Enhanced boron removal via seed-induced crystal growth of barium perborate in sequential fluidized-bed crystallization.

Chemical oxo-precipitation (COP) is an enhanced precipitation method for boron removal with the conversion of boric acid to perborate anions. When using barium-based precipitant, the boron can be effectively precipitated as barium perborates (BaPBs). The phase transformation of BaPBs from amorphous (A-BaPB, Ba(B(OH)3OOH)2) to crystalline (C-BaPB, BaB2(OO)2(OH)4) form is crucial for effective boron removal. However, scaling up this phase transformation of BaPBs is hindered by poor diffusion. This study aims to promote the growth of C-BaPB through seed-induced crystal growth, eliminating the need for phase transformation. By examining the relationship between crystal growth rate and supersaturation, surface spiral growth was identified as the rate-limiting step of the growth of micron-sized seeds near pHpzc. To enable continuous crystal growth, granular seeds of C-BaPB were prepared and employed as the medium for fluidized-bed crystallization (FBC). The system reached steady state 3 hydraulic retention times, achieving 90% boron removal. The effect of surface loading, ionic strength, and dosages on steady-state crystal growth rate was studied, revealing a shift of the rate-limiting step in FBC to diffusion. Lastly, the system that constituted of two FBCs in-series for sequential crystallization of A-BaPB and C-BaPB was demonstrated. The integrated system provided 97.8% of boron removal from synthetic wastewater containing 500 mg-B/L, with 92.3% of boron crystallized on the granular seeds of BaPBs.

Boron contamination and its risk management in terrestrial and aquatic environmental settings.

Boron (B) is released to terrestrial and aquatic environments through both natural and anthropogenic sources. This review describes the current knowledge on B contamination in soil and aquatic environments in relation to its geogenic and anthropogenic sources, biogeochemistry, environmental and human health impacts, remediation approaches, and regulatory practices. The common naturally occurring sources of B include borosilicate minerals, volcanic eruptions, geothermal and groundwater streams, and marine water. Boron is extensively used to manufacture fiberglass, thermal-resistant borosilicate glass and porcelain, cleaning detergents, vitreous enamels, weedicides, fertilizers, and B-based steel for nuclear shields. Anthropogenic sources of B released into the environment include wastewater for irrigation, B fertilizer application, and waste from mining and processing industries. Boron is an essential element for plant nutrition and is taken up mainly as boric acid molecules. Although B deficiency in agricultural soils has been observed, B toxicity can inhibit plant growth in soils under arid and semiarid regions. High B intake by humans can be detrimental to the stomach, liver, kidneys and brain, and eventually results in death. Amelioration of soils and water sources enriched with B can be achieved by immobilization, leaching, adsorption, phytoremediation, reverse osmosis, and nanofiltration. The development of cost-effective technologies for B removal from B-rich irrigation water including electrodialysis and electrocoagulation techniques is likely to help control the predominant anthropogenic input of B to the soil. Future research initiatives for the sustainable remediation of B contamination using advanced technologies in soil and water environments are also recommended.

Comparison of RetCam and Smartphone-Based Photography for Retinopathy of Prematurity Screening.

This study aimed to compare the clinical performance between a smartphone-based fundus photography device and a contact imaging device for retinopathy of prematurity (ROP) screening. All patients were first examined with binocular indirect ophthalmoscopy (BIO), which served as the reference standard. The patients were then assessed by two devices. Imaging quality, ability to judge the zone and stage of ROP, agreement with the BIO results, vital signs, and pain scores were compared between these two devices. In total, 142 eyes of 71 infants were included. For the smartphone-based fundus photography, image quality was graded excellent or acceptable in 91.4% of examinations, although it was still significantly inferior to that of the contact imaging device (p < 0.001). The smartphone-based fundus photography images had moderate agreement with the BIO results regarding the presence or absence of plus disease (Cohen's κ = 0.619), but evaluating the zone (p < 0.001) and stage (p < 0.001) of ROP was difficult. Systemic parameters, except for heart rate, were similar between the two imaging devices (all p > 0.05). In conclusion, although the smartphone-based fundus photography showed moderate agreement for determining the presence or absence of plus disease, it failed to identify the zone and stage of ROP.

Eye irrigation as a first-line treatment and diagnostic method for emergency department patients who complain of ocular foreign bodies.

This prospective study aimed at determine whether eye irrigation removes ocular foreign bodies (FBs) and whether ocular pain predicts FBs. Emergency department patients complaining of ocular FBs were enrolled. In the irrigation group (n = 52), pain was evaluated with a visual analog scale before and after irrigation, and the presence of FBs was determined under a slit-lamp. In the nonirrigation group (n = 27), the evaluations were performed upon arrival. The corneal FB retention rate was found significantly lower in the irrigation (13/52, 25%) than in the nonirrigation groups (13/27, 48%; P = 0.04). After irrigation, those without FBs had more patients experiencing pain reduction (67%) compared to those with retained FBs (46%; P = 0.14) and had a greater magnitude of change in pain score (mean ± SD, - 2.6 ± 2.7 vs. - 0.7 ± 1.4; P = 0.02). An improvement in ocular pain score ≥ 5 points after irrigation predicted the absence of FBs with a negative predictive value of 100%. Eye irrigation significantly lowered corneal FB retention; if ocular pain decreased considerably, the probability of retained FBs was low, making irrigation-associated pain score reduction a feasible diagnostic method to exclude FB retention without needing specialized ophthalmic examinations.

A Study on the Sound Insulation Performance of Cross-laminated Timber.

Cross-laminated Timber (CLT) has become an emerging board material of wood construction that is strong enough to sustain a high-rise building. However, many wooden congregate housing units overseas that utilize CLT have poor sound environments because the low mass of such wood influences sound insulation performance. In this research, we explored the effect of different CLT walls on sound insulation performance and integrated applicable sound insulation simulation tools to simplify the process of designing a CLT wall structure. This research aimed at a double wall and CLT combined with a gypsum board as the research object. The sound insulation performance test was carried out in a laboratory, while the sound insulation performance of the structure was predicted through simulation tools and prediction models and then compared with the measured values to verify the applicability of the simulation tool. The CLT with a double wall and CLT with gypsum board (CLT + GB) achieved Rw of 50 dB. The numerical simulation had better prediction performance than INSUL at the double wall, while the double wall with cavity structure was close to the measured result via mass law calculation. The INSUL-predicted CLT with a gypsum board at 500 Hz~3150 Hz was close to the measured value.

Process optimization for the synthesis of ceramsites in terms of mechanical strength and phosphate adsorption capacity.

Red mud (RM), an industrial waste of bauxite refinery, shows great potential in adsorptive phosphate immobilization but granulation of RM enables the ease for field application. Red-mud-based ceramsites with 12 compositions that blended Korean red mud, American red mud, ocher, and bentonite were synthesized through firing process (600-1000 °C). The porosity, bulk density, mechanical strength, mineralogical composition, and phosphate adsorption capacity of granulated RM were characterized and analyzed. The crystallization of plagioclases, nepheline and gehlenite was observed in the ceramsites with high alkali flux content, which enhanced both porosity and phosphate adsorption capacity. The characteristics of the ceramsites without phase transition were highly correlated with porosity. The mechanical strength of ceramsites was governed by crack population, describable by the Weibull distribution model, and thus the maximal tensile stress correlated negatively with porosity. Results showed that 32 wt % of KRREM and USREM treated at 1000 and 900 °C, respectively, yielded the best performing ceramites in terms of mechanical strength and phosphate adsorption capacity. Ultimately, the phosphate adsorption capacity, as affected by initial phosphate concentration, contact time, and temperature, of the optimized ceramsites was studied.

Recent advances in adsorption and coagulation for boron removal from wastewater: A comprehensive review.

The anthropogenic emission of boron to river has become a serious problem that deteriorates the water quality and endangers the ecosystem. Although boron is a micronutrient, it is toxic to plants, animals and humans upon exposure. In this review, we first present the sources of the boron-containing streams and their composition, and then summarize the recent progress of boron removal methods based on adsorption and coagulation systematically. The boron-spiked streams are produced from coal-fired and geothermal power plants, the manufacturing and the activities of oil/gas excavation and mining. The adsorbents for boron removal are classified into the ones functionalized by chelating groups, the ones on the basis of clays or metal oxide. Three subgroups reside in the coagulation approach: electrocoagulation, chemical precipitation and chemical oxo-precipitation. The hybrid technology that combines membrane process and adsorption/coagulation was covered as well. To provide a comprehensive view of each method, we addressed the reaction mechanism, specified the strength and weakness and summarized the progress in the past 5 years. Ultimately, the prospective for future research and the possible improvement on applicability and recyclability were proposed.

Potential Role and Significance of Ocular Demodicosis in Patients with Concomitant Refractory Herpetic Keratitis.

PURPOSE: To evaluate the role of Demodex infestation of the eyelids in patients with recurrent herpetic keratitis. PATIENTS AND METHODS: This is a retrospective and noncomparative case series. Twenty-seven patients with ocular demodicosis and recurrent herpetic keratitis under conventional treatments were enrolled. Demographic data and clinical photographs were collected. Ocular demodicosis was confirmed by eyelash examination under a microscope. Eyelid scrub was initiated in these patients after proving Demodex infestation. Response after treatment was reviewed. RESULTS: Herpetic keratitis was characterized by epithelial defect, including dendritic lesions (seven eyes, 25.9%), geographic ulcer (three eyes, 11.1%), and neurotrophic ulcer (two eyes, 7.4%), associated with stromal involvement in 12 cases. Six cases with stromal reactivation, including disciform keratitis (two eyes, 7.4%), immune ring (three eyes, 11.1%), and ghost vessel (one eye, 3.7%), presented no epithelial defect. Active anterior uveitis with keratic precipitates was found in 15 cases. Demodex blepharitis was diagnosed with cylindrical dandruff along their lashes in all patients. Other ocular findings include meibomian gland dysfunction (15 eyes, 55.6%), mal-aligned lashes (eight eyes, 29.6%), telangiectasia (14 eyes, 51.9%), conjunctivitis (18 eyes, 66.7%), and ocular rosacea (three eyes, 11.1%). Initial unstable clinical presentations showed deterioration of corneal melting into descemetocele, corneal perforation, recalcitrant stromal infiltration/uveitis, and uncontrollable IOP, despite antiherpetic medication. After treatment of Demodex blepharitis, infestation was under control, followed by subjective improvement of ocular symptoms and a stable clinical outcome. CONCLUSION: Ocular demodicosis should be considered in patients with unstable recurrent herpetic keratitis. A prompt diagnosis and appropriate treatment may curb the progression of herpetic corneal infection.

Ocular manifestation, comorbidities, and detection of severe acute respiratory syndrome-coronavirus 2 from conjunctiva in coronavirus disease 2019: A systematic review and meta-analysis.

The coronavirus disease 2019 (COVID 19) pandemic has presented major challenges to ophthalmologists. Reports have shown that ocular manifestations can be the first presenting symptoms of COVID 19 infection and conjunctiva may be a portal of entry for the severe acute respiratory syndrome (SARS) associated coronavirus 2 (SARS CoV 2). The purpose of this article is to provide general guidance for ophthalmologists to understand the prevalence of ocular presentation in COVID 19 patients and to reduce the risk of transmission during practice. Relevant studies published in the period of November 1, 2019, and July 15, 2020, regarding ocular manifestations of COVID 19 and detection of SARS CoV 2 in the eye were included in this systematic review and meta analysis. The pooled prevalence of the ocular manifestations has been estimated at 7% (95% confidence interval [CI]: 0.03-0.10) among COVID 19 patients. The pooled detection rate of SARS CoV 2 from conjunctiva was low (1%, 95% CI: 0.00-0.03). Conjunctival symptoms were the most common ocular manifestations in COVID 19, but the positive detection rate of the SARS CoV 2 virus by reverse transcription-polymerase chain reaction of conjunctival tears or secretions remained low. No study has shown a definite transmission of COVID 19 through ocular mucosa or secretions. In summary, ocular manifestations in COVID 19 patients commonly comprise ocular surface symptoms. Although a low prevalence of ocular symptoms was encountered among patients infected by SARS CoV 2, it is imperative for all ophthalmologists to understand the full spectrum of COVID 19 symptoms or signs including those of the eyes as well as to adopt appropriate protective measures during clinical practice.

Proposed measures to be taken by ophthalmologists during the coronavirus disease 2019 pandemic: Experience from Chang Gung Memorial Hospital, Linkou, Taiwan.

PURPOSE: Although Taiwan was one of the first countries to develop coronavirus disease 2019 (COVID-19), with effective antiepidemic measures, Taiwan has effectively controlled the spread of the disease. The purpose of this article is to provide useful safety strategies for ophthalmologists in daily practice during the COVID-19 pandemic. MATERIALS AND METHODS: Infection control strategies in the hospital and Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, are discussed. RESULTS: Ophthalmologists are at high risk of contracting COVID-19 infection, as they have close contact with patients during ocular examinations, and are also facing high patient volume in outpatient clinics as well as emergency consultations. Furthermore, ocular symptoms, such as conjunctivitis, may be the presenting signs of COVID-19 infection. We provide our strategies, which include hospital's gate control with triage station, patient volume control, proper personal protective equipment, and consultation with telemedicine technology, to decrease the risk of cross-infection between medical staffs and patients. CONCLUSION: To achieve the goal of preventing viral spread and maximizing patient and medical staffs' safety, besides providing proper protective equipment, it is also crucial for staffs and patients to strictly follow antiepidemic measures. We hope that our experience can help ophthalmologists and health-care workers to have a safer working environment when facing COVID-19 pandemic.

The removal of phosphate by thermally treated red mud from water: The effect of surface chemistry on phosphate immobilization.

This study investigated thermal treatment of red mud (RM) and its effect on phase composition, surface property, and sorption capacity exemplified by phosphate. Dehydration (∼600 °C), decomposition of carbonate minerals (700 °C-800 °C), and silicate/aluminate formation (900 °C-1000 °C) occurred upon thermal treatment of RM. Grain growth and vitrification that rendered initial morphology changes and decreased the specific surface area of RM from 26.5 to 4.1 m2/g when treated from 600 to 1000 °C, respectively. Surface acidity, i.e., intrinsic acidity constant and surface acidity density, decreased as well after thermal treatment at 600 °C due to burnouts of organics then increased upon further elevated-temperature treatment because of phase transformation. Thermal activation enhanced phosphate adsorption density (µmol/m2). Multilayer sorption aided by leached metal ions was responsible for phosphate immobilization.

Eye-related Emergency Department Visits with Ophthalmology Consultation in Taiwan: Visual Acuity as an Indicator of Ocular Emergency.

To investigate the epidemiology of eye-related emergency department (ED) visits and to determine if visual acuity (VA) could be an indicator for determining the timing for managing ocular emergencies, we have conducted the retrospective study which included patients visited the ED for eye-related reasons and had received ophthalmology consultations at a referral center in Taiwan in 2015. Among 46,514 consultations, 5,493 were ophthalmology consultations (11.8%). After exclusion, 5,422 were eligible for analysis. Among them, 1,165 (21.5%) had not likely emergent diagnoses, 4,048 (74.7%) had likely emergent diagnoses, and 209 patients (3.9%) could not be determined. The logMAR VA was 0.31 ± 0.48, 0.66 ± 0.78, and 1.00 ± 0.94 in groups with not likely emergent, likely emergent, and undetermined diagnoses, respectively. Among all eye-related ED visits, 10.3% of patients received ophthalmologic intervention or were admitted to the ophthalmology ward. A LogMAR VA score of 0.45 (decimal equivalent of 0.4) had the highest discrimination power for identifying whether a patient needed ophthalmology intervention or admission to ophthalmology ward (area under the curve: 0.802, sensitivity: 0.800, specificity: 0.672). In our study, we found VA could be an indicator for determining the priority and time of ocular emergencies requiring ophthalmic intervention in patients visiting the ED for eye-related reasons.

The role of fluoroaluminate complexes on the adsorption of fluoride onto hydrous alumina in aqueous solutions.

Activated alumina (AA) has been extensively applied in the defluorination of industrial wastewaters and groundwater. Although the dissolution of AA due to formation of fluoroaluminate complexes (AlFx3-x), especially in acidic condition, has been observed, its role on fluoride uptake by alumina has not been discussed in any previous literature, most of which consider F- as the sole adsorbed species. The present study described the effect of fluoroaluminate complexes on fluoride adsorption onto alumina. Results indicated that fluoroaluminate complexes, major fluoride species at pH < 6, were responsible for total fluoride adsorbed. Free fluoride ions were adsorbed mainly in the alkaline pH region, e.g., pH > 6. The dissolution of AA during defluorination was measured and analyzed by the thermodynamic solubility model. The surface concentration of F- and AlFx3-x were calculated considering electrostatic interactions. Characterization of fluoride-laden AA by XPS revealed that the fraction of surface Al-F species decreased with pH, which suggested the transition of the surface fluorinated species to that of free fluoride ions. The stability constants of four surface complexes, namely, AlOH-FAl2+, AlOH-F2Al+, AlOH2+-F- and AlOH-F-, were 106.88, 105.36, 102.72 and 102.36, respectively. Obviously fluoroaluminate complexes exhibited stronger chemical bonds with the surface hydroxy species than free fluoride.

Electrocoagulation of tetrafluoroborate (BF4-) and the derived boron and fluorine using aluminum electrodes.

Tetrafluoroborate anion (BF4-) is found in the streams of flue-gas desulfurization and borosilicate glasses etching which deteriorates water quality through slow hydrolysis into boric acid and fluoride. Decomposition and electrocoagulation (EC) of BF4- were studied using metallic aluminum as the sacrificial electrode. The dissolved Al(III) from the anode could efficiently decompose BF4- in forms of fluoroaluminate complexes, and the derived boric acid and fluoride ion were removed by sweep flocculation. Major variables were investigated to optimize EC, including the reaction pH, initial concentration of BF4-, current density and electrolyte type. The mechanism of EC process was elucidated with the kinetics of consecutive reactions. Experimental results suggested that the removal of BF4- and total fluoride were less influenced by pH, and that of total boron reached a maximum at pH 8 which favored the surface complexation between borate species and EC precipitates. Under the conditions: [BF4-]0 = 9.3 mM, [NaCl] = 10 mM, pH = 8.0, current density = 5 mA/cm2, 98.3% of BF4- was decomposed and the removal of total fluoride and boron attained 98.2% and 74.1%, respectively within 3 h. EC using the Al electrode outperformed the conventional chemical coagulation and reduced the levels of BF4, B(OH)3 and F- in aqueous solution synergically.

Adsorption characteristics of ammonium ion onto hydrous biochars in dilute aqueous solutions.

This research aims at studying the characteristics of ammonium adsorption onto hydrous bamboo biochar. Results showed that pH played the most important role in ammonium adsorption. High ionic strength enhanced the ammonium adsorption capacity of bamboo biochar. Ammonium adsorption was exothermic and spontaneous. FTIR results showed shift, disappearance, or appearance of specific functional groups on the bamboo biochar surface. Surface precipitation and complex formation contributed to the adsorption of ammonium onto hydrous bamboo biochar. Biochar can be an effective adsorbate for ammonium removal from water. Additionally, the formation of nitrogen containing precipitates on the biochar surface, potentially, leads to the in-situ synthesis of slow-release fertilizer.

Solubility products of sparingly soluble barium perborates in aqueous solution that contains B(OH)3 and H2O2 at 25°C.

Chemical oxo-precipitation (COP) has become a promising method for treating boron wastewater at room temperature; it uses hydrogen peroxide to convert boric acid to perborate species, which are precipitated using alkaline earth metals. In this work, solubility models of barium perborates were established to predict residual boron levels from COP. The solubility product constants (pKsp) of two major barium perborates - amorphous Ba(B(OH)3OOH)2 (A-BaPB) and crystalline BaB(OH)2(OO)2B(OH)2 (C-BaPB) - were experimentally estimated (8.335±0.109 and 9.190±0.057, respectively) to define the solubility curves of BaPBs at given pH, ionic strength and concentrations of barium and peroxide species. The characterization of precipitates that were formed by COP confirmed that the boron levels in aqueous solution were governed by the phase transformation of A-BaPB to C-BaPB. The predictive solubility models of barium perborates can perfectly predict the residual concentration of boron after COP treatment and can be used to optimize the process for reducing boron concentrations in wastewater.

THz-bandwidth tunable slow light in semiconductor optical amplifiers.

We report tunable fractional delays of 250% for 700 fs pulses propagating in a 1.55 mum semiconductor optical amplifier at room temperature. This large fractional delay is attributed to a spectral hole created by the propagating pulses for pulses with duration shorter than the carrier heating relaxation time. Delay can be tuned electrically by adjusting the current with low amplitude variation across the tuning range.

Functional links between the Prp19-associated complex, U4/U6 biogenesis, and spliceosome recycling.

The Prp19-associated complex, consisting of at least eight protein components, is involved in spliceosome activation by specifying the interaction of U5 and U6 with pre-mRNA for their stable association with the spliceosome after U4 dissociation. We show here that yeast cells depleted of one or two of the Prp19-associated components, accumulate the free form of U4. In NTC25-deleted cells, the level of U6 was also reduced. Extracts prepared from NTC25-deleted cells contained neither free U4 nor U6 and were ineffective in spliceosome recycling in the in vitro splicing reaction. Overexpression of U6 partially rescued the temperature-sensitive growth defect and decreased the relative amount of free U4 in NTC25-deleted cells, indicating that the accumulation of free U4 was a consequence of insufficient amounts of U6 snRNA. Extracts prepared from U6-overproducing NTC25-deleted cells containing free-form U6 were capable of spliceosome recycling, suggesting a role of free U6 RNP in spliceosome recycling. Our results demonstrate that in addition to direct participation in spliceosome activation, the Prp19-associated complex has an indirect role in spliceosome recycling through affecting the biogenesis of U4/U6 snRNP in the in vivo splicing reaction.

Functional and physical interactions between components of the Prp19p-associated complex.

The Prp19p-associated complex is essential for the yeast pre-mRNA splicing reaction. The complex consists of at least eight protein components, but is not tightly associated with spliceosomal snRNAs. By a combination of genetic and biochemical methods we previously identified four components of this complex, Ntc25p, Ntc85p, Ntc30p and Ntc20p, all of them being novel splicing factors. We have now identified three other components of the complex, Ntc90p, Ntc77p and Ntc31p. These three proteins were also associated with the spliceosome during the splicing reaction in the same manner as Prp19p, concurrently with or immediately after dissociation of U4 snRNA. Two-hybrid analysis revealed that none of these proteins interacted with Prp19p or Ntc25p, but all interacted with Ntc85p. An interaction network between the identified components of the Prp19p-associated complex is demonstrated. Biochemical analysis revealed that Ntc90p, Ntc31p, Ntc30p and Ntc20p form a subcomplex, which, through interacting with Ntc85p and Ntc77p, can associate with Prp19p and Ntc25p to form the Prp19p-associated complex. Genetic analysis suggests that Ntc31p, Ntc30p and Ntc20p may play roles in modulating the function of Ntc90p.