Dynamical splayed ferromagnetic ground state in the quantum spin ice Yb(2)Sn(2)O(7)

From magnetic, specific heat, (170)Yb Mössbauer effect, neutron diffraction, and muon spin relaxation measurements on polycrystalline Yb(2)Sn(2)O(7), we show that below the first order transition at 0.15 K all of the Yb(3+) ions are long-range magnetically ordered and each has a moment of 1.1 μ(B) which lies at ≃ 10° to a common fourfold cubic axis. The four sublattice moments have four different directions away from this axis and are therefore noncoplanar. We term this arrangement splayed ferromagnetism. This ground state has a dynamical component with a fluctuation rate in the megahertz range. The net ferromagnetic exchange interaction has an anisotropy that favors the local threefold axis. We discuss our results in terms of the phase diagram proposed by Savary and Balents [Phys. Rev. Lett. 108, 037202 (2012)] for a pyrochlore lattice of Kramers 1/2 effective spins.

One-year clinical and MR imaging outcome after partial meniscal replacement in stabilized knees using a collagen meniscus implant

PURPOSE

The purpose of the study was to evaluate the clinical and radiological outcomes after medial/lateral collagen meniscus substitution (CMI) at 12 months postoperatively.

METHODS

Sixty-seven patients (m:f = 47:20, mean age 36 ± 10 years) underwent arthroscopic CMI after previous subtotal medial (n = 55) or lateral meniscectomy (n = 12) due to persistent joint line pain (n = 25) or to prophylactic reasons (n = 42). Clinical follow-up consisted of IKDC score, Tegner score, Lysholm score, and visual analog scale for pain and satisfaction (preinjury, preoperatively, and 12 months postoperatively; follow-up rate 90 %). MRI scans were analyzed according to the Genovese criteria.

RESULTS

Nineteen patients (29 %) showed a normal (A), 35 nearly normal (B), 5 abnormal (C), and 1 patient severely abnormal total IKDC score (D). The median Tegner preinjury score was 7 (range 2-10) and at follow-up 6 (range 2-10). The mean Lysholm score before surgery was 68 ± 20 and 93 ± 9 at follow-up. Preoperatively, the mean VAS pain was 4.4 ± 3.1 and 2.0 ± 1.0 at follow-up. Clinical failure of the CMI occurred in 3 patients (n = 1 infection, n = 1 failure of the implant, n = 1 chronic synovitis). On MRI, the CMI was completely resorbed in 3 patients (5 %), partially resorbed in 55 (92 %), and entirely preserved in 3 (5 %) patients. In 5 patients (8 %) the CMI was isointense, in 54 (90 %) slightly and 1 (2 %) highly hyperintense. 43 (72 %) patients showed an extrusion of the CMI implant of more than 3 mm.

CONCLUSIONS

Significant pain relief and functional improvement throughout all scores at 1 year was noted. The CMI undergoes significant remodeling, degradation, resorption, and extrusion in most of the patients. No difference in outcomes between the medial and lateral CMI was observed.

LEVEL OF EVIDENCE

Prospective therapeutic study, Level IV.

Magnetic order, field-induced phase transitions and magnetoresistance in the intercalated compound Fe0.5TiS2

Measurements of the magnetic susceptibility, magnetization, electrical resistivity and neutron diffraction have been performed for the compound Fe(0.5)TiS(2) in which Fe atoms are intercalated between S-Ti-S tri-layers. It has been shown that this compound with a monoclinic crystal structure exhibits an antiferromagnetic (AF) ground state below the Néel temperature T(N) ≈ 140 K. Small deviations from the stoichiometry and some disordering effects caused by the additional low-temperature heat treatment do not affect substantially the AF state in Fe(0.5)TiS(2). According to neutron diffraction data the magnetic structure at 2 K is described by the propagation vector k = (1/4,0,1/4). The Fe magnetic moments with a value of (2.9 ± 0.1) μ(B) are directed at an angle of (78.5 ± 1.8)° to the layers. Application of the magnetic field at T < T(N) induces a metamagnetic phase transition to the ferromagnetic (F) state, which is accompanied by the large magnetoresistance effect (|Δρ/ρ| up to 27%). Below 100 K, the field-induced AF-F transition is found to be irreversible, as evidenced by magnetoresistance and neutron diffraction measurements. The magnetization reversal in the metastable F state is accompanied at low temperatures by substantial hysteresis (ΔH ~ 100 kOe) which is associated with the Ising character of Fe ions.

Incommensurate magnetic order in TbTe3

We report a neutron diffraction study of the magnetic phase transitions in the charge-density wave (CDW) TbTe(3) compound. We discover that in the paramagnetic phase there are strong 2D-like magnetic correlations, consistent with the pronounced anisotropy of the chemical structure. A long-range incommensurate magnetic order emerges in TbTe(3) at T(mag1) = 5.78 K as a result of continuous phase transitions. We observe that near the temperature T(mag1) the magnetic Bragg peaks appear around the position (0, 0, 0.24) (or its rational multiples), that is fairly close to the propagation vector (0,0,0.29) associated with the CDW phase transition in TbTe(3). This suggests that correlations leading to the long-range magnetic order in TbTe(3) are linked to the modulations that occur in the CDW state.

Cell differentiation and matrix organization in engineered teeth

Embryonic dental cells were used to check a series of criteria to be achieved for tooth engineering. Implantation of cultured cell-cell re-associations led to crown morphogenesis, epithelial histogenesis, organ vascularization, and root and periodontium development. The present work aimed to investigate the organization of predentin/dentin, enamel, and cementum which formed and mineralized after implantation. These implants were processed for histology, transmission electron microscopy, x-ray microanalysis, and electron diffraction. After two weeks of implantation, the re-associations showed gradients of differentiating odontoblasts. There were ciliated, polarized, and extended cell processes in predentin/dentin. Ameloblasts became functional. Enamel crystals showed a typical oriented arrangement in the inner and outer enamel. In the developing root, odontoblasts differentiated, cementogenesis occurred, and periodontal ligament fibroblasts interacted with the root surface and newly formed bone. The implantation of cultured dental cell re-associations allows for reproduction of complete functional differentiation at the cell, matrix, and mineral levels.

Oral health-related quality of life of elderly Germans--comparison of GOHAI and OHIP-14

OBJECTIVE

To obtain information about the subjective oral health status of non-clinical elderly populations of urban regions of Germany, one in the East and one in the West, by using OHIP-14 and, for first time, the GOHAI, and, furthermore, to compare the results obtained by use of both instruments.

BASIC RESEARCH DESIGN

Cross-sectional.

CLINICAL SETTING

Randomly chosen, non-clinical elderly population in urban regions of Germany.

PARTICIPANTS

197 participants (51% male) born in the years 1930-1932.

MAIN OUTCOME MEASURES

GOHAI, OHIP-14.

RESULTS

Median GOHAI score was 54; median OHIP-14 score was 2. Scores indicative of severely impaired oral health were rare. The effect of living in eastern or western Germany was of minor significance. Although the internal consistency of both measures was comparable and the same positive association with psychological wellbeing, absence of dry mouth, burning mouth, and removable dentures (p < 0.05) was observed, differences occurred. In simultaneous analysis of all items, factor analysis revealed only partial overlap of the items in extracted factors. Furthermore, the extreme score indicating no impairment was five times more frequent for OHIP-14. Of those who scored zero in OHIP-14, only 20% had the GOHAI equivalent score of 60, and for some GOHAI items the answer category for highest impairment was obtained.

CONCLUSIONS

GOHAI scores for this randomly chosen non-clinical group enable comparison with scores for Germany measured in the future. The differences between GOHAI and OHIP-14 make it necessary to select the most appropriate instrument for a planned purpose and study population.

Identification of single photoswitchable molecules in nanopores of silica xerogels using powder diffraction

Single photoswitchable molecules of (CN3H6)2[Fe(CN)5NO] (GuNP) are embedded into nanopores of an SiO2xerogel. It is shown that it is possible to identify the structural motif (`fingerprint') of the embedded complex by analyzing neutron powder diffraction data in a limitedQrange (Q< 37 nm−1) using the Debye approach. The structural study reveals that the pores are occupied by GuNP monomers with a fill factor of 60–80%. The mutual arrangement of the anion and cations in the GuNP monomer is slightly changed (∼1% elongation), while the bond lengths within the anion and cation are changed by less than 0.2% with respect to the single-crystalline form of GuNP.

Correlation between RhoB and Estrogen Receptor α (ERα) Expressions: From Experimental Data to Human Breast Tumors

Introduction: Hormonotherapy (HT) of breast cancers (BC) is strongly limitated by the resistances. Because Rho proteins are key elements in the cross-talks between ERα and growth factors signaling, they may be involved in the response to HT. RhoB could play a negative role in oncogenesis but there is no valid data regarding RhoB expression in BC. Experimental results: Our data suggest that RhoB participates in the balance of expression of ERα. The inhibition of the expression of RhoB using two sequences of interfering RNA in hormonodependent cell lines (MCF-7, T47D, ZR75) and in anti-estrogen resistant cell lines (LCC2, LCC9), decreases the expression of ERα both at the protein and mRNA levels. Moreover, in Mouse Embryonic Fibroblasts and uteri collected from RhoB knock-out mice, a dramatic decrease of ERα expression is observed. We therefore investigated the expression level of RhoB and ERα in BC tumors. Patients and methods: A tissue microarray (TMA) was constructed from a cohort of 113 patients (pts) enrolled in a randomized trial for adjuvant tamoxifen (median follow-up: 249.9 months). RhoB, ERα, and PR expressions were measured by immunochemistry. Cut-off used for ERα and PR + was 10% of stained cells. The expression of RhoB was calculated with the IRS score. Correlation of RhoB expression score with clinically diagnostic and prognostic variables was assessed using Man Whitney and Spearman's rank tests. Univariate survival analysis was performed for disease free survival (DFS) by applying the log-rank test to RhoB expression levels stratified by median value. TMA results: 65 (58.6%) were grade I-II; 74(66.1%) were ERα+ and 59(52.7%) PR+; 23 (22.1%) presented lymphovascular (LV) invasion. 39 pts (34.8%) had lymph nodes (LN) +. Pts under tamoxifen (n=62) had a less favorable pathological profile regarding + LN (p=0.0039), pathological tumour size (p=0.0486) and number of mitoses (p=0.0556). Age, ERα/PR status, histological grade or type and LV invasion status were similar in the two groups. We found less RhoB IRS expression in pts with tumor grade III (median 8 [1;12]) than in grade I-II (median 9 [3;12], p=0.0142). RhoB IRS expression was much higher in ERa + tumors (median:10.5 [3;12]) than in ERa negative tumors (median=8 [1;12], p=0.0023). RhoB IRS score was not correlated with the presence or not of LV invasion (p=0.26), neither with the presence of LN invasion (p= 0.74). Furthermore, RhoB expression is i) strongly correlated with the % of expression of ERα (Spearman'sρ=0.3659; p = 0.001) and PR (Spearman's ρ=0.2544 ; p=0.0076) ii) inversely correlated with histologic size (Spearman's ρ= -0.2344 ; p = 0.0166) and with number of mitose (Spearman's ρ=-0.2009 ; p=0.0362). The DFS of pts with ERα + tumors under tamoxifen or not was not affected by the level of RhoB expression. Conclusion: The analysis of 113 human breast tumors allowed to confirm experimental results, demonstrating that RhoB expression is strongly correlated with ERα expression. The role of RhoB as a potential suppressor gene of tumours in BC and its role in the response to HT have then to be investigated further.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5146.

Cancer testis antigen expression and immune responses by prostate cancer patients: Implications for prognosis and immunotherapy

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Background: Prostate cancer (PC) is the most frequent malignancy in men and it continues to be one of the most common fatal cancers. Treatment options in advanced castration-resistant prostate cancer (CRPC) are limited. Cancer testis (CT) antigens are expressed in a variety of human cancers, but not in normal tissues except for MHC deficient spermatogonia, and represent promising targets for immunotherapy. Little is known about CT antigen expression in relation to disease progression. The aim of this study was to investigate which CT antigens are expressed and immunogenic and hence represent promising targets for patients with prostate cancer and correlate these findings with clinicopathological characteristics. Methods: To determine the expression of 6 CT antigens in prostate cancer immunohistochemistry was performed on tissue micro arrays. We investigated 6 CT antigens (NY-ESO.1, MAGE-C1, MAGE-C2, GAGE, MAGE-A1 and MAGE-A4) in benign hyperplasia (n=45), early (n=388) and late stage (n=71) prostate cancer. To determine the occurrence of spontaneous antibodies against cancer testis antigens, ELISA and Western blot was performed for NY-ESO-1, MAGE-C1 and MAGE-C2 with sera from prostate cancer patients. Results: CT antigens are increasingly expressed in late stage prostate cancers. As an exception we found MAGE-C2 to be expressed early in the course of disease, frequently inducing MAGE-C2 specific antibodies. In later stage metastatic prostate cancer patients NY-ESO-1 is more often expressed, inducing NY-ESO-1 specific antibodies. Conclusions: Cancer testis (CT) antigens are prognostic markers, frequently inducing immune responses and may be suitable for immunotherapeutic intervention in patients with prostate cancer.

No significant financial relationships to disclose.