Reconciling scaling of the optical conductivity of cuprate superconductors with Planckian resistivity and specific heat

Materials tuned to a quantum critical point display universal scaling properties as a function of temperature T and frequency ω. A long-standing puzzle regarding cuprate superconductors has been the observed power-law dependence of optical conductivity with an exponent smaller than one, in contrast to T-linear dependence of the resistivity and ω-linear dependence of the optical scattering rate. Here, we present and analyze resistivity and optical conductivity of La_2-xSr_xCuO₄ with x = 0.24. We demonstrate ℏω/k_BT scaling of the optical data over a wide range of frequency and temperature, T-linear resistivity, and optical effective mass proportional to [Formula: see text] corroborating previous specific heat experiments. We show that a T, ω-linear scaling Ansatz for the inelastic scattering rate leads to a unified theoretical description of the experimental data, including the power-law of the optical conductivity. This theoretical framework provides new opportunities for describing the unique properties of quantum critical matter.

P-384 Efficacy of endometrial microbiome metagenomic analysis with recurrent implantation failure and recurrent pregnancy loss: multicenter study in Japan

Study question

Does the result of endometrial microbiome metagenomic analysis (EMMA), a next generation sequencing (NGS)-based test of the intrauterine microbiome, have an impact on pregnancy rate after the test?

Summary answer

After recommend treatment with antimicrobial and probiotic therapy, the group diagnosed as dysbiosis by EMMA achieved pregnancy significantly earlier than the group with Normal result.

What is known already

Using NGS technology, EMMA testing can determine the composition of the endometrial microbiome by analysing bacterial 16S ribosomal RNA with a focus on the lactobacillus population. Endometrial flora in patients undergoing in vitro fertilization (IVF) is often composed of pathogenic microorganisms which decrease implantation rates, such as the Enterobacteriaceae family, Staphylococcus spp., Escherichia coli and Gram-negative bacteria. Other studies also indicate that Lactobacillus spp. is a major microorganism in the endometrium. Especially, lactobacillus-dominated microbiota (LDM, defined as > 90% Lactobacillus spp.) in the endometrium has been reported to lead to better pregnancy outcomes than non-LDM (<90% Lactobacillus spp.).

Study design, size, duration

This study was a prospective, multicenter cohort study of 527 patients (under 42 years old) with recurrent implantation failure (RIF) and recurrent pregnancy loss (RPL) at 14 IVF treatment facilities in Japan from June 2019 to August 2021. Defining RIF as three or more failed implantation attempts and RPL as two or more miscarriages, we examined the prognosis of two additional embryo transfers (ETs) after the EMMA test in patients who underwent the test.

Participants/materials, setting, methods

Endometrial tissue was obtained by aspiration from patients in day 15-25 of their menstrual cycles, and sample tissues were analyzed by NGS for EMMA. Participant centers treated patients according to the therapies specified in the reports, including antibiotic treatments, probiotic treatments, re-analysis, and embryo transfer. Multivariate analysis was performed using a generalized linear model with the endpoint of ongoing pregnancy. For the time-to-event analyses, we used Kaplan-Meier survival analysis to compare time to ongoing pregnancy.

Main results and the role of chance

The results of the first EMMA were as follows: 229 patients (43.4%) were normal with Lactobacillus spp. >90% (Normal group), 110 patients (20.9%) were abnormal with less than 90% Lactobacillus spp. and predominantly pathogenic bacteria (Abnormal group), and 188 patients (35.7%) were mild with low absolute amounts of bacteria and ultralow biomass indicating almost sterile (Mild + Ultralow group). There were no significant differences in background factors such as age, duration of infertility, number of previous ETs, or history of deliveries among the three groups. Gardnerella was the most pathogenic bacteria detected in patients with Abnormal EMMA results. All patients in the Abnormal group were treated with antimicrobials and probiotics, and those in Mild + Ultralow group were treated with probiotics. Odds ratio for ongoing pregnancy rate was 1.10(95%CI 0.67-1.82, p = 0.699) in Abnormal group and 1.23(95%CI 0.80-1.89, p = 0.342) in Mild + Ultralow group, respectively. After the intervention, ongoing pregnancies were comparable to those in Normal group.Analysis of time to pregnancy using Kaplan-Meier survival curves showed that Abnormal group had a significantly higher rate of ongoing pregnancies during the observation period than the other groups (p = 0.031).

Limitations, reasons for caution

Since this study was not necessarily limited to euploid embryos transferred after testing, an aging bias cannot be excluded. Since this study was conducted with all patients receiving EMMA, the effectiveness of the test needs to be further validated by comparison to patients without EMMA testing.

Wider implications of the findings

This study is the first multicenter study to demonstrate that the intervention based on EMMA reports improve pregnancy outcome in the patients with RIF and RPL. We suggest that the EMMA procedure, which aims at establishing an appropriate uterine microbiome, may be important for implantation and pregnancy continuation.

Trial registration number

UMIN000036917

A Kirschner wire as a transverse-axis guide to improve acetabular cup positioning

PURPOSE

To compare cup-positioning accuracy in total hip arthroplasty (THA) with or without use of a Kirschner wire as a transverse-axis guide for pelvic alignment.

METHODS

Records of 18 men and 73 women (mean age, 60 years) who underwent primary THA with (n=49) or without (n=42) use of a Kirschner wire as a transverse-axis guide for pelvic alignment were reviewed. A 2.4-mm Kirschner wire as a transversea-xis guide was inserted to the anterior superior iliac spine and was parallel to a line linking the left and right anterior superior iliac spine. The safe zone for cup positioning was defined as 30º to 50° abduction and 10º to 30º anteversion. Of the 5 operative surgeons, 2 were classified as experienced (total surgical volume >300) and 3 as inexperienced (total surgical volume of <50). The proportion of patients with the cup in the safe zone was compared in patients with or without use of the transverse-axis guide and in experienced and inexperienced surgeons.

RESULTS

For inexperienced surgeons, the use of the transverse-axis guide significantly improved the proportion of patients with the cup in the safe zone from 90% to 100% for abduction, from 50% to 82.4% for anteversion, and from 40% to 82.4% for both. Patients with the cup inside or outside the safe zone were comparable in terms of body height, weight, BMI, subcutaneous fat thickness, incision length, and acetabular cup size.

CONCLUSION

The use of the transverse-axis guide improved the accuracy of cup positioning by inexperienced surgeons.

Functional folate receptor beta-expressing macrophages in osteoarthritis synovium and their M1/M2 expression profiles

OBJECTIVE

The distribution of folate receptor (FR)-β+ macrophages and their M1/M2 expression profiles were examined in osteoarthritis (OA) synovial tissues, and compared to those in rheumatoid arthritis (RA) synovial tissues and CD163+ macrophages in both OA and RA synovial tissues.

METHOD

The phenotypes and fluorescein isothiocyanate (FITC)-folate uptake of FR-β+ synovial macrophages were analysed by flow cytometry. The distribution of FR-β+ macrophages in OA and RA synovial tissues was examined by immunofluorescent microscopy. Tumour necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), interleukin (IL)-10, and transforming growth factor (TGF)-β expression in FR-β+ macrophages was detected by double-immunostaining in both OA and RA synovial tissues.

RESULTS

FR-β+ macrophages were predominantly present in the synovial lining layer in OA patients. The proportion of CD163-FR-β+ cells in synovial mononuclear cells (MNCs) was increased in OA compared to RA synovial tissues. FR-β(high) macrophages from OA synovial tissues represented the majority of folic acid-binding cells. Although FR-β+ or CD163+ macrophages in the synovial tissues of OA and RA patients expressed a mixed pattern of M1 and M2 macrophage markers, there were more M2 markers expressing synovial macrophages in OA than in RA patients.

CONCLUSIONS

The distribution and M1/M2 expression profiles of FR-β+ synovial macrophages were different between OA and RA synovial tissues. Thus, the findings underscore that the M1/M2 paradigm using surface markers FR-β and CD163 is an oversimplification of macrophage subsets. Functional FR-β present on OA synovial macrophages provides a potential tool for the diagnosis and treatment of OA.

Anisotropies in the optical ac and dc conductivities in lightly doped La(2 - x)Sr(x)CuO4: the role of deep and shallow acceptor states

We investigate the origin of the optical ac and dc conductivity anisotropies observed in the low temperature orthorhombic phase of lightly doped, untwinned La(2 - x)Sr(x)NiO(4) single crystals. We show that these anisotropies can be naturally ascribed to the emergence of two odd parity, rotational-symmetry-broken, localized impurity acceptor states, one deeper and one shallower, resulting from the trapping of doped holes by the Coulomb potential provided by the Sr ions. These two lowest-energy, p-wave-like states are split by orthorhombicity and are partially filled with holes. This leaves a unique imprint in the optical ac conductivity, which shows two distinct far-infrared continuum absorption energies corresponding to the photoionization of the deep and shallow acceptor states. Furthermore, we argue that the existence of two independent and orthogonal channels for hopping conductivity, directly associated with the two orthorhombic directions, also quantitatively explains the observed low temperature anisotropies in the dc conductivity.

Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide

The doping of charge carriers into the CuO(2) planes of copper oxide Mott insulators causes a gradual destruction of antiferromagnetism and the emergence of high-temperature superconductivity. Optimal superconductivity is achieved at a doping concentration p beyond which further increases in doping cause a weakening and eventual disappearance of superconductivity. A potential explanation for this demise is that ferromagnetic fluctuations compete with superconductivity in the overdoped regime. In this case, a ferromagnetic phase at very low temperatures is predicted to exist beyond the doping concentration at which superconductivity disappears. Here we report on a direct examination of this scenario in overdoped La(2-x)Sr(x)CuO(4) using the technique of muon spin relaxation. We detect the onset of static magnetic moments of electronic origin at low temperature in the heavily overdoped nonsuperconducting region. However, the magnetism does not exist in a commensurate long-range ordered state. Instead it appears as a dilute concentration of static magnetic moments. This finding places severe restrictions on the form of ferromagnetism that may exist in the overdoped regime. Although an extrinsic impurity cannot be absolutely ruled out as the source of the magnetism that does occur, the results presented here lend support to electronic band calculations that predict the occurrence of weak localized ferromagnetism at high doping.

p53 overexpression in Ewing's sarcoma/primitive neuroectodermal tumour is an uncommon event

Aim-To determine the presence of p53 overexpression in Ewing's sarcoma/primitive neuroectodermal tumours (ETs) and to assess whether p53 accumulation has any prognostic value.Methods-From a prospectively compiled database of 76 patients with ETs, suitable tumour tissue was available for 38. The monoclonal antibody pAb1801 was used to detect p53 nuclear protein overexpression. Results-Nuclear staining was detected in the tumours of three (8%) of the 38 patients. Where tumours stained positively, over 10% of the tumour nuclei were postively stained. All three patients whose tumours overexpressed p53 died and in a relatively short time compared with the patients who did not overexpress p53 (mean 3.7 months compared with a mean of 38.7 months in the p53 negative group).Conclusion-Overexpression of p53 in ETs is an uncommon event. Overexpression of p53 has repeatedly been shown to correlate closely with p53 point missense mutations and therefore this oncogenic event appears not to be of primary pathogenic importance in ETs. There is a tentative indication that those uncommon ETs in which p53 overexpression can be detected may be-have more aggressively.

Towards a two-dimensional superconducting state of La(2-x)Sr(x)CuO4 in a moderate external magnetic field

We report a novel aspect of the competition and coexistence between magnetism and superconductivity in the high-T(c) cuprate La(2-x)Sr(x)CuO4 (La214). With a modest magnetic field applied H parallel c axis, we monitored the infrared signature of pair tunneling between the CuO2 planes and discovered the complete suppression of interlayer coupling in a series of underdoped La214 single crystals. We find that the in-plane superconducting properties remain intact, in spite of enhanced magnetism in the planes.

X-ray absorption spectra reveal the inapplicability of the single-band Hubbard model to overdoped cuprate superconductors

X-ray absorption spectra on the overdoped high-temperature superconductors Tl2Ba2CuO(6+delta) and La(2-x)SrxCuO(4+/-delta) reveal a striking departure in the electronic structure from that of the underdoped regime. The upper Hubbard band, identified with strong correlation effects, is not observed on the oxygen K edge, while the lowest-energy prepeak gains less intensity than expected above p approximately 0.21. This suggests a breakdown of the Zhang-Rice singlet approximation and a loss of correlation effects or a significant shift in the most fundamental parameters of the system, rendering single-band Hubbard models inapplicable. Such fundamental changes suggest that the overdoped regime may offer a distinct route to understanding in the cuprates.

Universal versus material-dependent two-gap behaviors of the high-Tc cuprate superconductors: angle-resolved photoemission study of La2-xSrxCuO4

We have investigated the doping and temperature dependences of the pseudogap and superconducting gap in the single-layer cuprate La2-xSrxCuO4 by angle-resolved photoemission spectroscopy. The results clearly exhibit two distinct energy and temperature scales, namely, the gap around (pi, 0) of magnitude Delta* and the gap around the node characterized by the d-wave order parameter Delta0. In comparison with Bi2212 having higher Tc's, Delta0 is smaller, while Delta* and T* are similar. This result suggests that Delta* and T* are approximately material-independent properties of a single CuO2 plane, in contrast to the material-dependent Delta0, representing the pairing strength.

Inhibition of Notch pathway prevents osteosarcoma growth by cell cycle regulation

The study shows constitutive activation of the Notch pathway in various types of malignancies. However, it remains unclear how the Notch pathway is involved in the pathogenesis of osteosarcoma. We investigated the expression of the Notch pathway molecules in osteosarcoma biopsy specimens and examined the effect of Notch pathway inhibition. Real-time PCR revealed overexpression of Notch2, Jagged1, HEY1, and HEY2. On the other hand, Notch1 and DLL1 were downregulated in biopsy specimens. Notch pathway inhibition using γ-secretase inhibitor and CBF1 siRNA slowed the growth of osteosarcomas in vitro. In addition, γ-secretase inhibitor-treated xenograft models exhibited significantly slower osteosarcoma growth. Cell cycle analysis revealed that γ-secretase inhibitor promoted G1 arrest. Real-time PCR and western blot revealed that γ-secretase inhibitor reduced the expression of accelerators of the cell cycle, including cyclin D1, cyclin E1, E2, and SKP2. On the other hand, p21^cip1 protein, a cell cycle suppressor, was upregulated by γ-secretase inhibitor treatment. These findings suggest that inhibition of Notch pathway suppresses osteosarcoma growth by regulation of cell cycle regulator expression and that the inactivation of the Notch pathway may be a useful approach to the treatment of patients with osteosarcoma.

Traumatic spinal-cord herniation associated with pseudomeningocele after lower-thoracic nerve-root avulsion

BACKGROUND

Traumatic spinal-cord herniation after nerve root avulsion is rare. We report on the first patient with spinal-cord herniation associated with pseudomeningocele in the lower conus medullaris region after nerve avulsion.

CASE

This 72-year-old man presented with progressive pain in the left leg and motor weakness after two traumatic accidents. Constructive interference in steady-state (CISS) imaging showed the attachment of the spinal cord to the wall of a herniated pseudomeningocele and associated syringomyelia at the level of T12. At the time of surgery, a herniated pseudomeningocele was observed. The lateral portion of the spinal cord that had herniated into the pseudomeningocele was detached from its wall; this was followed by repair of the dural defect. A redundant nerve root was observed inside the pseudomeningocele, suggesting nerve root avulsion as the primary lesion. To facilitate cerebrospinal fluid drainage from the syringomyelia, we next performed dorsal root entry zone (DREZ)tomy to the pseudomeningocele. Postoperatively, he manifested significant clinical improvement.

CONCLUSIONS

This is the first report of spinal cord herniation after nerve root avulsion in the conus medullaris region. CISS imaging is highly useful for the demonstration of spinal cord herniation, syringomyelia and pseudomeningocele. To restore neurological function in patients with progressive symptoms, we recommend surgical treatment.

Inhomogeneous magnetic-field response of YBa2Cu3Oy and La2-xSrxCuO4 persisting above the bulk superconducting transition temperature

We report that in YBa2Cu3Oy and La2-xSrxCuO4 there is a spatially inhomogeneous response to the magnetic field for temperatures T extending well above the bulk-superconducting transition temperature Tc. An inhomogeneous magnetic response is observed above Tc even in ortho-II YBa2Cu3O6.50, which has highly ordered doping. The degree of the field inhomogeneity above Tc tracks the hole-doping dependences of both Tc and the density of the superconducting carriers below Tc, and therefore is apparently coupled to superconductivity.

Observation of a 500 meV collective mode in La2-xSrxCuO4 and Nd2CuO4 using resonant inelastic X-ray scattering

Utilizing resonant inelastic x-ray scattering, we report a previously unobserved mode in the excitation spectrum of La2-xSrxCuO4 and Nd2CuO4 at 500 meV. The mode is peaked around the (pi, 0) point in reciprocal space and is observed to soften, and broaden, away from this point. Samples with x=0, 0.01, 0.05, and 0.17 were studied. The new mode is found to be rapidly suppressed with increasing Sr content and is absent at x=0.17, where it is replaced by a continuum of excitations. This mode is only observed when the incident x-ray polarization is normal to the CuO planes.

Spinal cord infarction following endoscopic variceal ligation

STUDY DESIGN

A case report of spinal cord infarction following endoscopic variceal ligation.

OBJECTIVES

To describe an exceedingly rare case of spinal cord infarction following endoscopic variceal ligation.

SETTING

Department of Orthopaedic Surgery, Kagoshima, Japan.

METHODS

A 75-year-old woman with cirrhosis caused by hepatitis C virus, who was admitted to our hospital for the treatment of esophageal varices, experienced numbness of the hands and lower extremities bilaterally following an endoscopic variceal ligation procedure. Sensory and motor dysfunction below C6 level progressed rapidly, resulting in inability to move the lower extremities the following day. Magnetic resonance imaging of the spine revealed abnormal spinal cord signal on T2-weighted images from approximately C6 through T5 levels, which was diagnosed as spinal cord infarction.

RESULTS

The patient underwent hyperbaric oxygen treatment. Her symptoms and signs related to spinal cord infarction gradually remitted, and nearly complete disappearance of neurological deficits was noted within 3 months after the start of treatment.

CONCLUSION

We speculate that the pathogenesis of the present case may have involved congestion of the abdominal-epidural-spinal cord venous network owing to ligation of esophageal varices and increased thoracoabdominal cavity pressure.

Microscopic annealing process and its impact on superconductivity in T'-structure electron-doped copper oxides

High-transition-temperature superconductivity arises in copper oxides when holes or electrons are doped into the CuO(2) planes of their insulating parent compounds. Whereas hole doping quickly induces metallic behaviour and superconductivity in many cuprates, electron doping alone is insufficient in materials such as R(2)CuO(4) (R is Nd, Pr, La, Ce and so on), where it is necessary to anneal an as-grown sample in a low-oxygen environment to remove a tiny amount of oxygen in order to induce superconductivity. Here we show that the microscopic process of oxygen reduction repairs Cu deficiencies in the as-grown materials and creates oxygen vacancies in the stoichiometric CuO(2) planes, effectively reducing disorder and providing itinerant carriers for superconductivity. The resolution of this long-standing materials issue suggests that the fundamental mechanism for superconductivity is the same for electron- and hole-doped copper oxides.

Hypoplasia of the atlas causing cervical myelopathy with situs inversus totalis

STUDY DESIGN

A case report of myelopathic hypoplasia of the atlas with situs inversus totalis.

OBJECTIVES

To describe a case of cervical myelopathy caused by hypoplasia of the atlas with situs inversus totalis, and to briefly review the pertinent literature.

SETTING

Department of Orthopaedic Surgery, Kagoshima, Japan.

METHODS

The history, results of examination, and findings of radiographic imaging studies for a 56-year-old man with a 10-year history of progressive myelopathy who presented to our hospital are described.

RESULTS

Imaging studies revealed congenital hypoplasia of the atlas, ossification of the posterior longitudinal ligament at the levels of C3-C4, and situs inversus totalis. He underwent laminectomy of the atlas and laminoplasty of C3-C7 for decompression of the spinal cord. Operative intervention resulted in significant neurological improvement and relief of occipital neuralgia.

CONCLUSION

To our knowledge, no case of myelopathic hypoplasia of the atlas with situs inversus totalis has previously been described. When encountering inherited disorders such as situs inversus totalis, a thorough search must be made for anomalies of the craniovertebral junction.

Constituents of the quasiparticle spectrum along the nodal direction of high-Tc cuprates

Applying the Kramers-Kronig consistent procedure, developed earlier, we investigate in detail the formation of the quasiparticle spectrum along the nodal direction of high-Tc cuprates. The heavily discussed "70 meV kink" on the renormalized dispersion exhibits a strong temperature and doping dependence when purified from structural effects such as bilayer splitting, diffraction replicas, etc. This dependence is well understood in terms of fermionic and bosonic constituents of the self-energy. The latter follows the evolution of the spin-fluctuation spectrum, emerging below some doping dependent temperature and sharpening below Tc, and is mainly responsible for the formation of the kink in question.

High-energy spin excitations in the electron-doped superconductor Pr(0.88)LaCe(0.12)CuO(4-delta) with T(c) = 21 K

We use high-resolution inelastic neutron scattering to study the low-temperature magnetic excitations of the electron-doping superconductor Pr(0.88)LaCe(0.12)CuO(4-delta) (T(c) = 21 +/- 1 K) over a wide energy range (4 meV < or = homega < or = 330 meV). The effect of electron doping is to cause a wave vector (Q) broadening in the low-energy (homega < or = 80 meV) commensurate spin fluctuations at (0.5, 0.5) and to suppress the intensity of spin-wave-like excitations at high energies (homega > or = 100 meV). This leads to a substantial redistribution in the spectrum of the local dynamical spin susceptibility chi''(omega), and reveals a new energy scale similar to that of the lightly hole-doped YB2Cu3O(6.353) (T(c) = 18 K).

Electronic inhomogeneity and breakdown of the universal thermal conductivity of cuprate superconductors

We report systematic, high-precision measurements of the low-T (down to 70 mK) thermal conductivity kappa of YBa2Cu3O(y), La(2-x)Sr(x)CuO4, and Bi2Sr2CaCu2O(8+delta). Careful examinations of the Zn- and hole-doping dependences of the residual thermal conductivity kappa0/T, as well as the in-plane anisotropy of kappa0/T in Bi2Sr2CaCu2O(8+delta), indicate a breakdown of the universal thermal conductivity, a notable theoretical prediction for d-wave superconductors. Our results point to an important role of electronic inhomogeneities, which are not considered in the standard perturbation theory for thermal conductivity, in the underdoped to optimally doped regime.

An efficient construction of conditionally replicating adenoviruses that target tumor cells with multiple factors

Despite the enormous potential of conditionally replicating adenoviruses (CRAs), the time-consuming and laborious methods required to construct CRAs have hampered both the development of CRAs that can specifically target tumors with multiple factors (m-CRA) and the efficient analysis of diverse candidate CRAs. Here, we present a novel method for efficiently constructing diverse m-CRAs. Elements involving viral replication, therapeutic genes, and adenoviral backbones were separately introduced into three plasmids of P1, P2, and P3, respectively, which comprised different antibiotic resistant genes, different ori, and a single loxP (H) sequence. Independently constructed plasmids were combined at 100% accuracy by transformation with originally prepared Cre and specific antibiotics in specific Escherichia coli; transfection of the resulting P1+2+3 plasmids into 293 cells efficiently generated m-CRAs. Moreover, the simultaneous generation of diverse m-CRAs was achieved at 100% accuracy by handling diverse types of P1+2 and P3. Alternatively, co-transfection of P1+3 and P2 plasmids into Cre-expressing 293 cells directly generated m-CRA with therapeutic genes. Thus, our three-plasmid system, which allows unrestricted construction and efficient fusion of individual elements, should expedite the process of generating, modifying, and testing diverse m-CRAs for the development of the ideal m-CRA for tumor therapy.

Delayed segmental motor paralysis following laminoplasty: two case reports

STUDY DESIGN

Two patients who experienced the onset of segmental motor paralysis several years after laminoplasty are presented.

OBJECTIVES

To discuss the mechanism of development of delayed segmental motor paralysis following laminoplasty.

SETTING

A department of orthopaedic surgery in Japan.

METHODS

One patient experienced motor weakness in his deltoid and biceps muscles on the left side 5 years after laminoplasty. The other patient noticed motor weakness in his deltoid and biceps on the right side 7 years after laminoplasty. CT myelography revealed posterior spur formation and hypertrophic facet joints on the hinged side at the C4-C5 level in both patients.

RESULTS

Posterior foraminotomy was performed at the C4-C5 level on the hinged side in both patients. Postoperatively, motor weakness in the deltoid and biceps muscles was improved in both patients.

CONCLUSIONS

Although spondylotic changes, including spur formation and disc herniation, have occasionally developed in operated segments after laminoplasty, few patients have required additional surgery for treatment of relapse of neurological deficits. It has been believed that spinal cord is rarely compressed by the spondylotic changes since it shifts posteriorly in the enlarged spinal canal. However, laminoplasty disturbs the facet joints since the medial portion of dorsal cortex and cancellous bone in facet joints is drilled out to make a trough. Facet joints disturbed in this fashion undergo degeneration over time after surgery. Nerve roots may occasionally be compressed by degenerated facet joints and spurs that have developed at the entrance of root canal, resulting in segmental motor paralysis several years after laminoplasty. Careful long-term observation is necessary after this procedure.

Multiple bosonic mode coupling in the electron self-energy of (La2-xSrx)CuO4

High resolution angle-resolved photoemission spectroscopy data along the (0,0)-(pi,pi) nodal direction with significantly improved statistics reveal fine structure in the electron self-energy of the underdoped (La2-xSrx)CuO4 samples in the normal state. Fine structure at energies of (40-46) meV and (58-63) meV, and possible fine structure at energies of (23-29) meV and (75-85) meV, have been identified. These observations indicate that, in (La2-xSrx)CuO4, more than one bosonic modes are involved in the coupling with electrons.

Magic doping fractions for high-temperature superconductors

We report hole-doping dependence of the in-plane resistivity rho(ab) in a cuprate superconductor La(2-x)Sr(x)CuO4, carefully examined using a series of high-quality single crystals. Our detailed measurements find a tendency towards charge ordering at particular rational hole-doping fractions of 1/16, 3/32, 1/8, and 3/16. This observation appears to suggest a specific form of charge order and is most consistent with the recent theoretical prediction of the checkerboard-type ordering of the Cooper pairs at rational doping fractions x = (2m+1)/2n, with integers m and n.

Electronic phase diagram of high-Tc cuprate superconductors from a mapping of the in-plane resistivity curvature

We propose that resistivity curvature mapping (RCM) based on the in-plane resistivity data is a useful way to objectively draw electronic phase diagrams of high-Tc cuprates, where various crossovers are important. In particular, the pseudogap crossover line can be conveniently determined by RCM. We show experimental phase diagrams obtained by RCM for Bi2Sr2-zLazCuO6+delta, La2-xSrxCuO4, and YBa2Cu3Oy, and demonstrate the universal nature of the pseudogap crossover. Intriguingly, the electronic crossover near optimum doping depicted by RCM appears to occur rather abruptly, suggesting that the quantum-critical regime, if it exists, must be very narrow.

Increased expression of humanin peptide in diffuse-type pigmented villonodular synovitis: implication of its mitochondrial abnormality

OBJECTIVES

To define the pathogenesis of pigmented villonodular synovitis (PVNS), by searching for highly expressed genes in primary synovial cells from patients with PVNS.

METHODS

A combination of subtraction cloning and Southern colony hybridisation was used to detect highly expressed genes in PVNS in comparison with rheumatoid synovial cells. Northern hybridisation was performed to confirm the differential expression of the humanin gene in PVNS. Expression of the humanin peptide was analysed by western blotting and immunohistochemistry. Electron microscopic immunohistochemistry was performed to investigate the distribution of this peptide within the cell.

RESULTS

68 highly expressed genes were identified in PVNS. Humanin genes were strongly expressed in diffuse-type PVNS, but were barely detected in nodular-type PVNS, rheumatoid arthritis, or osteoarthritis. Humanin peptide was identified in synovium from diffuse-type PVNS, and most of the positive cells were distributed in the deep layer of the synovial tissue. Double staining with anti-humanin and anti-heat shock protein 60 showed that humanin was expressed mainly in mitochondria. Electron microscopy disclosed immunolocalisation of this peptide, predominantly around dense iron deposits within the siderosome.

CONCLUSIONS

Increased expression of the humanin peptide in mitochondria and siderosomes is characteristic of synovial cells from diffuse-type PVNS. Humanin is an anti-apoptotic peptide which is encoded in the mitochondrial genome. Present findings suggest that mitochondrial dysfunction may be the principal factor in pathogenesis of diffuse-type PVNS and that humanin peptide may play a part in the neoplastic process in this form of PVNS.

A universal scaling relation in high-temperature superconductors

Since the discovery of superconductivity at elevated temperatures in the copper oxide materials there has been a considerable effort to find universal trends and correlations amongst physical quantities, as a clue to the origin of the superconductivity. One of the earliest patterns that emerged was the linear scaling of the superfluid density (rho(s)) with the superconducting transition temperature (T(c)), which marks the onset of phase coherence. This is referred to as the Uemura relation, and it works reasonably well for the underdoped materials. It does not, however, describe optimally doped (where T(c) is a maximum) or overdoped materials. Similarly, an attempt to scale the superfluid density with the d.c. conductivity (sigma(dc)) was only partially successful. Here we report a simple scaling relation (rho(s) proportional, variant sigma(dc)T(c), with sigma(dc) measured at approximately T(c)) that holds for all tested high-T(c) materials. It holds regardless of doping level, nature of dopant (electrons versus holes), crystal structure and type of disorder, and direction (parallel or perpendicular to the copper-oxygen planes).

Magnetic order in lightly doped La2-xSrxCuO4

We study long wavelength magnetic excitations in lightly doped La2-xSrxCuO4 (x</=0.03) detwinned crystals. The lowest energy magnetic anisotropy induced gap can be understood in terms of the antisymmetric spin interaction inside the antiferromagnetic (AF) phase. The second magnetic resonance, analyzed in terms of in-plane spin anisotropy, shows unconventional behavior within the AF state; it led to the discovery of collective spin excitations pertaining to a field induced magnetically ordered state. This state persists in a 9 T field to more than 100 K above the Néel temperature in x=0.01.

Spin-flop transition and the anisotropic magnetoresistance of Pr(1.3-x)La(0.7)CexCuO4: unexpectedly strong spin-charge coupling in the electron-doped cuprates

We use transport and neutron-scattering measurements to show that a magnetic-field-induced transition from noncollinear to collinear spin arrangement in adjacent CuO2 planes of lightly electron-doped Pr(1.3-x)La(0.7)CexCuO4 (x=0.01) crystals affects significantly both the in-plane and out-of-plane resistivity. In the high-field collinear state, the magnetoresistance (MR) does not saturate but exhibits an intriguing fourfold-symmetric angular dependence, oscillating from being positive at B//[100] to being negative at B//[110]. The observed MR of more than 30% at low temperatures induced by a modest modification of the spin structure indicates an unexpectedly strong spin-charge coupling in electron-doped cuprates.

Evolution of the Hall coefficient and the peculiar electronic structure of the cuprate superconductors

Although the Hall coefficient R(H) is an informative transport property of metals and semiconductors, its meaning in the cuprate superconductors has been ambiguous because of its unusual characteristics. Here we show that a systematic study of R(H) in La2-xSrxCuO4 single crystals over a wide doping range establishes a qualitative understanding of its peculiar evolution, which turns out to reflect a two-component nature of the electronic structure caused by an unusual development of the Fermi surface recently uncovered by photoemission experiments.

Primary malignant peripheral nerve sheath tumor of the cauda equina in a child case report

STUDY DESIGN

A case report of primary malignant peripheral nerve sheath tumor (MPNST) of the cauda equina in a child is presented, and the literature is reviewed.

OBJECTIVE

To discuss the problems involved in the treatment of primary intradural MPNSTs.

SETTING

A department of orthopaedic surgery in Japan.

METHODS

A 4-year-old boy complained of low-back pain radiating to the left calf. MRI revealed an intradural tumor at L3-L5 level. Following laminectomy of L3, L4 and L5, the tumor was removed en bloc. Based on pathological and immunohistological findings, the tumor was diagnosed as an MPNST.

RESULTS

Although adjuvant chemotherapy was administered local recurrence and cerebral and spinal metastases of the tumor were found 6 months after the operation. Following additional incomplete removal of the recurrent tumor, radiation therapy was administered. Although recurrent and metastatic tumors disappeared or diminished in size by radiation, tumors increased in size thereafter, despite additional adjuvant chemotherapy. At 21 months after the first operation, he died of pneumonia.

CONCLUSIONS

Reported clinical outcomes for patients with primary intradural MPNST are very poor. Although no gold standard for the treatment of tumors has been established yet, surgical removal of tumors combined with postoperative high-dose radiation may be recommended.

Thermal conductivity of Pr1.3-xLa0.7CexCuO4 single crystals and signatures of stripes in an electron-doped cuprate

It was recently demonstrated that the anisotropic phonon heat transport behavior is a good probe of the stripe formation in La(2-x)Sr(x)CuO(4) (LSCO) [Phys. Rev. B 67, 104503 (2003)]]. Using this probe, we examined an electron-doped cuprate Pr(1.3-x)La(0.7)Ce(x)CuO(4) (PLCCO) and found that essentially the same features as those in LSCO are observed. Moreover, the in-plane resistivity rho(ab) of lightly doped PLCCO shows metallic behavior (drho(ab)/dT>0) in the Néel ordered state with a mobility comparable to that in LSCO. It is discussed that these peculiar properties in common with LSCO signify the existence of stripes in electron-doped cuprates.

LY309887, antifolate via the folate receptor suppresses murine type II collagen-induced arthritis

OBJECTIVE

To examine the effect of LY309887, an inhibitor of glycinamide ribonucleotide formyltransferase in de novo purine biosynthesis on murine type collagen-induced arthritis (CIA).

METHODS

CIA was induced by immunization with bovine type II collagen in adjuvant. The expression of folate receptors was examined in dissected synovial tissues and bone marrow cells from arthritic and non-arthritic mice by the semi-quantitative reverse transcription-polymerase chain reaction. LY309887 was administered to CIA mice after the onset of arthritis. Mice were monitored for arthritis index for 21 days. Levels of IgG1 and IgG2a antibodies against bovine type II collagen were measured in sera from CIA mice with or without LY309887 treatment by the enzyme-linked immunosorbent assay. Histologic analyse were also performed in synovial tissues from arthritic joints with or without LY309887 treatment.

RESULTS

Levels of mRNA of folate receptor beta (FR-beta) were elevated in arthritic joints from CIA mice, compared with those in nonarthritic joints. The expression of mRNA of FR-beta was dominant in bone marrow cells of CIA mice. The administration of LY309887 suppressed the disease progression of CIA mice as defined by the lower arthritis index, and decreased production of serum IgG1 and IgG2a anti-type II collagen antibody, and the damage to cartilage or bone.

CONCLUSION

The administration of LY309887 was effective on CIA mice. It was suggested that LY309887 might be useful in the treatment of rheumatoid arthritis.

Josephson plasmon and inhomogeneous superconducting state in La2-xSrxCuO4

We report on the interlayer far infrared response for a series of La2-xSrxCuO4 crystals with 0.08<x<0.20 focusing on the survey of the Josephson plasmon resonance (JPR). The analysis of the JPR mode provides information on the local variation of the superfluid density within the CuO2 planes thus empowering one with a tool for "microscopy" on the superconducting condensate. Our results uncover the presence of regions with characteristic length of approximately 100-200 A within which superconductivity is strongly depressed or completely depleted. An examination of the doping trends suggests that development of superconducting inhomogeneities is triggered by the formation of the unidirectional spin density wave state in La2-xSrxCuO4 at x=1/8.

Anisotropic electromagnetic response of lightly doped La2-xSrxCuO4 within the CuO2 planes

Using infrared spectroscopy, we show that spin self-organization in untwinned La2-xSrxCuO4 (LSCO) crystals has profound consequences for the dynamical conductivity sigma(omega). The electronic response of CuO2 planes acquires significant anisotropy in the spin ordered state with enhancement of the conductivity along the direction of the diagonal spin stripes by up to a factor of 2. An examination of the anisotropic response indicates that the diagonal spin texture in weakly doped LSCO is also accompanied by the modulation of charge density. The electronic response of the charge stripes is found to be gapless consistent with the hypothesis of the metallic ground state. Our experiments directly show that the striped ordered systems reveal new degrees of freedom not present in ordinary one-dimensional conductors.

Anisotropic magnetoresistance in lightly doped La(2)-(x)Sr(x)CuO(4): impact of antiphase domain boundaries on the electron transport

Detailed behavior of the magnetoresistance (MR) is studied in lightly doped antiferromagnetic La(1.99)Sr(0.01)CuO(4), where, thanks to the weak-ferromagnetic moment due to spin canting, the antiferromagnetic (AF) domain structure can be manipulated by the magnetic field. The MR behavior demonstrates that CuO(2) planes indeed contain antiphase AF-domain boundaries in which charges are confined, forming antiphase stripes. The data suggest that a high magnetic field turns the antiphase stripes into in-phase stripes, and the latter appear to give better conduction than the former, which challenges the notion that the antiphase character of stripes facilitates charge motion.

Magnetic-field-induced localization of quasiparticles in underdoped La(2-x)SrxCuO4 single crystals

Magnetic-field-induced ordering of electrons around vortices is a striking phenomenon recently found in high-T(c) cuprates. To identify its consequence in the quasiparticle dynamics, the magnetic-field (H) dependence of the low-temperature thermal conductivity kappa of La(2-x)SrxCuO4 crystals is studied for a wide doping range. It is found that the behavior of kappa(H) in the subkelvin region changes drastically across optimum doping, and the data for underdoped samples are indicative of unusual magnetic-field-induced localization of quasiparticles; this localization phenomenon is probably responsible for the unusual "insulating normal state" under high magnetic fields.

Magnetic shape-memory effects in a crystal

Magnetic fields affect the motion of electrons and the orientation of spins in solids, but are thought to have little impact on crystal structure, particularly in compounds with low magnetic susceptibility, such as antiferromagnets. Here we describe an unexpected magnetic effect on crystal shape, in which the direction of the crystal's axes are swapped and the shape changes when a magnetic field is applied; this in turn induces curious memory effects in resistivity and magnetic susceptibility. Ironically, this phenomenon occurs in one of the most well-studied two-dimensional antiferromagnets, La(2-x)Sr(x)CuO(4).

Electromagnetic response of static and fluctuating stripes in cuprate superconductors

Using infrared spectroscopy, we found that changes in the in-plane charge dynamics attributable to static stripe order in La(1.275)Nd(0.6)Sr(0.125)CuO(4) or superconductivity in La(1.875)Sr(0.125)CuO(4) are confined to energies smaller than 100 cm(-1). An absorption peak in the low- omega conductivity of the Nd-doped compound is suggestive of localization effects due to the reduced dimensionality of static charge stripes. Neither superconductivity nor static stripe ordering has a noticeable effect on the depression of the scattering rate at omega<1000 cm(-1) characteristic of the pseudogap state in other classes of moderately doped cuprates.