Appendectomy and asthma: a search for an association in older subjects.

INTRODUCTION: Several risk factors found to be associated with postoperative complications and cancer surgery, which carry a significant morbidity risk to cancer patients. Therefore, prehabilitation is necessary to improve the functional capability and nutritional status of a patient prior to surgery, so that the patient can withstand any postoperative activity and associated deterioration. Thus, this study aims to assess the effectiveness of prehabilitation interventions on the functional status of patients with gastric and oesophageal cancer who underwent esophagectomy and gastrectomy. MATERIAL AND METHODS: An interventional study was carried out among oesophageal and gastric cancer patients who had undergone surgery at the National Cancer Institute of Malaysia. The prehabilitation process took a maximum of two weeks, depending on the patient's optimisation before surgery. The prehabilitation is based on functional capacity (ECOG performance status), muscle function (handgrip strength), cardio-respiratory function (peak flow meter) and nutritional status (calorie and protein). Postoperative outcomes are measured based on the length of hospital stay, complications, and Clavien-Dindo Classification. RESULTS: Thirty-one patients were recruited to undergo a prehabilitation intervention prior to gastrectomy (n=21) and esophagectomy (n=10). Demographically, most of the cancer patients were males (67.7%) with an ideal mean of BMI (23.5±6.0). Physically, the majority of them had physical class (ASA grade) Grade 2 (67.7%), ECOG performance status of 1 (61.3%) and SGA grade B (51.6%). The functional capacity and nutritional status showed a significant improvement after one week of prehabilitation interventions: peak expiratory flow meter (p<0.001), handgrip (p<0.001), ECOG performance (p<0.001), walking distance (p<0.001), incentive spirometry (p<0.001), total body calorie (p<0.001) and total body protein (p=0.004). However, those patients who required two weeks of prehabilitation for optimization showed only significant improvement in peak expiratory flow meter (p<0.001), handgrip (p<0.001), and incentive spirometry (p<0.001). Prehabilitation is significantly associated postoperatively with the length of hospital stay (p=0.028), complications (p=0.011) and Clavien-Dindo Classification (p=0.029). CONCLUSION: Prehabilitation interventions significantly increase the functional capacity and nutritional status of cancer patients preoperatively; concurrently reducing hospital stays and complications postoperatively. However, certain cancer patients might require over two weeks of prehabilitation to improve the patient's functional capacity and reduce complications postoperatively.

Time-resolved Coulomb collision of single electrons.

A series of recent experiments have shown that collision of ballistic electrons in semiconductors can be used to probe the indistinguishability of single-electron wavepackets. Perhaps surprisingly, their Coulomb interaction has not been seen due to screening. Here we show Coulomb-dominated collision of high-energy single electrons in counter-propagating ballistic edge states, probed by measuring partition statistics while adjusting the collision timing. Although some experimental data suggest antibunching behaviour, we show that this is not due to quantum statistics but to strong repulsive Coulomb interactions. This prevents the wavepacket overlap needed for fermionic exchange statistics but suggests new ways to utilize Coulomb interactions: microscopically isolated and time-resolved interactions between ballistic electrons can enable the use of the Coulomb interaction for high-speed sensing or gate operations on flying electron qubits.

Magnetic Resonance Imaging-Defined Osteophyte Presence and Concomitant Cartilage Damage in Knees With Incident Tibiofemoral Osteoarthritis: Data From the Pivotal Osteoarthritis Initiative Magnetic Resonance Imaging Analyses Study.

OBJECTIVE: To describe compartmental frequencies of magnetic resonance image (MRI)-defined osteophytes and co-localized cartilage damage and evaluate the associations of osteophyte size with any ipsicompartmental cartilage damage in knees with incident tibiofemoral radiographic knee osteoarthritis (OA). METHODS: We evaluated knees from the Osteoarthritis Initiative without radiographic knee OA at baseline that developed radiographic knee OA during a 4-year interval. Semiquantitative MRI scoring of osteophytes and cartilage damage was performed at the time point when radiographic knee OA was diagnosed, defined as Kellgren/Lawrence grade of ≥2, using the MRI Osteoarthritis Knee Score instrument. The frequencies of maximum osteophyte size and maximum grade of ipsicompartmental (i.e., patellofemoral, medial tibiofemoral, lateral tibiofemoral, posterior femur) cartilage damage were assessed. Generalized estimating equations were used to determine the association of MRI-defined maximum osteophyte size with presence of any (excluding focal superficial defects) ipsicompartmental cartilage damage. RESULTS: A total of 296 knees that did not have tibiofemoral radiographic knee OA at the baseline visit but developed radiographic knee OA during the 48-month observational period were included. In the patellofemoral, medial tibiofemoral, and lateral tibiofemoral compartments, the most frequent osteophyte grade was 1 (67.6%, 59.1%, and 51.7%, respectively) and was 0 (51.7%) in the posterior femur. For all compartments except the posterior femur, a linear trend was found between increasing maximum osteophyte size and the presence of any concomitant cartilage damage. CONCLUSION: In this sample of knees with incident tibiofemoral radiographic knee OA, the patellofemoral joint showed more severe cartilage damage than other compartments regardless of concomitant osteophyte size. In the posterior femur, cartilage damage was rare despite the presence or size of concomitant osteophytes.

Continuous-variable tomography of solitary electrons.

A method for characterising the wave-function of freely-propagating particles would provide a useful tool for developing quantum-information technologies with single electronic excitations. Previous continuous-variable quantum tomography techniques developed to analyse electronic excitations in the energy-time domain have been limited to energies close to the Fermi level. We show that a wide-band tomography of single-particle distributions is possible using energy-time filtering and that the Wigner representation of the mixed-state density matrix can be reconstructed for solitary electrons emitted by an on-demand single-electron source. These are highly localised distributions, isolated from the Fermi sea. While we cannot resolve the pure state Wigner function of our excitations due to classical fluctuations, we can partially resolve the chirp and squeezing of the Wigner function imposed by emission conditions and quantify the quantumness of the source. This tomography scheme, when implemented with sufficient experimental resolution, will enable quantum-limited measurements, providing information on electron coherence and entanglement at the individual particle level.

LO-Phonon Emission Rate of Hot Electrons from an On-Demand Single-Electron Source in a GaAs/AlGaAs Heterostructure.

Using a recent time-of-flight measurement technique with 1 ps time resolution and electron-energy spectroscopy, we develop a method to measure the longitudinal-optical-phonon emission rate of hot electrons traveling along a depleted edge of a quantum Hall bar. Comparison to a single-particle model implies the scattering mechanism involves a two-step process via an intra-Landau-level transition. We show that this can be suppressed by control of the edge potential profile, and a scattering length >1 mm can be achieved, allowing the use of this system for scalable single-electron device applications.

Engineering the spin polarization of one-dimensional electrons.

We present results of magneto-focusing on the controlled monitoring of spin polarization within a one-dimensional (1D) channel, and its subsequent effect on modulating the spin-orbit interaction (SOI) in a 2D GaAs electron gas. We demonstrate that electrons within a 1D channel can be partially spin polarized as the effective length of the 1D channel is varied in agreement with the theoretical prediction. Such polarized 1D electrons when injected into a 2D region result in a split in the odd-focusing peaks, whereas the even peaks remain unaffected (single peak). On the other hand, the unpolarized electrons do not affect the focusing spectrum and the odd and even peaks remain as single peaks, respectively. The split in odd-focusing peaks is evidence of direct measurement of spin polarization within a 1D channel, where each sub-peak represents the population of a particular spin state. Confirmation of the spin splitting is determined by a selective modulation of the focusing peaks due to the Zeeman energy in the presence of an in-plane magnetic field. We suggest that the SOI in the 2D regime is enhanced by a stream of polarized 1D electrons. The spatial control of spin states of injected 1D electrons and the possibility of tuning the SOI may open up a new regime of spin-engineering with application in future quantum information schemes.

Unusual case of lipoma arborescens in the subacromial-subdeltoid bursa.

A 38-year-old female presented with a 10-month history of right shoulder pain with impingement symptoms. She was diagnosed on magnetic resonance (MR) imaging to have supraspinatus tendon tear and degenerative changes contributing to subacromial impingement. She also had lipoma arborescens of the subacromial-subdeltoid bursa, an uncommon condition in a particularly rare location. Lipoma arborescens is a benign intra-articular condition characterized by lipomatous proliferation of synovium with replacement of subsynovial tissue by mature adipocytes. It is typically a monoarticular process affecting the knee. Due to the presence of pathognomonic fat, diagnosis is usually straightforward with MR as the preferred imaging modality.

You can never have too many accessories - a case of two accessory muscles of the ankle.

Accessory muscles are relatively rare anatomic duplications of muscles that may appear anywhere in the muscular system. Though a wide array of accessory and supernumery muscles involving the ankle have been described in the literature, this is the first reported case we are aware of that features two accessory muscles. Accessory muscles are typically asymptomatic and often picked up as incidental findings but are important to be identified in the presence of chronic persistent ankle pain and the absence of other more common aetiologies.

Time-of-Flight Measurements of Single-Electron Wave Packets in Quantum Hall Edge States.

We report time-of-flight measurements on electrons traveling in quantum Hall edge states. Hot-electron wave packets are emitted one per cycle into edge states formed along a depleted sample boundary. The electron arrival time is detected by driving a detector barrier with a square wave that acts as a shutter. By adding an extra path using a deflection barrier, we measure a delay in the arrival time, from which the edge-state velocity v is deduced. We find that v follows 1/B dependence, in good agreement with the E[over →]×B[over →] drift. The edge potential is estimated from the energy dependence of v using a harmonic approximation.

Anomalous critical fields in quantum critical superconductors.

Fluctuations around an antiferromagnetic quantum critical point (QCP) are believed to lead to unconventional superconductivity and in some cases to high-temperature superconductivity. However, the exact mechanism by which this occurs remains poorly understood. The iron-pnictide superconductor BaFe2(As(1-x)P(x))2 is perhaps the clearest example to date of a high-temperature quantum critical superconductor, and so it is a particularly suitable system to study how the quantum critical fluctuations affect the superconducting state. Here we show that the proximity of the QCP yields unexpected anomalies in the superconducting critical fields. We find that both the lower and upper critical fields do not follow the behaviour, predicted by conventional theory, resulting from the observed mass enhancement near the QCP. Our results imply that the energy of superconducting vortices is enhanced, possibly due to a microscopic mixing of antiferromagnetism and superconductivity, suggesting that a highly unusual vortex state is realized in quantum critical superconductors.

Clock-controlled emission of single-electron wave packets in a solid-state circuit.

We demonstrate the energy- and time-resolved detection of single-electron wave packets from a clock-controlled source transmitted through a high-energy quantum Hall edge channel. A quantum dot source is loaded with single electrons which are then emitted ~150 meV above the Fermi energy. The energy spectroscopy of emitted electrons indicates that at high magnetic field these electrons can be transported over several microns without inelastic electron-electron or electron-phonon scattering. Using a time-resolved spectroscopic technique, we deduce the wave packet size at picosecond resolution. We also show how this technique can be used to switch individual electrons into different electron waveguides (edge channels).

A surface-patterned chip as a strong source of ultracold atoms for quantum technologies.

Laser-cooled atoms are central to modern precision measurements. They are also increasingly important as an enabling technology for experimental cavity quantum electrodynamics, quantum information processing and matter-wave interferometry. Although significant progress has been made in miniaturizing atomic metrological devices, these are limited in accuracy by their use of hot atomic ensembles and buffer gases. Advances have also been made in producing portable apparatus that benefits from the advantages of atoms in the microkelvin regime. However, simplifying atomic cooling and loading using microfabrication technology has proved difficult. In this Letter we address this problem, realizing an atom chip that enables the integration of laser cooling and trapping into a compact apparatus. Our source delivers ten thousand times more atoms than previous magneto-optical traps with microfabricated optics and, for the first time, can reach sub-Doppler temperatures. Moreover, the same chip design offers a simple way to form stable optical lattices. These features, combined with simplicity of fabrication and ease of operation, make these new traps a key advance in the development of cold-atom technology for high-accuracy, portable measurement devices.

Towards a quantum representation of the ampere using single electron pumps.

Electron pumps generate a macroscopic electric current by controlled manipulation of single electrons. Despite intensive research towards a quantum current standard over the last 25 years, making a fast and accurate quantized electron pump has proved extremely difficult. Here we demonstrate that the accuracy of a semiconductor quantum dot pump can be dramatically improved by using specially designed gate drive waveforms. Our pump can generate a current of up to 150 pA, corresponding to almost a billion electrons per second, with an experimentally demonstrated current accuracy better than 1.2 parts per million (p.p.m.) and strong evidence, based on fitting data to a model, that the true accuracy is approaching 0.01 p.p.m. This type of pump is a promising candidate for further development as a realization of the SI base unit ampere, following a redefinition of the ampere in terms of a fixed value of the elementary charge.

Tunable nonadiabatic excitation in a single-electron quantum dot.

We report the observation of nonadiabatic excitations of single electrons in a quantum dot. Using a tunable-barrier single-electron pump, we have developed a way of reading out the excitation spectrum and level population of the dot by using the pump current as a probe. When the potential well is deformed at subnanosecond time scales, electrons are excited to higher levels. In the presence of a perpendicular magnetic field, the excited states follow a Fock-Darwin spectrum. Our experiments provide a simple model system to study nonadiabatic processes of quantum particles.

Effect of functional electrical stimulation (FES) combined with robotically assisted treadmill training on the EMG profile.

Functional electrical stimulation (FES) is used to assist spinal cord injury patients during walking. However, FES has yet to be shown to have lasting effects on the underlying neurophysiology which lead to long-term rehabilitation. A new approach to FES has been developed by which stimulation is timed to robotically controlled movements in an attempt to promote long-term rehabilitation of walking. This approach was tested in a rodent model of spinal cord injury. Rats who received this FES therapy during a 2-week training period exhibited peak EMG activity during the appropriate phase of the gait cycle; whereas, rats who received stimulation which was randomly timed with respect to their motor activity exhibited no clear pattern in their EMG profile. These results from our newly developed FES system serve as a launching point for many future studies to test and understand the long-term effect of FES on spinal cord rehabilitation.

Wide spectral range confocal microscope based on endlessly single-mode fiber.

We report an endlessly single mode, fiber-optic confocal microscope, based on a large mode area photonic crystal fiber. The microscope confines a very broad spectral range of excitation and emission wavelengths to a single spatial mode in the fiber. Single-mode operation over an optical octave is feasible. At a magnification of 10 and λ = 900 nm, its resolution was measured to be 1.0 µm (lateral) and 2.5 µm (axial). The microscope's use is demonstrated by imaging single photons emitted by individual InAs quantum dots in a pillar microcavity.

Clinics in diagnostic imaging (129). Posterior cruciate ligament ganglion cyst.

Ganglion cysts arising from the posterior cruciate ligament (PCL) of the knee are rare. We describe a 21-year-old Chinese woman who presented with right knee pain following a twisting injury six months prior. Her pain was exacerbated by squatting, although her range of knee motion was full. Magnetic resonance imaging showed a lobulated, well-defined, T1-hypointense and T2-hyperintense, septated cystic mass arising from the posterior aspect of the PCL. The diagnosis of a PCL ganglion cyst was confirmed by computed tomography-guided aspiration of the cyst. Due to persistent mild knee pain, the patient eventually underwent arthroscopic decompression of the ganglion cyst. The clinical features, diagnosis and management of PCL ganglion cysts are discussed.

Single-photon emitting diode based on a quantum dot in a micro-pillar.

We have fabricated a single-photon emitting diode based on a quantum dot in a micro-pillar cavity. By temperature tuning the dot emission into resonance with the cavity mode we see an enhancement in the collected photon intensity at 40 K. We perform autocorrelation measurements on the electroluminescence at fixed bias, observing photon anti-bunching. Due to the low resistance and capacitance of our device we can inject current pulses shorter than the lifetime of the quantum state, producing single-photon emission with g((2))(0) = 0.17.

Efficient single photon detection by quantum dot resonant tunneling diodes.

We demonstrate that the resonant tunnel current through a double-barrier structure is sensitive to the capture of single photoexcited holes by an adjacent layer of quantum dots. This phenomenon could allow the detection of single photons with low dark count rates and high quantum efficiencies. The magnitude of the sensing current may be controlled via the thickness of the tunnel barriers. Larger currents give improved signal to noise and allow sub-mus photon time resolution.

Suppression of insulin-like growth factor signalling pathway and collagen expression in keloid-derived fibroblasts by quercetin: its therapeutic potential use in the treatment and/or prevention of keloids.

BACKGROUND: Keloids are characterized by abnormal proliferation of fibroblasts and overproduction of collagen. Insulin-like growth factor (IGF)-I is mitogenic for fibroblasts and a stimulatory factor for collagen synthesis. OBJECTIVES: We have assessed the in vitro effects of quercetin on proliferation, collagen synthesis and the expression of the IGF system in keloid-derived fibroblasts. METHODS: Fibroblasts were isolated from earlobe keloids and exposed to quercetin at different concentrations. The inhibitory effects of quercetin on fibroblast proliferation were assayed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Western and Northern blot analyses. RESULTS: Quercetin inhibited keloid fibroblast (KF) proliferation in a dose-dependent manner. Significant growth inhibition was observed on day 2 of culture. The dose required for 50% growth inhibition was approximately 25 microg mL-1. Collagen 1 expression was significantly decreased while collagen 3 was almost undetectable following quercetin treatment. Basal levels of IGF-I receptor (IGF-IR) beta subunits, p85 subunit of phosphatidylinositol 3-kinase, c-Raf, phospho-Raf-1, phospho-MEK 1/2, phospho-mitogen-activated protein kinase, phospho-Elk-1 and phospho-Akt-1 were significantly reduced when KF cells were exposed to quercetin for 24 h. Blocking IGF-IR activity with IGF-IR antibody or neutralizing endogenous IGF-I activity with IGF-I antibody led to significant growth inhibition suggesting the role of IGF-I in regulation of KF proliferation. CONCLUSIONS: Because the IGF system plays an important part in fibroblast cell proliferation and collagen production, the described activities of quercetin on the IGF system and collagen expression may provide a novel approach for the use of quercetin in treatment and/or prevention of hypertrophic scar and keloid.