The relationship between contact lens ultraviolet light transmittance and myopia progression: a large-scale retrospective cohort study.

Background: The prevalence of myopia is increasing dramatically around the world, and many studies have suggested the possibility that ultraviolet (UV) light is effective to prevent the onset and progression of myopia. However, UV is a risk factor for diseases that cause refractive errors such as cataract and pterygium. In this study, we evaluated the relationship between UV exposure and myopia progression. Methods: The dataset consisted of a total of 337 396 eyes of patients in the 12-to-29-year age range, who were prescribed soft contact lenses (SCL) for refractive error at Okada Eye Clinic in Japan between 2002 and 2011. They were tracked over a five-year period and did not change the type of SCL. In this retrospective cohort study based on medical records, we divided patients into two groups, one prescribed SCL with UV protection (UV-SCL), and another prescribed SCL without UV protection (UV + SCL). Results: Change in refractive power over five years was measured and results compared. It was -0.413 diopter (D) in the UV-SCL group and -0.462 D in the UV + SCL group. Thus, the progression of myopia was slower in the UV-SCL group. The results were also analyzed separately by gender and degree of myopia at the time of initial prescription, which all showed significant differences (P < 0.001). Conclusion: Results suggest that UV exposure may advance myopia. Further research is needed to investigate the underlying mechanisms that could explain this.

Microdialysis-integrated HPLC system with dual-electrode detection using track-etched membrane electrodes for in vivo monitoring of dopamine dynamics.

A capillary high-performance liquid chromatography (HPLC) system equipped with a dual-electrode detector utilizing track-etched membrane electrodes (TEMEs) was combined with a microdialysis sampling setup. The electrochemical detector benefits from the high electrolysis efficiency of TEMEs, allowing for calibration-free coulometric detection and simplifying data analysis to determine the dopamine recovery through a dialysis probe. Additionally, this system was used for in vivo monitoring of dopamine in the right striatum of a mouse brain. Temporal changes in dopamine levels, including an exponential decay immediately after the dialysis probe insertion and an excess release of dopamine induced by a high concentration of potassium ions, confirmed the system's proper operation. Furthermore, subsequent measurements following the intraperitoneal injection of mirtazapine showed no increase in dopamine levels in the right dorsal striatum. The dual-electrode system displayed characteristic dopamine detection behavior, with anodic and cathodic peak pairs indicative of reversible electrochemical reactions. This capability facilitated the identification of the dopamine peak within the complex chromatogram of the mouse brain dialysate. The consistency between dopamine collection efficiency from standard solutions and dialysate indicated the absence of interfering electroactive substances overlapping with the dopamine peak in the chromatogram. This integrated analysis system successfully tracked temporal fluctuations in dopamine concentration within the mouse brain.

Diversity in Lacrimal Pathway Morphology Among Patients with Congenital Nasolacrimal Duct Obstruction.

Purpose: This prospective observational study aimed to explore the diversity in lacrimal pathway morphology among patients with congenital nasolacrimal duct obstruction (CNLDO) by examining dacryocystography (DCG) images. Patients and Methods: The study included 64 patients who underwent DCG before undergoing general anesthesia probing for unilateral CNLDO. Several parameters were measured from the lateral view of the DCG images: (1) the lacrimal sac (LS) and the nasolacrimal duct (NLD) angle, (2) the angle formed by the superior orbital rim (SOR), LS, and the NLD, (3) LS length, and (4) bony NLD length. Additionally, frontal views of the DCG images were utilized to measure (5) LS-NLD angle and (6) LS angle concerning the midline. Results: The average age of the patients was 34.3 months. The mean ± standard deviation of the measurements of the above parameters was (1) -1.2° ± 16.5° (range: -44.6° ± 46.6°), (2) -5.0° ± 10.3° (range: -24.0° ± 19.0°), (3) 10.2 ± 2.4 mm (range: 6.5-16.0 mm), (4) 8.0 ± 2.5 mm (range: 3.1-14.8 mm), (5) 15.6° ± 11.2° (range: -16.8° ± 41.0°), and (6) 15.1 ± 5.2° (range: 3.3°-29.8°). All parameters, except for parameter (3), conformed to a normal distribution. Conclusion: This study provides valuable anthropometric data derived from DCG images, highlighting the substantial variability in lacrimal pathway morphology among patients with CNLDO. Furthermore, anatomical constraints made probing with a straight metal bougie anatomically infeasible in 25.0% of the patients included in this study.

Understanding the morphology of the lacrimal pathway is crucial for the successful probing treatments in patients with congenital nasolacrimal duct obstruction (CNLDO). This study represents an initial effort to quantify anthropometric parameters of the lacrimal drainage system through dacryocystography images, specifically aiming to highlight the limitations of blind probing procedure. The results underscore significant variations in the morphology of the lacrimal drainage system among patients, which could impact diagnostic approaches and treatment strategies. Additionally, the findings suggest that patients with CNLDO who do not respond to blind probing may have underlying anatomical complexities. Therefore, rather than relying on repeated blind probing, employing dacryoendoscopy-guided probing under direct visualization could offer a more effective therapeutic alternative for complicated cases of CNLDO.

Immune checkpoint inhibitors for metastatic uveal melanoma: a meta-analysis.

Several studies have evaluated immune checkpoint inhibitors (ICIs) for metastatic uveal melanoma; however, the efficacy of ICIs in the previous studies varied greatly. In this systematic review, we searched for prospective or retrospective studies on single or dual-ICIs for metastatic uveal melanoma treatment. A random-effect model meta-analysis with generic inverse-variance was conducted, and 36 articles representing 41 cohorts of 1414 patients with metastatic uveal melanoma were included. The pooled outcomes were as follows: objective response rate (ORR) was 5.6% (95% confidence interval [95%CI] 3.7-7.5%; I2, 36%), disease control rate (DCR) was 32.5% (95% CI 27.2-37.7%; I2, 73%), median progression-free survival was 2.8 months (95% CI 2.7-2.9 months; I2, 26%), and median overall survival (OS) was 11.2 months (95% CI 9.6-13.2 months; I2, 74%). Compared to single-agent ICI, dual ICI led to better ORR (single-agent: 3.4% [95% CI 1.8-5.1]; dual-agent: 12.4% [95% CI 8.0-16.9]; P < 0.001), DCR (single-agent: 29.3%, [95% CI 23.4-35.2]; dual-agent: 44.3% [95% CI 31.7-56.8]; P = 0.03), and OS (single-agent: 9.8 months [95% CI 8.0-12.2]; dual-agent: 16.3 months [95% CI 13.5-19.7]; P < 0.001). Our analysis provided treatment outcomes as described above. Dual-ICIs appear better than single-agent ICIs for the treatment of metastatic uveal melanoma.

Association of high disease activity and serum IL-6 levels with the incidence of inflammatory major organ events in Behçet disease: a prospective registry study.

Background: Little is known about the relationship between the disease activity of Behçet disease (BD) and the incidence of inflammatory major organ events. Objectives: In this prospective registry study, we investigated the association between the Behçet Disease Current Activity Form (BDCAF) and incidence of inflammatory major organ events, defined as the inflammation of the ocular, central nervous, intestinal, and vascular systems in BD. Methods: We enrolled participants from Japanese multicenter prospective cohorts. The BDCAF was evaluated annually. BD-related symptoms, including inflammatory major organ events, were monitored. The association between BDCAF and inflammatory major organ events was analyzed by time-to-event analysis. An unsupervised clustering of the participants' BDCAF, therapeutic agents, and multiple serum cytokines was also performed to examine their association with inflammatory major organ events. Results: A total of 260 patients were included. The patients had a median BDCAF score of 2 [Interquartile range, 1-3] at the enrolment and remained disease active at 1- and 2-year follow-ups, indicating residual disease activity in BD. Patients with a BDCAF score of 0 had a longer inflammatory major organ event-free survival at 52 weeks than those with a score of 1 or higher (p=2.2 x 10-4). Clustering analysis revealed that patients who did not achieve remission despite treatment with tumor necrosis factor inhibitors had high serum inflammatory cytokine levels and incidences of inflammatory major organ events. Among the elevated cytokines, IL-6 was associated with inflammatory major organ events. Conclusion: This study suggests that treatment strategies targeting overall disease activity and monitoring residual serum IL-6 may help prevent inflammatory major organ events in BD.

Effect of Long-Acting Diquafosol Sodium on Astigmatism Measurement Repeatability in Preoperative Cataract Cases with Dry Eyes: A Multicenter Prospective Study.

INTRODUCTION: Dry eye can compromise corneal astigmatism measurement repeatability during preoperative cataract surgery examination. No previous studies have analyzed the effectiveness of long-acting 3% diquafosol sodium (LA-DQS) on astigmatism measurement repeatability. This research assessed the effect of LA-DQS on astigmatism measurement repeatability in preoperative patients with cataract and short tear break-up time (TBUT) type dry eyes in both eyes of the same patient. Correlations between repeatability and TBUT, corneal high-order aberrations (HOAs), and corneal astigmatism magnitude were also analyzed. METHODS: In total, 122 eyes (61 patients) with short TBUT-type dry eye were enrolled. Preoperatively, only one eye of all patients was treated with LA-DQS for 4 weeks. TBUT and corneal HOAs were checked using CASIA 2 before and 4 weeks post-treatment. The cylindrical power and meridian of astigmatism were measured at 3- and 4-week post-treatment using IOLMaster 700. Power vectors J0 and J45 were used for astigmatism calculations. Repeatability of astigmatism measurements was assessed as the within-subject standard deviation (Sw). The relative effects of TBUT and HOAs on J0 Sw and J45 Sw were also analyzed. Comparative changes in these variables were evaluated between treated and non-treated eyes, with additional analysis of their correlations. RESULTS: Treated eyes exhibited significant improvements in TBUT, HOAs, and post-treatment measurements of J0 Sw and J45 Sw at 3 and 4 weeks. In non-treated eyes, J0 Sw and J45 Sw showed significant correlation with TBUT and corneal HOAs. HOAs showed stronger relative associations with J0 Sw and J45 Sw than TBUT. In non-treated eyes, no significant correlation was found between cylindrical power and astigmatism measurement repeatability. CONCLUSIONS: In short TBUT-type dry eye, preoperative treatment with LA-DQS significantly improved astigmatism measurement repeatability. This may improve the precision of intraocular lens (IOL) power calculations regardless of the magnitude of corneal astigmatism, especially when toric IOLs are used.

Otoscopy-assisted intranasal cyst marsupialization for congenital dacryocystocele.

We describe 3 infants with congenital dacryocystocele resistant to conservative treatment who were treated with a novel, simple intranasal cyst marsupialization (ICM) technique. Otoscopy-guided ICM was performed by an otolaryngologist in the manner of otoscopic myringotomy for cases with nasal cyst distension. All 3 infants were treated successfully by a single surgical procedure under topical anesthesia in an office setting.

Projection Mapping under Environmental Lighting by Replacing Room Lights with Heterogeneous Projectors.

Projection mapping (PM) is a technique that enhances the appearance of real-world surfaces using projected images, enabling multiple people to view augmentations simultaneously, thereby facilitating communication and collaboration. However, PM typically requires a dark environment to achieve high-quality projections, limiting its practicality. In this paper, we overcome this limitation by replacing conventional room lighting with heterogeneous projectors. These projectors replicate environmental lighting by selectively illuminating the scene, excluding the projection target. Our contributions include a distributed projector optimization framework designed to effectively replicate environmental lighting and the incorporation of a large-aperture projector, in addition to standard projectors, to reduce high-luminance emitted rays and hard shadows-undesirable factors for collaborative tasks in PM. We conducted a series of quantitative and qualitative experiments, including user studies, to validate our approach. Our findings demonstrate t hat our projector-based lighting system significantly enhancesthe contrast and realism of PM results even under e nvironmental lighting compared to typical lights. Furthermore, our method facilitates a substantial shift in the perceived color mode from the undesirable aperture-color mode, where observers perceive the projected object as self-luminous, to the surface-color mode in PM.

Lacrimal sac massage for congenital nasolacrimal duct obstruction: a multicentre randomised controlled trial.

AIM: Congenital nasolacrimal duct obstruction (CNLDO) is the most common cause of epiphora and mucous discharge in the newborn. We conducted a multicentre randomised controlled trial to determine whether Crigler massage promotes the resolution of CNLDO in infants under 1 year of age. METHODS: A total of 102 infants aged 3-11 months with unilateral CNLDO were enrolled in the study. Patients were randomly assigned to the massage and non-massage groups (n=51/group). As an allocation adjustment factor, the patients were divided into age groups of 3-5, 6-8 and 9-11 months. In the massage group, the guardian performed 10 strokes two times per day for each day until resolution or 1 month. The primary endpoint was a comparison of the 1-month resolution rate in the massage and non-massage groups. RESULTS: This study included 49 male and 53 female patients with a mean age of 6.4±2.4 months. Overall, in this study, the resolution rate was not significantly different between the massage and non-massage groups (31.4% and 33.3%, respectively). However, the resolution rate was higher in the massage group in the 3-5 months age group among the protocol-compliant patients after excluding those with insufficient massage frequency (the massage group, 68.8% and the non-massage group, 28.6%, p=0.022). CONCLUSIONS: There was no increase in the resolution rate after 1 month of lacrimal sac massage in patients 3-11 months old with unilateral CNLDO. However, in protocol-compliant younger age groups, Crigler massage may be effective. TRIAL REGISTRATION NUMBER: UMIN Clinical Trial Registry (UMIN000032840; www.umin.ac.jp/).

Association of PDGFRA polymorphisms with the risk of corneal astigmatism in a Japanese population.

Corneal astigmatism is reportedly associated with polymorphisms of the platelet-derived growth factor receptor alpha (PDGFRA) gene region in Asian populations of Chinese, Malay, and Indian ancestry and populations of European ancestry. In this study, we investigated whether these PDGFRA polymorphisms are associated with corneal astigmatism in a Japanese population. We recruited 1,535 cases with corneal astigmatism (mean corneal cylinder power across both eyes: ≤ - 0.75 diopters [D]) and 842 controls (> - 0.75 D) to genotype 13 single-nucleotide polymorphisms (SNPs) in the PDGFRA gene region. We also performed imputation analysis in the region, with 179 imputed SNPs included in the statistical analyses. The PDGFRA SNPs were not significantly associated with the cases with corneal astigmatism ≤ - 0.75 D. However, the odds ratios (ORs) of the minor alleles of SNPs in the upstream region of PDGFRA, including rs7673984, rs4864857, and rs11133315, tended to increase according to the degree of corneal astigmatism, and these SNPs were significantly associated with the cases with corneal astigmatism ≤ - 1.25 D or ≤ - 1.50 D (Pc < 0.05, OR = 1.34-1.39). These results suggest that PDGFRA SNPs play a potential role in the development of greater corneal astigmatism.

HLA-DRB1*04:05 is involved in the development of Vogt-Koyanagi-Harada disease-like immune-related adverse events in patients receiving immune checkpoint inhibitors.

Immune checkpoint inhibitors (ICIs) activate anti-tumor activity by inhibiting immune checkpoint molecules that suppress inflammatory T-cell activity. However, ICIs can initiate excessive immune responses, thereby causing immune-related adverse events (irAEs). ICI-associated uveitis (ICIU) is an irAE that affects the eyes. Although Vogt-Koyanagi-Harada disease (VKH)-like uveitis is a common form of ICIU, it is unclear which factors determine the ICIU form. We retrospectively reviewed the medical records of nine ICIU cases treated with ICIs for malignancies. We also performed HLA typing in seven cases to investigate the association between HLA and disease type. Fisher's exact test was used for the statistical analysis. Five of the ICIU cases were VKH-like ICIUs, and four were non-VKH-like ICIUs. No association was found between mean age, sex, primary disease, ICI, time to onset, and disease type. Four patients with VKH-like uveitis underwent HLA genotyping and were all positive for HLA-DRB1*04:05. All 3 patients with non-VKH-like uveitis were negative for HLA-DRB1*04:05. Statistical analysis showed that HLA-DRB1*04:05 was significantly associated with developing VKH-like ICIU (P = 0.029). In ICIU, HLA-DRB1*04:05 was associated with the pathogenesis of VKH-like uveitis, suggesting that ICI-associated VKH-like uveitis has a similar pathogenesis to VKH.

Modified Technique of Setting Capsulotomy Thickness in Reducing Capsulotomy-Related Complications During Femtosecond Laser-Assisted Cataract Surgery: A Prospective, Comparative Cohort Study.

INTRODUCTION: Although uncommon, incomplete capsulotomy, anterior capsule tags and anterior capsule tears are still encountered during femtosecond laser-assisted cataract surgery (FLACS), resulting in surgical complications. This highlights the need to improve femtosecond laser-assisted capsulotomy technique to reduce capsulotomy-related complications. Therefore, the purpose of this study was to investigate the efficacy of a newly developed, modified technique of setting capsulotomy irradiation thickness in lowering the incidence of capsulotomy-related complications in FLACS. METHODS: This open-label prospective, comparative cohort study included 440 eyes (220 patients) treated with FLACS using the LenSx laser system (Alcon Laboratories, Inc. Fort Worth, TX, USA). Varying capsulotomy irradiation thicknesses were applied in each eye of the same patient. In Group 1, capsulotomy irradiation thickness was set between the upper edge of the highest point of the anterior capsule and the lower edge of the lowest point of the anterior capsule (modified technique). In Group 2, this was set between the center of the highest point of the anterior capsule and the center of the lowest part of the anterior capsule (conventional technique). Incidence rates of incomplete capsulotomy, anterior capsule tags and tears, and posterior capsule tears were compared. RESULTS: Preoperative baseline characteristics showed no significant differences. Mean total of the irradiation thicknesses was 877.1 ± 81.9 µm in Group 1 and 808.9 ± 80.0 in Group 2, with a statistically significant difference (P < 0.001). Incidences of incomplete capsulotomy were 1.8% and 7.7%, anterior capsule tags were 2.3% and 8.6%, and anterior capsule tears were 0% and 3.2% in Groups 1 and 2, respectively. These differences were statistically significant (P = 0.006, 0.005, and 0.015, respectively). No posterior capsule tears were reported in either group. CONCLUSION: The modified technique for capsulotomy in FLACS may significantly reduce the occurrence of capsulotomy-related complications, maximizing the benefits of FLACS.

Circadian Fluctuation Changes in Intraocular Pressure Measured Using a Contact Lens Sensor in Patients with Glaucoma after the Adjunctive Administration of Ripasudil: A Prospective Study.

Nocturnal and circadian intraocular pressure (IOP) fluctuations are important issues in glaucoma treatment. Ripasudil 0.4% eye drops, a new glaucoma medication, lowers IOP by increasing aqueous humor outflow through the trabecular meshwork. We aimed to compare differences between circadian IOP fluctuations measured using a contact lens sensor (CLS) before and after administering 0.4% ripasudil eye drops adjunctively to patients with primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG). Patients with POAG (n = 1) and NTG (n = 5) underwent 24 h IOP monitoring with a CLS before and after administering ripasudil eye drops every 12 h (8 a.m., 8 p.m.) for 2 weeks without discontinuing currently used glaucoma medications. No vision-threatening adverse event occurred. The reduction in IOP fluctuation and the reduction in the SD of IOP in 24 h, awake time and sleep time did not reach statistical significance. The baseline office-hour IOP, which was measured using Goldmann applanation tonometry (GAT), ranged in the low teens, and the reduction in office-hour IOP also did not show a significant difference. Further study is necessary to evaluate whether the low baseline IOP with less IOP reduction relates to attenuated IOP fluctuation reduction.

Replication Study of the Association of GAS6 and PROS1 Polymorphisms with Behçet's Disease in a Japanese Population.

PURPOSE: To investigate whether polymorphisms of GAS6 and PROS1, which each encode protein ligands for a family of tyrosine kinase receptors, are associated with Behçet's disease (BD) in a Japanese population. METHODS: We recruited 734 Japanese patients with BD and 1789 Japanese healthy controls. In all participants, we genotyped two single-nucleotide polymorphisms (SNPs) reportedly associated with BD: rs9577873 in GAS6 and rs4857037 in PROS1. RESULTS: We found that GAS6 rs9577873 was not significantly associated with BD. In contrast, PROS1 rs4857037, specifically the A allele, was associated with increased risk for BD. The A allele was also significantly associated with BD under additive and recessive genetic models. Expression analysis revealed that this allele was significantly associated with increased PROS1 expression. CONCLUSIONS: Our findings suggest that increased PROS1 expression related to the A risk allele of rs4857037 affects tyrosine kinase receptor signaling, contributing to the development of BD.

Comparing the effectiveness of two surgical techniques for treating lower lid epiblepharon in children: a randomized controlled trial.

A multicenter randomized controlled trial was conducted to compare the effectiveness of incisional and nonincisional surgical techniques for treating lower lid epiblepharon in children. The study included 89 eyes from 50 children aged 3-15 years (mean, 7.5 ± 2.4 years) with moderate lower lid epiblepharon. Patients were randomly assigned to either incisional (modified Hotz procedure with lid margin splitting; 45 eyes of 25 patients) or nonincisional (44 eyes of 25 patients) surgery groups. Treatment outcomes and changes in astigmatism were evaluated 6 months after surgery. Incisional surgery provided a significantly higher percentage (77.8%) of well-corrected treatment results (P = 0.026; odds ratio, 2.88; 95% confidence interval, 1.07-8.22) than nonincisional surgery (55.4%). The mean change in astigmatism 6 months after surgery was - 0.24 ± 0.42 and - 0.01 ± 0.47 D in the incisional and nonincisional surgery groups, respectively. The improvement in astigmatism was significantly higher in the incisional surgery group than in the nonincisional surgery group (P = 0.008). The incisional surgical treatment for moderate epiblepharon in children resulted in a higher number of well-corrected patients, indicating an absence of both ciliary touch and superficial keratitis as well as statistically significant improvements in astigmatism correction.

A false decrease in the automatically measured atrial pacing threshold when using the automatic pacing threshold adjustment algorithm.

Automatic pacing threshold adjustment algorithms and remote monitoring are widely used to improve the utility of pacemakers and ensure patient safety. However, healthcare providers involved in the management of permanent pacemakers should know the potential pitfalls of these functions. In this report, we present a case of atrial pacing failure induced by the automatic pacing threshold adjustment algorithm that went unnoticed even under remote monitoring.

Ten-year follow-up of infliximab treatment for uveitis in Behçet disease patients: A multicenter retrospective study.

Purpose: To evaluate 10-year outcome of infliximab (IFX) treatment for uveitis in Behçet disease (BD) patients using a standardized follow-up protocol. Design: Retrospective longitudinal cohort study. Participants: 140 BD uveitis patients treated with IFX enrolled in our previous study. Methods: Medical records were reviewed for demographic information, duration of IFX treatment, number of ocular attacks before IFX initiation, best corrected visual acuity (VA) at baseline and 1, 2, 3, 4, 5, and 10 years after IFX initiation, uveitis recurrence after IFX initiation and main anatomical site, concomitant therapies, and adverse events (AEs). Main outcome measures: 10-year IFX continuation rate and change in LogMAR VA. Results: Of 140 BD patients, 106 (75.7%) continued IFX treatment for 10 years. LogMAR VA improved gradually after initiation of IFX, and the improvement reached statistical significance from 2 years of treatment. Thereafter, significant improvement compared with baseline was maintained until 10 years, despite a slight deterioration of logMAR VA from 5 years. However, eyes with worse baseline decimal VA < 0.1 showed no significant improvement from baseline to 10 years. Uveitis recurred after IFX initiation in 50 patients (recurrence group) and did not recur in 56 (non-recurrence group). Ocular attacks/year before IFX initiation was significantly higher in the recurrence group (2.82 ± 3.81) than in the non-recurrence group (1.84 ± 1.78). In the recurrence group, uveitis recurred within 1 year in 58% and within 2 years in 74%. Seventeen patients (34%) had recurrent anterior uveitis, 17 (34%) had posterior uveitis, and 16 (32%) had panuveitis, with no significant difference in VA outcome. In addition, logMAR VA at 10 years did not differ between the recurrence and non-recurrence groups. AEs occurred among 43 patients (30.7%), and 24 (17.1%) resulted in IFX discontinuation before 10 years. Conclusions: Among BD patients with uveitis who initiated IFX, approximately 75% continued treatment for 10 years, and their VA improved significantly and was maintained for 10 years. Uveitis recurred in one-half of the patients, but visual acuity did not differ significantly from the patients without recurrence.

Determination of trace perchlorate in river water by ion chromatography with online matrix removal and sample concentration.

This paper proposes a simple ion chromatographic approach to determine trace amounts of perchlorate in river water samples. Determination of the trace perchlorate by ion chromatography typically faces two challenges: interference by matrix ions such as chloride, nitrate, and sulfate in the samples and insufficient detection sensitivity. In the present study, online pretreatment of the samples with an OnGuard II Ba/Ag/H disposable sample pretreatment cartridge prevented the sulfate peak tailing from overlapping with the perchlorate peak on the chromatogram. In addition, the matrix removal enabled as large as 10 mL of sample to be loaded into a high exchange capacity anion concentrator, significantly improving perchlorate's detection sensitivity. The proposed approach achieved a detection limit (S/N = 3) of 0.046 µg L-1 without using a costly mass spectrometer and successfully determined sub µg L-1 levels of perchlorate in river water.

Integrated continuous flow method with dual feedback-based controls for online analysis and process control.

The concept of an integrated automated continuous flow method with dual feedback controls is presented for diluting a stock solution to provide a solution of a given concentration. The one control is used for the online process monitoring by a feedback-based flow ratiometry, where the product (the diluted liquid) is titrated through the rapid bidirectional scan of the product/reagent flow ratio. The feedback control limits the scanning to the necessary range to increase the analytical throughput. The other control is used for the process control to output the product with a preset concentration. The merging ratio of the stock solution and a solvent (diluent) is changed based on the information from the online analysis. The concept was verified by applying it to producing 0.1 mol dm-3 CH3COOH. When the stock concentration was changed from 0.1 (reference concentration) to 0.3 and then 0.2 mol dm-3, the system searched for the suitable merging ratio and converged the output concentration to the reference value within 7.43 min with a relative error below 1.05%. The mean throughput rate of the process analysis was 11.2 titrations min-1. Successful results were also obtained for the 0.1 mol dm-3 HCl production. The present concept could be the basis for process control with reduced wasteful output and effluent treatment with eco-friendly treated water discharge, resulting in the contribution to SDGs' goals of 6 (Clean water and sanitation), 9 (Industry, innovation and infrastructure), and 14 (Life below water).