Spontaneous Absorption Research Articles

Spectroscopic investigation of Er3+ in fluorotellurite glasses for 2.7 μm luminescence

Er3+ doped fluorotellurite glass (TeO2–BaF2–NaF) with different Er3+ concentrations were prepared, glass thermal stability and structure were investigated by differential scanning calorimetry (DSC) test and Raman spectrum, respectively. 2.7 μm light emission was observed under 980 nm excitation in these fluorotellurite glasses. The 2.7 μm emission properties were investigated through the measured absorption and emission spectra. The spontaneous transition probability (A), branching ratio (β), emission and absorption cross sections were calculated and the values were relatively larger than some reported values, which indicated that this kind of fluorotellurite glass has potential application as host material for 2.7 μm lasers.

Electromagnetic fluctuations in magnetized plasmas. I. The rigorous relativistic kinetic theory

Using the system of the Klimontovich and Maxwell equations, the general linear fluctuation theory for magnetized plasmas is developed. General expressions for the electromagnetic fluctuation spectra (electric and magnetic fields) from uncorrelated plasma particles in plasmas with a uniform magnetic field are derived, which are covariantly correct within the theory of special relativity. The general fluctuation spectra hold for plasmas of arbitrary composition, arbitrary momentum dependences of the plasma particle distribution functions, and arbitrary orientations of the wave vector with respect to the uniform magnetic field. Moreover, no restrictions on the values of the real and the imaginary parts of the frequency are made. The derived fluctuation spectra apply to both non-collective fluctuations and collective plasma eigenmodes in magnetized plasmas. In the latter case, kinetic equations for the components of fluctuating electric and magnetic fields in magnetized plasmas are derived that include the effect of spontaneous emission and absorption. In the limiting case of an unmagnetized plasmas, the general fluctuation spectra correctly reduce to the unmagnetized fluctuation spectra derived before.

329 Partial recovery of exocrine pancreatic function and intestinal fat absorption after ivacaftor treatment

Objectives Ivacaftor treatment results in rapid improvement of lung function and weight gain. We hypothesize that the reported ivacaftor induced weight gain is related to recovery of exocrine pancreatic function and improved intestinal fat absorption. Methods We measured fecal elastase-1 (FE), FEV1 and body height and weight, in a 13-year old girl with CF (dF508/S1251N) with proven pancreatic insufficiency (FE Results The patient reported a striking improvement in the general condition and body weight. FEV1 increased from 57% to 89%. Despite a decrease in the total dietary energy intake of 9%, the z-score of the BMI increased from 0.1 to 0.9 (+0.8SDS), after 3 months of ivacaftor treatment compared to baseline. FE increased to 54 ug/g. The CFA without PERT was 88%. Conclusion Our results, based on a single case study, suggest a partial recovery of exocrine pancreatic function, already, after 3 month of ivacaftor treatment. These findings are paralleled by a trend towards normalization of the spontaneous intestinal fat absorption. Noteworthy in this case is the increase in BMI, despite the still below normal CFA and decreased dietary intake. The latter suggests that, besides improved intestinal energy absorption, also lower total daily energy expenditure relates to the observed weight gain in CF patients during successful ivacaftor treatment.

Time-reversal-symmetric single-photon wave packets for free-space quantum communication.

Readout and retrieval processes are proposed for efficient, high-fidelity quantum state transfer between a matter qubit, encoded in the level structure of a single atom or ion, and a photonic qubit, encoded in a time-reversal-symmetric single-photon wave packet. They are based on controlling spontaneous photon emission and absorption of a matter qubit on demand in free space by stimulated Raman adiabatic passage. As these processes do not involve mode selection by high-finesse cavities or photon transport through optical fibers, they offer interesting perspectives as basic building blocks for free-space quantum-communication protocols.

The Association Between Modic Changes of Lumbar Endplates and Spontaneous Absorption of Herniated Intervertebral Discs.

Herniated disc (HD) is one of the most common causes of lower back pain. Treatment for HD includes conservative therapy and surgical intervention. Following conservative treatment, spontaneous absorption of HD occurs in some patients. To assess whether modic changes are associated with spontaneous absorption of HD, 85 patients with or without modic changes were followed up after 6 months of conservative treatment. As result, we found modic changes of lumbar endplates are associated with poor absorption of HD after conservative treatment. In addition, patients with modic changes exhibit significantly increased cartilage content and decreased neovascularization and macrophage infiltration in HD tissues, all of which are known to impair spontaneous absorption of herniated tissues. At molecular level, modic changes are associated with decreased expression of matrix metalloproteinase-3 gene, which is a key matrix-degrading enzyme for tissue absorption. Our study established a strong association between modic changes of lumbar endplates and spontaneous absorption of lumbar HD, which provided a potential novel method for prediction of spontaneous absorption.

Massive subcutaneous emphysema following laparoscopic nephroureterectomy: An unusual presentation

Sir, Laparoscopic approach to surgery has expanded its horizon tremendously. It is a preferred approach in many general, urological and thoracic procedures. Massive subcutaneous emphysema is a rare complication of laparoscopic surgery. We report here such a complication after laparoscopic nephroureterectomy using carbon dioxide (CO2) as an insufflating gas. A 62 yr old male, weight 65kg, American Society of Anesthesiologists physical status II was scheduled for nephroureterectomy for sarcoma left kidney through transperitoneal approach. The only positive history revealed in preoperative evaluation was hypertension since 2 yrs. In the operating room, intravascular cannulation was established after baseline routine monitoring [electrocardiography, non-invasive blood pressure, pulse oximetric oxygen saturation (SpO2) and end-tidal CO2, (ETCO2)]. Standard general anaesthesia induction and intubation was performed using injection fentanyl, propofol and vecuronium bromide. Patient was maintained on O2:N2O (35:65) and isoflurane. Pneumoperitoneum was created using CO2 insufflation and was maintained for 4 hours. Intraoperatively, cardiovascular parameters, EtCO2 and peak inspiratory pressure remained normal throughout. The intra- abdominal pressure was in the range of 12-13 mm Hg. Maximum EtCO2 noticed during this period was 42mm Hg, which was normalised by increasing minute ventilation. 3 h after creation of pneumo-peritoneum, patient was noted to have developed marked subcutaneous emphysema over face, neck and chest. Skin crepitus was more on lateral aspects of neck bilaterally. It involved both the eyelids. Caudal extent of emphysema could not be demarcated due to patient positioning and surgical drapes. Arterial blood gas analysis (ABG) was obtained and found to be normal. All ventilatory parameters including EtCO2 were within normal limits at this moment. The surgeon was notified about emphysema. Pneumoperitoneum was deflated after nephrectomy. Uretrectomy was done after opening the abdomen. Entire surgery lasted for 6 hrs. Facial swelling and crepitus over neck started resolving gradually after deflation of pneumoperitoneum. At the end of surgery, direct laryngoscopy was done to exclude the presence of pharyngeal emphysema and laryngeal oedema which may accompany subcutaneous emphysema of face and neck and can cause airway obstruction. Arterial blood gas (ABG) values were repeated and found to be normal. The patient was extubated after confirming audible leak on positive pressure ventilation, after deflating the endotracheal tube cuff, ruling out tracheal compression by neck emphysema. Gaseous collection was allowed to be drained by spontaneous absorption and exhalation. Patient was transferred to ICU for further monitoring. Postoperative chest radiograph in intensive care unit (ICU) confirmed the diagnosis of surgical emphysema in the neck and chest and ruled out pneumothorax and pneumomediastinum. Patient remained stable in post operative period and was transferred to ward next day. Massive subcutaneous emphysema is an extremely rare complication.[1,2] On palpation, it produces an unusual crackling sensation as the gas in pushed through the tissues. Severity of emphysema can be compared on a four point scale.[3] (0) No subcutaneous emphysema, (1) Mild emphysema with crepitus at trocar insertion site, (2) Mild emphysema with crepitus extending to the abdomen and thighs. (3) Massive emphysema extending to the chest, neck and face. Prolonged surgery and pneumoperitoneum of >200 minutes, insufflation of CO2 at pressure ≥15 mm Hg, 6 or more ports and old age due to decrease in natural subcutaneous resistance are the factors which predispose to the risk of development of subcutaneous emphysema.[4,5] The patient had massive subcutaneous emphysema probably due to prolonged pneumoperitoneum of 4 hours duration. Age of the patient was another possible factor which may be responsible for such massive emphysema. Absence of rise in EtCO2 was unusual, a finding contrary to most reports where an increase in EtCO2 was found along with massive subcutaneous emphysema. Our findings are consistent with the finding of Giorgakis and Fernandez-Diaz where they found no increase in EtCO2 intraoperatively.[6] In view of the paucity of literature showing massive subcutaneous emphysema in the absence of increased EtCO2, we wished to share our experience. We recommend that the patient should be closely examined under the drapes intraoperatively even if ventilatory parameters are normal on monitor.

Fluid absorption in the isolated midgut of adult female yellow fever mosquitoes (Aedes aegypti).

The transepithelial voltage (Vte) and the volume of isolated posterior midguts of adult female yellow fever mosquitoes (Aedes aegypti) were monitored. In all experiments, the initial Vte after filling the midgut was lumen negative, but subsequently became lumen positive at a rate of approximately 1 mV min(-1). Simultaneously, the midgut volume decreased, indicating spontaneous fluid absorption. When the midguts were filled and bathed with mosquito saline, the average rate of fluid absorption was 36.5±3.0 nl min(-1) (N=4, ±s.e.m.). In the presence of theophylline (10 mmol l(-1)), Vte reached significantly higher lumen-positive values, but the rate of fluid absorption was not affected (N=6). In the presence of NaCN (5 mmol l(-1)), Vte remained close to 0 mV (N=4) and fluid absorption was reduced (14.4±1.3 nl min(-1), N=3, ±s.e.m.). When midguts were filled with buffered NaCl (154 mmol l(-1) plus 1 mmol l(-1) HEPES) and bathed in mosquito saline with theophylline, fluid absorption was augmented (50.0±5.8 nl min(-1), N=12, ±s.e.m.). Concanamycin A (10 µmoll(-1)), ouabain (1 mmol l(-1)), and acetazolamide (1 mmol l(-1)) affected Vte in different ways, but all reduced fluid absorption by 60-70% of the value before addition of the drugs.

Effect of CdSe quantum dots doping on the switching time, localised electric field and dielectric parameters of ferroelectric liquid crystal

A systematic study highlighting the effect of cadmium selenide quantum dots (CdSe QDs) with varying concentrations of 0.05, 0.10 and 1.0 wt% doping on the electrooptical and dielectric parameters of ferroelectric liquid crystal (FLC) is presented. No considerable change is observed in phase transition temperature and tilt angle with CdSe QDs doping at lower and higher dopant level. Substantial enhancement of localised electric field at higher doping level (1.0 wt%) of CdSe QDs manifested the ≈48% reduction in the switching response of FLC nanocolloids at 30°C. Reduction in the spontaneous polarisation, dielectric constant and absorption strength could be attributed to the antiparallel correlation among dopant and matrix molecules, ion capturing in the capping additive layer and enhancement of the rotational viscosity of the nanocolloids, respectively. Goldstone mode relaxation frequency is found to be decreased with doping up to 0.10 wt% concentration and showed reverse effect at higher QDs concentration. QDs doping effect on the photoluminescence intensity is also discussed.

Facile and highly efficient removal of trace Gd(III) by adsorption of colloidal graphene oxide suspensions sealed in dialysis bag

A facile, highly efficient and second-pollution-free strategy to remove trace Gd(III) from aqueous solutions by adsorption of colloidal graphene oxide (GO) suspensions in dialysis bag has been developed. The effects of pH, ionic strength and temperature on Gd(III) adsorption, and the pH-dependent desorption were investigated. The maximum adsorption capacity of Gd(III)on GO at pH=5.9±0.1 and T=303K was 286.86mgg−1, higher than any other currently reported. The Gd(III)-saturated GO suspension could resume colloidal state in 0.1M HNO3 with desorption rate of 85.00% in the fifth adsorption–desorption cycle. Gd(III) adsorption rate on GO was dependent more on pH and ionic strength than on temperature. The abundant oxygen-containing functional groups such as carboxyl and hydroxyl played a vital role on adsorption. The thermodynamics and kinetics investigations revealed that the adsorption of Gd(III) on GO was an endothermic, spontaneous and monolayer absorption process, which well fitted the pseudo-second-order model. GO could be a promising adsorbent applied in the enrichment and removal of lanthanides from aqueous solutions. More significantly, the combination of colloidal GO suspension with dialysis membrane facilely solves the re-pollution of the treated solutions due to the great difficulties in separation and recovery of GO.

Electro-optical behaviour and dielectric dynamics of harvested ferroelectric LiNbO3 nanoparticle-doped ferroelectric liquid crystal nanocolloids

Nanocolloids comprising harvested ferroelectric LiNbO3 nanoparticles (≈25 nm) and ferroelectric liquid crystals were prepared and investigated. The impact of the amount of dispersed nanoparticles (0.01 wt%, 0.05 wt%, 0.10 wt%) on the electro-optical, dielectric and material parameters of the ferroelectric liquid crystals (FLCs) has been demonstrated. The dopant strongly influences the switching characteristics and has an effect on the saturation voltage of the FLC materials. Electro-optical measurements demonstrated that a relatively large (0.10 wt%) LiNbO3 dopant concentration decreases the response time and saturation voltage by approximately 40% and 25% respectively, compared with non-doped FLCs. The effect of LiNbO3 nanoparticle concentration on the material and dynamical parameters (i.e. spontaneous polarization, dielectric permittivity, dielectric absorption, dielectric strength, dc conductivity, and rotational viscosity) is presented. The observed behaviours are discussed in terms of capture of impurity ions on the surface of the harvested LiNbO3 nanoparticles. Ion capturing leads to enhancement of the localized electric field inside the smectic layers. The fast switching response and the low operational voltage of these FLC nanocolloids support their application in nanometric scale electronic devices.

Spontaneous absorption of extensive subinternal limiting membrane hemorrhage in shaken baby syndrome.

The Shaken Baby Syndrome (SBS) is characterized by subdural hematomas (SH), retinal hemorrhages (RH), and multiple fractures of long bones without external evidence of head trauma. Subinternal limiting membrane (ILM) hemorrhage, also known as macular schisis, is a characteristic finding of this entity. There is no guideline on the right time to indicate surgical treatment. This report describes an abused child with massive sub-ILM hemorrhage, which showed spontaneous absorption after less than two months of follow-up. Due to the possible spontaneous resolution, we suggest an initial conservative treatment in cases of sub-ILM hemorrhage related to SBS.

Theoretical studies on mid-infrared amplification in Ho3+-doped chalcogenide glass fibers

This paper investigated the MIR emission of Ho3+-doped Ge20Ga5Sb10S65 chalcogenide glasses upon excitation of 900nm laser diode. The spontaneous emission probability, absorption cross-section, and emission cross-section were calculated using the Judd-Ofelt theory and the Fuchbauer–Ladenburg equation. Theoretical studies of the Ho3+-doped chalcogenide glass fiber amplifier operating in the MIR wavelength range, specifically around the 2.86μm wavelength, were performed based on the rate and light propagation equations. The results indicate that the chalcogenide glass fiber presented a larger signal MIR gain and wider MIR gain spectrum. The maximum signal gain was 36dB and the gain width was 20dB.

Clinical Improvement After Spontaneous Partial or Complete Absorption 0f Herniated Lumbar Disc.

Background Data: Intervertebral disc herniation is a common disease that usually occurs in middle aged active persons. It presents by back pain and involved nerve root radiculopathy. Some neurologic symptoms in the majority of patients improve after a period of conservative therapy due to regression in the size of the herniated disc. The exact mechanism of disc regression is not yet clear, however clinical improvement and MRI follow up can document this condition.Study Design: Retrospective clinical case review. Purpose: To assess the clinical improvement of patients with herniated lumbar disc if it occurred by the conservative treatment due to partial or complete spontaneous disc absorption without conveying surgery. Patients and Methods: Here we present fifty cases with single symptomatic disc herniation followed for one year showing the extent of clinical improvement by the conservative treatment, MRI changes and the fate of these fifty patients during and after a one year period of follow up. Male to female ratio was 3:2. The mean age was38.6 years. Results: History of trauma preceding the disc herniation was given only in 5 (10%) patients. Left sciatica was reported in 34 (68%) and right in 16 (32%) patients. Motor weakness was found only in 5 (10%) patients. L4-5 was the commonest disc to be involved and was found to be herniated in 26 (52%) patients. 44 (88%) patients showed improvement without surgical intervention, while 6 (12%) patients only were operated upon. Conclusion: Herniated intervertebral discs have the potentials for spontaneous regression. Conservative treatment can be tried for all cases even those with mild neurologic deficits at least for 2 months. Surgical treatment should be applied only for patients with severe neurologic deficits or for those with persistent intractable sciatica. (2012ESJ031)

The interaction of a screw dislocation with point defects in bcc iron

In this study, we calculate the interaction energy of intrinsic point defects vacancies and interstitials) with screw dislocations in body-centered cubic iron. First (we calculate the dipole tensor of a defect in the bulk crystal using molecular statics. Using a formulation based on linear elasticity theory, we calculate the interaction energy of the defect and the dislocation using both isotropic and anisotropic strain fields. Second, we perform atomistic calculations using molecular statics methods to directly calculate the interaction energy. Results from these two methods are compared. We verify that continuum methods alone are unable to correctly predict the interactions of defects and dislocations near the core. Although anisotropic theory agrees qualitatively with atomistics far from the core, it cannot predict which dumbbell orientations are stable and any continuum calculations must be used with caution. Spontaneous absorption by the core of both vacancies and dumbbells is seen. This paper demonstrates and discusses the differences between continuum and atomistic calculations of interaction energy between a dislocation core and a point defect.

Thermal Characteristics of Channel Water Confined in Nanopores with Crystalline Pore-Wall Structure in [M(H2bim)3](TMA)·nH2O

Thermal properties of channel water within crystalline nanopores of [M(H2bim)3](TMA)·nH2O (M = Co, Ru) were characterized by adiabatic calorimetry, where H2bim and TMA denote 2,2′-biimidazole and 1,3,5-benzenetricarboxylic acid, respectively. Temperature dependence of the heat capacities and spontaneous heat release or absorption rates disclosed the presence of two phase transitions and one glass transition at low temperatures in the both Co- and Ru-complex crystals. Combined with the results of M = Cr crystal, it was suggested that very slight differences in the pore size and shape strongly affect the phase behavior of the channel water. As the n value increases among the three crystals, the entropies of the channel water at 0 °C increased toward the value of pure water and the temperature dependence of the heat capacities around 0 °C seemed to somewhat resemble that of pure water as well. The glass transition was observed to occur at essentially the same temperature around 100 K among the three, indicat...

Evaluation of pulsed Nd:YAG laser posterior hyaloidotomy as an emergency treatment for blinding premacular subhyaloid hemorrhage.

Purpose:This study aimed to evaluate the benefits of Nd:YAG laser posterior hyaloidotomy as a method allowing rapid drainage of subhyaloid hemorrhage into the vitreous gel.Design:Nonrandomized, prospective, interventional, controlled case series.Methods:Nd:YAG laser posterior hyaloidotomy was performed in four eyes of three patients with premacular subhyaloid hemorrhage. The etiologies were bleeding tendency, proliferative diabetic retinopathy, and idiopathic. Four eyes of four patients with premacular subhyaloid hemorrhage were managed conservatively. The etiologies were proliferative diabetic retinopathy and Valsalva retinopathy.Results:A rapid resolution of subhyaloid hemorrhage with improvement of visual acuity was achieved in all patients treated with Nd:YAG laser posterior hyaloidotomy, without evidence of damage to the retina or choroid. With regard to the conservatively managed eyes, there was a tendency towards slow spontaneous absorption of hemorrhage during the follow-up period.Conclusion:Nd:YAG laser posterior hyaloidotomy was a safe and effective procedure for rapid resolution of premacular subhyaloid hemorrhage, allowing rapid restoration of visual acuity, visualization of the underlying retina, expedited access for macular photocoagulation and avoidance of vitrectomy.

Spin-forbidden radiative decay rates from the3 3P1,2and3 1P1states of helium

We have calculated atomic helium spontaneous decay rates and absorption oscillator strengths for the spin-forbidden transitions from $3 {}^{3}{P}_{1,2}$ and $3 {}^{1}{P}_{1}$ to all lower ${}^{1}{S}_{0}$ and ${}^{3}{S}_{1}$ states. In particular we found ${A}_{10}=44.33(4) {\mathrm{s}}^{\ensuremath{-}1}$ for the $E$1 transition $3 {}^{3}{P}_{1}$--$1 {}^{1}{S}_{0}$ and 0.1147(1) ${\mathrm{s}}^{\ensuremath{-}1}$ for the $M$2 transition $3 {}^{3}{P}_{2}$--$1 {}^{1}{S}_{0}$.

Localization of surface plasmon polaritons in hexagonal arrays of Moiré cavities

In view of the progress on the confinement of light, we report on the dispersion characteristics of surface plasmon polaritons (SPPs) on two-dimensional Moiré surfaces in the visible part of the electromagnetic spectrum. Polarization dependent spectroscopic reflection measurements show omnidirectional confinement of SPPs. The resonance wavelength of SPP cavity modes can be adjusted by tuning the propagation direction of SPPs. The results may have an impact on the control of spontaneous emission and absorption with applications in light emitting diodes and solar cells, as well as in quantum electrodynamics experiments.

A case of bilateral, spontaneous absorption of lenses

Spontaneous absorption of lenses or cataracts is rare. We report a case of bilateral spontaneous lens absorption in a 36-year-old woman for which no cause could be determined despite extensive laboratory testing.

Nanoscale carbon particles and the stability of lipid bilayers

The transfer of various nano-scale fullerenes into lipid bilayers has been studied using all-atom (AA) and coarse-grained (CG) molecular dynamics (MD) simulations. The free energy change, when C60, C180, and C540 fullerenes are transferred from water to the interior of a lipid [dioleoylphosphatidylcholine (DOPC)] bilayer, has been calculated. Upon entering the lipid bilayer, the largest (2.4 nm diameter) fullerene causes local distortions in the bilayer surface, which were previously observed in carbon nanotube simulations. These local distortions, however, do not lead to any free energy barriers to bilayer entry. The free energy profiles confirm spontaneous absorption of all three fullerenes. Qualitative agreement was observed when comparing fullerene partitioning in water/bilayer systems to water–hexane systems. In contrast to these nonspecific single fullerene properties, extensive CG-MD simulations of fullerene rich lipid bilayers reveal substantial impact of fullerene-size on the bilayer stability. While previous CG-MD simulations indicated that bilayer bound C60 aggregates have little effect on the bilayer structure, the present MD simulations indicate that C540 aggregation has drastic effects. Specifically, the observed destabilization likely has implications for understanding the cytotoxic mechanisms of nano-carbon particles upon uptake by biological cells.