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  Item type:Publication, Access status: Metadata only ,

  Counter-ion driven loss of freezable water weakens donnan exclusion in a cation-exchange membrane

  (Elsevier, 2026)

  Department of Chemistry

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  Graduate School of Sciences and Engineering

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  KUHyTech (Koç University Hydrogen Technologies Center)

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  KUYTAM (Koç University Surface Science and Technology Center)

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  Yes

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  Ion-exchange membranes are defined by their permselectivity, which arises from their ability to exclude co-ions through Donnan exclusion. Yet, the factors limiting the predictability of co-ion exclusion are not fully understood. Here, we show that the identity of the counter-ion alone can weaken Donnan exclusion in a commercial cation-exchange membrane (Fumasep FKS-50) which is not captured by current thermodynamic models. Equilibrating the membranes with NaCl, KCl, and CsCl solutions progressively reduces the water content. Differential scanning calorimetry reveals that this reduction occurs almost entirely from the freezable water population, while the bound water remains sufficient to satisfy the effective hydration of the counter-ions and fixed sulfonate charges. Comparison of our experimental data with thermodynamic models shows that the Donnan-Manning model substantially improves agreement with experiment over the ideal-Donnan model and describes co-ion partitioning reasonably well for the NaCl- and KCl-equilibrated membranes, although small deviations remain at low salt concentrations. In contrast, it systematically under-predicts co-ion uptake in the Cs+ form across the entire concentration range, despite the integration of the experimentally determined differences in the membrane water content. Together with the retention of strongly associated hydration water, this finding indicates that the larger deviations for the Cs+ form cannot be explained by differences in membrane hydration alone. We instead attribute them to the redistribution of water within the membrane. Accordingly, the depletion of bulk-like water lowers the effective dielectric constant, while the accompanying loss of weakly associated water allows Cs+ to approach closer toward the fixed sulfonate groups. Both effects strengthen the Coulombic interaction between the counter-ion and the fixed charges, screening the effective fixed charge concentration and weakening Donnan exclusion. These results identify counter-ion driven loss of freezable water as a mechanism that limits the predictive capability of conventional thermodynamic models of co-ion partitioning, with direct implications for membrane permselectivity under the mixed-cation conditions encountered in practical separations.

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  Item type:Publication, Access status: Metadata only ,

  Clonazepam-test

  (Wiley, 2026)

  Yapar, F. S.

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  Dogan, A. E.

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  Gürses, C.

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  The authors have no conflicts of interest to disclose. The data that support the findings of this study are available from the corresponding author upon reasonable request.

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  Item type:Publication, Access status: Metadata only ,

  Educational background, clinical practices, and perspectives of physiotherapists on Scoliosis-specific exercises in Türkiye: a cross-sectional survey

  (Wiley, 2026)

  Atli, E.

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  Ozyemisci Taskiran, O.

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  School of Medicine

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  Yes

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  Taşkıran, Özden Özyemişçi

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  Background and Purpose The present study aimed to investigate the experiences and perspectives of physiotherapists trained in scoliosis‐specific exercises (SSE) regarding their training processes and clinical practices. Methods A cross‐sectional, web‐based survey was conducted to examine the educational background, clinical practices, and professional perspectives of physiotherapists trained in SSE. The survey consisted of 30 items organized into four main sections: demographics, educational background, clinical practices, and professional perspectives. Physiotherapists who had completed formal training in at least one SSE school recognized by SOSORT, had at least one year of clinical experience in SSE and had treated 30 or more patients with scoliosis annually were included in the study. Results The median age of 39 physiotherapists (36 women, 3 men) was 30 years (IQR = 28–33). The median duration of general clinical experience was 7.4 years, while the median duration of SSE experience was 3.4 years. ISST (International Schroth Three Dimensional Scoliosis Therapy) (87.2%) and SEAS (Scientific Exercise Approach to Scoliosis) (48.7%) were the most common training methods, and more than half (51%) had completed training in at least two SSE schools. Among all physiotherapists, 87% perceived themselves as competent in delivering SSE, 54% disagreed that certified training was sufficient to instruct 3D scoliosis exercises to patients with AIS, and 79% agreed that an observership program was necessary following certified training. Sixty‐four percent of participants perceived SSE as complex for adolescents. Physiotherapists who perceived themselves as competent had longer SSE clinical experience ( p = 0.046). However, no statistically significant association was found between self‐perceived competence and perceived SSE complexity in adolescents ( p = 0.636). Physiotherapists who did not perceive SSE as complex for adolescents had longer SSE clinical experience ( p = 0.007). Discussion This study reflects the perspectives of physiotherapists in Turkey who have received SSE training and offers unique insights into their professional experiences. The majority of physiotherapists reported self‐perceived competence in delivering SSE; however, more than half perceived SSE as complex for adolescents.

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  Item type:Person,

  Zeynalova, Humay

  Undergraduate Student

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  Item type:Publication, Access status: Metadata only ,

  Single-session versus Hypofractionated Gamma Knife radiosurgery for large parasagittal meningiomas: a retrospective comparative study

  (MDPI, 2026)

  Nazari, Amir Salar

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  School of Medicine

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  KUH (Koç University Hospital)

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  Yes

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  Veznikli, Mert

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  Large parasagittal meningiomas (PSMs) present significant surgical challenges due to their proximity to the superior sagittal sinus, and the optimal radiosurgical strategy for large tumors remains debated. This study compared local control (LC) and treatment-related radiological and clinical outcomes after single-session (ss-GKRS) and hypofractionated (hf-GKRS) Gamma Knife radiosurgery in PSMs ≥8 cm3. Methods: Eighty-seven patients with 87 radiologically confirmed PSMs treated between April 2006 and February 2025 were reviewed. Patients with histopathologically confirmed atypical or anaplastic meningiomas or imaging features suspicious for higher-grade disease were excluded. Fifty-nine patients underwent ss-GKRS and 28 received hf-GKRS. The median tumor volume was 11.2 cm3 (range 8–37.8 cm3). LC was defined as tumor volume regression or stability on serial MRI. Radiological complications were defined as new or worsening peritumoral T2 hyperintensity, and clinical complications as new neurological symptoms. Time to local progression was compared using the log-rank test, with an exploratory volume cut point from ROC analysis. Results: The median follow-up was 62 months (range 12–186 months). Overall crude LC was 93.1%, including 89.8% (53/59) after ss-GKRS and 100% (28/28; exact 95% CI 87.7–100%) after hf-GKRS. All six local progressions occurred in the ss-GKRS group; however, freedom from local progression did not differ significantly between the groups (log-rank p = 0.137). In an exploratory volume-stratified analysis, LC was 100% in both groups for tumors ≤11.75 cm3. Among tumors >11.75 cm3, crude LC was 71.4% (15/21) after ss-GKRS and 100% (16/16) after hf-GKRS (Fisher exact p = 0.027). Post-treatment radiological edema occurred in 39.0% after ss-GKRS versus 25.0% after hf-GKRS (p = 0.235). Conclusions: Overall freedom from local progression did not differ significantly between ss-GKRS and hf-GKRS. No local failures were observed after hf-GKRS during its shorter available follow-up, including among tumors >11.75 cm3 in an exploratory analysis. These findings support hf-GKRS as a feasible treatment option for selected larger PSMs, but neither treatment superiority nor a definitive tumor-volume threshold can be established from this retrospective cohort.

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