Room-temperature ferroelectricity in strained SrTiO3

Systems with a ferroelectric to paraelectric transition in the vicinity of room temperature are useful for devices. Adjusting the ferroelectric transition temperature (T(c)) is traditionally accomplished by chemical substitution-as in Ba(x)Sr(1-x)TiO(3), the material widely investigated for microwave devices in which the dielectric constant (epsilon(r)) at GHz frequencies is tuned by applying a quasi-static electric field. Heterogeneity associated with chemical substitution in such films, however, can broaden this phase transition by hundreds of degrees, which is detrimental to tunability and microwave device performance. An alternative way to adjust T(c) in ferroelectric films is strain. Here we show that epitaxial strain from a newly developed substrate can be harnessed to increase T(c) by hundreds of degrees and produce room-temperature ferroelectricity in strontium titanate, a material that is not normally ferroelectric at any temperature. This strain-induced enhancement in T(c) is the largest ever reported. Spatially resolved images of the local polarization state reveal a uniformity that far exceeds films tailored by chemical substitution. The high epsilon(r) at room temperature in these films (nearly 7,000 at 10 GHz) and its sharp dependence on electric field are promising for device applications.

Probing Nanoscale Ferroelectricity by Ultraviolet Raman Spectroscopy

We demonstrated that ultraviolet Raman spectroscopy is an effective technique to measure the transition temperature (Tc) in ferroelectric ultrathin films and superlattices. We showed that one-unit-cell-thick BaTiO3 layers in BaTiO3/SrTiO3 superlattices are not only ferroelectric (with Tc as high as 250 kelvin) but also polarize the quantum paraelectric SrTiO3 layers adjacent to them. Tc was tuned by approximately 500 kelvin by varying the thicknesses of the BaTiO3 and SrTiO3 layers, revealing the essential roles of electrical and mechanical boundary conditions for nanoscale ferroelectricity.

Further evaluation of intensified and increased total dose of cyclophosphamide for the treatment of primary breast cancer: findings from National Surgical Adjuvant Breast and Bowel Project B-25

PURPOSE

In 1989, the National Surgical Adjuvant Breast and Bowel Project initiated the B-22 trial to determine whether intensifying or intensifying and increasing the total dose of cyclophosphamide in a doxorubicin-cyclophosphamide combination would benefit women with primary breast cancer and positive axillary nodes. B-25 was initiated to determine whether further intensifying and increasing the cyclophosphamide dose would yield more favorable results.

PATIENTS AND METHODS

Patients (n = 2,548) were randomly assigned to three groups. The dose and intensity of doxorubicin were similar in all groups. Group 1 received four courses, ie, double the dose and intensity of cyclophosphamide given in the B-22 standard therapy group; group 2 received the same dose of cyclophosphamide as in group 1, administered in two courses (intensified); group 3 received double the dose of cyclophosphamide (intensified and increased) given in group 1. All patients received recombinant human granulocyte colony-stimulating factor. Life-table estimates were used to determine disease-free survival (DFS) and overall survival.

RESULTS

No significant difference was observed in DFS (P =.20), distant DFS (P =.31), or survival (P =.76) among the three groups. At 5 years, the DFS in groups 1 and 2 (61% v 64%, respectively; P =. 29) was similar to but slightly lower than that in group 3 (61% v 66%, respectively; P = 08). Survival in group 1 was concordant with that in groups 2 (78% v 77%, respectively; P =.71) and 3 (78% v 79%, respectively; P =.86). Grade 4 toxicity was 20%, 34%, and 49% in groups 1, 2, and 3, respectively. Severe infection and septic episodes increased in group 3. The decrease in the amount and intensity of cyclophosphamide and delays in therapy were greatest in courses 3 and 4 in group 3. The incidence of acute myeloid leukemia increased in all groups.

CONCLUSION

Because intensifying and increasing cyclophosphamide two or four times that given in standard clinical practice did not substantively improve outcome, such therapy should be reserved for the clinical trial setting.

Odontogenic tumours: a retrospective study of 1642 cases in a Chinese population

A total of 1642 odontogenic tumour cases retrieved from the files of the College of Stomatology, Sichuan University, China were retrospectively analyzed for gender, age, tumour site and relative frequency of various types, and the data compared with that of previous reports. The final diagnosis in each case was based on the WHO 2005 histopathological classification of odontogenic tumours. Of these tumours 1592 (97.0%) were benign and 50 (3.0%) were malignant. Ameloblastoma (40.3%) was the most frequent type, followed by keratocystic odontogenic tumour (35.8%), odontoma (4.7%) and odontogenic myxoma (4.6%). The mean age of the patients was 32.1, with a wide range (3-84 years). The male-female ratio and maxilla-mandible ratio were 1.4:1 and 1:4.0, respectively. Ameloblastoma and keratocystic odontogenic tumours, important indications of extensive surgical procedures, are not considered rare in this Chinese population, whereas odontoma is uncommon.

Green tea epigallocatechin gallate: a natural inhibitor of fatty-acid synthase

We discover that epigallocatechin gallate (EGCG) from green tea is an inhibitor of fatty-acid synthase (FAS) from chicken liver. Its inhibition of FAS is composed of reversible fast-binding inhibition, through which 52 microM EGCG can inhibit 50% of the activity of FAS, and irreversible slow-binding inactivation following saturation kinetics with the dissociation constant of 0.352 mM and limiting rate constant of 0.0168 min(-1). The marked inhibition of ketoacyl reduction shows that the inhibition is related to beta-ketoacyl reductase of FAS. The observable protection of NADPH and competitive inhibition of NADPH for ketoacyl reduction indicate that EGCG may compete with NADPH for the same binding site. The synthetic inhibitor C75 does not show obvious fast-binding inhibition, but does exhibit irreversible slow-binding biphasic inactivation, which is demonstrated to be a second-order reaction. That the inactivation by C75 is protected by malonyl-CoA indicates C75 is similar to cerulenin in being a covalent inactivator of the beta-ketoacyl synthase.

MAPK signaling and the kidney

Following an overview of the biochemistry of mitogen-activated protein kinase (MAPK) pathways, the relevance of these signaling events to specific models of renal cell function and pathophysiology, both in vitro and in vivo, will be emphasized. In in vitro model systems, events activating the principal MAPK families [extracellular signal-regulated and c-Jun NH(2)-terminal kinase and p38] have been best characterized in mesangial and tubular epithelial cell culture systems and include peptide mitogens, cytokines, lipid mediators, and physical stressors. Several in vivo models of proliferative or toxic renal injury are also associated with aberrant MAPK regulation. It is anticipated that elucidation of downstream effector signaling mechanisms and a clearer understanding of the immediate and remote upstream activating pathways, when applied to these highly clinically relevant model systems, will ultimately provide much greater insight into the basis for specificity now seemingly absent from these signaling events.

Suppression of hadrons with large transverse momentum in central Au+Au collisions at root square[s(NN)] = 130 GeV

Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 GeV/c<p(T)<5 GeV/c have been measured by the PHENIX experiment at RHIC in Au+Au collisions at root square[s(NN)] = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p+p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p+p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies.

Outcomes among African-Americans and Caucasians in colon cancer adjuvant therapy trials: findings from the National Surgical Adjuvant Breast and Bowel Project

BACKGROUND

African-Americans generally have lower survival rates from colon cancer than Caucasian Americans. This disparity has been attributed to many sources, including diagnosis at later disease stage and other unfavorable disease features, inadequate treatment, and socioeconomic factors. The randomized clinical trial setting ensures similarity in disease stage and a uniform treatment plan between blacks and whites. In this study, we evaluated survival and related end points for African-American and Caucasian patients with colon cancer participating in randomized clinical trials of the National Surgical Adjuvant Breast and Bowel Project (NSABP) to determine whether outcomes were less favorable for African-Americans.

METHODS

The study included African-American (n = 663) or Caucasian (n = 5969) patients from five serially conducted, randomized clinical trials of the NSABP. We compared recurrence-free survival, disease-free survival (recurrence, new primary cancer, or death), and survival (death from any cause) between blacks and whites by using statistical modeling to account for differences in patient and disease characteristics between the groups. Statistical tests were two-sided.

RESULTS

Dukes' stage and number of positive lymph nodes were remarkably similar between African-American and Caucasian patients in each trial. Over all trials combined, an 8% (95% confidence interval [CI] = -6% to 25%; P =.27) excess risk of colon cancer recurrence that was not statistically significant was observed for blacks. A greater disparity in survival was seen, with blacks experiencing a statistically significant 21% (95% CI = 6%-37%; P =.004) greater risk of death. Treatment efficacy appeared similar between the groups.

CONCLUSIONS

While the overall survival prognosis was less favorable for African-Americans compared with Caucasians in these trials, other outcomes measured were considerably more similar than those seen in the population at large, suggesting that earlier detection and adjuvant therapy could appreciably improve colon cancer prognosis for African-Americans. Continued investigations into causes of the deficits noted are warranted.

Characterization of a rat Na+-dicarboxylate cotransporter

The metabolism of Krebs cycle intermediates is of fundamental importance for eukaryotic cells. In the kidney, these intermediates are transported actively into epithelial cells. Because citrate is a potent inhibitor for calcium stone formation, excessive uptake results in nephrolithiasis due to hypocitraturia. We report the cloning and characterization of a rat kidney dicarboxylate transporter (SDCT1). In situ hybridization revealed that SDCT1 mRNA is localized in S3 segments of kidney proximal tubules and in enterocytes lining the intestinal villi. Signals were also detected in lung bronchioli, the epididymis, and liver. When expressed in Xenopus oocytes, SDCT1 mediated electrogenic, sodium-dependent transport of most Krebs cycle intermediates (Km = 20-60 microM), including citrate, succinate, alpha-ketoglutarate, and oxaloacetate. Of note, the acidic amino acids L- and D-glutamate and aspartate were also transported, although with lower affinity (Km = 2-18 mM). Transport of citrate was pH-sensitive. At pH 7.5, the Km for citrate was high (0.64 mM), whereas at pH 5.5, the Km was low (57 microM). This is consistent with the concept that the -2 form of citrate is the transported species. In addition, maximal currents at pH 5.5 were 70% higher than those at pH 7.5, and our data show that the -3 form acts as a competitive inhibitor. Simultaneous measurements of substrate-evoked currents and tracer uptakes under voltage-clamp condition, as well as a thermodynamic approach, gave a Na+ to citrate or a Na+ to succinate stoichiometry of 3 to 1. SDCT1-mediated currents were inhibited by phloretin. This plant glycoside also inhibited the SDCT1-specific sodium leak in the absence of substrate, indicating that at least one Na+ binds to the transporter before the substrate. The data presented provide new insights into the biophysical characteristics and physiological implications of a cloned dicarboxylate transporter.

Imaging findings of extraventricular neurocytoma: report of 3 cases and review of the literature

Extraventricular neurocytoma (EVN) is rare entity with similar biologic behavior and histopathologic characteristics to neurocytomas that occur in the lateral ventricles, according to the 2007 World Health Organization classification. We report the cases of 3 patients with extraventricular neurocytoma, which presented as large tumors in the left frontal and parietal lobes and in the sellar region. MR imaging showed cystic degeneration, calcification and/or hemorrhage, intense enhancement, and perilesional edema. EVN should be considered in the differential diagnosis for large, heterogeneous, enhancing brain tumors that occur in young people.

The role of TGF-β1-miR-21-ROS pathway in bystander responses induced by irradiated non-small-cell lung cancer cells

Background:

Many studies have indicated an important implication of radiation-induced bystander effects (RIBEs) in cancer radiotherapy, but the detailed signalling remains unclear.

Methods:

The roles of tumour growth factor-beta1 (TGF-β1) and miR-21 in medium-mediated RIBEs in H1299 non-small-cell lung cancer cells were investigated using DNA damage, changes in proliferation and levels of reactive oxygen species (ROS) as end points. SB431542, a specific inhibitor of TGF-β type 1 receptor kinases, was used to inhibit TGF-β1 pathways in irradiated and bystander cells. Exogenous miR-21 regulation was achieved through inhibitor or mimic transfection.

Results:

Compared with relative sham-radiation-conditioned medium, radiation-conditioned medium (RCM) from irradiated cells 1 h post radiation (1-h RCM) caused an increase in ROS levels and DNA damage in bystander cells, while 18-h RCM induced cell cycle delay and proliferation inhibition. All these effects were eliminated by TGF-βR1 inhibition. One-hour RCM upregulated miR-21 expression in bystander cells, and miR-21 inhibitor abolished bystander oxidative stress and DNA damage. Eighteen-hour RCM downregulated miR-21 of bystander cells, and miR-21 mimic eliminated bystander proliferation inhibition. Furthermore, the dysregulation of miR-21 was attenuated by TGF-βR1 inhibition.

Conclusions:

The TGF-β1–miR-21–ROS pathway of bystander cells has an important mediating role in RIBEs in H1299 cells.

Comparison of a paraspinal approach with a percutaneous approach in the treatment of thoracolumbar burst fractures with posterior ligamentous complex injury: a prospective randomized controlled trial

OBJECTIVE

This prospective randomized controlled study compared the efficacy and safety of two paraspinal muscle-sparing surgical approaches for the management of neurologically intact patients with thoracolumbar burst fractures and posterior ligamentous complex injuries.

METHODS

Patients were randomized to undergo either percutaneous (n=31) or paraspinal (n=30) fluoroscopically-guided pedicle screw-rod fixation, and were followed for ≥3 years. Preoperative postural reduction was attempted in all patients.

RESULTS

The percutaneous approach was associated with significantly less intraoperative blood loss and shorter duration of surgery and hospitalization, as well as less pain and better functional recovery at 3 months after surgery compared with the paraspinal approach. Paraspinal surgery resulted in significantly better correction of kyphosis and restoration of vertebral height compared with percutaneous surgery. There were no differences in long-term clinical outcomes between the two groups.

CONCLUSIONS

The minimally invasive percutaneous approach appears to be better in cases of successful postural reduction. The paraspinal approach results in better surgical correction and is, therefore, recommended for patients without successful postural reduction.