Discovery of orbital ordering in Bi2Sr2CaCu2O8+x.

The primordial ingredient of cuprate superconductivity is the CuO2 unit cell. Theories usually concentrate on the intra-atom Coulombic interactions dominating the 3d9 and 3d10 configurations of each copper ion. However, if Coulombic interactions also occur between electrons of the 2p6 orbitals of each planar oxygen atom, spontaneous orbital ordering may split their energy levels. This long-predicted intra-unit-cell symmetry breaking should generate an orbitally ordered phase, for which the charge transfer energy ε separating the 2p6 and 3d10 orbitals is distinct for the two oxygen atoms. Here we introduce sublattice-resolved ε(r) imaging to CuO2 studies and discover intra-unit-cell rotational symmetry breaking of ε(r). Spatially, this state is arranged in disordered Ising domains of orthogonally oriented orbital order bounded by dopant ions, and within whose domain walls low-energy electronic quadrupolar two-level systems occur. Overall, these data reveal a Q = 0 orbitally ordered state that splits the oxygen energy levels by ~50 meV, in underdoped CuO2.

Differentiated roles of Lifshitz transition on thermodynamics and superconductivity in La2-xSrxCuO4.

The effect of Lifshitz transition on thermodynamics and superconductivity in hole-doped cuprates has been heavily debated but remains an open question. In particular, an observed peak of electronic specific heat is proposed to originate from fluctuations of a putative quantum critical point p* (e.g., the termination of pseudogap at zero temperature), which is close to but distinguishable from the Lifshitz transition in overdoped La-based cuprates where the Fermi surface transforms from hole-like to electron-like. Here we report an in situ angle-resolved photoemission spectroscopy study of three-dimensional Fermi surfaces in La2-xSrxCuO4 thin films (x = 0.06 to 0.35). With accurate kz dispersion quantification, the said Lifshitz transition is determined to happen within a finite range around x = 0.21. Normal state electronic specific heat, calculated from spectroscopy-derived band parameters, reveals a doping-dependent profile with a maximum at x = 0.21 that agrees with previous thermodynamic microcalorimetry measurements. The account of the specific heat maximum by underlying band structures excludes the need for additionally dominant contribution from the quantum fluctuations at p*. A d-wave superconducting gap smoothly across the Lifshitz transition demonstrates the insensitivity of superconductivity to the dramatic density of states enhancement.

Evidence for a vestigial nematic state in the cuprate pseudogap phase.

The CuO2 antiferromagnetic insulator is transformed by hole-doping into an exotic quantum fluid usually referred to as the pseudogap (PG) phase. Its defining characteristic is a strong suppression of the electronic density-of-states D(E) for energies |E| < [Formula: see text], where [Formula: see text] is the PG energy. Unanticipated broken-symmetry phases have been detected by a wide variety of techniques in the PG regime, most significantly a finite-Q density-wave (DW) state and a Q = 0 nematic (NE) state. Sublattice-phase-resolved imaging of electronic structure allows the doping and energy dependence of these distinct broken-symmetry states to be visualized simultaneously. Using this approach, we show that even though their reported ordering temperatures T DW and T NE are unrelated to each other, both the DW and NE states always exhibit their maximum spectral intensity at the same energy, and using independent measurements that this is the PG energy [Formula: see text] Moreover, no new energy-gap opening coincides with the appearance of the DW state (which should theoretically open an energy gap on the Fermi surface), while the observed PG opening coincides with the appearance of the NE state (which should theoretically be incapable of opening a Fermi-surface gap). We demonstrate how this perplexing phenomenology of thermal transitions and energy-gap opening at the breaking of two highly distinct symmetries may be understood as the natural consequence of a vestigial nematic state within the pseudogap phase of Bi2Sr2CaCu2O8.

Midterm outcomes after aortic valve neocuspidization with glutaraldehyde-treated autologous pericardium.

OBJECTIVE: We had previously reported the short-term results of the aortic valve neocuspidization (AVNeo) procedure. We have now evaluated the midterm results with the longest follow-up of 118 months. METHODS: From April 2007 through December 2015, 850 patients were treated with AVNeo using autologous pericardium. Medical records of these patients were retrospectively reviewed. The procedure was on the basis of independent tricuspid replacement using autologous pericardium. The distances between the commissures were measured with an original sizing device, the pericardial cusp was trimmed using an original template, and then sutured to the annulus. RESULTS: There were 534 patients with aortic stenosis, 254 with aortic regurgitation, 61 with aortic stenoregurgitation, 19 with infective endocarditis, and 5 with a previous aortic valve procedure. Besides 596 patients with tricuspid aortic valve, 224 patients had bicuspid valve, 28 had unicuspid valve, and 2 had quadricuspid valve. There were 444 male and 406 female patients. The median age was 71 (range, 13-90) years old. Preoperative echocardiography revealed a peak pressure gradient average of 68.9 ± 36.3 mm Hg with aortic stenosis. Surgical annular diameter was 20.9 ± 3.3 mm. There was no conversion to a prosthetic valve replacement. There were 16 in-hospital mortalities. Postoperative echocardiography revealed a peak pressure gradient average of 19.5 ± 10.3 mm Hg 1 week after surgery and 15.2 ± 6.3 mm Hg 8 years after surgery. Fifteen patients needed reoperation (13 infective endocarditis, 1 break of thread, and 1 tear of cusp case). The mean follow-up period was 53.7 ± 28.2 months. Actuarial freedom from death, cumulative incidence of reoperation, and that of recurrent moderate aortic regurgitation or greater was 85.9%, 4.2%, and 7.3%, respectively, with the longest follow-up of 118 months. CONCLUSIONS: The midterm outcomes of AVNeo using autologous pericardium were satisfactory in 850 patients with various aortic valve diseases. However, further randomized, multicenter prospective studies are needed to confirm the results of the current study.

Antiferroic electronic structure in the nonmagnetic superconducting state of the iron-based superconductors.

A major problem in the field of high-transition temperature (Tc) superconductivity is the identification of the electronic instabilities near superconductivity. It is known that the iron-based superconductors exhibit antiferromagnetic order, which competes with the superconductivity. However, in the nonmagnetic state, there are many aspects of the electronic instabilities that remain unclarified, as represented by the orbital instability and several in-plane anisotropic physical properties. We report a new aspect of the electronic state of the optimally doped iron-based superconductors by using high-energy resolution angle-resolved photoemission spectroscopy. We find spectral evidence for the folded electronic structure suggestive of an antiferroic electronic instability, coexisting with the superconductivity in the nonmagnetic state of Ba1-x K x Fe2As2. We further establish a phase diagram showing that the antiferroic electronic structure persists in a large portion of the nonmagnetic phase covering the superconducting dome. These results motivate consideration of a key unknown electronic instability, which is necessary for the achievement of high-Tc superconductivity in the iron-based superconductors.

Commensurate 4a0-period charge density modulations throughout the Bi2Sr2CaCu2O8+x pseudogap regime.

Theories based upon strong real space (r-space) electron-electron interactions have long predicted that unidirectional charge density modulations (CDMs) with four-unit-cell (4a0) periodicity should occur in the hole-doped cuprate Mott insulator (MI). Experimentally, however, increasing the hole density p is reported to cause the conventionally defined wavevector QA of the CDM to evolve continuously as if driven primarily by momentum-space (k-space) effects. Here we introduce phase-resolved electronic structure visualization for determination of the cuprate CDM wavevector. Remarkably, this technique reveals a virtually doping-independent locking of the local CDM wavevector at [Formula: see text] throughout the underdoped phase diagram of the canonical cuprate Bi2Sr2CaCu2O8 These observations have significant fundamental consequences because they are orthogonal to a k-space (Fermi-surface)-based picture of the cuprate CDMs but are consistent with strong-coupling r-space-based theories. Our findings imply that it is the latter that provides the intrinsic organizational principle for the cuprate CDM state.

The adenosine A2A receptor antagonist, istradefylline enhances anti-parkinsonian activity induced by combined treatment with low doses of L-DOPA and dopamine agonists in MPTP-treated common marmosets.

The adenosine A2A receptor antagonist, istradefylline improves motor function in patients with advanced Parkinson's disease (PD) optimally treated with a combination of L-DOPA and a dopamine agonist without increasing the risk of troublesome dyskinesia. However, the effects of istradefylline on motor function when administered in combination with low dose of L-DOPA and dopamine agonists as occurs in early PD are unknown. We investigated whether istradefylline enhances the combined anti-parkinsonian effects of a suboptimal dose of L-DOPA and a threshold dose of either the non-ergot dopamine agonist, ropinirole or the ergot dopamine agonist, pergolide in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated common marmoset. Threshold doses of ropinirole (0.025-0.075 mg/kg p.o.) and pergolide (0.01 mg/kg p.o.) produced a weak anti-parkinsonian effect. Co-administration of a suboptimal dose of L-DOPA (2.5mg/kg p.o.) with threshold doses of the dopamine agonists enhanced their anti-parkinsonian effect that led to increased 'ON' time without dyskinesia appearing. Administering istradefylline (10mg/kg p.o.) with the threshold doses of dopamine agonists and the suboptimal dose of L-DOPA in a triple combination caused a further enhancement of the anti-parkinsonian response but dyskinesia was still absent. In early PD, dopamine agonists are often used as first-line monotherapy, but efficacy is usually lost within a few years, at which time L-DOPA is added but with the risk of dyskinesia appearance. These results show that istradefylline is effective in improving motor function in combination with low dose dopaminergic drug treatment without provoking dyskinesia.

Aortic Valve Reconstruction Using Autologous Pericardium for Aortic Stenosis.

BACKGROUND: To determine the feasibility of original aortic valve reconstruction (AVRec) for patients with aortic stenosis (AS), 416 consecutive cases were reviewed. METHODS AND RESULTS: AVRecs for AS were performed for 416 patients from April 2007 through April 2013. All 416 patients were retrospectively reviewed. One hundred and fourteen patients had bicuspid valves and 16 had unicuspid valves. There were 182 men and 234 women. Mean age was 71.2±12.0 years old. On preoperative echocardiography, peak pressure gradient averaged 79.0±33.6 mmHg. Surgical annular diameter was 20.1±2.8 mm. The procedure is based on independent tricuspid replacement by autologous pericardium using original sizing apparatus and template. There was no conversion to prosthetic valve replacement. There were 8 in-hospital mortalities due to non-cardiac cause. On postoperative echocardiography, peak pressure gradient averaged 21.2±10.7 mmHg 1 week after surgery and 14.3±5.0 mmHg 5.5 years after surgery. Four reoperations were done for infective endocarditis. The other 412 patients had less than mild regurgitation. No thrombo-embolic events were recorded. The mean follow-up period was 25.2±17.5 months. Freedom from reoperation was 96.7% with 73-month follow-up. CONCLUSIONS: Medium-term results were excellent. Original AVRec was feasible for the patients with AS. Long-term data will be presented in the future.

The adenosine A2A receptor antagonist, istradefylline enhances the anti-parkinsonian activity of low doses of dopamine agonists in MPTP-treated common marmosets.

The adenosine A2A receptor antagonist, istradefylline, enhances anti-parkinsonian activity in patients with advanced Parkinson׳s disease (PD) already treated with combinations of L-DOPA and dopamine agonist drugs but who are still exhibiting prolonged 'OFF' periods. In contrast, the effects of istradefylline on motor function when administered in combination with low dose dopamine agonist therapy in early PD are unknown. We now investigate whether istradefylline administered with a threshold dose of either the non-ergot dopamine agonist, ropinirole or the ergot dopamine agonist, pergolide enhances anti-parkinsonian activity in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated common marmoset. Both ropinirole (0.01-0.1mg/kg p.o.) and pergolide (0.003-0.1mg/kg p.o.) administered alone produced dose dependent increases in locomotor activity, a reduction in motor disability. Threshold doses of ropinirole (0.025-0.075mg/kg p.o.) and pergolide (0.01-0.075mg/kg p.o.) were then selected that in individual animals caused a small but non-significant anti-parkinsonian effect. Administration of istradefylline (10mg/kg p.o.) alone resulted in a decrease in motor disability and increase in 'ON' time but dyskinesia was not observed. Combined administration of pergolide or ropinirole with istradefylline resulted in an increase in the reversal of motor disability and increase in 'ON' time compared to that produced by either treatment alone but dyskinesia was still not observed. These results show that istradefylline is effective in improving motor function when combined with low dose dopamine agonist treatment. In early PD, this may avoid dose escalation or allow a reduction in dopamine agonist dosage without a loss of efficacy and prevent dopaminergic side-effects from becoming treatment limiting.

Clinical/pharmacological aspect of adenosine A2A receptor antagonist for dyskinesia.

Dopamine replacement therapy using the dopamine precursor, l-3,4-dihydroxyphenylalanine (l-DOPA), with a peripheral dopa decarboxylase inhibitor is the most effective treatment currently available for the symptoms of Parkinson's disease (PD). However, the long-term use of dopaminergic therapies for PD is often limited by the development of motor response complications, such as dyskinesia. Adenosine A2A receptors are a promising nondopaminergic target for the treatment of PD. The treatment of motor response complications involves combinations of regular and controlled release L-DOPA, perhaps with the addition of a COMT inhibitor or the use of a longer-acting dopamine agonist. However, when dyskinesia is already established, the increase in dopaminergic load produced by the addition of a dopamine agonist can result in an increase in the severity and duration of dyskinesia. Currently, there are no well-tolerated antidyskinesia agents available. Amantadine, which may exert its effects through the inhibition of N-methyl-D-aspartate (NMDA) receptors, shows some effects on established dyskinesia. Dyskinesia has a negative impact on the quality of life of patients, sometimes being more disabling than PD itself. Although some patients prefer experiencing dyskinesia than being in the OFF state and unable to move, alternative, more effective therapies are still required for severe disabling dyskinesia to afford patients an improved quality of life while in the ON state. The mechanisms causing and maintaining the dyskinesia have not been clarified. The application of a nondopaminergic approach to modify the basal ganglial activity would be helpful to better understand and treat dyskinesia. The use of an adenosine A2A receptor may provide one such approach. In this literature review, we will summarize the current knowledge from both clinical and nonclinical studies on the effects of adenosine A2A receptor blockade on dyskinesia.

Effects of the adenosine A2A receptor antagonist on cognitive dysfunction in Parkinson's disease.

Parkinson's disease (PD) is primarily characterized by motor abnormalities, but cognitive changes also occur in the early and late stages of the disease process. In PD patients, cognitive dysfunction is associated with reduced quality of life, as well as increased morbidity and mortality, resulting in increases in caregiver burden, and health-related costs. Therefore, safe and effective approaches are needed to treat cognitive dysfunction in PD patients. The underlying pathophysiology of cognitive dysfunction is complex and not fully understood, however. α-Synuclein, amyloid-related proteins, and cholinergic deficits have been reported to partially contribute to cognitive dysfunction. Changes in cortical dopamine (DA) content may also be responsible for early cognitive changes in patients with PD. Certainly, dopaminergic afferents to the frontal cortex degenerate in PD, and there is a reduction of DA content in the prefrontal cortex (PFC). It has also been reported that PFC dopaminergic input plays an important role in working memory performance. Moreover, PFC DA levels and working memory performance are significantly reduced by a 6-hydroxydopamine lesion in the PFC of a rat. Recent findings in the areas of pharmacological manipulation and genetic ablation suggest that the adenosine A2A receptor is also related to cognitive functions, especially working memory. In addition, the blockade of adenosine A2A receptors reverses cognitive dysfunction in PFC-lesioned rats, and this blocking effect may be due to an increase in PFC DA content. Therefore, adenosine A2A receptor antagonists not only improve motor performance, but they may also lead to improved cognitive function in those with PD.

Direct phase-sensitive identification of a d-form factor density wave in underdoped cuprates.

The identity of the fundamental broken symmetry (if any) in the underdoped cuprates is unresolved. However, evidence has been accumulating that this state may be an unconventional density wave. Here we carry out site-specific measurements within each CuO2 unit cell, segregating the results into three separate electronic structure images containing only the Cu sites [Cu(r)] and only the x/y axis O sites [Ox(r) and O(y)(r)]. Phase-resolved Fourier analysis reveals directly that the modulations in the O(x)(r) and O(y)(r) sublattice images consistently exhibit a relative phase of π. We confirm this discovery on two highly distinct cuprate compounds, ruling out tunnel matrix-element and materials-specific systematics. These observations demonstrate by direct sublattice phase-resolved visualization that the density wave found in underdoped cuprates consists of modulations of the intraunit-cell states that exhibit a predominantly d-symmetry form factor.

Ovary hyperstimulation syndrome accompanying molar pregnancy: case report and review of the literature.

PURPOSE: To describe a naturally conceived woman with ovary hyperstimulation syndrome (OHSS) accompanying molar pregnancy and review the literature on this condition. METHODS: We report a 31-year-old 2 parous naturally conceived woman with OHSS accompanying partial molar pregnancy. Dilatation and evacuation (D&E) were performed at 10 weeks of gestation. The signs and symptoms of OHSS were the severest on day 8 after D&E, when hCG had already decreased. This case is reported in detail. We also review the literature. RESULTS: A literature search yielded seven cases of this condition. Any type of molar pregnancy, i.e., complete, partial, or invasive, can accompany OHSS. The initial manifestation of OHSS occurred at a median of the 12th week of gestation (range 7-16), which may be later compared with OHSS caused by ovulation induction. In all cases, OHSS aggravated after D&E. CONCLUSIONS: We must be aware that OHSS can occur during molar pregnancy, and can be exacerbated after D&E.

Adenosine A2A-receptor antagonist istradefylline enhances the motor response of L-DOPA without worsening dyskinesia in MPTP-treated common marmosets.

The adenosine A2A-receptor antagonist istradefylline decreases OFF time in patients with Parkinson's disease who are already treated with optimal doses of dopaminergic medication but can cause an increase in non-troublesome dyskinesia. Preclinical experiments have shown that A2A antagonists are most effective in potentiating motor function when combined with sub-maximal doses of L-DOPA. However, the effects of combining istradefylline with sub-optimal L-DOPA treatment on established dyskinesia have not been studied. We now examine the effects of acute and repeated administration of istradefylline on dyskinesia in MPTP-treated common marmosets previously primed to exhibit involuntary movements by prior exposure to L-DOPA. In these animals, single dose acute oral administration of istradefylline (10 mg/kg) enhanced and prolonged the anti-parkinsonian effects of a sub-optimal dose of L-DOPA (2.5 mg/kg). The chronic co-administration of istradefylline (10 mg/kg) with L-DOPA (2.5 mg/kg) for 21 days did not worsen the severity of existing dyskinesia. Rather, the severity of dyskinesia tended to be reduced over the 21-day treatment period. These results suggest that istradefylline can be used to potentiate the effects of sub-optimal doses of L-DOPA in the treatment of Parkinson's disease without causing or worsening dyskinesia.

Aortic valve reconstruction using autologous pericardium for ages over 80 years.

BACKGROUND: We performed original aortic valve reconstruction using autologous pericardium; the feasibility for elderly patients is reviewed. METHODS: From April 2007 through September 2011, aortic valve reconstruction was carried out in 86 patients over the age of 80 years. Twenty-seven patients were male and 59 were female. Mean age was 82.9 ± 2.5 years. Seventy-two patients had aortic stenosis and 14 had aortic regurgitation. Mean preoperative surgical annular diameter was 19.5 ± 2.5 mm. There were 80 (90.7%) cases of small aortic annulus. Mean preoperative logistic EuroSCORE was 22.9 ± 15.8. RESULTS: Isolated aortic valve reconstructions were performed in 51 patients. Concomitant procedures included coronary artery bypass grafting in 6, hemiarch aortic replacements in 6, 9 maze procedures, and some combinations. No conversion to valve replacement was required. Mean follow-up was 1243 days. There were 3 hospital deaths due to noncardiac causes. No reoperation was needed. Survival at 56 months was 87.0%. No thromboembolic event occurred. Echocardiography 3.5 years after surgery revealed an average peak pressure gradient of 14.6 ± 3.8 mm Hg. No moderate or severe regurgitation was recorded. CONCLUSIONS: Aortic valve reconstruction is feasible for patients older than 80 years, resulting in good hemodynamics and a better quality of life, without anticoagulation.

Reconstruction of bicuspid aortic valve with autologous pericardium--usefulness of tricuspidization.

BACKGROUND: This study describes the surgical treatment of bicuspid aortic valve with original aortic valve reconstruction. METHODS AND RESULTS: Aortic valve reconstruction was done in 102 patients with bicuspid aortic valve from April 2007 through September 2011. Thirty-four patients with ascending aortic diameter >45 mm underwent hemi-arch aortic replacement concomitantly. Seventy-seven patients had aortic stenosis, and 25 had aortic regurgitation (AR). Mean age was 63.7±10.0 years old. There were 55 men and 47 women. Harvested pericardium is treated with 0.6% glutaraldehyde solution. The distance between commissures is measured with an original sizing instrument. For bicuspid valve with raphe, the raphe is considered as a commissure in order to measure the distance between each commissure. Without a raphe, we create a new annular margin and commissure using coronary ostium and the sizing instrument as a guide. Then, pericardium is trimmed with original template. Three cusps are sutured independently. The preoperative averaged peak pressure gradient of 71.1±39.0 mmHg was decreased to 16.2±8.8, 13.3±6.0, and 13.9±5.6 mmHg, respectively 1 week, 1 year, and 3 years after operation. AR was trivial. One reoperation was recorded. Mean follow-up was 733 days. There were 5 late mortalities. No thromboembolic event was recorded. CONCLUSIONS: Medium-term results were excellent. Tricuspidization gave good opening and closure of aortic valve with excellent hemodynamics.

A total of 404 cases of aortic valve reconstruction with glutaraldehyde-treated autologous pericardium.

OBJECTIVE: To determine the feasibility of original aortic valve reconstruction, 404 consecutive cases were reviewed. The early results are reported here. METHODS: Aortic valve reconstruction was performed for 404 patients from April 2007 through September 2011. The results for all 404 patients were reviewed retrospectively. There were 289 patients with aortic stenosis and 115 patients with aortic regurgitation. One hundred two patients had bicuspid aortic valves, 13 patients had unicuspid valves, and 2 patients had quadricuspid valves. There were 201 males and 203 females. Mean age was 69.0 ± 12.9 years. Preoperative echocardiography revealed an average peak pressure gradient of 79.6 ± 32.5 mm Hg with aortic stenosis. Surgical annular diameter was 20.3 ± 3.2 mm. The surgical procedure is based on the independent tricuspid replacement by autologous pericardium. First, the distance between the commissure is measured with an original sizing apparatus, then the pericardial cusp is trimmed using an original template, and it is sutured to the annulus. RESULTS: There were no conversions to prosthetic valve replacement. There were 7 in-hospital mortalities resulting from a noncardiac cause. Postoperative echocardiography revealed an average peak pressure gradient of 19.8 ± 10.2 mm Hg 1 week after surgery and 13.8 ± 3.7 mm Hg 3.5 years after surgery. Two patients needed reoperation because of infective endocarditis. The other 402 patients showed less than mild aortic regurgitation. No thromboembolic events were recorded. The mean follow-up period was 23.7 ± 13.1 months. Freedom from reoperation was 96.2% at 53 months of follow-up. CONCLUSIONS: Original aortic valve reconstruction was feasible in patients with various aortic valve diseases. Long-term data will be disclosed in the future.

Aortic valve reconstruction with autologous pericardium for dialysis patients.

OBJECTIVES: This study aimed to report on original aortic valve reconstruction for patients on dialysis. METHODS: Aortic valve reconstruction has been performed on 404 cases from April 2007 through September 2011. Among them, 54 cases on haemodialysis were retrospectively studied. Forty-seven patients had aortic stenosis, 5 had aortic regurgitation (AR), and 2 had infective endocarditis. Mean age was 70.2 ± 8.5 years. There were 35 males and 19 females. There were 27 primary aortic valve reconstructions, 11 with CABG, 6 with ascending aortic replacement, 5 with mitral valve repair and 4 with maze. First, in the procedure, harvested pericardium was treated with 0.6% glutaraldehyde solution. After resecting the cusps, we measured the distance between commissures with original sizing instrument. Then, the pericardium was trimmed with the original template. Three cusps were sutured to each annulus. RESULTS: Peak pressure gradient averaged to 66.0 ± 28.2 mmHg preoperatively, and decreased to 23.4 ± 10.7, 13.8 ± 5.5 and 13.3 ± 2.3 mmHg, 1 week, 1 year, and 3 years after the operation, respectively. No calcification was detected with echocardiographic follow-up. Recurrence of AR was not recorded with the mean follow-up of 847 days except for 1 case reoperated on for infective endocarditis 2.5 years after the operation. Three hospital deaths were recorded due to non-cardiac causes. Other patients were in good condition. There was no thromboembolic event. CONCLUSIONS: Medium-term results are excellent. Since warfarin for dialysis patients becomes problematic, a postoperative warfarin-free status is desirable. Aortic valve reconstruction can provide patients with a better quality of life without warfarin.

Effect of doping on the magnetostructural ordered phase of iron arsenides: a comparative study of the resistivity anisotropy in doped BaFe2As2 with doping into three different sites.

To unravel the role of doping in iron-based superconductors, we investigated the in-plane resistivity of BaFe(2)As(2) doped at one of the three different lattice sites, Ba(Fe(1-x)Co(x))(2)As(2), BaFe(2)(As(1-x)P(x))(2), and Ba(1-x)K(x)Fe(2)As(2), focusing on the doping effect in the low-temperature antiferromagnetic/orthorhombic (AFO) phase. A major role of doping in the high-temperature paramagnetic/tetragonal (PT) phase is known to change the Fermi surface by supplying charge carriers or exerting chemical pressure. In the AFO phase, we found a clear correlation between the magnitude of the residual resistivity and the resistivity anisotropy. This indicates that the resistivity anisotropy originates from anisotropic impurity scattering due to dopant atoms. The magnitude of the residual resistivity was also found to be a parameter controlling the suppression rate of the AFO ordering temperature. Therefore, the dominant role of doping in the AFO phase is to introduce disorder to the system, distinct from that in the PT phase.

Aortic valve reconstruction of unicuspid aortic valve by tricuspidization using autologous pericardium.

BACKGROUND: Unicuspid aortic valve is a rare anatomic variant, but patients may require intervention for severe valve dysfunction at a young age. We introduce a new reconstructive technique for diseased unicuspid valve by tricuspidization with glutaraldehyde-treated autologous pericardium. METHODS: From April 2007 through January 2011, we performed 304 cases of aortic valve reconstruction using glutaraldehyde-treated autologous pericardium. During the same period, we encountered 9 patients with unicuspid aortic valve, including 8 male patients and 1 female patient. Mean age was 48.9±19.9 years (14-78 years). Two patients had aortic stenosis (AS), 1 had aortic regurgitation (AR), and 6 patients had both. Our original aortic valve reconstruction technique is characterized by the independent replacement of 3 leaflets with separate measurement of length between each commissure. In the case of a unicuspid aortic valve, we create a new commissure at a higher point along the raphe at the same level with the 1 normally existing commissure. RESULTS: No early mortality or major morbidity was recorded. Postoperative echocardiography showed trivial or no AR, with the peak pressure gradients averaging 10.6±3.3 mm Hg. One-year follow-up echocardiography revealed that the peak pressure gradients averaged 8.6±3.7 mm Hg, with trivial or no AR. The mean follow-up period was 551.1±51.4 days. All 9 patients are in good condition. No reoperation or any additional intervention has been necessary. CONCLUSIONS: Diseased unicuspid aortic valves were treated by our original aortic valve reconstruction technique with excellent early results. We continue to study the long-term results.