Articles de revues : « Membrana cellulare »

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Boatti, Leonardo. « Dalla mentalitŕ talebana alla democrazia degli affetti in un gruppo di bambini ». GRUPPI, n^o 1 (octobre 2010) : 63–73. http://dx.doi.org/10.3280/gru2010-001006.

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La psicoterapia analitica dell'etŕ evolutiva viene a trovarsi in questi ultimi anni in una fase di profondo rinnovamento dal punto di vista metodologico e operativo. Viviamo in una societŕ "narcisistica", improntata sulla soddisfazione immediata del bisogno e delle mete pulsionali. Ciň comporta un'ipotrofia dell'area preconscia-transizionale, dello sviluppo della capacitŕ di pensiero e del mantenimento dei legami. Kaës sottolinea l'importanza di un buon sviluppo dell'area transizionale o preconscia, indispensabile per tollerare l'attesa, la frustrazione, necessaria per lo sviluppo della capacitŕ riflessiva. Lebovici afferma che «molti adolescenti della generazione attuale non sanno che agire e sono condannati a non elaborare le loro emozioni, che non sanno rappresentare». In parallelo sempre piů bambini non sanno giocare: "presentano" piů che rappresentano i propri vissuti. Il terapeuta dell'etŕ evolutiva si trova ad affrontare gruppi di bambini la cui modalitŕ di comunicare le proprie emozioni č prevalentemente sensoriale-corporea. Viene messa a dura prova la capacitŕ contenitiva e conservativa il pensare. Il faticoso lavoro del terapeuta consiste nel permanere in una situazione bioniana di K- e nel tradurre in parole e pensieri, attraverso rappresentazioni e gioco (play), espressione di ciň che sta avvenendo in quel momento nel gruppo, le comunicazioni affettive ed emotive espresse con la sensorialitŕ e il corpo. Ciň permette nel tempo la creazione di una membrana preconscia (membrana di contatto bioniana) capace, come la membrana cellulare, di favorire lo scambio fra dentro e fuori, fra conscio e inconscio. Nell'abstract la esemplificazione clinica tratta un gruppo di bambini il cui cambiamento della composizione ha determinato lo scontro anche violento fra i rappresentanti delle due modalitŕ di comunicazione degli affetti. In particolare l'arrivo di due femmine favorisce il faticoso e doloroso cambiamento della struttura e soprattutto della mentalitŕ del gruppo: da una mentalitŕ talebana a una mentalitŕ democratica degli affetti. Si assiste a un conflitto fra una modalitŕ maschile improntata sull'azione e sul gioco (game) come veicolo delle emozioni e una modalitŕ femminile improntata sulla parola e sul pensiero.

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Masola, V., S. Granata, M. Proglio, G. Gambaro, A. Lupo et G. Zaza. « Eparanasi : un nuovo biomarker di fibrosi e un potenziale target farmacologico per ridurre la progressione del danno renale cronico ». Giornale di Clinica Nefrologica e Dialisi 24, n^o 2 (26 janvier 2018) : 10–15. http://dx.doi.org/10.33393/gcnd.2012.1131.

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Il trattamento poli-farmacologico ha determinato, nel corso degli anni, un significativo rallentamento della progressione della malattia renale cronica verso lo stadio di uremia terminale, ma siamo ancora distanti dallo sviluppo di interventi terapeutici in grado di bloccare questo inesorabile e irreversibile processo. Studi clinico-patologici hanno chiaramente dimostrato che il principale elemento coinvolto nel danno renale è la fibrosi tubulo-interstiziale e che il meccanismo patogenetico alla base di questa condizione ha inizio in larga parte nel compartimento tubulare. In particolare, il processo di transizione epitelio-mesenchimale gioca un ruolo importante nella genesi del danno cronico. Durante questo processo, le cellule epiteliali tubulari subiscono un incremento significativo di markers di superficie di natura mesenchimale e, grazie al rimodellamento del citoscheletro e alla degradazione della membrana basale, sono in grado di migrare nell'interstizio dove svolgono un ruolo chiave nel processo patogenetico. In questo contesto, sembra avere un ruolo chiave l'enzima eparanasi, una endo-β-D-glucuronidasi che taglia le catene dell'eparan-solfato a livello di siti specifici intracatena, e partecipa attivamente alla degradazione e al rimodellamento della matrice extracellulare. La degradazione dei vari costituenti dell'ECM, inclusi i proteoglicani eparan-solfato fa-vorisce il rilascio di fattori trofici quali il FGF-2 che induce l'espressione dei marcatori mesenchimali alfa-SMA, VIM e FN, porta alla degradazione della membrana basale mediante la secrezione di metalloproteinasi della matrice ed aumenta la motilità cellulare. L'epressione dell'eparanasi è regolata da fattori di trascrizione, dalla metilazione del DNA e da varie molecole endogene. L'importanza di questo enzima è stata confermata clinicamente dal riscontro di una sua iperespressione in preparati istologici di biopsie effettuate in soggetti affetti da nefropatie croniche (per esempio, nefropatia diabetica). Pertanto visto l'importante ruolo dell'eparanasi sono in fase di standardizzazione numerose strategie per inibire la sua espressione genica e/o la sua attività enzimatica. Infine, è stato proposto il suo possibile utilizzo come biomarker di progressione del danno tubulo-interstiziale da utilizzare routinariamente in ambito nefrologico.

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Matarrese, Paola, et Giuseppe Marano. « Modulazione dei recettori β-adrenergici e differenze di genere ». CARDIOLOGIA AMBULATORIALE 30, n^o 1 (31 mai 2022) : 20–24. http://dx.doi.org/10.17473/1971-6818-2022-1-5.

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Lo scompenso cardiaco (SC), processo evolutivo comune di più malattie cardiovascolari a differente eziologia (ad es. infarto del miocardio, ipertensione, cardiomiopatie, disturbi valvolari e altre), è diventato sempre più comune nella popolazione anziana, influenzando drasticamente il tasso di sopravvivenza e la qualità della vita. L’iperattività del sistema nervoso simpatico (SNS) che si associa allo SC determina un aumento delle catecolamine circolanti epinefrina e norepinefrina che, attraverso l’attivazione dei recettori beta-adrenergici (β-AR), svolgono un ruolo critico nella regolazione della funzione del sistema cardiovascolare. Una caratteristica distintiva dello SC è la diminuzione o la desensibilizzazione dei recettori β1-adrenergici (β1-AR) sulla membrana delle cellule cardiache. Le catecolamine e lo stress ossidativo sono coinvolti nella regolazione della densità dei β-AR. Lo stress ossidativo associato alla disfunzione mitocondriale sembra giocare un ruolo importante nella fisiopatologia dello SC. Infatti, una condizione di stress ossidativo è stata osservata sia in pazienti con SC che in modelli animali, e un’eccessiva esposizione a specie reattive dell’ossigeno (ROS) diminuisce l’espressione di β1-AR in cardiomiociti murini, sebbene i meccanismi sottostanti rimangano ancora non chiari. Recentemente, è stato scoperto che il recettore periferico delle benzodiazepine (PBR) svolge un ruolo chiave oltre che nell’energetica cellulare, nella regolazione della fisiologia mitocondriale e dell’equilibrio redox nei cardiomiociti. Nel presente studio, abbiamo valutato gli effetti delle catecolamine e dei ligandi del PBR sulla densità dei β1- e β2-AR nei monociti umani isolati da sangue periferico, che sono noti per esprimere entrambi i β-AR. La densità dei β-AR è stata misurata mediante citometria a flusso utilizzando anticorpi selettivi diretti contro un epitopo extracellulare di β1-AR o β2-AR. Il trattamento dei monociti con benzodiazepine induceva una riduzione della densità del β1-AR, ma non del β2-AR, sulla membrana dei monociti che veniva ripristinata utilizzando [1-(2-chlorophenyl)-N-methyl-(1-meth-ylpropyl)-3 isoquinolinecarboxamide] (PK11195), un antagonista del PBR. Questi risultati suggeriscono un possibile ruolo del PBR nella regolazione della densità del β1-AR proponendo i monociti isolati dal sangue periferico sia come modello in vitro utile per lo studio del sistema recettoriale β-adrenergico che come potenziali biomarcatori di progressione della malattia e risposta alla terapia.

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Wang, Jing, Jennifer B. Ptacek, Karla Kirkegaard et Esther Bullitt. « Double-membraned Liposomes Sculpted by Poliovirus 3AB Protein ». Journal of Biological Chemistry 288, n^o 38 (1 août 2013) : 27287–98. http://dx.doi.org/10.1074/jbc.m113.498899.

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Infection with many positive-strand RNA viruses dramatically remodels cellular membranes, resulting in the accumulation of double-membraned vesicles that resemble cellular autophagosomes. In this study, a single protein encoded by poliovirus, 3AB, is shown to be sufficient to induce the formation of double-membraned liposomes via the invagination of single-membraned liposomes. Poliovirus 3AB is a 109-amino acid protein with a natively unstructured N-terminal domain. HeLa cells transduced with 3AB protein displayed intracellular membrane disruption; specifically, the formation of cytoplasmic invaginations. The ability of a single viral protein to produce structures of similar topology to cellular autophagosomes should facilitate the understanding of both cellular and viral mechanisms for membrane remodeling.

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Putri, Venesa Thalia, Ayu Pramita et Theresia Evila Purwanti Sri Rahayu. « Sintesis Selulosa Asetat dari Tanaman Lidah Mertua (Sansevieria trifasciata) sebagai Membran Pereduksi CO (Karbon Monoksida) pada Asap Rokok ». Jurnal Rekayasa Hijau 5, n^o 3 (14 mars 2022) : 281–90. http://dx.doi.org/10.26760/jrh.v5i3.281-290.

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ABSTRAKPenelitian ini bertujuan untuk mengetahui proses pembuatann membran selulosa dari tanaman Lidah mertua (Sansevieria trifasciata) yang mampu menurunkan kadar gas CO (karbon monoksida). Terdapat beberapa tahapan diantaranya persiapan alat dan bahan; proses ekstraksi yang terdiri dari delignifikasi dan bleaching; proses sintesis yang terdiri dari swelling-up, asetilasi, dan hidrolisis; uji kadar asetil selulosa; pembuatan membran selulosa, serta tahap pengujian dan analisis data yang dilakukan secara kuantitatif dan instrumentasi. Hasil penelitian ini adalah lidah mertua dapat diolah menjadi filter berbentuk membran yang mampu mereduksi karbon monoksida melalui proses sintesis selulosa asetat. Efektivitas membran selulosa Sansevieria trifasciata dalam menurunkan kandungan karbon monoksida pada rokok yang dibakar selama 5 menit adalah sebesar 70% ketika berada di dalam ruangan dan 87% ketika berada di luar ruangan. Pembuatan membran harus dilakukan dengan mengamati jenis bahan, kondisi CH3COOH, perlakuan setelah asetilasi, suhu oven, kadar asetil, dan homogenitas.Kata kunci: efektivitas, karbon monoksida, Lidah mertua, membran selulosa, merokok.ABSTRACTThis study aims to determine the process of making cellulose membranes from the mother-in-law's tongue plant (Sansevieria trifasciata) which is able to reduce CO (carbon monoxide) gas levels. There are several stages including the preparation of tools and materials; extraction process consisting of delignification and bleaching; synthesis process consisting of swelling-up, acetylation, and hydrolysis; test for acetyl cellulose content; manufacture of cellulose membranes, as well as the stages of testing and data analysis carried out quantitatively and instrumentation. The result of this research is that mother-in-law's tongue can be processed into a membrane-shaped filter that is able to reduce carbon monoxide through the synthesis of cellulose acetate. The effectiveness of Sansevieria trifasciata cellulose membrane in reducing the carbon monoxide content in cigarettes burned for 5 minutes was 70% when indoors and 87% when outdoors. The manufacture of membranes must be carried out by observing the type of material, CH3COOH conditions, treatment after acetylation, oven temperature, acetyl content, and homogeneity.Keywords: carbon monoxide, cellulose membrane, effectiveness, Sansevieria trifasciata, smoking.

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Sirolli, V., E. Ballone, S. Di Stante, L. Amoroso et M. Bonomini. « Cell Activation and Cellular-Cellular Interactions during Hemodialysis : Effect of Dialyzer Membrane ». International Journal of Artificial Organs 25, n^o 6 (juin 2002) : 529–37. http://dx.doi.org/10.1177/039139880202500607.

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During hemodialysis (HD), circulating blood cells can be activated and also engage in dynamic interplay. These phenomena may be important factors behind dialysis membrane bio(in)compatibility. In the present prospective cross-over study, we have used flow cytometry to evaluate the influence of different dialysis membranes on the activation of circulating blood cells (leukocytes, platelets) and their dynamic interactions (formation of circulating platelet-leukocyte and platelet-erythrocyte aggregates) during in vivo HD. Each patient (n = 10) was treated with dialyzers containing membranes of cellulose diacetate, polysulfone and ethylenevinylalcohol (EVAL) in a randomized order. Upregulation of adhesion receptor expression (CD15s, CD11b/CD18) occurred mainly with the cellulosic membrane, though an increase in CD11b/CD18 circulating on neutrophils was also found with both synthetic membranes. Circulating activated platelets (P-selectin/CD63-positive platelets) increased during HD sessions with cellulose diacetate and polysulfone. An increased formation of platelet-neutrophil aggregates was found at 15 and 30 min during dialysis with cellulose diacetate and polysulfone but not with EVAL. Platelet-erythrocyte aggregates also increased with cellulose diacetate and at 15 min with polysulfone as well. Generally in concomitance with the increase in platelet-neutrophil coaggregates, there was an increased hydrogen peroxide production by neutrophils. The results of this study indicate that cellular mechanisms can be activated during HD largely depending on the membrane material, EVAL causing less reactivity than the other two membranes. It appears that each dialysis membrane has multiple and different characteristics that may contribute to interactions with blood components. Our results also indicate that derivatizing cellulose (cellulose diacetate) may be a useful way to improve the biocompatibility of the cellulose polymer and that there may be great variability in the biocompatibility profile of synthetic membranes, dialysis with polysulfone being in general associated with a higher degree of cell activation than EVAL membrane.

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Wang, Yue, et Yangfang Chen. « The Role of Cellular Membrane Microvesicles in Acute Myelogenous Leukemia ». ISP Medicine 2, n^o 1 (1 janvier 2020) : 1–6. http://dx.doi.org/10.52274/ispmed20200213.

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Little is known about the role of cellular membrance microvesicles (MVs) in hematological malignancies, especially acute myelogenous leukemia (AML), a malignant disease characterized by uncontrolled proliferation of hematopoietic stem or progenitor cells, which can lead to bone marrow failure and eventually to death. The role of MVs in the pathogenesis of cancer has been reported previously. In this review, we summarized the current progress of MVs in AML, and their roles as potential biomarkers and therapeutically targets for this research area. In summary, we found that MVs may represent a novel biomarker for disease diagnosis and response to treatment, indicators of disease status and severity, as well as potential active modulator for driving drug resistance. Further studies are needed to better understanding deeply about the role of MVs in AML.

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Ariyanti, Dhita, Nurul Widiastuti et Nourma Safarina. « Kinerja Membran Plat Berpori Berbasis Selulosa Asetat yang Disintesis Secara Inversi Fasa untuk Ultrafiltrasi Bakteri E.coli di PDAM Surabaya ». Jurnal Teknologi Lingkungan 21, n^o 2 (30 juillet 2020) : 165–73. http://dx.doi.org/10.29122/jtl.v21i2.3945.

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ABSTRACTThe lack of consumable water in urban and industrial-dense areas encourages research on clean water treatment methods. Some current treatment methods, such as precipitation, adsorption, and UV light irradiation are ineffective for water with high levels of suspended solids, organic matter, and turbidity. Therefore, alternative approaches are required to support the availability of clean and consumable water. The membrane technology is an alternative filtration method proposed in the East Surabaya's municipal waterworks area. The membrane filtration method is quite simple and easy to operate. This study aimed to determine the performance of cellulose acetate-based porous plate membranes synthesized by phase inversion for E. coli bacteria's ultrafiltration. As a raw material, cellulose acetate is preferred because of its high hydrophilicity and good biocompatibility. Membrane synthesis was carried out through the phase inversion method with acetone solvents and non-solvent water in the coagulation bath. The positive test for E. coli bacteria was carried out through the MPN (Most Probable Number) method on the municipal waterworks water samples before and after filtering with membranes. The results showed that the synthesis of cellulose acetate membrane had good homogeneity. This result was supported by the results of ANOVA single factor statistical data analysis. Also, cellulose acetate membrane had good permeability and flux performance as ultrafiltration of E. coli bacteria with a flux of 37.25 L/m2.hour.bar at a sufficient pressure of 5 bar. Test results for the presence of E. coli bacteria in PDAM water samples using the MPN method gave an initial indication that the water sample after filtration with cellulose acetate membrane was negative. Keywords: membrane, cellulose acetate, permeability, water fluxABSTRAKMinimnya air bersih yang layak konsumsi di daerah perkotaan dan padat industri mendorong penelitian tentang metode pengolahan air bersih. Kurangnya efektivitas metode pengolahan sebelumnya seperti pengendapan, adsorbsi, dan penyinaran dengan sinar UV untuk air dengan kadar suspended solids, zat organik, dan kekeruhan yang tinggi, diperlukan metode alternatif untuk mendukung ketersediaan air bersih layak konsumsi. Metode filtrasi alternatif yang ditawarkan di PDAM di kawasan Surabaya Timur. Metode filtrasi dengan membran sangat sederhana dan mudah dalam operasionalnya. Penelitian ini bertujuan untuk mengetahui kinerja membran plat berpori berbasis selulosa asetat yang disintesis secara inversi fasa untuk ultrafiltrasi bakteri E.coli. Selulosa asetat dipilih sebagai bahan baku membran karena selulosa asetat merupakan bahan polimer yang memiliki hidrofilitas tinggi dan biokompatibilitas yang baik. Sintesis membran dilakukan melalui metode inversi fasa dengan pelarut aseton dan nonpelarut air dalam bak koagulasi. Uji positif bakteri E.coli dilakukan melalui metode MPN (Most Probable Number) pada sampel air PDAM sebelum dan sesudah difiltrasi dengan membran. Hasil penelitian menunjukkan bahwa sintesis membran selulosa asetat memiliki homogenitas baik yang ditunjukkan oleh hasil analisis data statistika ANOVA single factor. Selain itu, membran selulosa asetat memiliki kinerja permeabilitas dan fluks yang baik sebagai ultrafiltrasi bakteri E.coli dengan ketercapaian fluks sebesar 37,25 L/m2.jam.bar pada tekanan efektif sebesar 5 bar. Hasil uji keberadaan bakteri E.coli pada sampel air PDAM dengan metode MPN memberikan indikasi awal bahwa sampel air setelah filtrasi dengan membran selulosa asetat adalah negatif.Kata kunci: membran, selulosa asetat, permeabilitas, fluks air

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Ali, Asmadi, Rosli Mohd Yunus, Mohamad Awang, Anwar Johari et Ramli Mat. « Effect of Cellulose Acetate Phthalate (CAP) on Characteristics and Morphology of Polysulfone/Cellulose Acetate Phthalate (PSf/CAP) Blend Membranes ». Applied Mechanics and Materials 493 (janvier 2014) : 640–44. http://dx.doi.org/10.4028/www.scientific.net/amm.493.640.

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Polysulfone (PSf) membrane is catogorized as hydrophobic membrane that easily fouled during membrane operation process. The presence of second hydrophilic polymer which added into membrane casting solutions plays a crucial role in adjusting the membrane properties. This hydrophilic polymer was employed in hydrophobic polymer membranes in order to improve hydrophilicity and performance as well as formed antifouling ultrafiltration (UF) membranes. In this study, a hydrophilic polymer, cellulose acetate phthalate (CAP) was added into polysulfone (PSf) membrane casting solutions by blending technique to produce PSf/CAP blend membranes. Flat sheet asymmetric PSf/CAP blend membranes were prepared by wet phase inversion method. The results revealed that an increase in CAP increased the hydrophilicity properties of PSf/CAP blend membranes compared to pure PSf membrane. The significant changes in size and numbers of microvoids and macrovoids in the morphological structures of PSf/CAP blend membranes were due to CAP promote the instantaneous liquid-liquid demixing during phase inversion process.

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Singh, Amit Kant, et Reena Rani Verma. « Role of Resting Membrane Potential in the Regulation of Cellular Functions ». International Physiology 5, n^o 2 (2017) : 131–34. http://dx.doi.org/10.21088/ip.2347.1506.5217.17.

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Alvianto, Dikianur, Fara Aulia Agustin Nurhadi, Angky Wahyu Putranto, Bambang Dwi Argo, Mochammad Bagus Hermanto et Yusuf Wibisono. « Sintesis dan Karakterisasi Membran Selulosa Asetat dengan Penambahan Antibiofouling Alami Ekstrak Bawang Putih ». ALCHEMY Jurnal Penelitian Kimia 18, n^o 2 (4 septembre 2022) : 193. http://dx.doi.org/10.20961/alchemy.18.2.57199.193-204.

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Teknologi membran merupakan teknologi yang dapat memisahkan dua fasa (permeat dan umpan). Kendala dalam teknologi membran yaitu bahan yang terkandung dalam umpan dan mengakibatkan terjadinya fouling (penutupan pori). Salah satu alternatif untuk mengurangi fouling yaitu menambahkan zat antibiofouling pada membran. Bahan yang dapat digunakan sebagai antibiofoulan alami adalah ekstrak bawang putih yang memiliki sifat antibakteri. Penelitian ini bertujuan untuk menganalisis pengaruh penambahan ekstrak bawang putih terhadap perbaikan karakteristik membran (ketebalan, kuat tarik, elastisitas), fluks air bersih, dan sifat antibiofouling pada bakteri Bacillus subtilis. Membran selulosa asetat dibuat dengan menggunakan metode inversi fasa dan pelarut dimetilformamida. Penambahan ekstrak bawang putih pada pembuatan membran selulosa asetat memiliki konsentrasi masing-masing sebesar 0,25% b/v (0,01 g), 0,5% b/v (0,02 g), 0,75% b/v (0,03 g), dan 0% b/v (kontrol) dengan ketebalan 0,3 mm. Hasil yang optimum diperoleh untuk membran dengan konsentrasi 0,5 % b/v yang menghasilkan pengujian kuat tarik sebesar 0,977 N/mm2 dan untuk membrane dengan konsentrasi 0,25% b/v yang memberikan elastistas pertambahan panjang sebesar 12,22%. Sifat antibakteri membran dengan penambahan ekstrak bawang putih ditunjukkan dengan berkurangnya penempelan bakteri Bacillus subtilis pada permukaan membran sebesar 41,5% – 87,7% area.Synthesis and Characterization of Cellulose Acetate Membrane with The Addition of Natural Antibiofouling Garlic Extract. Membrane technology is a technology that can separate two phases (permeate and feed). The main problem in membrane technology is the material contained in the feed, which causes fouling (pore closure). An alternative to reducing fouling is by adding anti-biofouling substances into the membrane. The material that can be used as a natural anti-biofoulant is garlic extract which has antibacterial properties. This study aimed to analyze the effect of adding garlic extract on the improvement of membrane characteristics (thickness, tensile strength, elasticity), clean water flux, and anti-biofouling properties of Bacillus subtilis bacteria. The cellulose acetate membrane was synthesized using dimethylformamide as solvent through the phase inversion method. The addition of garlic extract in the manufacture of cellulose acetate membranes had concentrations of 0.25% w/v (0.01 g), 0.5% w/v (0.02 g), 0.75% w/v (0.03 g), and 0% w/v (control) with a thickness of 0.3 mm. The optimum results were obtained for the membrane with a concentration of 0.5% w/v, which resulted in the tensile strength test of 0.977 N/mm2, and the membrane with a concentration of 0.25% w/v, which resulted in an elongation elasticity of 12.22%. The antibacterial properties of membranes with the addition of garlic extract were indicated by the adhesion reduction of Bacillus subtilis bacteria on the membrane surface by 41.5% – 87.7% area.

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Wymelenberg, Amber Vanden, Stuart Denman, Diane Dietrich, Jennifer Bassett, Xiaochun Yu, Rajai Atalla, Paul Predki, Ulla Rudsander, Tuula T. Teeri et Daniel Cullen. « Transcript Analysis of Genes Encoding a Family 61 Endoglucanase and a Putative Membrane-Anchored Family 9 Glycosyl Hydrolase from Phanerochaete chrysosporium ». Applied and Environmental Microbiology 68, n^o 11 (novembre 2002) : 5765–68. http://dx.doi.org/10.1128/aem.68.11.5765-5768.2002.

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ABSTRACT Phanerochaete chrysosporium cellulase genes were cloned and characterized. The cel61A product was structurally similar to fungal endoglucanases of glycoside hydrolase family 61, whereas the cel9A product revealed similarities to Thermobifida fusca Cel9A (E4), an enzyme with both endo- and exocellulase characteristics. The fungal Cel9A is apparently a membrane-bound protein, which is very unusual for microbial cellulases. Transcript levels of both genes were substantially higher in cellulose-grown cultures than in glucose-grown cultures. These results show that P. chrysosporium possesses a wide array of conventional and unconventional cellulase genes.

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Taylor, Matthew P., et Karla Kirkegaard. « Modification of Cellular Autophagy Protein LC3 by Poliovirus ». Journal of Virology 81, n^o 22 (5 septembre 2007) : 12543–53. http://dx.doi.org/10.1128/jvi.00755-07.

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ABSTRACT Poliovirus infection remodels intracellular membranes, creating a large number of membranous vesicles on which viral RNA replication occurs. Poliovirus-induced vesicles display hallmarks of cellular autophagosomes, including delimiting double membranes surrounding the cytosolic lumen, acquisition of the endosomal marker LAMP-1, and recruitment of the 18-kDa host protein LC3. Autophagy results in the covalent lipidation of LC3, conferring the property of membrane association to this previously microtubule-associated protein and providing a biochemical marker for the induction of autophagy. Here, we report that a similar modification of LC3 occurs both during poliovirus infection and following expression of a single viral protein, a stable precursor termed 2BC. Therefore, one of the early steps in cellular autophagy, LC3 modification, can be genetically separated from the induction of double-membraned vesicles that contain the modified LC3, which requires both viral proteins 2BC and 3A. The existence of viral inducers that promote a distinct aspect of the formation of autophagosome-like membranes both facilitates the dissection of this cellular process and supports the hypothesis that this branch of the innate immune response is directly subverted by poliovirus.

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Xing, Tong, Changqing Dong, Xiaoying Hu, Junjiao Zhang, Ying Zhao, Xiaoqiang Wang, Junjie Xue et Xuming Zhang. « Heat treatment’s effect on the wettability of cellulose membranes via a top-down approach ». BioResources 18, n^o 1 (22 décembre 2022) : 1251–59. http://dx.doi.org/10.15376/biores.18.1.1251-1259.

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Cellulose is a potential alternative to petroleum-derived polymers, and cellulose membranes are used in many applications such as sensors, flexible materials, and functional membranes. Most bottom-up methods are energy-, chemical-, and time-intensive compared to top-down methods for preparing cellulose membranes. Additionally, most methods to improve the hydrophobicity of cellulose membranes to increase their lifetime are complex and require large amounts of organic solvents. To balance sustainability, degradability, and service life from a whole life cycle perspective, which is the biggest challenge for the industrialization of cellulose membranes, a top-down approach was used here to prepare cellulose membranes using camphor pine, walnut, and loofah materials. The effect of low temperature heat treatment on the prepared membranes’ wettability and water stability were investigated. The results showed that the water stability of loofah cellulose membrane was influenced by both surface and internal wettability due to the non-homogeneous structure. The heat treatment temperature of 200 °C for loofah cellulose membrane, 150 °C for camphor pine cellulose membrane, and 225 °C for walnut cellulose membrane was more effective.

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CIOBANU, Gabriela, Lidia FAVIER et Maria HARJA. « ASYMMETRIC CELLULOSE ACETATE MEMBRANES USED IN SEPARATION APPLICATIONS ». Spring 185, n^o 1 (14 mai 2021) : 70–76. http://dx.doi.org/10.46909/journalalse-2021-007.

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This work focused on the use of cellulose acetate polymer for the preparation of porous asymmetric membranes using a phase inversion process. These membranes were characterised by scanning electron microscopy, a bubble-point method and sorption measurements. The preparation method used induced membrane anisotropy. The capacity of the membranes in the removal of electrolyte (NaCl) from aqueous solution was investigated. A good retention of 58.6% and a high flux rate of 8.9 × 10–4 m/s using NaCl solution of 200 mg/L concentration were obtained by cellulose acetate membranes prepared with water as non-solvent. The results showed that the membrane performance was affected by the membrane structure, which was determined by the conditions of membrane preparation.

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Olafiranye, Feyisayo, Win Kyaw et Oladipupo Olafiranye. « Resolution of Dialyzer Membrane-Associated Thrombocytopenia with Use of Cellulose Triacetate Membrane : A Case Report ». Case Reports in Medicine 2011 (2011) : 1–3. http://dx.doi.org/10.1155/2011/134295.

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Blood and dialyzer membrane interaction can cause significant thrombocytopenia through the activation of complement system. The extent of this interaction determines the biocompatibility of the membrane. Although the newer synthetic membranes have been shown to have better biocompatibility profile than the cellulose-based membranes, little is known about the difference in biocompatibility between synthetic membrane and modified cellulose membrane. Herein, we report a case of a patient on hemodialysis who developed dialyzer-membrane-related thrombocytopenia with use of synthetic membrane (F200NR polysulfone). The diagnosis of dialyzer membrane-associated thrombocytopenia was suspected by the trend of platelet count before and after dialysis, and the absence of other possible causes of thrombocytopenia. We observed significant improvement in platelet count when the membrane was changed to modified cellulose membrane (cellulose triacetate). In patients at high risk for thrombocytopenia, the modified cellulose membrane could be a better alternative to the standard synthetic membranes during hemodialysis.

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Abu-Zurayk, Rund, Nour Alnairat, Aya Khalaf, Abed Alqader Ibrahim et Ghada Halaweh. « Cellulose Acetate Membranes : Fouling Types and Antifouling Strategies—A Brief Review ». Processes 11, n^o 2 (6 février 2023) : 489. http://dx.doi.org/10.3390/pr11020489.

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Cellulose acetate (CA) is a semisynthetic, biodegradable polymer. Due to its characteristics, CA has several applications, including water membranes, filament-forming matrices, biomedical nanocomposites, household tools, and photographic films. This review deals with topics related to the CA membranes, which are prepared using different techniques, such as the phase inversion technique. CA membranes are considered very important since they can be used as microfiltration membranes (MF), ultrafiltration membranes (UF), nanofiltration membranes (NF), reverse osmosis (RO) membranes, and forward osmosis (FO) membranes. Membrane fouling results from the accumulation of materials that the membrane rejects on the surface or in the membrane’s pores, lowering the membrane’s flux and rejection rates. There are various forms of CA membrane fouling, for instance, organic, inorganic, particulate fouling, and biofouling. In this review, strategies used for CA membrane antifouling are discussed and summarized into four main techniques: feed solution pretreatment, cleaning of the membrane surface, membrane surface modification, which can be applied using either nanoparticles, polymer reactions, surface grafting, or surface topography, and surface coating.

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Sirolli, V., S. Di Stante, S. Stuard, L. Di Liberato, L. Amoroso, P. Cappelli et M. Bonomini. « Biocompatibility and Functional Performance of a Polyethylene Glycol Acid-Grafted Cellulosic Membrane for Hemodialysis ». International Journal of Artificial Organs 23, n^o 6 (juin 2000) : 356–64. http://dx.doi.org/10.1177/039139880002300603.

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In order to improve the biochemical reactivity of the cellulose polymer, which is mainly attributed to the presence of surface hydroxyl groups, derivatized cellulosic membranes have been engineered replacing or masking some or all of the hydroxyl groups in the manufacturing process of the membrane. The present study was set up to analyze both biocompatibility and functional performance of two different derivatized cellulosic membranes (cellulose diacetate; polyethylene glycol, PEG, acid-grafted cellulose) as compared to a synthetic membrane (polymethylmethacrylate, PMMA). Cellulose diacetate is prepared by substituting hydroxyl groups with acetyl groups; PEG cellulose is obtained by grafting PEG chains onto the cellulosic polymer with a smaller amount of substitution than cellulose diacetate. While the three dialyzers provided similar urea and creatinine removal, the dialyzer containing cellulose diacetate showed a reduced ability to remove β2-microglobulin compared to that containing PEG cellulose or PMMA. A transient reduction in leukocyte count was observed for both derivatized cellulosic membranes. The neutrophil and monocyte counts throughout the entire dialysis session showed a closer parallelism with the cellular expression of the adhesive receptor CD15s (sialyl-Lewis x molecole) than with CD11b/CD18 expression. Platelet activation, as indicated by the percentage of cells expressing the activation markers CD62P (P-selectin) and CD63 (gp53), occurred with all membranes at 15 min of dialysis and also with PMMA at 30 min. An increased formation of platelet-neutrophil and platelet-monocyte coaggregates was found at 15 and 30 min during dialysis with cellulose diacetate and PMMA but not with PEG cellulose. Generally in concomitance with the increase in platelet-neutrophil coaggregates, an increased hydrogen peroxide production by neutrophils occurred. Our results indicate that derivatizing cellulose may represent a useful approach to improve the biocompatibility of the cellulose polymer, though some homeostatic reactions remain activated. Our results also indicate that there may be a great variability in the biocompatibility profile of derivatized cellulosic membranes which most likely stem from the different type of structural modification rather than from the degree of hydroxyl group replacement.

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Ristovski, Miliça, Danny Farhat, Shelly Ellaine M. Bancud et Jyh-Yeuan Lee. « Lipid Transporters Beam Signals from Cell Membranes ». Membranes 11, n^o 8 (26 juillet 2021) : 562. http://dx.doi.org/10.3390/membranes11080562.

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Lipid composition in cellular membranes plays an important role in maintaining the structural integrity of cells and in regulating cellular signaling that controls functions of both membrane-anchored and cytoplasmic proteins. ATP-dependent ABC and P4-ATPase lipid transporters, two integral membrane proteins, are known to contribute to lipid translocation across the lipid bilayers on the cellular membranes. In this review, we will highlight current knowledge about the role of cholesterol and phospholipids of cellular membranes in regulating cell signaling and how lipid transporters participate this process.

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Tsuchiya, Masaki, Yuji Hara et Masato Umeda. « Membrane Phospholipid Dynamics and Cellular Functions ». membrane 41, n^o 5 (2016) : 196–201. http://dx.doi.org/10.5360/membrane.41.196.

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Nguyen, Thi Minh Chau, Thi Hue Luu, Hong Anh Thu Ngo et Thi Dung Tran. « Characterisation of membrane prepared from cellulose acetate and polyguanidine ». Ministry of Science and Technology, Vietnam 64, n^o 11 (25 novembre 2022) : 5–10. http://dx.doi.org/10.31276/vjst.64(11).05-10.

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In this study, membranes were prepared from hydrophilic cellulose acetate (CA) and antibacterial polyhexamethylene guanidine hydrochloride (PHMG) by phase inversion method to improve membrane separation and antifouling capacities. The influence of preparation conditions on membrane structure and separation performance has been investigated and evaluated. The experimental results indicated that the CA membranes prepared by the phase inversion method have an asymmetric structure with a dense top layer located onto a porous supporting layer. The concentration of CA in casting solution highly influences membrane structure and its separation capacity. When the CA concentration increased from 12.2 to 18.2%, at a filter pressure of 5 bar, the prepared membrane flux gradually decreased from 46.47 to 38.72 l/m2.h due to the increase in membrane surface thickness. In comparison with the pure CA membrane, the CA/PHMG membranes have higher average filtration yield (1.6 times), lower degree of membrane fouling, and much better antifouling properties.

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Sudiarti, Tety, Deana Wahyuningrum, Bunbun Bundjali et I. Made Arcana. « Thermal Stability and Morphology Analysis of Polymer Electrolyte Membranes Prepared from Cellulose Acetate-LiClO₄ ». Key Engineering Materials 811 (juillet 2019) : 120–25. http://dx.doi.org/10.4028/www.scientific.net/kem.811.120.

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Polymer electrolyte membranes of cellulose acetate-LiClO4 were prepared from the cellulose acetate with various ratios of lithium perchlorate in tetrahydrofuran (THF) as solvent. The properties of polymer electrolyte membranes with various ratios of lithium perchlorate were studied by Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The obtained TGA curves showed that these membranes were degraded thermally in three steps, which were attributed to dehydration, the main thermal degradation of the cellulose acetate chains, and the carbonization of the product to form ash. The thermal stability of the membrane decreased with the increase in LiClO4 content. The initial temperatures of the main degradation process decreased gradually from 330 °C in pure cellulose acetate membrane to 258 °C in cellulose acetate membrane containing 25% lithium perchlorate. The morphology of the membranes transformed from dense to the more porous membrane along with the increase in lithium perchlorate ratios on membranes.

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von Filseck, Joachim Moser. « Membranumbau durch ESCRT-III-Proteine ». BIOspektrum 28, n^o 4 (juin 2022) : 363–65. http://dx.doi.org/10.1007/s12268-022-1774-x.

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AbstractTo maintain their function, cellular membranes require membrane remodelling, mediated by protein machineries like the ESCRT-III that deforms and breaks membranes in different cellular functions. Its mechanism of function is still unknown. However, recent findings on the ESCRT-IIIs’ structural and dynamic features, such as their ability to alter their shape, membrane-binding and mechanical properties, allow formulating interesting new hypotheses on how they can remodel membranes.

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Sandhoff, Konrad. « Metabolic and cellular bases of sphingolipidoses ». Biochemical Society Transactions 41, n^o 6 (20 novembre 2013) : 1562–68. http://dx.doi.org/10.1042/bst20130083.

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Lysosomes are cellular stomachs. They degrade macromolecules and release their components as nutrients into the cytosol. Digestion of sphingolipids and other membrane lipids occurs at luminal intraendosomal vesicles and IMs (intraendosomal membranes). Sphingolipid and membrane digestion needs catabolic hydrolases with the help of lipid-binding proteins [SAPs (sphingolipid activator proteins)] and anionic lipids such as BMP [bis(monoacylglycero)phosphate]. Inherited defects of hydrolases or SAPs or uptake of cationic amphiphilic drugs cause lipid accumulation, eventually leading to death, especially in inherited sphingolipid storage diseases. IMs are formed during endocytosis and their lipid composition is adjusted for degradation. Their cholesterol content, which stabilizes membranes, decreases and the level of negatively charged BMP, which stimulates sphingolipid degradation, increases. At the level of late endosomes, cholesterol is transported out of the luminal vesicles preferentially by cholesterol-binding proteins, NPC (Niemann–Pick type C)-2 and NPC-1. Their defects lead to an endolysosomal accumulation of cholesterol and sphingolipids in Niemann–Pick type C disease. BMP and ceramide stimulate NPC-2-mediated cholesterol transfer, whereas sphingomyelin inhibits it. Anionic membrane lipids also activate sphingomyelin degradation by ASM (acid sphingomyelinase), facilitating cholesterol export by NPC-2. ASM is a non-specific phospholipase C and degrades more than 23 phospholipids. SAPs are membrane-perturbing proteins which solubilize lipids, facilitating glycolipid digestion by presenting them to soluble catabolic enzymes at acidic pH. High BMP and low cholesterol levels favour lipid extraction and membrane disintegration by saposin A and B. The simultaneous inherited defect of saposins A–D causes a severe membrane and sphingolipid storage disease, also disrupting the water permeability barrier of the skin.

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Alasfar, Reema H., Viktor Kochkodan, Said Ahzi, Nicolas Barth et Muammer Koç. « Preparation and Characterization of Polysulfone Membranes Reinforced with Cellulose Nanofibers ». Polymers 14, n^o 16 (15 août 2022) : 3317. http://dx.doi.org/10.3390/polym14163317.

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The mechanical properties of polymeric membranes are very important in water treatment applications. In this study, polysulfone (PSF) membranes with different loadings of cellulose nanofibers (CNFs) were prepared via the phase inversion method. CNF was characterized through transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The pore morphology, mechanical properties, membrane performance and hydrophilicity of pure PSF membranes and PSF/CNF membranes were investigated. The changes in membrane pore structure with the addition of different CNF contents were observed using SEM images. It was shown that the calculated membrane pore sizes correlate with the membrane water fluxes. The pure water flux (PWF) of fabricated membranes increased with the addition of CNFs into the PSF matrix. It was shown that the optimal CNF loading of 0.3 wt.% CNF improved both the elastic modulus and yield stress of the PSF/CNF membranes by 34% and 32%, respectively (corresponds to values of 234.5 MPa and 5.03 MPa, respectively). This result indicates a strong interfacial interaction between the PSF matrix and the reinforced nanofibers. The calculated compaction factor (CF) showed that the membrane resistance to compaction could be improved with CNF reinforcement. Compared to pure PSF membrane, the hydrophilicity was significantly enhanced with the incorporation of 0.1 wt.%, 0.2 wt.% and 0.3 wt.% CNF, as shown by the water contact angle (WCA) results. It can be concluded that CNFs are homogeneously dispersed within the PSF matrix at CNF loading less than 0.5 wt.%.

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Zakaria, M. A., K. F. Fridiasari, A. F. Ni’mah, A. Macorowalie, Y. Santoso, O. A. Saputra, M. Bagaskara, R. E. Mustofa, E. Pramono et C. Purnawan. « Thermal properties of hybrid membrane-based PVDF modified with cellulose and silylated cellulose ». Journal of Physics : Conference Series 2190, n^o 1 (1 mars 2022) : 012017. http://dx.doi.org/10.1088/1742-6596/2190/1/012017.

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Abstract Cellulose extracted from Oil Palm Empty Fruit Bunches has been successfully modified by amino-based and oxirane-based silylating compounds. The modified and unmodified cellulose was incorporated into polyvinylidene fluoride (PVDF) membranes through the phase-inversion. The resulted membranes were further analyzed using Differential Scanning Calorimetry (DSC) to distinguish the thermal properties, including melting temperature and crystallinity of the membranes. Moreover, the water uptake properties of the membranes were discussed in this study. The melting temperature of each membrane is not significantly different. However, PVDF/CellGPTMS has better thermal properties compared to others. The presence of cellulose and its modified product within PVDF membranes improved the crystallinity of the membranes.

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Kusumaatmaja, Ahmad, Wahyuna Nur, Chotimah et Kuwat Triyana. « Hydrophilic/Hydrophobic Property Changes on Polyacrylonitrile/Cellulose Acetate Nanofiber Membrane ». Materials Science Forum 990 (mai 2020) : 215–19. http://dx.doi.org/10.4028/www.scientific.net/msf.990.215.

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Nanofibers membrane are potential material for water filtration, and surface properties of the membrane are an important factor to avoid fouling on the membrane surface. The combination of filter material is known to influence the membrane surface properties. We investigated the mixture of polyacrylonitrile (PAN) and cellulose acetate (CA) on the nanofiber membrane by electrospinning. This blend was dissolved in dimethylformamide as feed polymer in electrospinning technique. We prepared the ratio of PAN to CA were 0:10, 4:6, 5:5, 6:4, and 10:0 in 8 wt%. All the membranes formed fiber, except 0:10 which only created a thin layer from the sprays. Contact angle measurements related to membrane surface properties were measured and resulted in 128o, 126o, and 125o for 4:6, 5:5 dan 6:4 membranes, respectively. This results indicated that all PAN/CA membranes had hydrophobic properties. The hydrophobic property was also observed by Fourier transform infrared (FTIR) spectroscopy, a sharp peak of-CH3 appeared. It is interesting while mixing two hydrophilic polymers we obtain a hydrophobic membrane.

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ABURIDEH, HANANE, ZAHIA TIGRINE, DJAMILA ZIOUI, SARAH HOUT, DJILALI TASSALIT et MOHAMED ABBAS. « WASTEWATER TREATMENT USING A MODIFIED CELLULOSE ACETATE MEMBRANE ». Cellulose Chemistry and Technology 55, n^o 5-6 (30 juin 2021) : 697–704. http://dx.doi.org/10.35812/cellulosechemtechnol.2021.55.59.

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The main objective of this work has been to study the performance of membranes developed for treating purified wastewater. Polymeric membranes have been developed from solutions containing cellulose acetate (AC) and polysulfone (PSF), using N,N-dimethylformamide (DMF) as solvent and polyethylene glycol (PEG) as additive. The phase inversion method was chosen as a technique for producing the membrane films. The incorporation of PEG allowed us to study the effect of the additive on the morphological structure, and to predict the performance of the membranes formed. Examining the flux, permeability and selectivity of the membranes allowed studying the efficiency and performance of each membrane. The application results achieved in wastewater treatment at Chenoua/TIPAZA station were very satisfactory and in accordance with the standards required by WHO. The optimal performance, in terms of permeability and selectivity, was obtained for the MC membrane with the composition: PSF/PEG/AC of 25/12/63.

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Fazullin, D. D., L. I. Fazullina et G. V. Mavrin. « Obtaining and properties of ultrafiltration cellulose acetate membranes on a nylon net support ». Perspektivnye Materialy 3 (2022) : 46–54. http://dx.doi.org/10.30791/1028-978x-2022-3-46-54.

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Composite membranes nylon-AC (NAC) were obtained by immersing a nylon mesh substrate in a 5 % solution of cellulose acetate (AC) in acetone. The AC content in the membrane ranged from 21 to 45 %, depending on the number of applied surface layers. According to the results of studying the properties of composite membranes, an increase in water absorption and total porosity of membranes after the application of the first layer of AC was found, and with the application of the next layer of AC, the values of water absorption and total porosity slightly decrease, which is due to the compaction of the membrane structure. Also, a decrease in the contact angle of the membrane wetting by 33° was revealed, which means an increase in the hydrophilic properties of the membrane, which increases the wettability and productivity of the obtained membranes. Composite membranes with two and three layers of AC: NAC2 and NAC3 were used to separate 0.5 % water-oil emulsion with particle sizes from 81 to 422 nm. The specific productivity of the NAC2 membrane by 0.5 % water-oil emulsion was 9433 dm3/(m2·h), the productivity of the NAC3 membrane was 3799 dm3/(m2·h) at a pressure of 0.55 MPa, which exceeds the performance of the commercial ultrafiltration membrane UPM-100 equal to 1843 dm3/(m2·h). According to the results of the study, the retention capacity of composite membranes for oil products from a water-oil emulsion was established, which was 61 % for NAC2 membranes and 75 % for NAC3 membrane. These indicators are not inferior to the retention capacity of a commercial ultrafiltration membrane of the UPM-100 brand.

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Colburn, Andrew, Ronald J. Vogler, Aum Patel, Mariah Bezold, John Craven, Chunqing Liu et Dibakar Bhattacharyya. « Composite Membranes Derived from Cellulose and Lignin Sulfonate for Selective Separations and Antifouling Aspects ». Nanomaterials 9, n^o 6 (7 juin 2019) : 867. http://dx.doi.org/10.3390/nano9060867.

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Cellulose-based membrane materials allow for separations in both aqueous solutions and organic solvents. The addition of nanocomposites into cellulose structure is facilitated through steric interaction and strong hydrogen bonding with the hydroxy groups present within cellulose. An ionic liquid, 1-ethyl-3-methylimidazolium acetate, was used as a solvent for microcrystalline cellulose to incorporate graphene oxide quantum dots into cellulose membranes. In this work, other composite materials such as, iron oxide nanoparticles, polyacrylic acid, and lignin sulfonate have all been uniformly incorporated into cellulose membranes utilizing ionic liquid cosolvents. Integration of iron into cellulose membranes resulted in high selectivity (>99%) of neutral red and methylene blue model dyes separation over salts with a high permeability of 17 LMH/bar. With non-aqueous (alcohol) solvent, iron–cellulose composite membranes become less selective and more permeable, suggesting the interaction of iron ions cellulose OH groups plays a major role in pore structure. Polyacrylic acid was integrated into cellulose membranes to add pH responsive behavior and capacity for metal ion capture. Calcium capture of 55 mg Ca2+/g membrane was observed for PAA-cellulose membranes. Lignin sulfonate was also incorporated into cellulose membranes to add strong negative charge and a steric barrier to enhance antifouling behavior. Lignin sulfonate was also functionalized on the commercial DOW NF270 nanofiltration membranes via esterification of hydroxy groups with carboxyl group present on the membrane surface. Antifouling behavior was observed for both lignin-cellulose composite and commercial membranes functionalized with lignin. Up to 90% recovery of water flux after repeated cycles of fouling was observed for both types of lignin functionalized membranes while flux recovery of up to 60% was observed for unmodified membranes.

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Naim, M. M., A. A. El-Shafei, A. A. Moneer et M. M. Elewa. « Ultrafiltration by a super-hydrophilic regenerated cellulose membrane ». Water Practice and Technology 10, n^o 2 (1 juin 2015) : 337–46. http://dx.doi.org/10.2166/wpt.2015.040.

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Ultrafiltration (UF) has received tremendous attention in concentration and purification of proteins in biotechnology, biomedicine and food production industries. Accordingly, in the present work innovated super-hydrophilic UF membranes were fabricated by the phase inversion technique, from a special casting solution formulation consisting of cellulose acetate in different solvents/additives, followed by complete deacetylation to form a regenerated cellulose membrane. Variables investigated included time of evaporation of as-cast membrane, temperature of coagulation water bath and post annealing of membrane. The membranes were used in ultrafiltrating yeast suspensions and examined by scanning electron microscopy (SEM), Fourier transform infrared, contact angle, porosity and pore size. The membrane performance was found to be strongly affected by each variable, and the best membrane gave a consistently high flux (27 kg/m2h) on prolonged operation, with almost zero salt rejection (%SR), when subjected to 5 bar operating pressure. The super-hydrophilic membrane morphologies indicated an asymmetric structure by SEM examination.

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Kohyama, Haruhiko. « Asymmetric Cellulose Triacetate Dialysis Membrane ». MEMBRANE 40, n^o 1 (2015) : 46–49. http://dx.doi.org/10.5360/membrane.40.46.

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Sasaki, M., T. Hosoda, T. Sugiyama, H. Watanabe, H. Tsukamoto et M. Saruhashi. « Vitamin-E Modified Cellulose Membrane. » membrane 19, n^o 6 (1994) : 400–410. http://dx.doi.org/10.5360/membrane.19.400.

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Sepúlveda, Rodrigo V., Fabrício L. Valente, Emily C. C. Reis, Fabiana R. Araújo, Renato B. Eleotério, Paulo V. S. Queiroz et Andréa P. B. Borges. « Bacterial cellulose and bacterial cellulose/polycaprolactone composite as tissue substitutes in rabbits' cornea ». Pesquisa Veterinária Brasileira 36, n^o 10 (octobre 2016) : 986–92. http://dx.doi.org/10.1590/s0100-736x2016001000011.

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ABSTRACT: In order to test the performance of bacterial cellulose/polycaprolactone composite (BC/PCL) and pure bacterial cellulose (BC) as tissue substitutes in rabbits' cornea, a superficial ulcer containing 5mm in diameter and 0.2mm deep was made in the right cornea of 36 rabbits, then a interlayer pocket was created from the basis of this ulcer. Twelve rabbits received BC/PCL membrane and 12 were treated with BC membranes, both membranes with 8mm in diameter. The remaining rabbits received no membrane constituting the control group. The animals were clinically followed up for 45 days. Three animals of each group were euthanized at three, seven, 21, and 45 days after implantation for histological examination of the cornea along with the implant. Clinical observation revealed signs of moderate inflammatory process, decreasing from day 20th in the implanted groups. Histology showed absence of epithelium on the membranes, fibroplasia close to the implants, lymph inflammatory infiltrate with giant cells, collagen disorganization, with a predominance of immature collagen fibers in both groups with implants. Although inflammatory response is acceptable, the membranes used does not satisfactorily played the role of tissue substitute for the cornea during the study period.

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Fazullin, Dinar D. « Composite Membranes with a Cellulose Acetate Working Layer on a Nylon Substrate ». Defect and Diffusion Forum 410 (17 août 2021) : 662–67. http://dx.doi.org/10.4028/www.scientific.net/ddf.410.662.

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Membrane technologies are currently among the most demanded. This is evidenced by their variety and a wide range of membrane applications in the most topical areas of human life. This work proposes a simple and inexpensive method for producing composite membranes for ultrafiltration and nanofiltration with a surface layer of cellulose acetate for water purification and water treatment processes. A nylon microfiltration membrane was used as a membrane base. The surface layer was obtained by immersion in a solution of cellulose acetate in acetone. Composite membranes with different retention properties were obtained depending on the number of deposited layers. The resulting membranes were examined for total porosity, water absorption, cellulose acetate content, contact angle, and IR absorption spectra. The specific productivity of the obtained membranes with respect to distilled water was also established.

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Matsumoto, Michiaki, Masashi Yamamoto et Kazuo Kondo. « Use of Bacterial Cellulose from Nata de Coco as Base Polymer for Liquid Membranes Containing Ionic Liquids ». Australian Journal of Chemistry 65, n^o 11 (2012) : 1497. http://dx.doi.org/10.1071/ch12307.

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Bacterial cellulose is becoming a promising biopolymer for membrane separation due to its biocompatibility. We prepared bacterial cellulose membranes from nata de coco, an indigenous dessert of the Philippines, as a support or a base polymer in the liquid membrane process. When we prepared bacterial cellulose membranes in the presence of Aliquat 336 as an ionic liquid, we obtained stable bacterial cellulose membranes. We carried out two different permeation experiments on lactate and organic nitrogen compounds. In the case of lactate permeation, the lactate remained in the membrane phase due to the strong interaction between the cellulose and the lactate by hydrogen bonding. For organic nitrogen compounds without strong hydrogen bonding moieties, quinoline and pyridine successfully permeated through the membranes. Higher selectivity against heptane was observed than previously reported results. The bacterial membranes from nata de coco containing Aliquat 336 were found to be promising for the separation of organic nitrogen compounds.

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Nicolson, Garth L., Gonzalo Ferreira de Mattos, Michael Ash, Robert Settineri et Pablo V. Escribá. « Fundamentals of Membrane Lipid Replacement : A Natural Medicine Approach to Repairing Cellular Membranes and Reducing Fatigue, Pain, and Other Symptoms While Restoring Function in Chronic Illnesses and Aging ». Membranes 11, n^o 12 (29 novembre 2021) : 944. http://dx.doi.org/10.3390/membranes11120944.

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Membrane Lipid Replacement (MLR) uses natural membrane lipid supplements to safely replace damaged, oxidized lipids in membranes in order to restore membrane function, decrease symptoms and improve health. Oral MLR supplements contain mixtures of cell membrane glycerolphospholipids, fatty acids, and other lipids, and can be used to replace and remove damaged cellular and intracellular membrane lipids. Membrane injury, caused mainly by oxidative damage, occurs in essentially all chronic and acute medical conditions, including cancer and degenerative diseases, and in normal processes, such as aging and development. After ingestion, the protected MLR glycerolphospholipids and other lipids are dispersed, absorbed, and internalized in the small intestines, where they can be partitioned into circulating lipoproteins, globules, liposomes, micelles, membranes, and other carriers and transported in the lymphatics and blood circulation to tissues and cellular sites where they are taken in by cells and partitioned into various cellular membranes. Once inside cells, the glycerolphospholipids and other lipids are transferred to various intracellular membranes by lipid carriers, globules, liposomes, chylomicrons, or by direct membrane–membrane interactions. The entire process appears to be driven by ‘bulk flow’ or mass action principles, where surplus concentrations of replacement lipids can stimulate the natural exchange and removal of damaged membrane lipids while the replacement lipids undergo further enzymatic alterations. Clinical studies have demonstrated the advantages of MLR in restoring membrane and organelle function and reducing fatigue, pain, and other symptoms in chronic illness and aging patients.

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Wibisono, Yusuf, Shari Amalia Rachmawati, Vera Septyaningrum Mylani, Nimatul Izza, Angky Wahyu Putranto et Shinta Rosalia Dewi. « Synthesis of Anti-biofoulant Green Nanoparticles Embedded Cellulose Acetate Membranes ». Proceedings 69, n^o 1 (4 novembre 2020) : 41. http://dx.doi.org/10.3390/cgpm2020-07199.

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Membranes were used in many aqueous applications, including in food processing, e.g., clarification of fruit juices. Typical drawbacks of membrane processes are membrane fouling, which promotes deterioration of processed products. During application of membranes for fruit juice clarification, biofouling occurred as the process deals with food substances. Biofouling is commonly dominated by bacterial attachment and growth on membrane surface, following the deposition of organic molecules from food substances. Natural antibiotics such as Olea europaea leaves extract might be used to improve the antibiofouling properties of membranes due to its phenolic contents. In this work, Olea europaea substances were obtained by extraction to get the green active solid nanoparticles. Phenolic green nanoparticles then filled into cellulose acetate as membrane matrix. The mixed matrix membrane, therefore, has a safe antibiofouling properties and is suitable for food application. The anti-biofoulant effect has been proven by decreasing bacterial attachment down to 23% from initial condition, especially for Gram-negative bacteria such as Eschericia coli.

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Kůdela, Vlastimil, Klaus Richau, Olen Ryba et Hans-Hartmuth Schwarz. « Orientation dependent concentration potentials of asymmetrical cellulose acetate membranes ». Collection of Czechoslovak Chemical Communications 51, n^o 7 (1986) : 1419–29. http://dx.doi.org/10.1135/cccc19861419.

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Orientation dependent (asymmetrical) membrane potentials were observed on both reverse osmosis and ultrafiltration cellulose acetate and polymer sulfone membranes in contact with electrolyte solutions. It was shown that this phenomenon can be observed only on asymmetrical membranes with a gradient of fixed charge molality in the active layer (skin), provided that the activity of the more concentrated solution is comparable with or higher than the fixed charge molality in the active layer. This holds also for partly hydrolyzed reverse osmosis membranes. The origin of the orientation dependence of the membrane potential can be explained by means of an analysis of Donnan potentials in given conditions. Diffusion potentials cannot play the decisive role. The asymmetry of osmotic fluxes observed only on reverse osmosis (annealed) membranes does not contribute to the orientation dependence of the membrane potential, because the asymmetrical dilution effect is compensated by the arising streaming potential.

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B. Patil, Mallikarjunagouda, et Amshumali M. K. « Sweetening of Natural Gas through Hollow Silica Nanoparticles Embedded Hydroxyethyl Cellulose Membrane ». Material Science Research India 15, n^o 3 (11 décembre 2018) : 256–62. http://dx.doi.org/10.13005/msri/150308.

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Membrane gas separation technique is a promising technique for separation of gases. Nanoparticles (NPs) of hollow spherical silica were synthesized by the hydrolysis and condensation of tetramethylorthosilicate (TMOS). The nanocomposite membranes were prepared by dispersing hollow silica in hydroxyethylcellulose (HEC) polymeric solution and were cast as membranes by solution casting-solvent evaporation procedure. The % loading of NP’s in membrane varied from 0.5 to 2 Wt. %. The effects of experimental parameters such as gas permeability and selectivity at constant pressure were measured for gas transport properties for the prepared membranes. Under constant operating conditions of feed pressure (4.0 MPa) and membrane thickness (50 μm), the CO2 permeability was determined to be in the range 1790-3620 Barrer for nanocomposite membrane from 0.5 to 2 Wt. %, while selectivity declined from 3.7 to 3.1 due to plasticization. This made us to come to the conclusion that the membrane has a double mode of sorption effect. The membranes were characterized with FTIR to confirm the formation of compound and with SEM to study the distribution of nanoparticles in the membrane matrix.

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Jun, Hyun-Sik, Meng Qi, Joshua Gong, Emmanuel E. Egbosimba et Cecil W. Forsberg. « Outer Membrane Proteins of Fibrobacter succinogenes with Potential Roles in Adhesion to Cellulose and in Cellulose Digestion ». Journal of Bacteriology 189, n^o 19 (20 juillet 2007) : 6806–15. http://dx.doi.org/10.1128/jb.00560-07.

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ABSTRACT Comparative analysis of binding of intact glucose-grown Fibrobacter succinogenes strain S85 cells and adhesion-defective mutants AD1 and AD4 to crystalline and acid-swollen (amorphous) cellulose showed that strain S85 bound efficiently to both forms of cellulose while mutant Ad1 bound to acid-swollen cellulose, but not to crystalline cellulose, and mutant Ad4 did not bind to either. One- and two-dimensional electrophoresis (2-DE) of outer membrane cellulose binding proteins and of outer membranes, respectively, of strain S85 and adhesion-defective mutant strains in conjunction with mass spectrometry analysis of tryptic peptides was used to identify proteins with roles in adhesion to and digestion of cellulose. Examination of the binding to cellulose of detergent-solubilized outer membrane proteins from S85 and mutant strains revealed six proteins in S85 that bound to crystalline cellulose that were absent from the mutants and five proteins in Ad1 that bound to acid-swollen cellulose that were absent from Ad4. Twenty-five proteins from the outer membrane fraction of cellulose-grown F. succinogenes were identified by 2-DE, and 16 of these were up-regulated by growth on cellulose compared to results with growth on glucose. A protein identified as a Cl-stimulated cellobiosidase was repressed in S85 cells growing on glucose and further repressed in the mutants, while a cellulose-binding protein identified as pilin was unchanged in S85 grown on glucose but was not produced by the mutants. The candidate differential cellulose binding proteins of S85 and the mutants and the proteins induced by growth of S85 on cellulose provide the basis for dissecting essential components of the cellulase system of F. succinogenes.

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Restaino, Odile Francesca, Sabrina Cuomo, Sergio D’Ambrosio, Valentina Vassallo, Seyedeh Fatemeh Mirpoor, Concetta Valeria L. Giosafatto, Raffaele Porta et Chiara Schiraldi. « Cellulose from Posidonia oceanica Sea Balls (Egagropili) as Substrate to Enhance Streptomyces roseochromogenes Cellulase Biosynthesis ». Fermentation 9, n^o 2 (21 janvier 2023) : 98. http://dx.doi.org/10.3390/fermentation9020098.

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Enhancing Streptomyces cellulase production by supplying lignocellulose biomasses has been poorly investigated so far. In this research the biosynthesis of Streptomyces roseochromogenes ATCC13400 cellulases was increased for the first time by addition of a cellulose fraction (2.5 g·L−1) to the growth medium, isolated from the marine origin Posidonia oceanica sea balls, generally called egagropili.. In shake flasks the cellulase production increased of 4.3 folds, compared to the control, up to 268 U·L−1 in 72 h, with a productivity of 3.7 U·L−1·h−1, while in batch it was further enhanced up to 347 U·L−1 in 45 h with a doubled productivity of 7.7 U·L−1·h−1 A downstream protocol was set up by coupling two ultrafiltration steps on 10 and 3 kDa membranes to recover the enzymes from the supernatant. A pool of three cellulases, having molecular weights between 115 and 47 kDa, was recovered. The optimal conditions for their enzymatic activity were 60 °C and pH 5.0, and they showed CMCase, FPase and β-glucosidase action. In conclusion, S. roseochromogenes might be considered a new cell factory for cellulase biotechnological production that might be enhanced by using the cellulose from egagropili, a well-known marine origin plant waste, as the substrate.

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MOKHTARI, JAVAD, et MOTAHAREH KANAFCHIAN. « CELLULOSE/WOLLASTONITE BASED GREEN MEMBRANES USING RICE STRAW : FABRICATION AND CHARACTERIZATION ». Cellulose Chemistry and Technology 56, n^o 3-4 (5 mai 2022) : 361–70. http://dx.doi.org/10.35812/cellulosechemtechnol.2022.56.32.

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Cellulose/wollastonite membranes were prepared with an environmentally friendly process using N-methylmorpholine-N-oxide (NMMO), which resulted in mesoporous membranes with slit-shaped pores. Cellulose and wollastonite were extracted from rice straw with different methods. Some parameters, such as weight ratios of cellulose and wollastonite in solution, concentration, thickness of the cast solution on the support layer and porosity of the support layer, influence the formation of the porous cellulose/wollastonite membrane. It was concluded that the porosity and pore size of the cellulose/wollastonite membrane decreased with lower cellulose and higher wollastonite amounts. The membranes became more brittle by increasing the amount of wollastonite, while pure cellulose membranes did not have enough strength to be placed on the polyester support layer. Also, the concentration of cellulose should not be too high or too low. The thickness of the cast solution on the support layer should not be too high, as it reduces the porosity; on the other hand, low thickness reduces the performance of the membrane.

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Gavrailov, Tasho, Ivan Chenchev, Maria Gevezova, Milena Draganova et Victoria Sarafian. « Effect on Cellular Vitality In Vitro of Novel APRF-Chlorhexidine Treated Membranes ». Journal of Functional Biomaterials 13, n^o 4 (7 novembre 2022) : 226. http://dx.doi.org/10.3390/jfb13040226.

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Introduction: Chlorhexidine (CHX) has been used for some time in clinical practice as a local antiseptic agent with excellent efficacy. The combination of CHX with APRF (Advanced-platelet rich fibrin) membrane has the potential to stimulate tissue regeneration and to provide a bactericidal effect. We hypothesize that this may reduce the rate of infections development and protect cell viability. Aim: The aim of this study was two-fold—to create a stable APRF membrane treated with different concentrations of CHX (0.01% and 0.02%) and to monitor its effect on the viability of PDL cells in vitro. This benefits the introduction of a new protocol for APRF membrane production -CHX-PRF and enriches the available evidence on the effect of this antiseptic agent on PDL (Periodontal ligament) cells. Materials and methods: APRF membranes were prepared by the addition of two concentrations (0.01% and 0.02%) of CHX. Membranes without the antiseptic were also prepared and used as control samples. PDL cells were cultivated on the membranes for 72 h. Cell number and vitality were examined by fluorescent cell viability assays. Results: Our results demonstrated that a concentration of 0.01% CHX allowed the production of a stable APRF membrane. This concentration slightly reduced the viability of PDL cells to 96.7%, but significantly decreased the average number of cells attached to the membrane—149 ± 16.5 cells/field compared to controls −336 ± 26.9 cells/field. APRF-CHX 0.02% membranes were unstable, indicating a dose-dependent cytotoxic effect of CHX. Conclusions: The introduced novel protocol leads to the production of a new type of APRF membrane—CHX-PRF. The incorporation of an antiseptic into the APRF membrane can improve its bactericidal activity and might serve as an important step for the prevention of postoperative infections.

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Alcoutlabi, Mataz, Hun Lee et Xiangwu Zhang. « Nanofiber-Based Membrane Separators for Lithium-ion Batteries ». MRS Proceedings 1718 (2015) : 157–61. http://dx.doi.org/10.1557/opl.2015.556.

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ABSTRACTNanofiber-based membranes were prepared by two different methods for use as separators for Lithium-ion batteries (LIBs). In the first method, Electrospinning was used for the fabrication of Polyvinylidene fluoride PVDF nanofiber coatings on polyolefin microporous membrane separators to improve their electrolyte uptake and electrochemical performance. The nanofiber-coated membrane separators show better electrolyte uptake and ionic conductivity than that for the uncoated membranes. In the second method, Forcespinning® (FS) was used to fabricate fibrous cellulose membranes as separators for LIBs. The cellulose fibrous membranes were made by the Forcespinning® of a cellulose acetate solution precursor followed by a subsequent alkaline hydrolysis treatment. The results show that the fibrous cellulose membrane-based separator exhibits high electrolyte uptake and good electrolyte/electrode wettability and therefore can be a good candidate for high performance and high safety LIB separators.

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Nicolson, Garth L., et Gonzalo Ferreira de Mattos. « A Brief Introduction to Some Aspects of the Fluid–Mosaic Model of Cell Membrane Structure and Its Importance in Membrane Lipid Replacement ». Membranes 11, n^o 12 (29 novembre 2021) : 947. http://dx.doi.org/10.3390/membranes11120947.

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Early cell membrane models placed most proteins external to lipid bilayers in trimolecular structures or as modular lipoprotein units. These thermodynamically untenable structures did not allow lipid lateral movements independent of membrane proteins. The Fluid–Mosaic Membrane Model accounted for these and other properties, such as membrane asymmetry, variable lateral mobilities of membrane components and their associations with dynamic complexes. Integral membrane proteins can transform into globular structures that are intercalated to various degrees into a heterogeneous lipid bilayer matrix. This simplified version of cell membrane structure was never proposed as the ultimate biomembrane description, but it provided a basic nanometer scale framework for membrane organization. Subsequently, the structures associated with membranes were considered, including peripheral membrane proteins, and cytoskeletal and extracellular matrix components that restricted lateral mobility. In addition, lipid–lipid and lipid–protein membrane domains, essential for cellular signaling, were proposed and eventually discovered. The presence of specialized membrane domains significantly reduced the extent of the fluid lipid matrix, so membranes have become more mosaic with some fluid areas over time. However, the fluid regions of membranes are very important in lipid transport and exchange. Various lipid globules, droplets, vesicles and other membranes can fuse to incorporate new lipids or expel damaged lipids from membranes, or they can be internalized in endosomes that eventually fuse with other internal vesicles and membranes. They can also be externalized in a reverse process and released as extracellular vesicles and exosomes. In this Special Issue, the use of membrane phospholipids to modify cellular membranes in order to modulate clinically relevant host properties is considered.

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Walani, Nikhil, et Ashutosh Agrawal. « Stability of lipid membranes with orthotropic symmetry ». Mathematics and Mechanics of Solids 25, n^o 2 (16 septembre 2019) : 234–62. http://dx.doi.org/10.1177/1081286519872236.

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Lipid membranes routinely undergo protein-mediated morphological remodeling during vital processes such as cellular transport and division. These membrane remodeling proteins can be broadly classified into two categories: one that generates a spherical shape and another that generates a cylindrical shape. To gain physical insights into membrane shape transitions, it is important to investigate the stability of membranes in the presence of these two types of proteins. However, the existing membrane theory is mostly restricted to the class of membranes that interact with the sphere shape-generating proteins and possess isotropic symmetry. In this work, we use curvature elasticity of the lipid membranes to derive the stability criterion for membranes that interact with the cylindrical-shape-generating proteins that possess orthotropic symmetry. We derive the convexity condition followed by the stability criterion for a generalized form of strain energy that can entertain material heterogeneity. The proposed framework would allow for a rigorous analysis of a broader set of membrane–protein interactions during key cellular processes.

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Takao, Shota, Saeid Rajabzadeh, Masahide Shibata, Chihiro Otsubo, Toyozo Hamada, Noriaki Kato, Keizo Nakagawa, Tooru Kitagawa, Hideto Matsuyama et Tomohisa Yoshioka. « Preparation of Chemically Resistant Cellulose Benzoate Hollow Fiber Membrane via Thermally Induced Phase Separation Method ». Membranes 12, n^o 12 (28 novembre 2022) : 1199. http://dx.doi.org/10.3390/membranes12121199.

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For the first time, we have successfully fabricated microfiltration (MF) hollow fiber membranes by the thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS) methods using cellulose acetate benzoate (CBzOH), which is a cellulose derivative with considerable chemical resistance. To obtain an appropriate CBzOH TIPS membrane, a comprehensive solvent screening was performed to choose the appropriate solvent to obtain a membrane with a porous structure. In parallel, the CBzOH membrane was prepared by the NIPS method to compare and evaluate the effect of membrane structure using the same polymer material. Prepared CBzOH membrane by TIPS method showed high porosity, pore size around 100 nm or larger and high pure water permeability (PWP) with slightly low rection performance compared to that by NIPS. On the contrary, CBzOH membranes prepared with the NIPS method showed three times lower PWP with higher rejection. The chemical resistance of the prepared CBzOH membranes was compared with that of cellulose triacetate (CTA) hollow fiber membrane, which is a typical cellulose derivative as a control membrane, using a 2000 ppm sodium hypochlorite (NaClO) solution. CBzOH membranes prepared with TIPS and NIPS methods showed considerable resistance against the NaClO solution regardless of the membrane structure, porosity and pore size. On the other hand, when the CTA membrane, as the control membrane, was subjected to the NaClO solution, membrane mechanical strength sharply decreased over the exposure time to NaClO. It is interesting that although the CBzOH TIPS membrane showed three times higher pure water permeability than other membranes with slightly lower rejection and considerably higher NaClO resistance, the mechanical strength of this membrane is more than two times higher than other membranes. While CBzOH samples showed no change in chemical structure and contact angle, CTA showed considerable change in chemical structure and a sharp decrease in contact angle after treatment with NaClO. Thus, CBzOH TIPS hollow fiber membrane is noticeably interesting considering membrane performance in terms of filtration performance, mechanical strength and chemical resistance on the cost of slightly losing rejection performance.

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Sundin, D. P., C. Meyer, R. Dahl, A. Geerdes, R. Sandoval et B. A. Molitoris. « Cellular mechanism of aminoglycoside tolerance in long-term gentamicin treatment ». American Journal of Physiology-Cell Physiology 272, n^o 4 (1 avril 1997) : C1309—C1318. http://dx.doi.org/10.1152/ajpcell.1997.272.4.c1309.

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In the rat, nephrotoxicity results from uptake of gentamicin at the apical membrane of proximal tubule (PT) cells. However, during continuous gentamicin treatment, the PT epithelium has been shown to recover. The mechanism(s) of cellular recovery and development of tolerance remains unknown. Therefore, we undertook studies designed to characterize cellular adaptations that occur during long-term gentamicin (LTG) treatment. After 19 days of gentamicin treatment, electron microscopy morphological evaluation revealed cellular recovery with an apparent mild decrease in height and number of microvilli. Enzymatic analysis of LTG PT membranes showed that apical and basolateral membranes had essentially returned to normal. Analysis of apical membrane lipid content revealed persistent statistically significant (P < 0.01) elevations in phosphatidylinositol (PI). In vivo immunogold morphological studies and biochemical studies in LTG rats revealed that endocytosis of gentamicin was selectively reduced, whereas the markers of fluid-phase (horseradish peroxidase) and receptor-mediated (beta2-microglobulin) endocytoses were unaffected or increased. Biochemical analysis showed that, although gentamicin binding to apical membranes isolated from LTG rats increased greater than twofold (P < 0.05) over membranes from untreated rats, in vivo cellular uptake, quantified with [3H]gentamicin, was reduced. Western blot analysis of LTG apical membranes and immunofluorescent staining of perfusion-fixed LTG kidneys showed no change in megalin levels or its apical membrane localization. These data imply that recovery of PT cells from and tolerance to LTG treatment involve a selective inhibition of gentamicin uptake across the apical membrane. They indicate that the mediators of gentamicin endocytosis were affected differently: PI levels increased, whereas megalin levels did not change. We conclude that selective inhibition of gentamicin uptake during LTG treatment is not affected by a reduction in PI or megalin levels. We postulate that trafficking of gentamicin and/or gentamicin-containing endocytic structures is reduced in LTG rats, allowing cells to develop tolerance to gentamicin.

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Lopatina, Anastasiia, Mohammadamin Esmaeili, Ikenna Anugwom, Mika Mänttäri et Mari Kallioinen-Mänttäri. « Effect of Low Concentrations of Lithium Chloride Additive on Cellulose-Rich Ultrafiltration Membrane Performance ». Membranes 13, n^o 2 (5 février 2023) : 198. http://dx.doi.org/10.3390/membranes13020198.

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Various water treatment processes make extensive use of porous polymeric membranes. A key objective in membrane fabrication is to improve membrane selectivity without sacrificing other properties such as permeability. Herein, LiCl (0–2 wt.%) was utilised as a preforming agent in fabricating biomass-derived cellulosic membranes. The fabricated membranes were characterised by dope solution viscosity, surface and cross-sectional morphology, pure water flux, relative molecular mass cut-off (MWCO, 35 kDa), membrane chemistry, and hydrophilicity. The results demonstrated that at the optimum LiCl concentration (0.4 wt.%), there is an interplay of thermodynamic instability and kinetic effects during membrane formation, wherein the membrane morphology and hydrophilicity can be preferably altered and thus lead to the formation of the membrane with better rejection at no detriment to its permeability.

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