Enhancing Rose Bengal penetration in ex vivo human corneas using iontophoresis.

Aim: Rose Bengal photodynamic antimicrobial therapy (RB-PDAT) has poor corneal penetration, limiting its efficacy against acanthamoeba keratitis (AK). Iontophoresis enhances corneal permeation of charged molecules, piquing interest in its effects on RB in ex vivo human corneas. Methods: Five donor whole globes each underwent iontophoresis with RB, soaking in RB, or were soaked in normal saline (controls). RB penetration and corneal thickness was assessed using confocal microscopy. Results: Iontophoresis increased RB penetration compared with soaking (177 ± 9.5 µm vs. 100 ± 5.7 µm, p < 0.001), with no significant differences in corneal thickness between groups (460 ± 87 µm vs. 407 ± 69 µm, p = 0.432). Conclusion: Iontophoresis significantly improves RB penetration and its use in PDAT could offer a novel therapy for acanthamoeba keratitis. Further studies are needed to validate clinical efficacy.

The study aimed to improve a new treatment for eye infections known as photodynamic antimicrobial therapy. It investigated whether the use of electricity through a technique called iontophoresis could help a chemical called Rose Bengal go deeper into the eye in order to target more severe infections. The iontophoresis machine was custom built, with patient-contacting components 3D printed. The experiments were performed using donated human eye tissue and found that iontophoresis significantly improved the penetration depth of Rose Bengal as compared with the current technique of only soaking the eye in Rose Bengal.

Discordant Phenotypes of Nephritis in Patients with X-linked Agammaglobulinemia.

PURPOSE: To define the clinical and histological characteristics of nephritis in patients with X-linked agammaglobulinemia (XLA) and their immunological profiles. METHODS: The clinical, immunological, and histological findings of nine patients with XLA and nephritis were retrospectively analyzed. RESULTS: Based on kidney histological findings, patients with XLA and nephritis could be divided into two groups, viz., chronic glomerulonephritis (CGN) and tubulointerstitial nephritis (TIN). The two groups showed different immunological profiles. Patients in the CGN group exhibited an atypical immunological profile of XLA, with pathogenic leaky B cells producing immunoglobulins that may play a role in forming immune complexes and causing immune-mediated glomerulonephritis. In contrast, patients in the TIN group exhibited a typical immunological profile of XLA, suggesting that antibody-independent/other BTK-dependent mechanisms, or immunoglobulin replacement therapy (IgRT)-related immune/nonimmune-mediated nephrotoxicity causes TIN. CONCLUSION: Nephritis occurring in patients with XLA could have links between their renal pathology and immunological status. Careful observation is recommended to detect kidney pathology in patients with XLA on IgRT.

Update on "Cell Therapy" Clinics Offering Treatments of Ocular Conditions Using Direct-To-Consumer Marketing Websites in the U.S.

PURPOSE: To assess the scope of U.S.-based companies advertising and administering non-Federal Drug Administration (FDA) approved cell-based therapy (herein called NFACT) for ocular conditions based on information from companies' public websites after the FDA's legal actions against specific NFACT clinics in 2018 and 2019. Current findings are compared to previously published data from 2017. DESIGN: Trend study looking at U.S.-based companies that use direct-to-consumer marketing and have websites advertising therapy for ocular conditions. METHODS: A systematic and extensive keyword-based Internet search was utilized to identify, document, and analyze U.S. business websites offering NFACT for ocular conditions as of August 2022. Main outcomes measured include, clinic locations, marketed ocular conditions, types of NFACT offered, source of stem cells used, routes of administration, and treatment costs. RESULTS: From the prior analysis in 2017 to the 2019 analysis, there was a decrease in the number of NFACT clinics from 76 to 62 and companies from 40 to 39. Given the concerning persistence of NFACTs in August 2019 an additional analysis was performed in 2022 which showed a drastic decrease in NFACT clinics from 62 in 2019 to 18 in 2023 and from 39 companies to 13 in 2023. In both 2019 and 2022, the most commonly referenced ocular condition was age-related macular degeneration (2019 - 72%, 2022 - 92%). The state with the most clinics was in Texas (2019 - 12; 2022 - 5). Autologous adipose-derived stem cells were the most common cell type used in both analyses. CONCLUSIONS: In 2019 U.S.-based direct-to-consumer companies marketing NFACT persisted despite (1) a lack of high-quality clinical evidence supporting the efficacy of these procedures, (2) the association of some of these treatments with severe vision loss, and (3) increasing FDA oversight and recent legal action. In 2022 the number of clinics and companies decreased, but their persistence is a reminder that continued concern is necessary and ophthalmic associations need to continue advocacy efforts to protect patients from these potentially predatory organizations.

Faricimab in Previously Treated Eyes With Neovascular Age-Related Macular Degeneration: An Assessment of Durability and Treatment Outcomes.

BACKGROUND AND OBJECTIVE: This study evaluated the efficacy and durability of faricimab in patients with neovascular age-related macular degeneration (nAMD) who were previously treated with anti-vascular endothelial growth factor (anti-VEGF) agents. PATIENTS AND METHODS: This retrospective case series was conducted at a single tertiary center in the United States. It focused on nAMD patients who transitioned to faricimab after initial anti-VEGF therapy, with a follow-up period of at least 9 months. "Complete dryness" was defined as the absence of intra- and/or subretinal fluid on optical coherence tomography. Durability was gauged by the extension of treatment intervals relative to the injection frequency of the previous agent. RESULTS: Sixty-two eyes from 62 patients were included. Treatment interval ranged from 5 to 10 weeks; 10 (16%) patients were able to be extended by 2 or more weeks compared to their previous regimen. Median (interquartile range [IQR]) central field thickness was 310 µm (254, 376) on initiating faricimab and declined by the ninth month (P values at 3, 6, and 9 months were 0.01, 0.02, and 0.07, respectively). Median (IQR) visual acuity at initiation of faricimab was 0.4 (0.20, 0.50) and did not change by the ninth month. Complete anatomical dryness was present in 10 (16%) eyes before switching; 90% remained dry at 9 months. Of 52 (84%) incompletely dry eyes before switching, 15% achieved complete dryness by 9 months on faricimab. CONCLUSIONS: Faricimab modestly improved the treatment intervals for a small proportion of previously treated patients on anti-VEGF therapy. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].

Natural History and Genomic Landscape of Chemotherapy-Resistant Muscle-Invasive Bladder Cancer.

PURPOSE: Patients with residual invasive bladder cancer after neoadjuvant chemotherapy (NAC) and radical cystectomy have a poor prognosis. Data on adjuvant therapy for these patients are conflicting. We sought to evaluate the natural history and genomic landscape of chemotherapy-resistant bladder cancer to inform patient management and clinical trials. METHODS: Data were collected on patients with clinically localized muscle-invasive urothelial bladder cancer treated with NAC and cystectomy at our institution between May 15, 2001, and August 15, 2019, and completed four cycles of gemcitabine and cisplatin NAC, excluding those treated with adjuvant therapies. Survival was estimated using the Kaplan-Meier method, and multivariable Cox proportional hazards models were used to identify predictors of recurrence-free survival (RFS). Genomic alterations were identified in targeted exome sequencing (Memorial Sloan Kettering Integrated Mutation Profiling of Actionable Cancer Targets) data from post-NAC specimens from a subset of patients. RESULTS: Lymphovascular invasion (LVI) was the strongest predictor of RFS (hazard ratio, 2.15 [95% CI, 1.37 to 3.39]) on multivariable analysis. Patients with ypT2N0 disease without LVI had a significantly prolonged RFS compared with those with LVI (70% RFS at 5 years). Lymph node yield did not affect RFS. Among patients with sequencing data (n = 101), chemotherapy-resistant tumors had fewer alterations in DNA damage response genes compared with tumors from a publicly available chemotherapy-naïve cohort (15% v 29%; P = .021). Alterations in CDKN2A/B were associated with shorter RFS. PIK3CA alterations were associated with LVI. Potentially actionable alterations were identified in more than 75% of tumors. CONCLUSION: Although chemotherapy-resistant bladder cancer generally portends a poor prognosis, patients with organ-confined disease without LVI may be candidates for close observation without adjuvant therapy. The genomic landscape of chemotherapy-resistant tumors is similar to chemotherapy-naïve tumors. Therapeutic opportunities exist for targeted therapies as adjuvant treatment in chemotherapy-resistant disease.

Synthesis and Performance of Bio-Based Amphoteric Surfactants.

As the global surfactant market continues to expand, there is an increasing need to develop bio-based alternatives in the shift towards a circular economy. This study focuses on the synthesis of polar, amphoteric, amine-oxide surfactants starting from biomass-derived monosaccharides and demonstrating their potential in various applications. The synthesis involved a reductive amination of the sugars with an alkylamine and formaldehyde followed by oxidation to produce N-oxide surfactants. These bio-based surfactants exhibited promising properties, including high solubility, foamability, surface tension reduction, and critical micelle concentration. In particular, N-GalA1.10 and N-GalA1.12 showed comparable performance to commercial surfactants. Furthermore, these bio-based surfactants demonstrated significantly lower skin irritation potential when compared to petrochemical-derived counterparts like sodium laureth sulfate (SLES), making them potentially suitable for personal care products. The biodegradability assessment revealed that N-GalA1.12 exhibited good biodegradation, indicating its potential environmental compatibility. In conclusion, this study highlights the potential of bio-based N-oxide surfactants derived from monosaccharides as sustainable and skin-friendly alternatives to traditional amphoteric surfactants, like cocamidopropyl betaine (CAPB).

NCCN Guidelines® Insights: Bladder Cancer, Version 3.2024.

Bladder cancer, the sixth most common cancer in the United States, is most commonly of the urothelial carcinoma histologic subtype. The clinical spectrum of bladder cancer is divided into 3 categories that differ in prognosis, management, and therapeutic aims: (1) non-muscle-invasive bladder cancer (NMIBC); (2) muscle invasive, nonmetastatic disease; and (3) metastatic bladder cancer. These NCCN Guidelines Insights detail recent updates to the NCCN Guidelines for Bladder Cancer, including changes in the fifth edition of the WHO Classification of Tumours: Urinary and Male Genital Tumours and how the NCCN Guidelines aligned with these updates; new and emerging treatment options for bacillus Calmette-Guérin (BCG)-unresponsive NMIBC; and updates to systemic therapy recommendations for advanced or metastatic disease.

Accelerated Bayesian Inference for Molecular Simulations using Local Gaussian Process Surrogate Models.

While Bayesian inference is the gold standard for uncertainty quantification and propagation, its use within physical chemistry encounters formidable computational barriers. These bottlenecks are magnified for modeling data with many independent variables, such as X-ray/neutron scattering patterns and electromagnetic spectra. To address this challenge, we employ local Gaussian process (LGP) surrogate models to accelerate Bayesian optimization over these complex thermophysical properties. The time-complexity of the LGPs scales linearly in the number of independent variables, in stark contrast to the computationally expensive cubic scaling of conventional Gaussian processes. To illustrate the method, we trained a LGP surrogate model on the radial distribution function of liquid neon and observed a 1,760,000-fold speed-up compared to molecular dynamics simulation, beating a conventional GP by three orders-of-magnitude. We conclude that LGPs are robust and efficient surrogate models poised to expand the application of Bayesian inference in molecular simulations to a broad spectrum of experimental data.

Clinical Features and Treatment Outcomes of Carbapenem-Resistant Pseudomonas aeruginosa Keratitis.

Importance: Evaluation of the microbiological diagnostic profile of multidrug-resistant Pseudomonas aeruginosa keratitis and potential management with rose bengal-photodynamic antimicrobial therapy (RB-PDAT) is important. Objective: To document the disease progression of carbapenemase-resistant P aeruginosa keratitis after an artificial tear contamination outbreak. Design, Setting, and Participants: This retrospective observation case series included 9 patients 40 years or older who presented at Bascom Palmer Eye Institute and had positive test results for multidrug-resistant P aeruginosa keratitis between January 1, 2022, and October 31, 2023. Main Outcomes and Measures: Evaluation of type III secretion phenotype, carbapenemase-resistance genes blaGES and blaVIM susceptibility to antibiotics, and in vitro and in vivo outcomes of RB-PDAT against multidrug-resistant P aeruginosa keratitis. Results: Among the 9 patients included in the analysis (5 women and 4 men; mean [SD] age, 73.4 [14.0] years), all samples tested positive for exoU and carbapenemase-resistant blaVIM and blaGES genes. Additionally, isolates were resistant to carbapenems as indicated by minimum inhibitory concentration testing. In vitro efficacy of RB-PDAT indicated its potential application for treating recalcitrant cases. These cases highlight the rapid progression and challenging management of multidrug-resistant P aeruginosa. Two patients were treated with RB-PDAT as an adjuvant to antibiotic therapy and had improved visual outcomes. Conclusions and Relevance: This case series highlights the concerning progression in resistance and virulence of P aeruginosa and emphasizes the need to explore alternative therapies like RB-PDAT that have broad coverage and no known antibiotic resistance. The findings support further investigation into the potential effects of RB-PDAT for other multidrug-resistant microbes.

Clinical Outcomes in Patients With Traumatic Dehiscence of Penetrating Keratoplasty Grafts.

PURPOSE: The purpose of this study was to report clinical characteristics and outcomes of surgical repair for patients with traumatic dehiscence of penetrating keratoplasty (PKP) grafts. METHODS: Retrospective, consecutive chart review of patients evaluated at Bascom Palmer Eye Institute between 2015 and 2020 with traumatic dehiscence of penetrating keratoplasty grafts. RESULTS: The study cohort consisted of 65 eyes of 65 patients. The mean age at presentation was 72 years (SD 18), with a male predominance (65%). The most common indications for PKP included keratoconus (42%), corneal scar (31%), and Fuchs corneal dystrophy (8%). Dehiscence occurred as a result of blunt trauma in 94% of cases, and the mean wound length was 6.4 clock hours (SD 2.4), with a predominance of inferior dehiscence. The mean presenting visual acuity (VA) was 2.45 logMAR (SD 0.41), and the mean final VA was 2.17 logMAR (SD 0.99). Graft failure occurred in 64% of patients, and 22% underwent repeat PKP. When stratified by indication for corneal transplantation (keratoconus vs. other), there was no significant difference in graft age at the time of rupture, final VA, rate of graft failure, or rate of repeat PKP. CONCLUSIONS: Traumatic dehiscence of corneal grafts remains a rare but serious subtype of ocular trauma with generally poor visual prognoses. Presenting VA along with severity of trauma and posterior segment involvement tend to be the worst prognostic factors in final visual outcome.

Fe-Fe bonding in the rhombic Fe4 cores of the Zintl clusters [Fe4E18]4- (E = Sn and Pb).

We report here the synthesis and characterization of two endohedral Zintl-ion clusters, [Fe4Sn18]4- and [Fe4Pb18]4-, which contain rhombic Fe4 cores. The Fe-Fe bond lengths are all below 2.5 Å, distinctly shorter than in the corresponding Cu clusters, indicating the presence of Fe-Fe bonding. Subtle differences in the structure of the Fe4 core between the two clusters suggest that the change in tetrel element causes a change in electronic ground state, with a very short Fe-Fe bond length of 2.328 Å present across the diagonal of the rhombus in the lead case.

New Approaches to Overcoming Antimicrobial Resistance in Endophthalmitis.

Endophthalmitis is a rare but vision-threatening infection characterized by marked inflammation of intraocular fluids and tissues, uncommonly seen following surgery and intravitreal injection. Antimicrobials are used worldwide in the prophylaxis and treatment of bacterial and fungal infections of the eye and are standard treatment in the preoperative and postoperative care of surgical patients. However, antimicrobials are reported to be overprescribed in many parts of the world, which contributes to antimicrobial resistance (AMR). AMR complicates the prophylaxis and treatment of endophthalmitis. This article examines the prevalence and mechanisms of AMR in ocular microorganisms, emphasizing the importance of understanding AMR patterns for tailored treatments. It also explores prophylaxis and management strategies for endophthalmitis, with a discussion on the use of intracameral antibiotic administration. The use of prophylactic intracameral antibiotics during cataract surgery is common in many parts of the world but is still controversial in some locations, especially in the US. Finally, it highlights the role of stewardship in ophthalmology and its benefits in the treatment of endophthalmitis.

Response to 2 Induction Courses of Bacillus Calmette-Guèrin Therapy Among Patients With High-Risk Non-Muscle-Invasive Bladder Cancer: 5-year Follow-Up of a Phase 2 Clinical Trial.

Importance: With the ongoing bacillus Calmette-Guèrin (BCG) shortage, alternate therapeutic options for patients with high-risk non-muscle-invasive bladder cancer (NMIBC) are needed. Objective: To report the 5-year outcomes of a cohort from a prospective phase 2 trial of patients with high-risk NMIBC who underwent 12 instillations of induction BCG without maintenance. Design, Setting, and Participants: Between November 2015 and June 2018, patients at Memorial Sloan Kettering Cancer Center with primary or recurrent NMIBC (high-grade Ta, T1 tumors, with or without carcinoma in situ) were prospectively enrolled to receive 2 induction courses (12 intravesical instillations) of BCG without maintenance therapy. The analysis itself took place on July 28, 2023. Main Outcomes and Measures: Recurrence-free survival (RFS) and cancer-specific survival (CSS) was assessed by landmark analysis at 7.5 months. Recurrence was defined as pathologic high-grade disease. Results: Among 81 patients (65 men [84%] and 12 women [16%] with a median [IQR] age of 72 [64-77] years) who consented to participate in the study, 75 remained evaluable for long-term follow-up analysis. Twenty-one patients experienced high-grade recurrence, yielding a 5-year RFS rate of 69% (95% CI, 58%-81%), with a median (IQR) follow-up of 4.4 (3.8-5.3) years for patients without recurrence. Three patients died of bladder cancer, corresponding to a CSS rate of 97% (95% CI, 93%-100%) with a median (IQR) follow-up of 4.9 (4.2-5.7) years for survivors. Using 2 induction courses reduced the amount of BCG per patient from 27 vials to 12 vials. Conclusion and Relevance: Twelve induction instillations of BCG without maintenance for patients with high-risk NMIBC reduced the number of vials needed per patient while providing acceptable oncologic outcomes. Given the ongoing BCG shortage, this modified regimen may provide a suitable alternative in this setting.

Proliferative Sickle Cell Retinopathy: Outcomes of Vitreoretinal Surgery.

PURPOSE: To report the clinical presentation and outcomes in patients who underwent surgery for proliferative sickle cell retinopathy (PSCR). DESIGN: Retrospective, consecutive case series. SUBJECTS: All patients who underwent vitreoretinal surgery for complications secondary to PSCR between January 1, 2014, and December 31, 2021, at a university referral center. METHODS: Retrospective consecutive case series. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA), single operation anatomic success rate. RESULTS: The study included 65 eyes of 61 patients. Disease distribution included 24 (44.4%) eyes with hemoglobin SC disease, 14 (25.9%) with hemoglobin SS disease, 13 (24.1%) with sickle cell trait, and 3 (5.6%) with sickle cell-ß thalassemia. Preoperative transfusion was not performed in any study patients. Regional anesthesia with monitored anesthesia care (RA-MAC) was utilized in 58 (89.2%) eyes and general anesthesia in 7 (10.8%). In eyes that underwent surgery for retinal detachment (RD; N = 52) the rate of single operation anatomic success was 72.4% with combined scleral buckling/pars plana vitrectomy (SB/PPV; N = 29) compared with 47.8% with PPV alone (N = 23; P = 0.07). Mean BCVA at the last follow-up examination was 1.27 (20/372) in the SB/PPV group and 1.05 (20/226) in the PPV group (P = 0.48). In all SB cases, an encircling band was utilized and there were no known cases of anterior segment ischemia. All eyes that had surgery for vitreous hemorrhage (N = 13) underwent PPV with endolaser and mean BCVA improved from 1.67 (20/944) preoperatively to 0.45 (20/56) at last follow-up examination (P < 0.001). Mean preoperative BCVA, indication for surgery, single operation success rate, and mean BCVA at last follow-up examination did not differ based on sickle cell disease type (P > 0.05). CONCLUSIONS: In patients with RD, SB/PPV achieved slightly higher rates of single operation anatomic success compared with PPV alone. Visual acuity outcomes were similar in the 2 groups. The majority of patients received RA-MAC anesthesia and preoperative transfusions were not performed. There were no cases of postoperative anterior segment ischemia. Hemoglobin SC disease was the most common disease type in the current study and surgical outcomes did not differ between sickle cell disease types. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Design of a high-temperature cell for cobalt-60 irradiations of aqueous solutions with in situ UV-visible spectroscopy.

To understand the speciation of solutes in aqueous solutions in high temperature radiation environments, we report the design and fabrication of a custom-built, high temperature (≤300 °C) titanium irradiation cell with in situ optical spectroscopy capabilities, as afforded by coupled fiber optic cables. The wetted surfaces of the 8-inch tall cylindrical cell with 3.5 in. diameter are entirely made of titanium, sapphire, and gold, which are chemically and radiolytically inert. The initial benchmarking results are reported, including the baseline spectrum of deionized water as a function of temperature, the stability of a spectrum over 4 h at 100 °C, and an irradiated Fricke dosimetry solution under ambient irradiator temperature conditions (27.0 ± 0.5 °C). The average gamma radiation dose rate in the cell in its current configuration is 26.1 ± 1.3 Gy min-1. This cell has application in studying several processes throughout the nuclear fuel cycle, including the reactor coolant behavior.

Diagnostic outcome of pro bono neurogenetic diagnostic service in Sri Lanka: A wealth creation.

The inherited disease community in Sri Lanka has been widely neglected. This article aimed to present accumulated knowledge in establishing a pro bono cost-effective national, island-wide, free-of-charge molecular diagnostic service, suggesting a model for other developing countries. The project provided 637 molecular diagnostic tests and reports free of charge to a nation with limited resources. We pioneered the implementation of mobile clinics and home visits, where the research team acted as barefoot doctors with the concept of the doctor and the researcher at the patient's doorstep. Establishing pro bono, cost-effective molecular diagnostics is feasible in developing countries with limited resources and state funding through the effort of dedicated postgraduate students. This service could provide an accurate molecular diagnosis of Duchenne muscular dystrophy, Huntington's disease, Spinocerebellar ataxia, and Spinal muscular atrophy, a diagnostic yield of 54% (343/637), of which 43% (147/343) of the patients identified as amenable for available gene therapies. Initiated human resource development by double doctoral degree opportunities with international collaborations. Established a neurobiobank and a national registry in Sri Lanka, a rich and unique repository, wealth creation for translational collaborative research and sharing of information in neurological diseases, as well as a lodestar for aspiring initiatives from other developing countries.

Title-molecular diagnostics of dystrophinopathies in Sri Lanka towards phenotype predictions: an insight from a South Asian resource limited setting.

BACKGROUND: The phenotype of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) patients is determined by the type of DMD gene variation, its location, effect on reading frame, and its size. The primary objective of this investigation was to determine the frequency and distribution of DMD gene variants (deletions/duplications) in Sri Lanka through the utilization of a combined approach involving multiplex polymerase chain reaction (mPCR) followed by Multiplex Ligation Dependent Probe Amplification (MLPA) and compare to the international literature. The current consensus is that MLPA is a labor efficient yet expensive technique for identifying deletions and duplications in the DMD gene. METHODOLOGY: Genetic analysis was performed in a cohort of 236 clinically suspected pediatric and adult myopathy patients in Sri Lanka, using mPCR and MLPA. A comparative analysis was conducted between our findings and literature data. RESULTS: In the entire patient cohort (n = 236), mPCR solely was able to identify deletions in the DMD gene in 131/236 patients (DMD-120, BMD-11). In the same cohort, MLPA confirmed deletions in 149/236 patients [DMD-138, BMD -11]. These findings suggest that mPCR has a detection rate of 95% (131/138) among all patients who received a diagnosis. The distal and proximal deletion hotspots for DMD were exons 45-55 and 6-15. Exon 45-60 identified as a novel in-frame variation hotspot. Exon 45-59 was a hotspot for BMD deletions. Comparisons with the international literature show significant variations observed in deletion and duplication frequencies in DMD gene across different populations. CONCLUSION: DMD gene deletions and duplications are concentrated in exons 45-55 and 2-20 respectively, which match global variation hotspots. Disparities in deletion and duplication frequencies were observed when comparing our data to other Asian and Western populations. Identified a 95% deletion detection rate for mPCR, making it a viable initial molecular diagnostic approach for low-resource countries where MLPA could be used to evaluate negative mPCR cases and cases with ambiguous mutation borders. Our findings may have important implications in the early identification of DMD with limited resources in Sri Lanka and to develop tailored molecular diagnostic algorithms that are regional and population specific and easily implemented in resource limited settings.

Snap-shots of cluster growth: structure and properties of a Zintl ion with an Fe3 core, [Fe3Sn18]4.

The endohedral Zintl-ion cluster [Fe3Sn18]4- contains a linear Fe3 core with short Fe-Fe bond lengths of 2.4300(9) Å. The ground state is a septet, with significant σ and π contributions to the Fe-Fe bonds. The Sn18 cage is made up of two partially fused Sn9 fragments, and is structurally intermediate between [Ni2CdSn18]6-, where the fragments are clearly separated and [Pd2Sn18]4-, where they are completely fused. It therefore represents an intermediate stage in cluster growth. Analysis of the electronic structure suggests that the presence of the linear Fe-Fe-Fe unit is an important factor in directing reactions towards fusion of the two Sn9 units rather than the alternative of oligomerization via exo bond formation.

Modeling Henry's law and phase separations of water-NaCl-organic mixtures with solvation and ion-pairing.

Empirical measurements of solution vapor pressure of ternary acetonitrile (MeCN) H2O-NaCl-MeCN mixtures were recorded, with NaCl concentrations ranging from zero to the saturation limit, and MeCN concentrations ranging from zero to an absolute mole fraction of 0.64. After accounting for speciation, the variability of the Henry's law coefficient at vapor-liquid equilibrium (VLE) of MeCN ternary mixtures decreased from 107% to 5.1%. Solute speciation was modeled using a mass action solution model that incorporates solute solvation and ion-pairing phenomena. Two empirically determined equilibrium constants corresponding to solute dissociation and ion pairing were utilized for each solute. When speciation effects were considered, the solid-liquid equilibrium of H2O-NaCl-MeCN mixtures appear to be governed by a simple saturation equilibrium constant that is consistent with the binary H2O-NaCl saturation coefficient. Further, our results indicate that the precipitation of NaCl in the MeCN ternary mixtures was not governed by changes in the dielectric constant. Our model indicates that the compositions of the salt-induced liquid-liquid equilibrium (LLE) boundary of the H2O-NaCl-MeCN mixture correspond to the binary plateau activity of MeCN, a range of concentrations over which the activity remains largely invariant in the binary water-MeCN system. Broader comparisons with other ternary miscible organic solvent (MOS) mixtures suggest that salt-induced liquid-liquid equilibrium exists if: (1) the solution displays a positive deviation from the ideal limits governed by Raoult's law; and (2) the minimum of the mixing free energy profile for the binary water-MOS system is organic-rich. This work is one of the first applications of speciation-based solution models to a ternary system, and the first that includes an organic solute.