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2.
QJM ; 114(12): 857-864, 2022 Jan 09.
Article in English | MEDLINE | ID: mdl-32821936

ABSTRACT

BACKGROUND: Many patients with atopic diseases, including asthma, have sought complementary and alternative medicine and traditional Chinese medicine (TCM) treatments. But, limited clinical studies have yet examined TCM effects on medical utility in asthma patients. AIM: To assess the medical utility of TCM in patients with asthma. DESIGN: Population-based retrospective cohort study. METHODS: We performed a 13-year population-based retrospective cohort study. A total of 5235 asthma patients who were TCM users and 5235 propensity-score matched asthma patients who never used TCM were sampled from the Taiwan National Health Insurance Research Database from 2000 to 2012. We compared these two groups of patients to calculate their medical utility, including numbers of emergency visits and hospitalizations until 2013. Univariate analyses were performed using Chi-square tests for dichotomous variables and t-tests for continuous variables. Cox proportional hazard models were conducted to investigate the medical utility of asthma after TCM use. RESULTS: Compared with non-TCM patients, TCM patients had a significantly decreased medical utility of asthma admission [adjusted odds ratio (OR) = 0.63; 95% confidence interval (CI): 0.46-0.85; P < 0.05], especially in patients who used TCM for >60 days. Asthma medical utility in asthma emergencies was significantly higher for male than for female patients (adjusted OR = 1.45; 95% CI: 1.08-1.96). The most frequently used TCMs for asthma control or cough treatment were antitussive agents. CONCLUSION: This population-based retrospective cohort study showed a significantly decreased medical utility of emergency visits and admissions in TCM patients, especially using TCM for >60 days.


Subject(s)
Asthma , Drugs, Chinese Herbal , Asthma/drug therapy , Asthma/epidemiology , Cohort Studies , Female , Humans , Male , Medicine, Chinese Traditional , Retrospective Studies , Taiwan/epidemiology
3.
Rev Sci Instrum ; 92(1): 014101, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33514206

ABSTRACT

This study investigated the abnormal pupillary light reflex in patients with early diabetes mellitus (DM) without retinopathy by using a custom-made noninvasive portable pupilometer. The pupilometer recorded and analyzed the pupillary light reflex. Two light intensities, 0.2 cd and 1.2 cd, and four wavelengths of stimulus light-white (400 nm-800 nm), red (640 ± 5 nm), green (534 ± 5 nm), and blue (470 ± 5 nm)-were used to stimulate the pupil for 10 ms. The pupillary response was recorded for 15 s. A total of 40 healthy people and 40 people with DM without retinopathy participated in the experiment at the National Taiwan University Hospital. The mean and standard deviation of DM duration were 4.5 years and 3.9 years. Of the 16 indices, the duration that pupil restores from its minimum size to half of its resting size (DRP), maximum pupil restoration velocity (MRV), and average restoration velocity (ARV) exhibited the most significant differences between the healthy people and those with DM. Compared with healthy participants, DRP was 16.33% higher, and MRV and ARV were 17.45% and 4.58% lower, respectively, in those with DM. This might be attributable to the sympathetic nervous system (SNS) controlling the dilator muscle during the dark-adapted period and relaxing the pupil; the SNS had few degenerated nerve endings in people with DM. The three aforementioned indices might be used to evaluate the severity of autonomic neuropathy in early DM.


Subject(s)
Diabetes Mellitus/diagnosis , Diabetes Mellitus/physiopathology , Light , Reflex, Pupillary , Adult , Female , Humans , Male
4.
Phys Rev B ; 1012020.
Article in English | MEDLINE | ID: mdl-38855404

ABSTRACT

In this study, the inelastic neutron scattering probe of SIKA in ANSTO is employed to investigate the magnon dispersion curve in ferromagnetic SrRuO3 single crystal epitaxial films and to better understand the underlying mechanisms. This report presents the successful measurement of a magnon peak from the SrRuO3 films which contained an amount of material of only 0.9 mg. We reveal one significant magnon dispersion curve along [002] following the quadratic E ∝ Q 2 ) relation, which shows a magnon gap of 0.32 meV. We have discussed several possible mechanisms, such as the higher symmetry structure and the impurity levels, which may contribute to this smaller gap.

5.
Sci Rep ; 9(1): 18586, 2019 Dec 09.
Article in English | MEDLINE | ID: mdl-31819082

ABSTRACT

Temperature-dependent X-ray absorption near-edge structures, X-ray linear dichroism (XLD) and extended X-ray absorption fine structure (EXAFS) spectroscopic techniques were used to investigate the valence state, preferred orbital and local atomic structure that significantly affect the electrical and magnetic properties of a single crystal of YBaCuFeO5 (YBCFO). An onset of increase of resistivity at ~180 K, followed by a rapid increase at/below 125 K, is observed. An antiferromagnetic (AFM)-like transition is close to the temperature at which the resistivity starts to increase in the ab-plane and is also observed with strong anisotropy between the ab-plane and the c-axis. The XLD spectra at the Fe L3,2-edge revealed a change in Fe 3d eg holes from the preferential [Formula: see text] orbital at high temperature (300-150 K) to the [Formula: see text] orbital at/below 125 K. The analysis of the Fe K-edge EXAFS data of YBCFO further revealed an unusual increase in the Debye-Waller factor of the nearest-neighbor Fe-O bond length at/below 125 K, suggesting phonon-softening behavior, resulting in the breaking of lattice symmetry, particularly in the ab-plane of Fe-related square pyramids. These findings demonstrate a close correlation between electrical resistivity and coupling of the preferred Fe 3d orbital with lattice distortion of a single crystal of YBCFO.

6.
Proc Natl Acad Sci U S A ; 116(45): 22458-22463, 2019 Nov 05.
Article in English | MEDLINE | ID: mdl-31641068

ABSTRACT

This study investigates the evolution of superconductivity in K2-xFe4+ySe5 using temperature-dependent X-ray absorption and resonant inelastic X-ray scattering techniques. Magnetization measurements show that polycrystalline superconducting (SC) K1.9Fe4.2Se5 has a critical temperature (T c) of ∼31 K with a varying superconducting volume fraction, which strongly depends on its synthesis temperature. An increase in Fe-structural/vacancy disorder in SC samples with more Fe atoms occupying vacant 4d sites is found to be closely related to the decrease in the spin magnetic moment of Fe. Moreover, the nearest-neighbor Fe-Se bond length in SC samples exceeds that in the non-SC (NS) sample, K2Fe4Se5, which indicates a weaker hybridization between the Fe 3d and Se 4p states in SC samples. These results clearly demonstrate the correlations among the local electronic and atomic structures and the magnetic properties of K2-xFe4+ySe5 superconductors, providing deeper insight into the electron pairing mechanisms of superconductivity.

7.
QJM ; 112(10): 757-762, 2019 Oct 01.
Article in English | MEDLINE | ID: mdl-31218368

ABSTRACT

OBJECTIVES: To determine whether taking hydroxychloroquine (HCQ) could prevent the development of new-onset diabetes mellitus (DM) among patients with Sjögren syndrome (SS). METHODS: This is a nationwide, population-based, retrospective cohort study utilizing the Taiwan National Health Insurance Research Database (NHIRD). Data were collected from 1 January 1999, through 31 December 2013, using the International Classification of Diseases, Ninth Revision, Clinical Modification codes. In total, 7774 patients newly diagnosed with SS by at least three outpatient visits or one inpatient admission were selected from the NHIRD as participants. Patients who had previously been diagnosed with DM and whose follow-up durations shorter than 90 days were excluded. HCQ exposure group includes patients who had been diagnosed with SS no longer than 180 days previously, and had been prescribed HCQ for the first time for at least 90 days. The diagnosis of DM was defined as at least two outpatient visits or one inpatient admission with anti-diabetic medication prescription. RESULTS: Patients with SS treated with HCQ had a significantly lower cumulative incidence of new-onset DM than those not treated with HCQ (adjusted hazard ratio: 0.51, 95% confidence interval: 0.28-0.96, P < 0.05). HCQ use for 3 years or more had favorable protective effects (adjusted hazard ratio: 0.22, CI: 0.05-0.92). CONCLUSIONS: HCQ reduced the incidence of DM in a time and dose-dependent manner. Patients with SS who had taken HCQ for 3 years or more exhibited significant protective effects against developing new-onset DM.


Subject(s)
Antirheumatic Agents/therapeutic use , Diabetes Mellitus/epidemiology , Diabetes Mellitus/prevention & control , Hydroxychloroquine/therapeutic use , Sjogren's Syndrome/complications , Adult , Aged , Databases, Factual , Female , Glucose/metabolism , Humans , Incidence , Kaplan-Meier Estimate , Male , Middle Aged , Proportional Hazards Models , Retrospective Studies , Risk Reduction Behavior , Sjogren's Syndrome/drug therapy , Taiwan
8.
Sci Rep ; 9(1): 5160, 2019 Mar 26.
Article in English | MEDLINE | ID: mdl-30914713

ABSTRACT

This study probes the temperature-dependent strain that is strongly correlated with the orbital and magnetic structures of epitaxial films of Nd0.35Sr0.65MnO3 (NSMO) that are fabricated by pulsed laser deposition with two thicknesses, 17 (NS17) and 103 nm (NS103) on SrTiO3 (STO) substrate. This investigation is probed using X-ray diffraction (XRD) and absorption-based techniques, X-ray linear dichroism (XLD) and the X-ray magnetic circular dichroism (XMCD). XRD indicates a significant shift in the (004) peak position that is associated with larger strain in NS17 relative to that of NS103 at both 30 and 300 K. Experimental and atomic multiplet simulated temperature-dependent Mn L3,2-edge XLD results reveal that the stronger strain in a thinner NS17 film causes less splitting of Mn 3d eg state at low temperature, indicating an enhancement of orbital fluctuations in the band above the Fermi level. This greater Mn 3d orbital fluctuation can be the cause of both the enhanced ferromagnetism (FM) as a result of spin moments and the reduced Néel temperature of C-type antiferromagnetism (AFM) in NS17, leading to the FM coupling of the canted-antiferromagnetism (FM-cAFM) state in NSMO/STO epitaxial films at low temperature (T = 30 K). These findings are also confirmed by Mn L3,2-edge XMCD measurements.

9.
Lupus ; 27(14): 2279-2283, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30451639

ABSTRACT

BACKGROUND: Viral infection contributing to systemic lupus erythematosus (SLE) development has been largely reported. However, the SLE risk in patients with human papillomavirus (HPV) infection is unknown. METHODS: Data were retrieved from the Longitudinal Health Insurance Database (2000) in Taiwan. We identified 43,567 patients with HPV infection and 174,268 age- and sex-matched uninfected controls from 2002 to 2012. Individuals were followed up from index date (first date of diagnosis with HPV) until the occurrence of SLE, at the end of the study (December 2013), or when they were withdrawn from the insurance program. The incidence rate ratio (IRR) was calculated using the univariate Poisson regression. The adjusted hazard ratios (aHRs) were calculated, and sensitive and subgroups analyses were also conducted. RESULTS: Compared with the non-HPV controls, the IRR of SLE in HPV patients was 1.52 (95% confidence interval (CI): 1.09-2.12). The risk of SLE in HPV-infected individuals was significantly high (aHR: 1.48, 95% CI: 1.06-2.06) after adjusting for age, sex, and comorbidities. Men aged between 16 and 45 years were more susceptible to developing SLE (aHR: 21.57, 95% CI: 2.52-184.60, p = 0.0051). CONCLUSION: Our study showed a significantly higher risk of SLE among HPV-infected patients, especially in men aged between 16 and 45 years.


Subject(s)
Lupus Erythematosus, Systemic/epidemiology , Papillomavirus Infections/epidemiology , Adolescent , Adult , Case-Control Studies , Comorbidity , Female , Humans , Incidence , Kaplan-Meier Estimate , Male , Middle Aged , Proportional Hazards Models , Retrospective Studies , Risk Factors , Taiwan/epidemiology , Time Factors , Young Adult
10.
Sci Rep ; 8(1): 15779, 2018 Oct 25.
Article in English | MEDLINE | ID: mdl-30361523

ABSTRACT

This investigation reports on anisotropy in the magnetic interaction, lattice-orbital coupling and degree of phonon softening in single crystal Ni3TeO6 (NTO) using temperature- and polarization-dependent X-ray absorption spectroscopic techniques. The magnetic field-cooled and zero-field-cooled measurements and temperature-dependent Ni L3,2-edge X-ray magnetic circular dichroism spectra of NTO reveal a weak Ni-Ni ferromagnetic interaction close to ~60 K (TSO: temperature of the onset of spin ordering) with a net alignment of Ni spins (the uncompensated components of the Ni moments) along the crystallographic c-axis, which is absent from the ab-plane. Below the Néel temperature, TN~ 52 K, NTO is stable in the antiferromagnetic state with its spin axis parallel to the c-axis. The Ni L3,2-edge X-ray linear dichroism results indicate that above TSO, the Ni 3d eg electrons preferentially occupy the out-of-plane 3d3z2-r2 orbitals and switch to the in-plane 3dx2-y2 orbitals below TSO. The inherent distortion of the NiO6 octahedra and anisotropic nearest-neighbor Ni-O bond lengths between the c-axis and the ab-plane of NTO, followed by anomalous Debye-Waller factors and orbital-lattice in conjunction with spin-phonon couplings, stabilize the occupied out-of-plane (3d3z2-r2) and in-plane (3dx2-y2) Ni eg orbitals above and below TSO, respectively.

11.
Clin Radiol ; 73(9): 836.e17-836.e22, 2018 09.
Article in English | MEDLINE | ID: mdl-29945717

ABSTRACT

AIM: To demonstrate the risk of cataract associated with radiation exposure from neuro-interventional procedures. MATERIALS AND METHODS: This was a nationwide population-based, matched-cohort study. The exposed group (group E) comprised patients diagnosed with an aneurysm, cerebrovascular system anomaly, or subarachnoid haemorrhage who underwent a neuro-interventional procedure, such as brain digital subtraction angiography or endovascular embolisation. The comparison group (group C) included subjects who were never exposed to radiation from neuro-interventional procedures and were propensity score-matched by the date of enrolment, age, sex, and associated comorbidities. Multiple Cox proportional hazard regression analysis was used to estimate the hazard ratio (HR) of cataract risk due to radiation exposure while adjusting for potential confounding factors. RESULTS: There were 838 patients and 3,352 matched subjects in groups E and C, respectively. The incidence of cataracts was significantly greater among subjects in group E (adjusted HR [aHR] = 1.88; 95% confidence interval [CI] = 1.08-3.26), especially those aged >40 years (aHR = 2.14; 95% CI = 1.16-3.94). The number of computed tomography examinations was positively correlated, but not statistically significant, with an increased risk of cataract occurrence. CONCLUSIONS: Neuro-interventional procedures might be significantly associated with an increased risk of cataract occurrence.


Subject(s)
Cataract/etiology , Neuroimaging/adverse effects , Nuclear Medicine , Radiography, Interventional/adverse effects , Adult , Cataract/epidemiology , Female , Humans , Male , Middle Aged , Propensity Score , Risk Factors , Taiwan/epidemiology
12.
Sci Rep ; 8(1): 7758, 2018 May 17.
Article in English | MEDLINE | ID: mdl-29773822

ABSTRACT

Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C+ ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K-edge respectively indicate there is a reduction in the number of unpaired/dangling O 2p bonds in the surface region of ZnO-C:NW and the C 2p-derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.

14.
Sci Rep ; 7(1): 161, 2017 03 13.
Article in English | MEDLINE | ID: mdl-28279015

ABSTRACT

The local electronic and atomic structures of the high-quality single crystal of SrFeO3-δ (δ~0.19) were studied using temperature-dependent x-ray absorption and valence-band photoemission spectroscopy (VB-PES) to investigate the origin of anisotropic resistivity in the ab-plane and along the c-axis close to the region of thermal hysteresis (near temperature for susceptibility maximum, Tm~78 K). All experiments herein were conducted during warming and cooling processes. The Fe L 3,2-edge X-ray linear dichroism results show that during cooling from room temperature to below the transition temperature, the unoccupied Fe 3d e g states remain in persistently out-of-plane 3d 3z2-r2 orbitals. In contrast, in the warming process below the transition temperature, they change from 3d 3z2-r2 to in-plane 3d x2-y2 orbitals. The nearest-neighbor (NN) Fe-O bond lengths also exhibit anisotropic behavior in the ab-plane and along the c-axis below Tm. The anisotropic NN Fe-O bond lengths and Debye-Waller factors stabilize the in-plane Fe 3d x2-y2 and out-of-plane 3d 3z2-r2 orbitals during warming and cooling, respectively. Additionally, a VB-PES study further confirms that a relative band gap opens at low temperature in both the ab-plane and along the c-axis, providing the clear evidence of the charge-density-wave nature of SrFeO3-δ (δ~0.19) single crystal.

15.
Sci Rep ; 7: 40886, 2017 01 20.
Article in English | MEDLINE | ID: mdl-28106144

ABSTRACT

X-ray scattering (XRS), x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopic techniques were used to study the electronic and atomic structures of the high-quality Sr3Ir4Sn13 (SIS) single crystal below and above the transition temperature (T* ≈ 147 K). The evolution of a series of modulated satellite peaks below the transition temperature in the XRS experiment indicated the formation of a possible charge density wave (CDW) in the (110) plane. The EXAFS phase derivative analysis supports the CDW-like formation by revealing different bond distances [Sn1(2)-Sn2] below and above T* in the (110) plane. XANES spectra at the Ir L3-edge and Sn K-edge demonstrated an increase (decrease) in the unoccupied (occupied) density of Ir 5d-derived states and a nearly constant density of Sn 5p-derived states at temperatures T < T* in the (110) plane. These observations clearly suggest that the Ir 5d-derived states are closely related to the anomalous resistivity transition. Accordingly, a close relationship exists between local electronic and atomic structures and the CDW-like phase in the SIS single crystal.

16.
Sci Rep ; 5: 15439, 2015 Oct 20.
Article in English | MEDLINE | ID: mdl-26481557

ABSTRACT

This investigation studies the various magnetic behaviors of graphene oxide (GO) and reduced graphene oxides (rGOs) and elucidates the relationship between the chemical states that involve defects therein and their magnetic behaviors in GO sheets. Magnetic hysteresis loop reveals that the GO is ferromagnetic whereas photo-thermal moderately reduced graphene oxide (M-rGO) and heavily reduced graphene oxide (H-rGO) gradually become paramagnetic behavior at room temperature. Scanning transmission X-ray microscopy and corresponding X-ray absorption near-edge structure spectroscopy were utilized to investigate thoroughly the variation of the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups, as well as the C 2p(σ*)-derived states in flat and wrinkle regions to clarify the relationship between the spatially-resolved chemical states and the magnetism of GO, M-rGO and H-rGO. The results of X-ray magnetic circular dichroism further support the finding that C 2p(σ*)-derived states are the main origin of the magnetism of GO. Based on experimental results and first-principles calculations, the variation in magnetic behavior from GO to M-rGO and to H-rGO is interpreted, and the origin of ferromagnetism is identified as the C 2p(σ*)-derived states that involve defects/vacancies rather than the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups on GO sheets.


Subject(s)
Graphite/chemistry , Microscopy , Oxides/chemistry , X-Ray Absorption Spectroscopy , Microscopy/methods , Models, Theoretical , X-Ray Absorption Spectroscopy/methods
17.
Sci Rep ; 5: 11466, 2015 Jun 22.
Article in English | MEDLINE | ID: mdl-26098075

ABSTRACT

The correlation between sub-band gap absorption and the chemical states and electronic and atomic structures of S-hyperdoped Si have been extensively studied, using synchrotron-based x-ray photoelectron spectroscopy (XPS), x-ray absorption near-edge spectroscopy (XANES), extended x-ray absorption fine structure (EXAFS), valence-band photoemission spectroscopy (VB-PES) and first-principles calculation. S 2p XPS spectra reveal that the S-hyperdoped Si with the greatest (~87%) sub-band gap absorption contains the highest concentration of S(2-) (monosulfide) species. Annealing S-hyperdoped Si reduces the sub-band gap absorptance and the concentration of S(2-) species, but significantly increases the concentration of larger S clusters [polysulfides (Sn(2-), n > 2)]. The Si K-edge XANES spectra show that S hyperdoping in Si increases (decreased) the occupied (unoccupied) electronic density of states at/above the conduction-band-minimum. VB-PES spectra evidently reveal that the S-dopants not only form an impurity band deep within the band gap, giving rise to the sub-band gap absorption, but also cause the insulator-to-metal transition in S-hyperdoped Si samples. Based on the experimental results and the calculations by density functional theory, the chemical state of the S species and the formation of the S-dopant states in the band gap of Si are critical in determining the sub-band gap absorptance of hyperdoped Si samples.

18.
Eur J Surg Oncol ; 41(5): 702-6, 2015 May.
Article in English | MEDLINE | ID: mdl-25680953

ABSTRACT

BACKGROUND: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) can be complicated by pulmonary emboli (PE). Patients are at high risk due to surgery, underlying malignancy, immobility and indwelling lines. OBJECTIVES: This paper aims to identify clinically significant signs and symptoms preceding acute PE in post CRS-HIPEC patients, assess the PE investigative approach in this population and the significance of PE on patient management. METHOD: 25 cases with a positive and 50 controls with a negative CTPA for PE were isolated from the peritonectomy database at St George Hospital Sydney, January 2006 to July 2013. Vital signs, patient symptoms, adjunct investigation findings and patient outcomes were collected and graphed in Microsoft Excel. P values and 95% confidence intervals were calculated using GraphPad Prism version 6. RESULTS: 25 of 562 (4.4%) CRS-HIPEC patients were diagnosed with acute PE. Raised body temperature was the only statistically significant clinical finding that differentiated cases from controls (p value 0.02). Arterial blood gas results did not correlate with PE (p values 0.62; 0.29; 0.55, 0.84). Troponin, ECG and CXR were not routinely conducted. CXR and CTPA findings were similar between cases and controls (Table 4). PE patients required lower supplementary oxygen and escalation of care. CONCLUSION: Body temperature is the only statistically significant clinical finding observed with PE. We recommend a standardised investigative approach consisting of troponin, ECG and CXR. PE in CRS-HIPEC does not cause significant cardio-respiratory dysfunction, or escalation of care. PE rates are higher than other major surgeries, thus we propose a trial with increased chemical prophylaxis in CRS-HIPEC patients.


Subject(s)
Antineoplastic Agents/therapeutic use , Cytoreduction Surgical Procedures , Hyperthermia, Induced , Peritoneal Neoplasms/therapy , Peritoneum/surgery , Postoperative Complications/epidemiology , Pulmonary Embolism/epidemiology , Adult , Aged , Aged, 80 and over , Angiography , Appendiceal Neoplasms/pathology , Chest Pain/etiology , Colorectal Neoplasms/pathology , Dyspnea/etiology , Female , Humans , Infusions, Parenteral , Male , Middle Aged , Ovarian Neoplasms/pathology , Peritoneal Neoplasms/secondary , Postoperative Complications/diagnostic imaging , Pulmonary Embolism/complications , Pulmonary Embolism/diagnostic imaging , Risk Factors , Tomography, X-Ray Computed , Young Adult
19.
Sci Rep ; 4: 4525, 2014 Apr 10.
Article in English | MEDLINE | ID: mdl-24717290

ABSTRACT

Electronic structures of graphene oxide (GO) and hydro-thermally reduced graphene oxides (rGOs) processed at low temperatures (120-180°C) were studied using X-ray absorption near-edge structure (XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). C K-edge XANES spectra of rGOs reveal that thermal reduction restores C = C sp(2) bonds and removes some of the oxygen and hydroxyl groups of GO, which initiates the evolution of carbonaceous species. The combination of C K-edge XANES and Kα XES spectra shows that the overlapping π and π* orbitals in rGOs and GO are similar to that of highly ordered pyrolytic graphite (HOPG), which has no band-gap. C Kα RIXS spectra provide evidence that thermal reduction changes the density of states (DOSs) that is generated in the π-region and/or in the gap between the π and π* levels of the GO and rGOs. Two-dimensional C Kα RIXS mapping of the heavy reduction of rGOs further confirms that the residual oxygen and/or oxygen-containing functional groups modify the π and σ features, which are dispersed by the photon excitation energy. The dispersion behavior near the K point is approximately linear and differs from the parabolic-like dispersion observed in HOPG.

20.
Article in English | MEDLINE | ID: mdl-24110470

ABSTRACT

This paper proposed a wireless power harvesting system with micro-electro-mechanical-systems (MEMS) fabrication for noninvasive intraocular pressure (IOP) measurement on soft contact lens substructure. The power harvesting IC consists of a loop antenna, an impedance matching network and a rectifier. The proposed IC has been designed and fabricated by CMOS 0.18 um process that operates at the ISM band of 5.8 GHz. The antenna and the power harvesting IC would be bonded together by using flip chip bonding technologies without extra wire interference. The circuit utilized an impedance transformation circuit to boost the input RF signal that improves the circuit performance. The proposed design achieves an RF-to-DC conversion efficiency of 35% at 5.8 GHz.


Subject(s)
Intraocular Pressure/physiology , Tonometry, Ocular/methods , Animals , Equipment Design , Micro-Electrical-Mechanical Systems , Semiconductors , Swine , Tonometry, Ocular/instrumentation , Wireless Technology
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