Adsorption of Polystyrene from Theta Condition on Cellulose and Silica Studied by Quartz Crystal Microbalance

Adsorption of hydrophobic polymers from a nonpolar solvent medium is an underutilized tool for modification of surfaces, especially of soft matter. Adsorption of polystyrene (PS) from a theta solvent (50/50 vol % toluene/heptane) on ultrathin model films of cellulose was studied with a quartz crystal microbalance with dissipation monitoring (QCM-D), using three different PS grades with monodisperse molecular weights (Mws). Comparison of cellulose to silica as an adsorbent was presented. Adsorption on both surfaces was mainly irreversible under the studied conditions. Characteristically to polymer monolayer formation, the mass of the adsorbing polymer increased with its Mw. The initial step of the layer formation was similar on both surfaces, but silica showed a stronger tendency for the formation of a loosely bound overlayer upon molecular rearrangements as the adsorption process proceeded. Despite the slightly less extended layers formed on cellulose at increasing Mw values, the overall thickness of the adsorbing wet layers on both surfaces was of the similar order of magnitude as the radius of gyration of the adsorbate molecule. Decent degree of hydrophobization of cellulose could be reached with all studied PS grades when the time allowed for adsorption was sufficient. QCM-D, a method conventionally utilized for studying aqueous systems, turned out to be a suitable tool for studying the adsorption process of hydrophobic polymers on soft polymeric matter such as cellulose taking place in a nonpolar solvent environment

Protein Adsorption and Its Effects on Electroanalytical Performance of Nanocellulose/Carbon Nanotube Composite Electrodes

Protein fouling is a critical issue in the development of electrochemical sensors for medical applications, as it can significantly impact their sensitivity, stability, and reliability. Modifying planar electrodes with conductive nanomaterials that possess a high surface area, such as carbon nanotubes (CNTs), has been shown to significantly improve fouling resistance and sensitivity. However, the inherent hydrophobicity of CNTs and their poor dispersibility in solvents pose challenges in optimizing such electrode architectures for maximum sensitivity. Fortunately, nanocellulosic materials offer an efficient and sustainable approach to achieving effective functional and hybrid nanoscale architectures by enabling stable aqueous dispersions of carbon nanomaterials. Additionally, the inherent hygroscopicity and fouling-resistant nature of nanocellulosic materials can provide superior functionalities in such composites. In this study, we evaluate the fouling behavior of two nanocellulose (NC)/multiwalled carbon nanotube (MWCNT) composite electrode systems: one using sulfated cellulose nanofibers and another using sulfated cellulose nanocrystals. We compare these composites to commercial MWCNT electrodes without nanocellulose and analyze their behavior in physiologically relevant fouling environments of varying complexity using common outer- and inner-sphere redox probes. Additionally, we use quartz crystal microgravimetry with dissipation monitoring (QCM-D) to investigate the behavior of amorphous carbon surfaces and nanocellulosic materials in fouling environments. Our results demonstrate that the NC/MWCNT composite electrodes provide significant advantages for measurement reliability, sensitivity, and selectivity over only MWCNT-based electrodes, even in complex physiological monitoring environments such as human plasma.</p

FAKTOR-FAKTOR YANG BERHUBUNGAN DENGAN KEPEMILIKAN JAMBAN SEHAT DI DUSUN TANGGUNGREJO DESA KARANGPATIHAN KECAMATAN BALONG KABUPATEN PONOROGO

Latar Belakang: Penyediaan sarana jamban merupakan bagian dari usaha sanitasi yang cukup penting peranannya. Ditinjau dari sudut kesehatan lingkungan, pembuangan tinja yang tidak saniter dapat mencemari lingkungan terutama tanah dan sumber air. Kecamatan Balong merupakan Kecamatan dengan kepemilikan jamban sehat yang rendah dibandingkan dengan Kecamatan lain di Kabupaten Ponorogo. Dusun Tanggungrejo merupakan dusun dengan angka kepemilikan jamban tidak sehat paling tinggi dibanding dusun yang lainnya di Desa Karangpatihan Kecamatan Balong. Pengetahuan dan sikap masyarakat di Dusun Tanggungrejo terkait kepemilikan jamban sehat tergolong masih rendah. Metode: Penelitian ini menggunakan desain penelitian cross sectional. Sampel dalam penelitian ini sejumlah 87 sampel yang diperoleh dengan teknik cluster random sampling. Instrument yang digunakan adalah lembar checklist yang digunakan untuk mengukur tingkat pengetahuan dan sikap responden serta lembar observasi yang digunakan untuk menilai kepemilikan jamban sehat. Hasil: Hasil penelitian menunjukkan bahwa ada hubungan antara tingkat pendapatan kepala keluarga dengan kepemilikan jamban sehat di Dusun Tanggungrejo Desa Karangpatihan Kecamatan Balong Kabupaten Ponorogo (p=0,000<0,005, RP=13,250, CI=3,471-50,582), ada hubungan antara tingkat pengetahuan kepala keluarga dengan kepemilikan jamban sehat di Dusun Tanggungrejo Desa Karangpatihan Kecamatan Balong Kabupaten Ponorogo (p=0,000<0,005), RP=4,840, CI=2,481-9,444) dan ada hubungan antara sikap kepala keluarga dengan kepemilikan jamban sehat dengan di Dusun Tanggungrejo Desa Karangpatihan Kecamatan Balong Kabupaten Ponorogo (p=0,000<0,005, RP=6,989, CI=2,404-20,318). Kesimpulan: Tingkat pendapatan, tingkat pengetahuan dan sikap kepala keluarga berhubungan dengan kepemilikan jamban sehat di Dusun Tanggungrejo Desa Karangpatihan Kecamatan Balong Kabupaten Ponorogo

Charged ultrafiltration membranes based on TEMPO-oxidized cellulose nanofibrils/poly(vinyl alcohol) antifouling coating

This study reports the potential of TEMPO-oxidized cellulose nanofibrils (T-CNF)/poly(vinyl alcohol) (PVA) coatings to develop functionalized membranes in the ultrafiltration regime with outstanding antifouling performance and dimensional/pH stability. PVA acts as an anchoring phase interacting with the polyethersulfone (PES) substrate and stabilizing for the hygroscopic T-CNF via crosslinking. The T-CNF/PVA coated PES membranes showed a nano-textured surface, a change in the surface charge, and improved mechanical properties compared to the original PES substrate. A low reduction (4%) in permeance was observed for the coated membranes, attributable to the nanometric coating thickness, surface charge, and hydrophilic nature of the coated layer. The coated membranes exhibited charge specific adsorption driven by electrostatic interaction combined with rejection due to size exclusion (MWCO 530 kDa that correspond to a size of ∼35–40 nm). Furthermore, a significant reduction in organic fouling and biofouling was found for T-CNF/PVA coated membranes when exposed to BSA and E. coli. The results demonstrate the potential of simple modifications using nanocellulose to manipulate the pore structure and surface chemistry of commercially available membranes without compromising on permeability and mechanical stability

Mapping Nanocellulose- and Alginate-Based Photosynthetic Cell Factory Scaffolds:Interlinking Porosity, Wet Strength, and Gas Exchange

To develop efficient solid-state photosynthetic cell factories for sustainable chemical production, we present an interdisciplinary experimental toolbox to investigate and interlink the structure, operative stability, and gas transfer properties of alginate- and nanocellulose-based hydrogel matrices with entrapped wild-type Synechocystis PCC 6803 cyanobacteria. We created a rheological map based on the mechanical performance of the hydrogel matrices. The results highlighted the importance of Ca2+-cross-linking and showed that nanocellulose matrices possess higher yield properties, and alginate matrices possess higher rest properties. We observed higher porosity for nanocellulose-based matrices in a water-swollen state via calorimetric thermoporosimetry and scanning electron microscopy imaging. Finally, by pioneering a gas flux analysis via membrane-inlet mass spectrometry for entrapped cells, we observed that the porosity and rigidity of the matrices are connected to their gas exchange rates over time. Overall, these findings link the dynamic properties of the life-sustaining matrix to the performance of the immobilized cells in tailored solid-state photosynthetic cell factories.</p

Nanocellulose-based mechanically stable immobilization matrix for enhanced ethylene production: a framework for photosynthetic solid-state cell factories

Cell immobilization is a promising approach to create efficient photosynthetic cell factories for sustainable chemical production. Here, we demonstrate a novel photosynthetic solid-state cell factory design for sustainable biocatalytic ethylene production. We entrapped cyanobacteria within never-dried hydrogel films of TEMPO-oxidized cellulose nanofibers (TCNF) cross-linked with polyvinyl alcohol (PVA) to create a self-standing matrix architecture. The matrix is operational in the challenging submerged conditions and outperforms existing alginate-based solutions in terms of wet strength, long-term cell fitness, and stability. Based on rheological investigations, the critical strength of wet TCNF matrices is three times higher than in the existing immobilization matrices of alginate cross-linked with Ca2+. This is due to the rigid nature of the colloidal nanofiber network and the strong cross-linking with PVA, as opposed to polymeric alginate with reversible ionic Ca2+ bonds. The porous and hygroscopic nanofiber network also shields the cyanobacterial cells from environmental stress, maintaining photosynthetic activity during partial drying of films, and when submerged in the nutrient medium for long-term cultivation. Finally, TCNF matrices allow the ethylene-producing Synechocystis sp. PCC 6803 cells to operate in submerged conditions under high inorganic carbon loads (200 mM NaHCO3), where Ca2+-alginate matrices fail. The latter show severe cell leakage due to matrix disintegration already within 20 min of NaHCO3 supplementation. In contrast, TCNF-based matrices prevent cell leakage to the medium and restrict culture growth, leading to improved ethylene production yields. Furthermore, the operational capacity of the self-standing TNCF cell factory can be maintained long-term by periodically refreshing the nutrient medium. All in all, the results showcase the versatility and potential of cell immobilization with the never-dried colloidal TCNF matrix, paving the way towards novel biotechnological pathways using solid-state cell factories designed for efficient and sustainable production of e.g., monomers and fuels

Cellulose-inorganic hybrids of strongly reduced thermal conductivity

The employment of atomic layer deposition and spin coating techniques for preparing inorganic-organic hybrid multilayer structures of alternating ZnO-CNC layers was explored in this study. Helium ion microscopy and X-ray reflectivity showed the superlattice formation for the nanolaminate structures and atomic force microscopy established the efficient control of the CNCs surface coverage on the Al-doped Zeta nO by manipulating the concentration of the spin coating solution. Thickness characterization of the hybrid structures was performed via both ellipsometry and X-ray reflectivity and the thermal conductivity was examined by time domain thermoreflectance technique. It appears that even the incorporation of a limited amount of CNCs between the ZnO laminates strongly suppresses the thermal conductivity. Even small, submonolayer amounts of CNCs worked as a more efficient insulating material than hydroquinone or cellulose nanofibers which have been employed in previous studies.Peer reviewe

СОВРЕМЕННЫЕ ПОДХОДЫ К ПАТОГЕНЕЗУ ЛЕЙОМИОМЫ МАТКИ, ОСЛОЖНЕННОЙ МАТОЧНЫМ КРОВОТЕЧЕНИЕМ (ОБЗОР ЛИТЕРАТУРЫ)

ABSTRACT. The article describes the basic pathogenetic mechanisms of uterine bleeding occurrence in patients with uterine leiomyoma (UL). The pathogenesis of this disease is difficult and multi-factorial. Significant changes in the architectonics of the uterine vasculature are noted. Modern approaches to management of patients with UL and uterine bleeding are discussed from a clinical point of view using conservative, minimally invasive and surgical methods of treatment. РЕЗЮМЕ. В статье изложены основные патогенетические звенья возникновения маточных кровотечений у больных с лейомиомой матки (ЛМ). Патогенез данной патологии представляется сложным и многофакторным. Отмечены выраженные изменения в архитектонике сосудистой сети матки. С клинических позиций рассмотрены современные подходы к тактике ведения больных с ЛМ с маточными кровотечениями с применением консервативных, мини-инвазивных и хирургических методов лечения.