR dependence on spacer thickness are discussed, including selection rules for the oscillation period. Numerical calculations are performed using an envelope-function theory for several cases, and we show that our model is in good agreement with the exact result.Comment: 21 pages (preprint), 6 figure

On the Effect of Quantum Interaction Distance on Quantum Addition Circuits

We investigate the theoretical limits of the effect of the quantum interaction distance on the speed of exact quantum addition circuits. For this study, we exploit graph embedding for quantum circuit analysis. We study a logical mapping of qubits and gates of any $\Omega(\log n)$-depth quantum adder circuit for two $n$-qubit registers onto a practical architecture, which limits interaction distance to the nearest neighbors only and supports only one- and two-qubit logical gates. Unfortunately, on the chosen $k$-dimensional practical architecture, we prove that the depth lower bound of any exact quantum addition circuits is no longer $\Omega(\log {n})$, but $\Omega(\sqrt[k]{n})$. This result, the first application of graph embedding to quantum circuits and devices, provides a new tool for compiler development, emphasizes the impact of quantum computer architecture on performance, and acts as a cautionary note when evaluating the time performance of quantum algorithms.Comment: accepted for ACM Journal on Emerging Technologies in Computing System

Three-dimensional printed polylactic acid scaffold integrated with BMP-2 laden hydrogel for precise bone regeneration

Background Critical bone defects remain challenges for clinicians, which cannot heal spontaneously and require medical intervention. Following the development of three-dimensional (3D) printing technology is widely used in bone tissue engineering for its outstanding customizability. The 3D printed scaffolds were usually accompanied with growth factors, such as bone morphometric protein 2 (BMP-2), whose effects have been widely investigated on bone regeneration. We previously fabricated and investigated the effect of a polylactic acid (PLA) cage/Biogel scaffold as a carrier of BMP-2. In this study, we furtherly investigated the effect of another shape of PLA cage/Biogel scaffold as a carrier of BMP-2 in a rat calvaria defect model and an ectopic ossification (EO) model. Method The PLA scaffold was printed with a basic commercial 3D printer, and the PLA scaffold was combined with gelatin and alginate-based Biogel and BMP-2 to induce bone regeneration. The experimental groups were divided into PLA scaffold, PLA scaffold with Biogel, PLA scaffold filled with BMP-2, and PLA scaffold with Biogel and BMP-2 and were tested both in vitro and in vivo. One-way ANOVA with Bonferroni post-hoc analysis was used to determine whether statistically significant difference exists between groups. Result The in vitro results showed the cage/Biogel scaffold released BMP-2 with an initial burst release and followed by a sustained slow-release pattern. The released BMP-2 maintained its osteoinductivity for at least 14 days. The in vivo results showed the cage/Biogel/BMP-2 group had the highest bone regeneration in the rat calvarial defect model and EO model. Especially, the bone regenerated more regularly in the EO model at the implanted sites, which indicated the cage/Biogel had an outstanding ability to control the shape of regenerated bone. Conclusion In conclusion, the 3D printed PLA cage/Biogel scaffold system was proved to be a proper carrier for BMP-2 that induced significant bone regeneration and induced bone formation following the designed shape.This work was supported by the Mid-career Researcher Program through National Research Foundation of Korea (NRF) grant (2016R1A2B3015048) funded by the Korea Government (MSIP)

Effects of Dietary Linseed Oil and Propionate Precursors on Ruminal Microbial Community, Composition, and Diversity in Yanbian Yellow Cattle

The rumen microbial ecosystem is a complex system where rumen fermentation processes involve interactions among microorganisms. There are important relationships between diet and the ruminal bacterial composition. Thus, we investigated the ruminal fermentation characteristics and compared ruminal bacterial communities using tag amplicon pyrosequencing analysis in Yanbian yellow steers, which were fed linseed oil (LO) and propionate precursors. We used eight ruminally cannulated Yanbian yellow steers (510 ± 5.8 kg) in a replicated 4 × 4 Latin square design with four dietary treatments. Steers were fed a basal diet that comprised 80% concentrate and 20% rice straw (DM basis, CON). The CON diet was supplemented with LO at 4%. The LO diet was also supplemented with 2% dl-malate or 2% fumarate as ruminal precursors of propionate. Dietary supplementation with LO and propionate precursors increased ruminal pH, total volatile fatty acid concentrations, and the molar proportion of propionate. The most abundant bacterial operational taxonomic units in the rumen were related to dietary treatments. Bacteroidetes dominated the ruminal bacterial community and the genus Prevotella was highly represented when steers were fed LO plus propionate precursors. However, with the CON and LO diet plus malate or fumarate, Firmicutes was the most abundant phylum and the genus Ruminococcus was predominant. In summary, supplementing the diets of ruminants with a moderate level of LO plus propionate precursors modified the ruminal fermentation pattern. The most positive responses to LO and propionate precursors supplementation were in the phyla Bacteriodetes and Firmicutes, and in the genus Ruminococcus and Prevotella. Thus, diets containing LO plus malate or fumarate have significant effects on the composition of the rumen microbial community

Long-term effect of stereotactic body radiation therapy for primary hepatocellular carcinoma ineligible for local ablation therapy or surgical resection. Stereotactic radiotherapy for liver cancer

<p>Abstract</p> <p>Background</p> <p>We evaluated the long-term effect of stereotactic body radiation therapy (SBRT) for primary small hepatocellular carcinoma (HCC) ineligible for local therapy or surgery.</p> <p>Methods</p> <p>Forty-two HCC patients with tumors ≤ 100 cc and ineligible for local ablation therapy or surgical resection were treated with SBRT: 30-39 Gy with a prescription isodose range of 70-85% (median 80%) was delivered daily in three fractions. Median tumor volume was 15.4 cc (3.0-81.8) and median follow-up duration 28.7 months (8.4-49.1).</p> <p>Results</p> <p>Complete response (CR) for the in-field lesion was initially achieved in 59.6% and partial response (PR) in 26.2% of patients. Hepatic out-of-field progression occurred in 18 patients (42.9%) and distant metastasis developed in 12 (28.6%) patients. Overall in-field CR and overall CR were achieved in 59.6% and 33.3%, respectively. Overall 1-year and 3-year survival rates were 92.9% and 58.6%, respectively. In-field progression-free survival at 1 and 3 years was 72.0% and 67.5%, respectively. Patients with smaller tumor had better in-field progression-free survival and overall survival rates (<32 cc vs. ≥32 cc, <it>P </it>< 0.05). No major toxicity was encountered but one patient died with extrahepatic metastasis and radiation-induced hepatic failure.</p> <p>Conclusions</p> <p>SBRT is a promising noninvasive-treatment for small HCC that is ineligible for local treatment or surgical resection.</p

Evidence of the neuron-restrictive silencer factor (NRSF) interaction with Sp3 and its synergic repression to the mu opioid receptor (MOR) gene

Previously, we reported that the neuron-restrictive silencer element (NRSE) of mu opioid receptor (MOR) functions as a critical regulator to repress the MOR transcription in specific neuronal cells, depending on neuron-restriction silence factor (NRSF) expression levels [C.S.Kim, C.K.Hwang, H.S.Choi, K.Y.Song, P.Y.Law, L.N.Wei and H.H.Loh (2004) J. Biol. Chem., 279, 46464–46473]. Herein, we identify a conserved GC sequence next to NRSE region in the mouse MOR gene. The inhibition of Sp family factors binding to this GC box by mithramycin A led to a significant increase in the endogenous MOR transcription. In the co-immunoprecipitation experiment, NRSF interacted with the full-length Sp3 factor, but not with Sp1 or two short Sp3 isoforms. The sequence specific and functional binding by Sp3 at this GC box was confirmed by in vitro gel-shift assays using either in vitro translated proteins or nuclear extract, and by in vivo chromatin immunoprecipitation assays. Transient transfection assays showed that Sp3-binding site of the MOR gene is a functionally synergic repressor element with NRSE in NS20Y cells, but not in the NRSF negative PC12 cells. The results suggest that the synergic interaction between NRSF and Sp3 is required to negatively regulate MOR gene transcription and that transcription of MOR gene would be governed by the context of available transcription factors rather than by a master regulator

Stereotactic body radiation therapy with or without transarterial chemoembolization for patients with primary hepatocellular carcinoma: preliminary analysis

<p>Abstract</p> <p>Background</p> <p>The objectives of this retrospective study was to evaluate the efficacy of stereotactic body radiation therapy (SBRT) for small non-resectable hepatocellular carcinoma (HCC) and SBRT combined with transarterial chemoembolization (TACE) for advanced HCC with portal vein tumor thrombosis (PVTT).</p> <p>Methods</p> <p>Thirty one patients with HCC who were treated with SBRT were used for the study. We studied 32 HCC lesions, where 23 lesions (22 patients) were treated targeting small non-resectable primary HCC, and 9 lesions (9 patients) targeting PVTT using the Cyberknife. All the 9 patients targeting PVTT received TACE for the advanced HCC. Tumor volume was 3.6–57.3 cc (median, 25.2 cc) and SBRT dose was 30–39 Gy (median, 36 Gy) in 3 fractions for consecutive days for 70–85% of the planned target volume.</p> <p>Results</p> <p>The median follow up was 10.5 months. The overall response rate was 71.9% [small HCC: 82.6% (19/23), advanced HCC with PVTT: 44.4% (4/9)], with the complete and partial response rates of 31.3% [small HCC: 26.1% (6/23), advanced HCC with PVTT: 11.1% (1/9)], and 50.0% [small HCC: 56.5% (13/23), advanced HCC with PVTT: 33.3% (3/9)], respectively. The median survival period of small HCC and advanced HCC with PVTT patients was 12 months and 8 months, respectively. No patient experienced Grade 4 toxicity.</p> <p>Conclusion</p> <p>SBRT for small HCC and SBRT combined with TACE for advanced HCC with PVTT showed feasible treatment modalities with minimal side effects in selected patients with primary HCC.</p