Sutureless lamellar keratoplasty with lenticule from small incision lenticule extraction for treating limbal dermoid: A case report.

The present study reports the case of a superficial limbal dermoid surgically treated without suture by using a new technique of lamellar keratoplasty with allogenic lenticule from small incision lenticule extraction. The limbal lesion area was circumscribed by a trephine marker and lamellae were peeled off the anterior corneal stroma and sclera. After excision of the dermoid, the liquid on the bed was dried as much as possible and an appropriate stromal lenticule was attached to the implant bed without fibrin glue or suture. A bandage contact lens was applied to fix the graft. During postoperative follow-ups, the anterior segment optical coherence tomography, corneal refractive power, corneal topography and best-corrected visual acuity were examined to evaluate the surgical results. On the first day after the operation, the patient reported tearing and pain at the site. At one week after the operation, the patient reported no discomfort and conjunctival sutures were removed. At one month after the operation, the thickness of the lesion area was similar to that of the adjacent cornea, and the corneal curvature and refractive power of the lesion area were higher than that of the adjacent cornea. At three months after the operation, the patient was satisfied with the cosmetic outcome and no sign of corneal neovascularization, graft rejection or pseudo-pterygium formation was observed. The astigmatic error remained at 2.50 D. The present case provides insights into a potential treatment option for patients who need lamellar keratoplasty and may provide its benefit in contrast to conventional lamellar keratoplasty.

Comparison of the Performance of Different Bile Salts in Enantioselective Separation of Palonosetron Stereoisomers by Micellar Electrokinetic Chromatography.

Bile salts are a category of natural chiral surfactants which have ever been used as the surfactant and chiral selector for the separation of many chiral compounds by micellar electrokinetic chromatography (MEKC). In our previous works, the application of sodium cholate (SC) in the separation of four stereoisomers of palonosetron (PALO) by MEKC has been studied systematically. In this work, the parameters of other bile salts, including sodium taurocholate (STC), sodium deoxycholate (SDC), and sodium taurodeoxycholate (STDC) in the separation of PALO stereoisomers by MEKC were measured and compared with SC. It was found that all of four bile salts provide chiral recognition for both pairs of enantiomers, as well as achiral selectivity for diastereomers of different degrees. The structure of steroidal ring of bile salts has a greater impact on the separation than the structure of the side chain. The varying separation results by different bile salts were elucidated based on the measured parameters. A model to describe the contributions of the mobility difference of solutes in the aqueous phase and the selectivity of micelles to the chiral and achiral separation of stereoisomers was introduced. Additionally, a new approach to measure the mobility of micelles without enough solubility for hydrophobic markers was proposed, which is necessary for the calculation of separation parameters in MEKC. Under the guidance of derived equations, the separation by SDC and STDC was significantly improved by using lower surfactant concentrations. The complete separation of four stereoisomers was achieved in less than 3.5 min by using 4.0 mM of SDC. In addition, 30.0 mM of STC also provided the complete resolution of four stereoisomers due to the balance of different separation mechanisms. Its applicability for the analysis of a small amount of enantiomeric impurities in the presence of a high concentration of the effective ingredient was validated by a real sample.

Cerium-terephthalic acid metal-organic frameworks for ratiometric fluorescence detecting and scavenging·OH from fuel combustion gas.

Hydroxyl radical (•OH) in fuel combustion gas seriously damages human health. The techniques for simultaneously detecting and scavenging •OH in these gases are limited by poor thermal resistance. To meet this challenge, herein, metal organic frameworks (MOFs) with high thermal stability (80-400 °C) and dual function (•OH detection and elimination) are developed by coordinating Ce ions with terephthalic acid (TA) (Ce-BDC). Due to the reversible conversion between Ce3+ and Ce4+, and the high concentration of Ce3+ on the surface of Ce-BDC MOFs (89.6%), an •OH scavenging efficiency over 90% is realized. Ratiometric fluorescence (I440 nm/I355 nm) detection of •OH with a low detection limit of ∼4 µM is established by adopting Ce ions as an internal standard and TA as an •OH-responsive fluorophore. For real applications, the Ce-BDC MOFs demonstrate excellent •OH detection sensitivity and high •OH scavenging efficiency in gas produced from cigarettes, wood fiber and machine oil. Mouse model results show that the damage caused by •OH in cigarette smoke can be greatly reduced by Ce-BDC MOFs. This work provides a promising strategy for sensitively detecting and efficiently eliminating •OH in fuel combustion gas.

Sub-chronic low-dose arsenic in rice exposure induces gut microbiome perturbations in mice.

Long-term consumption of arsenic-contaminated rice has become a public health issue that urgently needs to be addressed. In this study, mice were exposed to arsenic in rice (low dose, 0.91 mg/kg; medium dose, 9.1 mg/kg) for 30 days and 60 days, respectively, and the effects on pathological structures of spleen and skin, as well as the structure of the fecal microbiome were examined. The findings revealed dose/time cumulative effects on pathological changes, with even a low dose exposure for 30 days causing destruction of splenic follicular structure and thickening of dermal keratinized and epidermal layers. The Firmicutes/Bacteroidetes ratio in the community and the positive/negative ratio in network links were higher in arsenic groups, suggesting that arsenic resulted in a less healthy and unstable microbiome for the host. Thus lifetime consumption of arsenic in rice may have potential health effects on humans and must be carefully assessed to safeguard human health. Furthermore, in arsenic groups, arsenic-resistant bacteria or arsenic hazards remediation bacteria changed to be the dominant bacteria and acted as the core bacteria in the network modules. Some microbial arsenic transforming genes (arsC, arsR, arsA, ACR3, and aoxB) differed, indicating that the gut microbiome changed to withstand arsenic stress. Furthermore, Faecalibaculum, Lachnospiraceae_NK4A136_group, Angelakisella, Ruminiclostridium, and Desulfovibrionaceae are positively associated with arsenic dosage and may be useful in the early detection of arsenicals.

The mycobiome in murine intestine is more perturbed by food arsenic exposure than in excreted feces.

Arsenic is a global pollutant that can accumulate in rice and has been confirmed to disturb the gut microbiome. By contrast, the influence on the gut mycobiome is seldom concerned because fungi comprise a numerically small proportion of the whole gut microcommunity. To expand the detection of the mycobiome in different gut sections of mammals and investigate the influence of food arsenic on the gut mycobiome in the digestive tract, we treated mice with feeds containing different compositions of arsenic species (7.3% sodium arsenate, 72.7% sodium arsenite, 1.0% sodium monomethylarsonate, and 19.0% sodium dimethylarsinate) in rice at a total arsenic dose of 30 mg/kg. After 60 days of exposure, the feces of four different sites, the ileum, cecum, colon, and excreted feces, were collected and analyzed by internal transcribed spacer gene sequencing. Among the samples, the major fungal phyla were Ascomycota, Basidiomycota, and Zygomycota; the top 10 fungal genera were Aspergillus, Verticillium, Penicillium, Cladosporium, Alternaria, Fusarium, Ophiocordyceps, Trametes, Mucor, and Nigrospora. In control mice, along the murine digestive tract, the mycobial richness and composition were significantly changed; Aspergillus and Penicillium possessed the higher ability to be stabilized in the murine gut, and larger proportions of positive correlations were observed among the major fungi. After arsenic exposure, the fungal composition was more disturbed in the intestinal tract than in feces. Along the digestive tract, arsenic can trigger larger mycobial variations, and the sensitivities of major fungi to arsenic were changed. Thus, the murine intestinal spatial mycobiota are more perturbed than excreted fecal mycobiota after food arsenic exposure. Feces are insufficient to be selected as a representative of the gut mycobiota in arsenic exposure studies.

High Quality Factor Enabled by Multiscale Phonon Scattering for Enhancing Thermoelectrics in Low-Solubility n-Type PbTe-Cu2Te Alloys.

The fundamental challenge for enhancing the thermoelectric performance of n-type PbTe to match p-type counterparts is to eliminate the Pb vacancy and reduce the lattice thermal conductivity. The Cu atom has shown the ability to fill the cationic vacancy, triggering improved mobility. However, the relatively higher solubility of Cu2Te limits the interface density in the n-type PbTe matrix, leading to a higher lattice thermal conductivity. In particular, a quantitative relationship between the precipitate scattering and the reduction of lattice thermal conductivity in the n-type PbTe with low solubility of Cu2Te alloys still remains unclear. In this work, trivalent Sb atoms are introduced, aiming at decreasing the solubility of Cu in PbTe for improving the precipitate volumetric density and ensuring n-type degenerate conduction. Benefiting from the multiscale hierarchical microstructures by Sb and Cu codoping, the lattice thermal conductivity is considerably decreased to 0.38 W m-1 K-1. The Debye-Callaway model quantifies the contribution from point defects and nano/microscale precipitates. Moreover, the mobility increases from 228 to 948 cm2 V-1 s-1 because of the elimination of cationic vacancies. Consequently, a high quality factor is obtained, enabling a superior peak figure of merit ZT of ∼1.32 in n-type Pb0.975Sb0.025Te by alloying with only ∼1.2% Cu2Te. The present finding demonstrates the significant role of low-solubility Cu2Te in advancing thermoelectrics in n-type PbTe.

Superconductivity related to the suppression of exciton formation in 1T-TiSe2.

In strongly correlated electron system, the impact of elementary substitution or intercalation plays a crucial role in determining electronic ground state among various macroscopic quantum phases such as charge order and superconductivity. Here, we report that simultaneous Cu intercalation and Ta substitution at Ti site in 1T-Cu x Ti0.8Ta0.2Se2 induce an intrinsic electronic phase diagram, characterized by an inherent superconducting transition in the x region of 0 ⩽ x ⩽ 0.12, with a maximum superconducting transition temperature T c of 2.5 K for x = 0.04, in contrast to the non-superconducting sample 1T-Cu0.04TiSe2. The increased density of free charge carriers screen the Coulomb interaction between electron-hole pairs effectively, promoting the occurrence of superconductivity favourably. Present results suggest that the Cu intercalation and the Ta substitution-induced suppression of the exciton condensation boost the superconductivity, shedding new light on the fundamental physics of the interplay between superconductivity, charge order, and electron correlation.

Reducing Effective Mass for Advancing Thermoelectrics in Sb/Bi-Doped AgCrSe2 Compounds.

Liquid-like materials have attracted increasing attention, owing to their phonon-liquid electron-crystal feature. As a typical representative, the superionic conductor AgCrSe2 is regarded as a promising thermoelectric for its intrinsic ultralow lattice thermal conductivity. The primary challenge for achieving high thermoelectric performance is to enhance the inferior electronic performance in AgCrSe2 compounds. Thus, it is very significant to manipulate band effective mass to achieve a higher power factor. In this work, the Sb/Bi elements are doped at Cr sites in Ag0.97CrSe2, i.e., Ag0.97Cr1-x(Sb/Bi)xSe2, aiming at producing a better overlap of electron orbits between different atoms for sharpening the valence band and decreasing the effective mass. In comparison to pristine AgCrSe2, a considerable improvement (>50%) in the power factor (∼387 µW m-1 K-2 at 750 K) is realized upon 3% Sb doping. The single parabolic band model clarifies that the decreased effective mass and optimized carrier concentration contribute to the enhanced electronic property. Furthermore, an ultralow lattice thermal conductivity (∼0.2 W m-1 K-1) is well-maintained for the sample with 3% Sb doping as a result of the nearly unchanged superionic conduction. Eventually, a high peak figure of merit zT (∼0.7 at 750 K) is obtained in Ag0.97Cr0.97Sb0.03Se2. The current finding provides an excellent avenue for advancing thermoelectrics in AgCrSe2 materials.

Extraordinary Role of Bi for Improving Thermoelectrics in Low-Solubility SnTe-CdTe Alloys.

As an environment-friendly alternative to traditional PbTe, many attempts have recently been made to improve thermoelectric SnTe. Effective strategies are mainly focused on valence band convergence, nanostructuring, interstitial defects, and alloying solubility. In particular, alloying SnTe with CdTe/GeTe triggers an inherent decline of valence band offset effectively owing to a high solubility of ∼20% of CdTe. However, to what level an additional element doping in low-solubility SnTe-CdTe alloys can play a role in enhancing the thermoelectric performance still remains a mystery. Here, a new strategy is shown that unexpected Bi doping, by alloying with only ∼3% CdTe, induces a significant enhancement of the thermoelectric figure of merit ZT to be ∼240% (ZT up to ∼1.3) at 838 K, which is mainly determined by the dramatically reduced lattice thermal conductivity above 800 K deriving from the exotic Bi doping and Cu-interstitial defects. More interestingly, combining experimental and theoretical evidences, the Bi-doping-driven band convergence is also beneficial to the improvement of thermoelectric performance below 800 K. The present findings demonstrate the extraordinary role of Bi for advancing the thermoelectric performance in SnTe alloys.

Highly Efficient Method for Suzuki Reactions in Aqueous Media.

Herein, we report the crystal structure and characterization of mono-6-(l-aminopropanol)-deoxy-ß-cyclodextrin (L n @ß-CD). A highly efficient, in situ generated catalyst, PdCl2(L n @ß-CD), was synthesized for palladium-catalyzed cross-coupling reactions under mild reaction conditions, and the use of this catalyst in Suzuki cross-couplings was investigated. Low palladium loadings of 0.01 mol % PdCl2(L n @ß-CD) (Pd accounted for approximately 8.4% of the catalyst by mass) were found to be highly efficient for Suzuki cross-couplings in water and afforded the corresponding biaryl compounds in excellent yields. The catalyst can be recycled and reused.

Thermodynamic models to elucidate the enantioseparation of drugs with two stereogenic centers by micellar electrokinetic chromatography.

An equilibrium model depicting the simultaneous protonation of chiral drugs and partitioning of protonated ions and neutral molecules into chiral micelles in micellar electrokinetic chromatography (MEKC) has been introduced. It was used for the prediction and elucidation of complex changes in migration order patterns with experimental conditions in the enantioseparation of drugs with two stereogenic centers. Palonosetron hydrochloride (PALO), a weakly basic drug with two stereogenic centers, was selected as a model drug. Its four stereoisomers were separated by MEKC using sodium cholate (SC) as chiral selector and surfactant. Based on the equilibrium model, equations were derived for a calculation of the effective mobility and migration time of each stereoisomer at a certain pH. The migration times of four stereoisomers at different pHs were calculated and then the migration order patterns were constructed with derived equations. The results were in accord with the experiment. And the contribution of each mechanism to the separation and its influence on the migration order pattern was analyzed separately by introducing virtual isomers, i.e., hypothetical stereoisomers with only one parameter changed relative to a real PALO stereoisomer. A thermodynamic model for a judgment of the correlation of interactions between two stereogenic centers of stereoisomers and chiral selector was also proposed. According to this model, the interactions of two stereogenic centers of PALO stereoisomers in both neutral molecules and protonated ions with chiral selector are not independent, so the chiral recognition in each pair of enantiomers as well as the recognition for diastereomers is not simply the algebraic sum of the contributions of two stereogenic centers due to their correlation.

Solvent-modified MEKC for the enantioseparation of palonosetron hydrochloride and related enantiomeric impurities.

The effect of ten water-soluble organic solvents on MEKC separation of palonosetron hydrochloride (PALO) stereoisomers using sodium cholate (SC) as chiral selector has been studied. The first chiral CE method fit for the analysis of unwanted PALO distomers (enantiomeric impurities) of low concentrations in the presence of high concentration of the main eutomer has been developed, based on solvent-modified MEKC mode. It was found that methanol provides the best separation among the solvents tested. And an SC concentration of 30 mM is proper to provide good resolutions in shorter time and adequate sample capacity, instead of 70 mM as previously reported. The developed method can be used to analyze unwanted PALO distomers of a few micrograms per milliliter in the presence of the main eutomer with a concentration as high as 1.0 mg/mL.

Separation mechanisms for palonosetron stereoisomers at different chiral selector concentrations in MEKC.

The separation mechanisms for palonosetron (PALO) stereoisomers in MEKC using sodium cholate (SC) as surfactant and chiral selector have been studied, in a wide range of concentrations below and above the CMC. It was found that SC micelles only provide chirally selective recognition for 3a carbon chiral center in PALO molecules. The resolution of the configurations of 2 carbon chiral center is achieved by the difference of mobility in continuous phase. A schematic diagram depicting the separation mechanisms and the corresponding migration orders among all of four stereoisomers was proposed based on the measured separation parameters. A MEKC method to achieve the complete separation of four stereoisomers in very short time using a very low chiral selector concentration, instead of high concentrations generally considered, was developed based on the understanding of the mechanisms.

Effect of low concentration sodium dodecyl sulfate on the electromigration of palonosetron hydrochloride stereoisomers in micellar electrokinetic chromatography.

The effect of low concentrations of sodium dodecyl sulfate (SDS) on the separation of palonosetron hydrochloride (PALO) stereoisomers by micellar electrokinetic chromatography (MEKC) has been investigated. It was found that the addition of SDS prolongs the migration time and the migration order of four stereoisomers changes regularly with the SDS concentration. Good separations for all the four stereoisomers were achieved at appropriate SDS concentration. The effect of SDS on the electromigration (mobilities) of PALO stereoisomers has been studied, in order to explain its effect on the separation by MEKC. It was found that low concentrations of SDS added into the separation media forms negatively charged complexes with PALO stereoisomers and hence reverses their electromigration direction. Furthermore, the migration order between two enantiomeric pairs is also reversed because the enantiomeric pair with a bigger positive mobility than that of another pair turns to have a bigger negative mobility when bound with SDS. Based on these results, the effect of SDS on the MEKC separation of PALO stereoisomers was elucidated reasonably. The performance of the developed chiral MEKC method was validated by the analysis of a real sample.

In vitro-expanded CD4(+)CD25(high)Foxp3(+) regulatory T cells controls corneal allograft rejection.

AIMS: Natural CD4(+)CD25(+) regulatory cells (nTregs) have been implicated in maintaining peripheral immune tolerance. This study aims to test whether immunotherapy using in vitro-expanded Treg (iTregs) could suppress allograft rejection in corneal transplantation model. METHODS: Natural CD4(+)CD25(+) T cells were freshly purified from naïve mice and expanded in vitro by culturing with anti-CD3/CD28-coated Dynabeads, interleukin (IL)-2 and transforming growth factor (TGF-ß1). Suppression ability of iTregs was assayed by co-culturing with CD4(+)CD25(-) T cells (Teff) in vitro and by targeting corneal allograft rejection in vivo. Tracking of iTreg after adoptive transfer in vivo were examined by CFSE labeling. RESULTS: Natural Treg cells were expanded by culturing with anti-CD3/CD28-coated Dynabeads in the presence of IL-2 and TGF-ß1. Compared with nTregs, iTregs had similar expression of CD62L, and PD- L1, lower expression of CD69, higher levels of PD-1, CD25, and Foxp3. iTreg cells exerted stronger suppression function than natural Treg cells when cocultured with CD4(+)CD25(-) T cells in vitro and prevented fully MHC-mismatched corneal allograft rejection. Survival of iTreg cells could suppress alloimmune reaction and most prone to migrate to graft draining LNs and spleens. Moreover, maintaining CD25 expression on iTregs was indicative for preservation of allosuppression. CONCLUSION: Therapeutic use of in vitro-expanded CD4(+)CD25(+) T cells may be a effective and safe tool for controlling allograft rejection and may help induce allograft tolerance.

Histone deacetylase inhibitors promote mice corneal allograft survival through alteration of CD4+ effector T cells and induction of Foxp3+ regulatory T cells.

Trichostatin A (TSA) is classical Histone deacetylase inhibitors (HDACIs) II which is used in treatment of advanced cutaneous T-cells lymphoma. Our works focused on the roles of TSA on immuno-modulatory. We found that the TSA could induce resting Teff cells into apoptotic cell death and inhibit Teff cells proliferation in a dose-dependent manner. We also observed down-regulation effects of various costimulatory/adhesion molecules on Teff cells and up-regulation of Foxp3 expression on CD4+ CD25+ T cells. Treatment with TSA could improve mice corneal allograft survival by promoting the proportions and allosuppressive function of CD4+ CD25+ regulatory T cells. Our findings suggest that the use of TSA allows the beneficial pharmacological effect on CD4+ CD25- T activation in vitro and enhancement of Foxp3+ Treg cells in vivo.

Vapor generation by UV irradiation for sample introduction with atomic spectrometry.

Volatile species of the conventional hydride-forming elements (As, Bi, Sb, Se, Sn, Pb, Cd, Te), Hg, transition metals (Ni, Co, Cu, Fe), noble metals (Ag, Au, Rh, Pd, Pt), and nonmetals (I, S) were generated following UV irradiation of their aqueous solutions to which low molecular weight carboxylic acids (formic, acetic, propionic) had been added. Free radicals arising from photodissociation of the latter provide a new and useful alternative to the common methods of chemical/electrochemical vapor generation techniques for the determination of these analytes by atomic spectrometry. Quantitative estimates of the efficiencies of these generation processes were not undertaken, although calculated signal-to-background ratios (>1500 for 5 ng/mL As, Sb, Bi, Se, and Te; 20 for 10 ng/mL Sn, Cu, Rh, Au, Pd, Pt, and Cd; 2400 for 1 ng/mL Hg; and 1000 for Co using ICP-TOF-MS detection) do provide clear evidence of the efficacy of this approach for sample introduction. In the case of Ni and Se, the tetracarbonyl and alkylated selenium compounds have been identified, respectively.

[Digital signal acquisition and processing software for atomic fluorescence spectrometry and its application to elemental speciation].

A program was developed to collect and process digital signal by using Visual C++ for atomic fluorescence spectrometry (AFS). The software solves the data acquisition problem of coupling AFS with HPLC and other successive separation techniques. This program employs three signal processing techniques, i.e. Savitzky-Golay smoothing, Fourier filter and wavelet denoising, to smooth and filter the noisy data. The processes and comparisons of these techniques have been discussed. The program was successfully applied to the preliminary study of Cd speciation by using cation exchange HPLC coupled to AFS, and will provide a new possibility for extending the application of atomic fluorescence spectrometry to the field of elemental speciation analysis.

UV vapor generation for determination of selenium by heated quartz tube atomic absorption spectrometry.

A new vapor generation technique utilizing UV irradiation coupled with atomic absorption for the determination of selenium in aqueous solutions is described. In the presence of low molecular weight organic acid solutions, inorganic selenium(IV) is converted by UV irradiation to volatile selenium species, which are then rapidly transported to a heated quartz tube atomizer for detection by atomic absorption spectrometry. Optimum conditions for photochemical vapor generation and interferences from concomitant elements were investigated. Identification of the volatile products using cryotrapping GC/MS analysis revealed that inorganic selenium(IV) is converted to volatile selenium hydride, selenium carbonyl, dimethyl selenide, and diethyl selenide in the presence of formic, acetic, propionic, and malonic acids, respectively. In acetic acid solution, the efficiency of generation was estimated to be 50 +/- 10%. No interference from Ni(2+) and Co(2+) at concentrations of 500 and 100 mg L(-)(1), respectively, was evident. A detection limit of 2.5 microg L(-)(1) and a relative sensitivity of 1.2 microg L(-)(1) (1% absorption) with a precision of 1.2% (RSD, n = 11) at 50 microg L(-)(1) were obtained.

Photochemical alkylation of inorganic selenium in the presence of low molecular weight organic acids.

Using a flow-through photochemical reactor and a low pressure mercury lamp as a UV source, alkyl selenium species are formed from inorganic selenium(IV) in the presence of low molecular weight organic acids (LMW acids). The volatile alkyl Se species were cryogenically trapped and identified by GC-MS and GC-ICP-MS. In the presence of formic, acetic, propionic and malonic acids, inorganic selenium(IV) is converted by UV irradiation to volatile selenium hydride and carbonyl, dimethylselenide and diethylselenide, respectively. Se(IV) was successfully removed from contaminated agricultural drainage waters (California, U.S.A.) using a batch photoreactor system Se. Photochemical alkylation may thus offer a promising means of converting toxic selenium salts, present in contaminated water, to less toxic dimethylselenide. The LMW acids and photochemical alkylation process may also be key to understanding the source of atmospheric selenium and are likely involved in its mobility in the natural anaerobic environment.