Period multiplication cascade at the order-by-disorder transition in uniaxial random field XY magnets.

Uniaxial random field disorder induces a spontaneous transverse magnetization in the XY model. Adding a rotating driving field, we find a critical point attached to the number of driving cycles needed to complete a limit cycle, the first discovery of this phenomenon in a magnetic system. Near the critical drive, time crystal behavior emerges, in which the period of the limit cycles becomes an integer n > 1 multiple of the driving period. The period n can be engineered via specific disorder patterns. Because n generically increases with system size, the resulting period multiplication cascade is reminiscent of that occurring in amorphous solids subject to oscillatory shear near the onset of plastic deformation, and of the period bifurcation cascade near the onset of chaos in nonlinear systems, suggesting it is part of a larger class of phenomena in transitions of dynamical systems. Applications include magnets, electron nematics, and quantum gases.

*The efficacy of the attachment-based SAFE® prevention program: a randomized control trial including mothers and fathers.

SAFE® is a primary prevention program to promote secure infant-parent attachment. SAFE explicitly addresses mothers and fathers. In this current first study, efficacy was assessed in a low-risk German sample using a randomized control trial with an active control intervention. A high rate of fathers' participation was achieved: in SAFE 84.6% and in the control group intervention 73.9% of the fathers participated. Infant-parent attachment was assessed at the end of the year-long programs. There was a significant difference between groups in terms of secure infant-father attachment, but not of infant-mother attachment. In SAFE, 84.6% of the infants were securely attached to their father (n = 39), in comparison to 65.8% in the control group (n = 38). The proportion of secure infant-mother attachment was 66.7% in the SAFE group (n = 54) and 64.0% in the control group (n = 50). The program was successful in promoting infant-father attachment security.

Trajectories of traumatic stress symptoms during conflict: A latent class growth analysis.

BACKGROUND: The ways in which traumatic stress symptoms unfold under situations of ongoing threat and trauma exposure are poorly understood. The current study aims to identify traumatic stress symptom trajectories during conflict, as well as potential risk factors. METHODS: Experience sampling methods were used to study traumatic stress symptoms during the 2014 Israel-Gaza conflict in 100 Israeli civilians exposed to rocket fire. Summary reports of traumatic symptoms were made twice-daily for 30 days via mobile phone. RESULTS: Latent class growth analysis revealed four distinct classes (low, reducing, moderate, and high) characterised by their trajectory of traumatic stress symptoms during the conflict. Female gender, not being in a relationship, and higher prior trauma exposure were identified as potential risk factors. LIMITATIONS: Data were not collected in the early phase of the conflict, the sample was relatively small, and only traumatic stress symptoms were investigated as outcomes. CONCLUSIONS: This study identified heterogeneous traumatic stress symptom trajectories among civilians during a conflict, with different subgroups showing distinct response patterns over time, associated with various risk factors. Investigating responses to ongoing trauma, and identifying predictors of different stress symptom trajectories has clinical implications for the targeted delivery of interventions. Further exploration of heterogeneous trajectories could potentially elucidate mechanisms that drive resilience and recovery, including in situations of ongoing exposure such as during conflict.

A mitochondrial HSP70 (HSPA9B) is linked to miltefosine resistance and stress response in Leishmania donovani.

BACKGROUND: Protozoan parasites of the genus Leishmania are responsible for leishmaniasis, a neglected tropical disease affecting millions worldwide. Visceral leishmaniasis (VL), caused by Leishmania donovani, is the most severe form of leishmaniasis with high rates of mortality if left untreated. Current treatments include pentavalent antimonials and amphotericin B. However, high toxicity and emergence of resistance hinder the success of these options. Miltefosine (HePC) is the first oral treatment available for leishmaniasis. While treatment with HePC has proven effective, higher tolerance to the drug has been observed, and experimental resistance is easily developed in an in vitro environment. Several studies, including ours, have revealed that HePC resistance has a multi-factorial origin and this work aims to shed light on this complex mechanism. METHODS: 2D-DIGE quantitative proteomics comparing the soluble proteomes of sensitive and HePC resistant L. donovani lines identified a protein of interest tentatively involved in drug resistance. To test this link, we employed a gain-of-function approach followed by mutagenesis analysis. Functional studies were complemented with flow cytometry to measure HePC incorporation and cell death. RESULTS: We identified a mitochondrial HSP70 (HSPA9B) downregulated in HePC-resistant L. donovani promastigotes. The overexpression of HSPA9B in WT lines confers an increased sensitivity to HePC, regardless of whether the expression is ectopic or integrative. Moreover, the increased sensitivity to HePC is specific to the HSPA9B overexpression since dominant negative mutant lines were able to restore HePC susceptibility to WT values. Interestingly, the augmented susceptibility to HePC did not correlate with an increased HePC uptake. Leishmania donovani promastigotes overexpressing HSPA9B were subjected to different environmental stimuli. Our data suggest that HSPA9B is capable of protecting cells from stressful conditions such as low pH and high temperature. This phenotype was further corroborated in axenic amastigotes overexpressing HSPA9B. CONCLUSIONS: The results from this study provide evidence to support the involvement of a mitochondrial HSP70 (HSPA9B) in experimental HePC resistance, a mechanism that is not yet fully understood, and reveal potential fundamental roles of HSPA9B in the biology of Leishmania. Overall, our findings are relevant for current and future antileishmanial chemotherapy strategies.

Erratum: Random Field Driven Spatial Complexity at the Mott Transition in VO_{2} [Phys. Rev. Lett. 116, 036401 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.116.036401.

Effectiveness of attachment based STEEP™ intervention in a German high-risk sample.

STEEP(TM) was one of the first attachment-based early intervention programs. The program applied findings from the Minnesota Longitudinal Study on Risk and Adaptation to the development of a supportive program for young high-risk mothers and their infants. STEEP's effectiveness was evaluated first in a randomized controlled study launched in 1987. The study showed effects of the one-year intervention on important individual and parenting variables, but not on quality of mother-infant attachment. In the current German study with young mothers at risk for abuse and neglect, a two-year adaptation of STEEP was evaluated within a quasi-experimental design. STEEP mother-infant pairs (N = 78) were compared with pairs who received standard services of the German Child Welfare System (GCWS, N = 29). Compared with GCWS pairs, significantly more mother-infant pairs in the intervention group showed secure attachment patterns in Ainsworth´s Strange Situation when the infants were 12 months of age. At the end of the intervention (infant age = 24 month), attachment security scores derived from Waters' Attachment Q-Sort were in the predicted direction and showed a medium effect size, but did not reach criteria of statistical significance. At both time points, the STEEP group showed significantly fewer signs of attachment disorganization than the comparison group.

Random Field Driven Spatial Complexity at the Mott Transition in VO(2).

We report the first application of critical cluster techniques to the Mott metal-insulator transition in vanadium dioxide. We show that the geometric universal properties of the metallic and insulating puddles observed by scanning near-field infrared microscopy are consistent with the system passing near criticality of the random field Ising model as temperature is varied. The resulting large barriers to equilibrium may be the source of the unusually robust hysteresis phenomena associated with the metal-insulator transition in this system.

Cardiopulmonary exercise testing and survival after elective abdominal aortic aneurysm repair†.

BACKGROUND: Cardiopulmonary exercise testing (CPET) is increasingly used in the preoperative assessment of patients undergoing major surgery. The objective of this study was to investigate whether CPET can identify patients at risk of reduced survival after abdominal aortic aneurysm (AAA) repair. METHODS: Prospectively collected data from consecutive patients who underwent CPET before elective open or endovascular AAA repair  (EVAR) at two tertiary vascular centres between January 2007 and October 2012 were analysed. A symptom-limited maximal CPET was performed on each patient. Multivariable Cox proportional hazards regression modelling was used to identify risk factors associated with reduced survival. RESULTS: The study included 506 patients with a mean age of 73.4 (range 44-90). The majority (82.6%) were men and most (64.6%) underwent EVAR. The in-hospital mortality was 2.6%. The median follow-up was 26 months. The 3-year survival for patients with zero or one sub-threshold CPET value ([Formula: see text] at AT<10.2 ml kg(-1) min(-1), peak [Formula: see text]<15 ml kg(-1) min(-1) or [Formula: see text] at AT>42) was 86.4% compared with 59.9% for patients with three sub-threshold CPET values. Risk factors independently associated with survival were female sex [hazard ratio (HR)=0.44, 95% confidence interval (CI) 0.22-0.85, P=0.015], diabetes (HR=1.95, 95% CI 1.04-3.69, P=0.039), preoperative statins (HR=0.58, 95% CI 0.38-0.90, P=0.016), haemoglobin g dl(-1) (HR=0.84, 95% CI 0.74-0.95, P=0.006), peak [Formula: see text]<15 ml kg(-1) min(-1) (HR=1.63, 95% CI 1.01-2.63, P=0.046), and [Formula: see text] at AT>42 (HR=1.68, 95% CI 1.00-2.80, P=0.049). CONCLUSIONS: CPET variables are independent predictors of reduced survival after elective AAA repair and can identify a cohort of patients with reduced survival at 3 years post-procedure. CPET is a potentially useful adjunct for clinical decision-making in patients with AAA.

Comparison of three contemporary risk scores for mortality following elective abdominal aortic aneurysm repair.

OBJECTIVE/BACKGROUND: A number of contemporary risk prediction models for mortality following elective abdominal aortic aneurysm (AAA) repair have been developed. Before a model is used either in clinical practice or to risk-adjust surgical outcome data it is important that its performance is assessed in external validation studies. METHODS: The British Aneurysm Repair (BAR) score, Medicare, and Vascular Governance North West (VGNW) models were validated using an independent prospectively collected sample of multicentre clinical audit data. Consecutive, data on 1,124 patients undergoing elective AAA repair at 17 hospitals in the north-west of England and Wales between April 2011 and March 2013 were analysed. The outcome measure was in-hospital mortality. Model calibration (observed to expected ratio with chi-square test, calibration plots, calibration intercept and slope) and discrimination (area under receiver operating characteristic curve [AUC]) were assessed in the overall cohort and procedural subgroups. RESULTS: The mean age of the population was 74.4 years (SD 7.7); 193 (17.2%) patients were women and the majority of patients (759, 67.5%) underwent endovascular aneurysm repair. All three models demonstrated good calibration in the overall cohort and procedural subgroups. Overall discrimination was excellent for the BAR score (AUC 0.83, 95% confidence interval [CI] 0.76-0.89), and acceptable for the Medicare and VGNW models, with AUCs of 0.78 (95% CI 0.70-0.86) and 0.75 (95% CI 0.65-0.84) respectively. Only the BAR score demonstrated good discrimination in procedural subgroups. CONCLUSION: All three models demonstrated good calibration and discrimination for the prediction of in-hospital mortality following elective AAA repair and are potentially useful. The BAR score has a number of advantages, which include being developed on the most contemporaneous data, excellent overall discrimination, and good performance in procedural subgroups. Regular model validations and recalibration will be essential.

In vivo oxidation in retrieved highly crosslinked tibial inserts.

The current study determined (I) the environment where oxidation in a series of retrieved, HXL UHMWPE tibial inserts occurred (in vivo or postexplant); and (II) the effect of fabrication variables (irradiation source, irradiation dose) and thermal processing after irradiation (annealing or remelting) on oxidation resistance. Hypotheses examined are (1) HXL UHMWPE tibial inserts have potential to oxidize in vivo, and (2) annealed HXL UHMWPE oxidizes at a higher rate in vivo than remelted HXL UHMWPE. Highly crosslinked UHMWPE tibial inserts (87), received by an IRB-approved retrieval laboratory from 20 surgeons at 10 institutions across the U.S., were analyzed from 2005 to 2011. Fourier transform infrared spectroscopy was used to determine oxidation and trans-vinylene index for each retrieved insert. Measured oxidation that was maximum subsurface was found in 56% of all HXL tibial inserts. This maximum oxidation correlated significantly with in vivo time, trans-vinylene index, and thermal processing after irradiation. Articular oxidation rate correlated with crosslinking irradiation dose and thermal processing after irradiation. Retrieved below-melt annealed tibial inserts had significantly higher articular oxidation rates than remelted tibial inserts (p < 0.001). Articular oxidation rates correlated positively with cross-linking irradiation dose and postirradiation thermal processing. Edge oxidation correlated with postirradiation thermal processing. Oxidation of HXL UHMWPE may have clinical implications for tibial inserts, since loss of UHMWPE toughness resulting from oxidation has led to fatigue damage in gamma-sterilized tibial inserts.

Spatial complexity due to bulk electronic nematicity in a superconducting underdoped cuprate.

Surface probes such as scanning tunnelling microscopy have detected complex electronic patterns at the nanoscale in many high-temperature superconductors. In cuprates, the pattern formation is associated with the pseudogap phase, a precursor to the high-temperature superconducting state. Rotational symmetry breaking of the host crystal in the form of electronic nematicity has recently been proposed as a unifying theme of the pseudogap phase. However, the fundamental physics governing the nanoscale pattern formation has not yet been identifed. Here we introduce a new set of methods for analysing strongly correlated electronic systems, including the effects of both disorder and broken symmetry. We use universal cluster properties extracted from scanning tunnelling microscopy studies of cuprate superconductors to identify the fundamental physics controlling the complex pattern formation. Because of a delicate balance between disorder, interactions, and material anisotropy, we find that the electron nematic is fractal in nature, and that it extends throughout the bulk of the material.

Morbidity and mortality associated with tracheotomy procedure in a university medical centre.

This prospective study assessed the morbidity and mortality associated with 192 consecutive tracheotomies. Complications were assessed including intraoperative and/or postoperative bleeding, infection, tracheoinnominate fistulae, tracheoesophageal fistulae, dislodgement of the tracheotomy tube, pneumothorax, wound infection and obstruction of the airway. 16% of the tracheotomy procedures resulted in complications. 22 tracheotomy procedures (11%) resulted in postoperative bleeding, 6 procedures (3%) had intraoperative bleeding which exceeded an estimated blood loss of 5 cc and 2 procedures (1%) developed a tracheoesophageal fistula. One patient (0.5%) experienced airway distress related to obstruction of the airway proximal to the tracheotomy tube. No patients required a return to the operating room to manage their complication, no patients developed a tracheoinnominate fistula and none of the tracheotomy sites became infected. The post tracheotomy ventilator wean to trach-collar supplemental oxygen protocol was accomplished with a mean of 6 days in 119 patients for whom data was available. Results demonstrate that the open tracheotomy procedure is a safe and frequently life saving manoeuvre in situations with an unsecured airway, and it provides better outcomes in patients requiring long term ventilatory support. Mortality rates are low and its potential morbidity is exceeded by its benefits.

Temporal manipulation of transferrin-receptor-1-dependent iron uptake identifies a sensitive period in mouse hippocampal neurodevelopment.

Iron is a necessary substrate for neuronal function throughout the lifespan, but particularly during development. Early life iron deficiency (ID) in humans (late gestation through 2-3 yr) results in persistent cognitive and behavioral abnormalities despite iron repletion. Animal models of early life ID generated using maternal dietary iron restriction also demonstrate persistent learning and memory deficits, suggesting a critical requirement for iron during hippocampal development. Precise definition of the temporal window for this requirement has been elusive due to anemia and total body and brain ID inherent to previous dietary restriction models. To circumvent these confounds, we developed transgenic mice that express tetracycline transactivator regulated, dominant negative transferrin receptor (DNTfR1) in hippocampal neurons, disrupting TfR1 mediated iron uptake specifically in CA1 pyramidal neurons. Normal iron status was restored by doxycycline administration. We manipulated the duration of ID using this inducible model to examine long-term effects of early ID on Morris water maze learning, CA1 apical dendrite structure, and defining factors of critical periods including parvalbmin (PV) expression, perineuronal nets (PNN), and brain-derived neurotrophic factor (BDNF) expression. Ongoing ID impaired spatial memory and resulted in disorganized apical dendrite structure accompanied by altered PV and PNN expression and reduced BDNF levels. Iron repletion at P21, near the end of hippocampal dendritogenesis, restored spatial memory, dendrite structure, and critical period markers in adult mice. However, mice that remained hippocampally iron deficient until P42 continued to have spatial memory deficits, impaired CA1 apical dendrite structure, and persistent alterations in PV and PNN expression and reduced BDNF despite iron repletion. Together, these findings demonstrate that hippocampal iron availability is necessary between P21 and P42 for development of normal spatial learning and memory, and that these effects may reflect disruption of critical period closure by early life ID.

Complications after two transphyseal bridging techniques for treatment of angular limb deformities of the distal radius in 568 Thoroughbred yearlings.

REASONS FOR PERFORMING STUDY: Surgical correction of carpal angular limb deformities by growth retardation is commonly undertaken with a screws and tension band wire loop technique (S&W) or a single transphyseal screw (STS). This study compares complications after S&W and STS bridging in the distal radius of Thoroughbred yearlings. OBJECTIVE: To compare the prevalence of complications serious enough to require follow-up radiographs following either S&W or STS surgery for growth manipulation in the distal radius of Thoroughbred yearlings. METHODS: Medical records and radiographs from Thoroughbred yearlings (age range 261-457 days) treated for carpal angular limb deformities at a single hospital over 2 years were reviewed. Each of the techniques was used exclusively during a single year. The complication threshold criterion for inclusion was the need for nonroutine radiographs of the operated site anytime after implant insertion or removal. RESULTS: Of 568 horses, 253 received S&W and 315 received STS. Horses were of similar age at the time of surgery for STS and S&W. Single transphyseal screws were left in place for a significantly shorter amount of time (16 days). Sex, the limb(s) treated and medial vs. lateral placement were not significantly different between techniques. Complications included physitis post implant removal, metaphyseal collapse post implant removal, infection, overcorrection and seroma formation severe enough to require radiography. Physitis and metaphyseal collapse occurred significantly more frequently with STS compared with S&W. Infection, overcorrection and seromas were not significantly different between techniques. CONCLUSION: The STS and S&W techniques are both viable treatment options for correction of carpal angular limb deformities. However, horses treated with the STS technique have a significantly increased risk of developing physitis or metaphyseal collapse. POTENTIAL RELEVANCE: Horses treated with STS bridging have a significantly increased risk of developing the post correction complications of moderate to severe physitis and metaphyseal collapse compared with horses treated with S&W bridging.

Using disorder to detect locally ordered electron nematics via hysteresis.

The interplay between charge, orbital and lattice degrees of freedom in correlated electron systems has resulted in many proposals for new electronic phases of matter. An electron nematic breaks the point group symmetry of the host crystal, often from C(6) or C(4) rotational symmetry to C(2). Electron nematics have been reported in several condensed matter systems including cuprate- and iron arsenic-based high-temperature superconductors, and they have been proposed to exist in many other materials. However, the combination of reduced dimensionality and material disorder typically limits the spatial range over which electron nematic order persists, rendering its experimental detection extremely difficult. Despite the tantalizing possible connection between the phase and high-temperature superconductivity, there is surprisingly little guidance in the literature about how to detect the remaining disordered electron nematic. Here we propose two protocols for detecting disordered electron nematics in condensed matter systems using non-equilibrium methods.

Low energy spin waves and magnetic interactions in SrFe2As2.

We report inelastic neutron scattering studies of magnetic excitations in antiferromagnetically ordered SrFe2As2 (T_{N}=200-220 K), the parent compound of the FeAs-based superconductors. At low temperatures (T=7 K), the magnetic spectrum S(Q,Planck's omega) consists of a Bragg peak at the elastic position (Planck's omega=0 meV), a spin gap (Delta< or =6.5 meV), and sharp spin-wave excitations at higher energies. Based on the observed dispersion relation, we estimate the effective magnetic exchange coupling using a Heisenberg model. On warming across T_{N}, the low-temperature spin gap rapidly closes, with weak critical scattering and spin-spin correlations in the paramagnetic state. The antiferromagnetic order in SrFe2As2 is therefore consistent with a first order phase transition, similar to the structural lattice distortion.

[New condylar head system for temporary condylar reconstruction in ablative tumour surgery]. / Neu entwickeltes Kiefergelenkkopfimplantat zur temporären Kondylus-Rekonstruktion in der ablativen Tumorchirurgie.

BACKGROUND: Based on own retrospective studies a condylar head add-on system for immediate, temporary reconstruction in patients undergoing ablative surgery requiring the removal of the manibular condyle has been developed in cooperation with the Department of Oral and Maxillofacial Surgery of the University of Tennessee, USA, and the Association for the Study of Internal Fixation (AO/ASIF). PURPOSE: The design of the new condylar head add-on system and its use in an anatomical dissection study on a human cadaver are introduced and discussed. DESIGN AND FIRST EXPERIENCES: The condylar replacement is made of commercial pure titanium and is conceived as an add-on system. It consists of a reconstruction plate (2.4 Uni-LOCK-System) und an adaptable condylar head that can be fitted on either side. The offset of the condylar head in a medial direction allows anatomically correct positioning of the implant. The slanted oval head shall provide a large contact area while maintaining function of the mandibular joint. The height-adjustable positioning of the condylar head add-on with four different fixations plates facilitates an intraoperative vertical correction of the condylar head without necessary bending of a new reconstruction plate. A condylar head add-on used on both sides and combined with the frequently used 2.4 Uni-LOCK-plate benefits from reduced storekeeping and turns out to be advantageous from an economic point of view. PERSPECTIVE: An international, prospective multi-center study evaluating the intraoperative applicability of the new condylar head add-on system and its functional as well as aesthetic results during the first two postoperative years has started in September 2006.

Efficient algorithm for random-bond ising models in 2D.

We present an efficient algorithm for calculating the properties of Ising models in two dimensions, directly in the spin basis, without the need for mapping to fermion or dimer models. The algorithm computes the partition function and correlation functions at a single temperature on any planar network of N Ising spins in O(N;{3/2}) time or less. The method can handle continuous or discrete bond disorder and is especially efficient in the case of bond or site dilution, where it executes in O(NlnN) time near the percolation threshold. We demonstrate its feasibility on the ferromagnetic Ising model and the +/-J random-bond Ising model and discuss the regime of applicability in cases of full frustration such as the Ising antiferromagnet on a triangular lattice.

Magnetic excitations of stripes near a quantum critical point.

We calculate the dynamical spin structure factor of spin waves for weakly coupled stripes. At low energy, the spin-wave cone intensity is strongly peaked on the inner branches. As energy is increased, there is a saddlepoint followed by a square-shaped continuum rotated 45 degrees from the low energy peaks. This is reminiscent of recent high energy neutron scattering data on the cuprates. The similarity at high energy between this semiclassical treatment and quantum fluctuations in spin ladders may be attributed to the proximity of a quantum critical point with a small critical exponent eta.

Hysteresis and noise from electronic nematicity in high-temperature superconductors.

An electron nematic is a translationally invariant state which spontaneously breaks the discrete rotational symmetry of a host crystal. In a clean square lattice, the electron nematic has two preferred orientations, while dopant disorder favors one or the other orientations locally. In this way, the electron nematic in a host crystal maps to the random field Ising model. Since the electron nematic has anisotropic conductivity, we associate each Ising configuration with a resistor network and use what is known about the random field Ising model to predict new ways to test for local electronic nematic order (nematicity) using noise and hysteresis. In particular, we have uncovered a remarkably robust linear relation between the orientational order and the resistance anisotropy which holds over a wide range of circumstances.