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1.
Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.  相似文献   
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Previous research indicates that the reward positivity (RewP), an electrophysiological correlate of sensitivity and biases towards rewarding stimuli, is modulated by affective and motivational variables. Studies have provided evidence that states and traits associated with negative affect and reduced approach motivation are correlated with smaller RewP amplitudes. However, the possible confound of affective valence and motivational direction was not addressed in these studies. In the present study, we examined if anger, an emotion associated with negative affect and increased approach motivation, would affect RewP amplitude. We also investigated if RewP amplitude was related to the motivational properties of reward stimuli. One hundred male participants completed two emotion inductions intended to elicit feelings of either neutrality or anger. Each was followed by a simple gambling task, in which correct choices were followed by images of women in lingerie or swimwear. Although the RewP was elicited following each induction, there was no difference in amplitude between the neutral and anger induction. However, RewP amplitude was positively correlated with how much participants liked the reward stimuli, and this correlation was statistically larger following the anger induction. These results support a motivational interpretation for the differences in RewP amplitude reported in previous studies, suggesting that motivational direction and intensity, rather than affective valence, underlie differences in RewP amplitude. Moreover, the RewP appears to be affected by interactions between motivational state and the motivational value of reward stimuli.  相似文献   
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Introduction

Fast track methodology or enhanced recovery schemes have gained increasing popularity in perioperative care. While evidence is strong for colorectal surgery, its importance in gastric and oesophageal surgery has yet to be established. This article reviews the evidence of enhanced recovery schemes on outcome for this type of surgery.

Methods

A systematic literature search was conducted up to March 2014. Studies were retrieved and analysed using predetermined criteria.

Results

From 34 articles reviewed, 18 eligible studies were identified: 7 on gastric and 11 on oesophageal resection. Three randomised controlled trials, five case-controlled studies and ten case series were identified. The reported protocols included changes to each stage of the patient journey from pre to postoperative care. The specific focus following oesophageal resections was on early mobilisation, a reduction in intensive care unit stay, early drain removal and early (or no) contrast swallow studies. Following gastric resections, the emphasis was on reducing epidural anaesthesia along with re-establishing oral intake in the first three postoperative days and early removal of nasogastric tubes.In the papers reviewed, mortality rates following fast track surgery were 0.8% (9/1,075) for oesophageal resection and 0% (0/329) for gastric resection. The reported morbidity rate was 16.5% (54/329) following gastric resection and 38.6% (396/1,075) following oesophageal resection. Length of stay was reduced in both groups compared with conventional recovery groups in comparative studies.

Conclusions

The evidence for enhanced recovery schemes following gastric and oesophageal resection is weak, with only three (low volume) published randomised controlled trials. However, the enhanced recovery approach appears safe and may be associated with a reduction in length of stay.  相似文献   
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This article is concerned with the design and performance optimization of feedback controllers for state-based switching bilinear systems (SBLSs), where subsystems take the form of bilinear systems in different state space polyhedra. First, by further dividing the subregions into smaller regions and designing region-dependent feedback controllers in the resulting regions, the SBLSs can be transformed into corresponding switching linear systems (SLSs). Then, for these SLSs, by imposing contractility conditions on the Lyapunov functions, an upper bound on the infinite horizon quadratic cost can be obtained. Optimizing this upper bound yields the controller design. The optimization problem is formulated as a linear matrix inequalities optimization problem, which can be solved efficiently. Finally, the stability of the close-loop system under the proposed controller is established step by step through a decreasing overall Lyapunov function.  相似文献   
7.
The mammalian suprachiasmatic nucleus (SCN) forms not only the master circadian clock but also a seasonal clock. This neural network of ∼10,000 circadian oscillators encodes season-dependent day-length changes through a largely unknown mechanism. We show that region-intrinsic changes in the SCN fine-tune the degree of network synchrony and reorganize the phase relationship among circadian oscillators to represent day length. We measure oscillations of the clock gene Bmal1, at single-cell and regional levels in cultured SCN explanted from animals raised under short or long days. Coupling estimation using the Kuramoto framework reveals that the network has couplings that can be both phase-attractive (synchronizing) and -repulsive (desynchronizing). The phase gap between the dorsal and ventral regions increases and the overall period of the SCN shortens with longer day length. We find that one of the underlying physiological mechanisms is the modulation of the intracellular chloride concentration, which can adjust the strength and polarity of the ionotropic GABAA-mediated synaptic input. We show that increasing day-length changes the pattern of chloride transporter expression, yielding more excitatory GABA synaptic input, and that blocking GABAA signaling or the chloride transporter disrupts the unique phase and period organization induced by the day length. We test the consequences of this tunable GABA coupling in the context of excitation–inhibition balance through detailed realistic modeling. These results indicate that the network encoding of seasonal time is controlled by modulation of intracellular chloride, which determines the phase relationship among and period difference between the dorsal and ventral SCN.The physiological and behavioral rhythms of all life on earth are bound to the Earth’s rotational cycle of ∼24 h. This fundamental rhythm is also affected by the planet’s slanted rotational axis, which causes seasonal variations in the length of the day. How life has adapted to anticipate this yearly rhythm is still debated.The suprachiasmatic nucleus (SCN), the central circadian (∼24 h) pacemaker in mammals, consists of ∼10,000 “clock” neurons. These single-cell clocks maintain endogenous rhythms by autoregulatory feedback loops of genes including period (Per) and brain and muscle Arnt-like 1 (Bmal1) (1). Although it was speculated that seasonal rhythms might be encoded in a single cell (2), single-cell oscillations remain similar regardless of the seasonal time that the SCN tissue encodes (3). Seasonal timing is thus proposed to be encoded in the network of the SCN (47) through spatial reorganization of the relative phases of clocks within individual cells (810). Subsets of SCN clocks form phase clusters (11) that map approximately to dorsal (shell, D-SCN) and ventral (core, V-SCN) regions of the SCN. When measured through a luciferase reporter monitoring oscillations in the Bmal1 gene, the D-SCN and V-SCN clusters show a phase gap, with the D-SCN leading the V-SCN. Although the D-SCN/V-SCN cluster structure is preserved across a moderate range of day length (8–16 h) (12), the phase gap increases with increasing day length (13). The mechanism for this phase gap remains unknown.Previous studies explain robust circadian timekeeping by in-phase synchronization of the SCN (14, 15), analogous to the classical phase model of Kuramoto (16). This in-phase state, however, is insufficient to explain the day length-dependent phase gap that is stably seen experimentally (12, 13). According to the phase model, a phase gap can result from the difference in period between the D-SCN and the V-SCN; a larger phase gap emerges when the difference in period of the D-SCN and V-SCN increases. Recent techniques have been proposed to estimate the coupling of biological oscillators from their time-course data using the Kuramoto formalism (17, 18). Using these techniques, we discover the phase clusters emerge through balancing of phase-repulsion (increasing the phase gap) and phase-attraction (decreasing the phase gap) in the SCN. This network motif is also predicted to decrease the period of the SCN as a whole as the phase gap increases, something we observe experimentally.One difference between the D-SCN and V-SCN is through the effects of the ionotropic γ-aminobutyric acid receptor (GABAA) (1921). Contrary to the convention that the GABAergic inputs are hyperpolarizing, high intracellular chloride concentration in some SCN neurons can cause GABA to depolarize the cells (20). We find that the effects of the phase-repulsive coupling disappear after pharmacological blockade of GABAA, by a surgical cut that severs physical connections between the clusters or by the chloride importer blocker, which decreases intracellular chloride and reverts the polarity of GABAA signaling back to its normal inhibitory state. One explanation for this, which we test here, is that there is a day length-dependent increase of the relative expression of the neuronal chloride importer (Nkcc1) vs. the exporter (Kcc2), in line with the recent finding of increased excitation by GABA under LD (22). However, how increasing intracellular chloride concentration leads to phase attractive or repulsive coupling remains a mystery.To answer how increasing intracellular chloride concentration leads to phase attractive or repulsive coupling, we appeal to detailed physiological modeling of the SCN. In a companion paper, we argue that GABA signaling normally has little effect on the SCN molecular clock (23). However, if GABA excites the D-SCN, a tonic signal is released that synchronizes the molecular clock in the D-SCN and can desynchronize and diminish oscillations the V-SCN, as well as increase this phase gap between the D-SCN and V-SCN. Here we show simulations that the day length-mediated increases in excitatory GABA in the D-SCN cause a shortening of the period in the D-SCN and a weakening of the synchronizing signal from the V-SCN, both of which increase the phase gap. We validate that these effects have a similar effect on the coupling in the Kuramoto framework as estimated from the experimental data, validating chloride’s role in coding day length.  相似文献   
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Australia has a large migrant population with variable fluency in English. Interpreting services help ensure that healthcare services are delivered appropriately to these populations. However, the use of professional interpreters in hospitals is expensive. There are also issues with service availability and convenience. Mobile devices containing software with translating abilities have promising potential to improve communication between patients and hospital staff as an adjunct to professional interpreters. It is highly convenient and inexpensive. There are concerns about the accuracy of the interpretation done with such software and more research needs to be carried out to support or allay these concerns. For now, clinically important and medicolegal related interpretation should be undertaken by professional interpreters whereas less crucial tasks may be performed with the help of interpreting software on mobile devices.  相似文献   
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