A non-Hermitian optical atomic mirror.

Explorations of symmetry and topology have led to important breakthroughs in quantum optics, but much richer behaviors arise from the non-Hermitian nature of light-matter interactions. A high-reflectivity, non-Hermitian optical mirror can be realized by a two-dimensional subwavelength array of neutral atoms near the cooperative resonance associated with the collective dipole modes. Here we show that exceptional points develop from a nondefective degeneracy by lowering the crystal symmetry of a square atomic lattice, and dispersive bulk Fermi arcs that originate from exceptional points are truncated by the light cone. From its nontrivial energy spectra topology, we demonstrate that the geometry-dependent non-Hermitian skin effect emerges in a ribbon geometry. Furthermore, skin modes localized at a boundary show a scale-free behavior that stems from the long-range interaction and whose mechanism goes beyond the framework of non-Bloch band theory. Our work opens the door to the study of the interplay among non-Hermiticity, topology, and long-range interaction.

Super- and sub-radiance from two-dimensional resonant dipole-dipole interactions.

We theoretically investigate the super- and sub-radiance from the resonant dipole-dipole interactions (RDDI) in a confined two-dimensional (2D) reservoir. The distinctive feature of 2D RDDI shows qualitatively and quantitatively different long-range behavior from RDDI in free space. We investigate the collective radiation properties of the singly-excited symmetric state under this 2D RDDI. This state also allows subradiant decays in much longer distances than the transition wavelength, showing longrange atom-atom correlations. We further study the dynamics of the subradiant states which can be accessed by imprinting spatially dependent phases on the atomic arrays. Our results demonstrate rich opportunities in engineering light-matter interactions in a confined 2D reservoir, and hold promise in applications of quantum light storage and single-excitation state manipulations.

Cooperative light scattering from helical-phase-imprinted atomic rings.

We theoretically investigate the light scattering of super- and subradiant states of an atomic ring prepared by single excitation with a photon which carries an orbital angular momentum (OAM). For excitations with linear polarizations, the helical phase imprinted (HPI) atomic ring presents a discrete C4 rotational symmetry when number of atoms N = 4n with integers n, while for circular polarizations with arbitrary N, the continuous and C N symmetries emerge for the super- and subradiant modes, respectively. The HPI superradiant modes predominantly scatter photons in the forward-backward direction, and the forward scattering can be further enhanced as atomic rings are stacked along the excitation direction. The HPI subradiant modes then preferentially scatter photons in the transversal directions, and when rings are stacked concentrically and on a plane, crossover from sub- to superradiance is observed which leads to splitting and localization of the far-field scattering patterns in the polar angle. The HPI super- and subradiant states are thus detectable through measuring the far-field radiation patterns, which further allow quantum storage and detection of a single photon with an OAM.

Directional subradiance from helical-phase-imprinted multiphoton states.

We theoretically investigate the far-field scattering properties of multiphoton super- and subradiant states which can be prepared by multiphoton excitations with orbital angular momentum (OAM). Due to multiphoton interference, the far-field patterns of the subradiant modes show directional scattering along the excitation direction or transverse scattering with number of peaks equal to the number of atoms. When more atoms are involved, we consider structures of stacked and concentric rings, which respectively show enhanced directional scattering and smoothed emission patterns. Our scheme gives insights to prepare many-body subradiant states, and is potentially applicable to quantum storage of multiphoton with OAM. By designing atomic spatial distributions, these cooperative states can tailor the far-field emission properties, which is useful for light collections and quantum information manipulations.

An unusual finding of schwannoma in the columellar area-A case report.

INTRODUCTION: Schwannomas are benign tumours of the nerve sheath that originate from Schwann cells. Less than 4% of these tumours arise in the sinonasal tract. Columellar involvement is extremely rare - three other cases involving the columella have been reported since 1967. PRESENTATION OF CASE: A 25-year-old woman presented with a swelling of the nasal columella from eight months into pregnancy. She presented with right nasal obstruction and discomfort over the nasal bridge. Pre-operative MRI and ultrasound were performed. The mass was surgically excised using an external septorhinoplasty approach giving a good cosmetic outcome. Histopathologic examination demonstrated schwannoma. DISCUSSION OF CASE: Nasal schwannoma may present with variable symptoms. We discuss the MRI and histological features of schwannoma. A literature review suggests that schwannomas may have accelerated growth in pregnancy. The open rhinoplasty approach is the favoured method for excision of schwannomas near the columellar region. CONCLUSION: Nasal schwannomas are rare in the sinonasal tract, however they need to be considered part of the differential diagnosis for nasal masses. The treatment of choice for these lesions is surgical excision.

Acute Osteochondral Fractures in the Lower Extremities - Approach to Identification and Treatment.

Chondral and osteochondral fractures of the lower extremities are important injuries because they can cause pain and dysfunction and often lead to osteoarthritis. These injuries can be misdiagnosed initially which may impact on the healing potential and result in poor long-term outcome. This comprehensive review focuses on current pitfalls in diagnosing acute osteochondral lesions, potential investigative techniques to minimize diagnostic errors as well as surgical treatment options. Acute osteochondral fractures are frequently missed and can be identified more accurately with specific imaging techniques. A number of different methods can be used to fix these fractures but attention to early diagnosis is required to limit progression to osteoarthritis. These fractures are common with joint injuries and early diagnosis and treatment should lead to improved long term outcomes.

Anatomical distribution of vertebral fractures: comparison of pediatric and adult spines.

SUMMARY: We compared the distribution of vertebral fractures in adults and children and found that fractures occurred in different locations in the two age groups. This likely relates to the different shape of the immature spine. INTRODUCTION: We hypothesized that the anatomical distribution of vertebral fractures (VF) would be different in children compared to adults. METHODS: We compared the distribution of VF defined using the Genant semi-quantitative method (GSQ method) in adults (N = 221; 545 fractures) and in children early in the course of glucocorticoid therapy (N = 44; 94 fractures). RESULTS: The average age in the adult cohort was 62.9 years (standard deviation (SD), 13.4 years), 26% was male, the mean lumbar spine Z-score was -1.0 (SD, 1.5), and the corresponding T-score was -2.4 (SD, 1.4). The pediatric cohort median age was 7.7 years (range, 2.1-16.6 years), the mean lumbar spine Z-score was -1.7 (SD, 1.5), 52% was male, and disease categories were acute lymphoblastic leukemia (66%), rheumatological conditions (21%), and nephrotic syndrome (14%). The VF distribution was biphasic in both populations, but the peaks differed in location. In adults, the peaks were at T7/T8 and at T12/L1. In children, the focus was higher in the thoracic spine, at T6/T7, and lower in the lumbar spine, at L1/L2. When children were assessed in two age-defined sub-groups, a biphasic VF distribution was seen in both, but the upward shift of the thoracic focus to T6 was observed only in the older group, with the highest rates of fracture present between ages 7 and 10 years. CONCLUSIONS: These results suggest that the anatomical distribution of VF differs between children and adults, perhaps relating to the different shape of the immature spine, notably the changing ratio of kyphosis to lordosis.

The accuracy of clinical kyphosis examination for detection of thoracic vertebral fractures: comparison of direct and indirect kyphosis measures.

OBJECTIVE: To compare the accuracies of two simple physical examination maneuvers for detecting the presence of thoracic vertebral fractures (VF) diagnosed by radiography: direct measurement of kyphosis angle (KA, in degrees) and indirect measurement using wall-occiput distance (WOD, in cm). METHODS: Subjects were 280 women (average age, 54.5 years; range, 18-92) referred for assessment of osteoporosis. KA was measured from T4 to T12 using a digital inclinometer while WOD was measured with the patient in a standardized position. VF were diagnosed on radiographs using semi-quantitative morphometry. RESULTS: KA and WOD were moderately correlated (r = 0.72, p<10(-11)). KA increased by 3.7(o) (95% CI, 2.6-4.8(o)) for each VF (p = 4x 10(-11)) and WOD rose 1.3 cm (95% CI, 0.8-1.7 cm) per VF (p = 2 x 10(-11)). The areas under the receiver operating characteristic curves were 0.72 (95% CI, 0.65-0.79) for KA and 0.76 (95% CI, 0.69-0.82) for WOD, which were not significantly different (p = 0.13). CONCLUSIONS: Given similar performances of direct and indirect measures of kyphosis, we propose that WOD should be used in clinical practice, with a clinical threshold of WOD>4.0 cm as an indication to consider spine radiography. At this WOD threshold, sensitivity was 41% (95% CI, 31-52%) and specificity was 92% (95% CI, 87-95%). WOD should be considered for use in the clinical assessment of osteoporosis patients.

Prognostic prediction across a gradient of total tumor volume in patients with hepatocellular carcinoma undergoing locoregional therapy.

BACKGROUND: The size and number of tumors are important prognostic indicators for hepatocellular carcinoma (HCC). However, it is difficult to assess the prognosis for patients with a variable number and size of tumors. By combining these two factors, we investigated the role and prognostic accuracy of total tumor volume (TTV) for HCC. METHODS: A total of 786 patients undergoing locoregional therapy (transarterial chemoembolization, percutaneous radiofrequency ablation and acetic acid or ethanol injection) for HCC were prospectively evaluated. RESULTS: The mean and median TTV was 177 cm3 (range, 0.1-3,591 cm3) and 21 cm3, respectively. Of all, 38%, 29%, 15%, 7% and 11% of patients had TTV of <10 cm3, 10-50 cm3, 50-200 cm3, 200-500 cm3 and >500 cm3, respectively. TTV was significantly larger in patients with higher serum α-fetoprotein (AFP) levels or with vascular invasion. The Child-Turcotte-Pugh score, performance status, vascular invasion, AFP level and TTV were significant independent prognostic predictors in the Cox proportional hazards model. After adjustment, patients with TTV 50-200 cm3 (relative risk [RR]: 1.74, p = 0.009), 200-500 cm3 (RR: 2.15, p = 0.006) and >500 cm3 (RR: 3.92, p < 0.001) had a significantly increased mortality risk in comparison to patients with TTV <10 cm3. CONCLUSIONS: TTV is a feasible prognostic predictor across a wide gradient and can be used to predict the mortality risk of HCC. Selecting appropriate cutoffs of TTV may help refine the design of cancer staging system and treatment planning. Future clinical trials of HCC may include this parameter for mortality risk stratification.

Fenofibrate attenuates endothelial monocyte adhesion in chronic heart failure: an in vitro study.

BACKGROUND: Inflammation is implicated in chronic heart failure (CHF). In this study, the potential inhibitory effect of peroxisome proliferator-activated receptor-alpha (PPARalpha) activator fenofibrate on monocyte adhesion in CHF patients was investigated in vitro. MATERIALS AND METHODS: Isolated peripheral blood mononuclear cells (PBMCs) were collected from 36 patients (aged 65 +/- 8 years) with symptomatic CHF and from 12 healthy control subjects. The cultured human aortic endothelial cells (HAECs) were stimulated with or without 2 ng mL(-1) tumour necrosis factor-alpha (TNF-alpha) and the inhibitory effects of fenofibrate at 25, 50, 100 and 200 microM on endothelial mononuclear cell adhesion were tested. Furthermore, the HAECs were stimulated with 70% sera obtained from CHF patients and control individuals, respectively, with or without pretreatments with fenofibrate. The endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) was then confirmed by mRNA expression and Western blot. RESULTS: We found that the increased adhesion of PBMCs to TNF-alpha-stimulated HAECs in CHF patients was reduced when the HAECs were pretreated with fenofibrate (31% inhibition, P = 0.0121). However, pretreatment of the isolated PBMCs collected from CHF patients with fenofibrate failed to suppress their adherence to TNF-alpha-stimulated HAECs. Furthermore, stimulation of cultured HAECs with CHF patient sera significantly increased VCAM-1 and ICAM-1 expression, which could also be inhibited by fenofibrate. CONCLUSIONS: The fenofibrate directly inhibits monocyte binding by TNF-alpha-activated HAECs, probably through preventing up-regulation of cell adhesion molecules by endothelial cells in response to inflammatory stimuli. This PPARalpha activator may have the potential to ameliorate vascular inflammation in patients with CHF.

Occurrence of tetrodotoxin and paralytic shellfish poisons in a gastropod implicated in food poisoning in southern Taiwan.

The toxicity of the gastropod Nassarius papillosus implicated in a food paralytic poisoning incident in Liuchiu Island, Taiwan, in October 2005 is reported. The symptoms of a victim (67 years old) were featured by general paresthesia, paralysis of phalanges and extremities, paralysis, coma, and aphasia. The remaining specimens of shell were assayed for toxicity. The range of specimen toxicity was found to be 63-474 mouse units (MU) per specimen for N. papillosus by a tetrodotoxin (TTX) bioassay. The mean (SD) toxicity of the digestive gland and other portions were 296 +/- 120 and 382 +/- 156 MU in N. papillosus. The toxin was partially purified from the acidic methanol extract of the gastropod by using a C18 solid-phase extraction column. The eluate was then filtered through a 3000 MW cut-off ultrafree microcentrifuge filter. It was shown that the toxin purified from gastropods analysed by high-performance liquid chromatography and liquid chromatography/mass spectrometry contained TTX 42-60 microg g(-1) (about 90%), whereas along with minor paralytic shellfish poisons (PSP) it was 3-6 microg g(-1) (about 10%).

Identification of regional air pollution characteristic and the correlation with public health in Taiwan.

This study aims to classify regions with different air pollution characteristics into groups in Taiwan, and further to evaluate and compare the air quality of various groups. A selected multivariate analysis technique, cluster analysis, is applied to the pollution monitoring dataset which including PM10, SO2, NO2, CO and O3. The obtained results have proved that the regions with similar air pollution characteristic can be appropriately grouped by applying cluster analysis. All 22 regions are classified into six groups, and the pollution pattern for each group is characterized as: Group 1 (high SO2/NO2; low PM10), Group 2 (high PM10), Group 3 (high SO2/PM10), Group 4 (low SO2/NO2/CO; high O3), Group 5 (low CO/NO2; high O3) and Group 6 (low PM10/SO2/NO2/O3/CO). Results from air quality evaluation indicate that the regions in group 6 (Ilan, Hualien and Taitung) have the best air quality while the regions in group 3 (Kaohsiung and Kaohsiung City) have the worst air quality in Taiwan. The results from correlation analysis reveal that incidence of the respiratory system disease is significantly positively correlated with pollution of NO2 and CO at 99% confidence level.

Angular momentum of a magnetically trapped atomic condensate.

For an atomic condensate in an axially symmetric magnetic trap, the sum of the axial components of the orbital angular momentum and the hyperfine spin is conserved. Inside an Ioffe-Pritchard trap (IPT) whose magnetic field (B field) is not axially symmetric, the difference of the two becomes surprisingly conserved. In this Letter we investigate the relationship between the values of the sum or difference angular momentums for an atomic condensate inside a magnetic trap and the associated gauge potential induced by the adiabatic approximation. Our result provides significant new insight into the vorticity of magnetically trapped atomic quantum gases.

Differential effects of peroxisome proliferator-activated receptor ligands and sulfonylurea plus statin treatment on plasma concentrations of adipokines in type 2 diabetes with dyslipidemia.

OBJECTIVES: Peroxisome proliferator-activated receptor gamma is the master regulator of adipocyte differentiation and controls many adipocyte genes in response to anti-diabetic thiazolidinediones (TZDs) and lipid-lowering fibrates. We hypothesized that the combination of TZD+fibrate may be better than the sulfonylurea + statin approach regarding modifying the adipokine profile in diabetic patients with dyslipidemia. METHODS: We measured the lipid profiles and circulating levels of adiponectin, resistin, and inflammatory markers before and after treatment in 24 type 2 diabetic patients with dyslipidemia (aged 64+/-9 years; M/F=5/19). The study patients were randomly assigned to receive an 8-week treatment of either rosiglitazone 4 mg daily and fenofibrate 160 mg daily (PPAR group) or glibenclamide 5 mg daily and atorvastatin 10 mg daily (non-PPAR group). RESULTS: Even though the administration of sulfonylurea+statin can achieve a greater reduction of total cholesterol and LDL-cholesterol levels and a comparable glucose control compared to PPAR treatment, their administration did not change the plasma adipokine levels significantly. In contrast, a significant greater increase of the plasma concentrations of adiponectin (P<0.0001), a trend to a greater decrease of the plasma resistin levels (P=0.061), a significantly greater increase of HDL-cholesterol (P=0.002), and a significantly greater reduction of triglyceride levels (P=0.018) were seen in the PPAR group. CONCLUSIONS: Considering the clinical significance of the adipokine-endothelial interaction in the progression and long-term prognosis of atherosclerosis, the differential effects of PPAR ligands and sulfonylurea+statin on plasma adipokine concentrations demonstrated in this study are interesting foci of investigation in the future.

The accuracy of historical height loss for the detection of vertebral fractures in postmenopausal women.

Historical height loss (HHL) can be calculated as the difference between a patient's tallest recalled height (TRH) and the current measured height (MH). We have examined the accuracy of HHL as a clinical test for the detection of prevalent vertebral fractures. Subjects were postmenopausal women aged 50 or older who had been referred for specialist assessment of osteoporosis risk (n=323; average age 66.0+/-9.2 years; range 50-92 years). MH was determined using a wall-mounted stadiometer. The presence of prevalent vertebral fractures was assessed by radiographic morphometry, with fracture defined as a vertebral height ratio<0.8. The positive likelihood ratio (LR+) for fracture was relatively flat until HHL>6.0 cm. With HHL from 6.1 to 8.0 cm, the LR+ was 2.8 [95% confidence interval (95%CI), 1.3, 6.0]. When HHL was >8.0 cm, the LR+ was 9.8 (95% CI, 3.0, 31.8). The area under the receiver operating characteristics curve for the ability of HHL to detect fracture was 0.66 (95% CI, 0.59, 0.72). At HHL>6.0 cm, sensitivity was 30% (95% CI, 22, 37%), and specificity was 94% (95% CI, 90, 97%). The positive predictive value was relatively low across a range of theoretical prevalence, rising above 80% only at very high prevalence rates (>50%). In contrast, the negative predictive value was high at the prevalence rates seen in most clinical practice, and dropped below 80% only when the prevalence exceeded 25%. This study shows that HHL6.0 cm should have spine radiographs to examine for the presence of vertebral fractures.

Intraneural perineurioma in a child with Beckwith-Wiedemann syndrome.

To the authors' knowledge, this is the first report of an intraneural perineurioma in a child with Beckwith-Wiedemann syndrome. Intraneural perineurioma, previously known as localized hypertrophic neuropathy, is a rare benign peripheral nerve sheath tumor arising from perineurium. This report adds a new entity in the spectrum of tumor formation in Beckwith-Wiedemann syndrome.

Cardiac aspergillosis in patients with acquired immunodeficiency syndrome: a case report and review of the literature.

Cardiac aspergillosis is uncommon in patients with acquired immunodeficiency syndrome (AIDS) in the absence of open heart surgery. We report a unique case of a 62-year-old man with AIDS who developed Aspergillus pancarditis with Aspergillus vegetations on mitral valve without evidence of pulmonary aspergillosis. There was extensive embolization to the brain and multiple foci of Aspergillus infection in kidneys and adrenal glands. There are only 10 documented cases of cardiac aspergillosis in the literature (1966-2003) in severely immunocompromised AIDS patients with CD4 T-lymphocyte counts ranging from 10 to 121 cells/muL. The cardiac aspergillosis could result from invasive pulmonary aspergillosis, either by hematogenous dissemination or by direct invasion, and skin Aspergillus infection can be carried through the bloodstream to the right heart in intravenous drug abusers. Most of the reported cases of cardiac aspergillosis were diagnosed at autopsy. Mortality among AIDS patients with cardiac aspergillosis is 100%, despite appropriate therapy.