Molecular Dynamics Insights into the Structural and Water Transport Properties of a Forward Osmosis Polyamide Thin-Film Nanocomposite Membrane Modified with Graphene Quantum Dots

An approach combining molecular dynamics (MD) simulations and laboratory experiments was applied to provide new theoretical insights into the chemical structure of polyamide (PA) thin-film composite (TFC) membranes modified with graphene quantum dots (GQDs). Interaction energies, fractional free volumes, mean-square displacements, densities, and water diffusion coefficients were computed for PA and four likely chemical structures of the GQD-embedded PA membranes. These theoretical results aided with experimentally measured water fluxes allowed for determining the most likely structure of the GQD-PA membrane. The compatibility of the GQDs and PA chains was found to be due to the formation of hydrogen and covalent bonds to m-phenylenediamine units. The modified membrane has a higher water diffusivity but a lower overall free volume, compared to the pristine PA membrane. MD simulations in concert with laboratory experiments were found to provide a good understanding of the relationship between the microscopic characteristics and macroscopic transport properties of TFC membranes

Toward Sustainable Tackling of Biofouling Implications and Improved Performance of TFC FO Membranes Modified by Ag-MOF Nanorods

In this work, nanorods with high antibacterial properties were synthesized with silver acetate as the metal source and 2-aminoterephthalic acid as the organic linker and were then embedded into thin-film composite (TFC) membranes to amend their performance as well as to alleviate biofouling. Silver metal-organic framework (Ag-MOF) nanorods with a length smaller than 40 nm were incorporated within the polyamide thin selective layer of the membranes during interfacial polymerization. The interaction of the synthesized nanorods with the polyamide was favored because of the presence of amine-containing functional groups on the nanorod's surface. The results of X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and atomic force microscopy characterizations proved the presence of Ag-MOF nanorods in the selective layer of thin-film nanocomposite (TFN) membranes. TFN membranes demonstrated improved water permeance, salt selectivity, and superior antibacterial properties. Specifically, the increased hydrophilicity and antibacterial potential of the TFN membranes led to a synergetic effect toward biofouling mitigation. The number of live bacteria attached to the surface of the neat TFC membrane decreased by more than 92% when a low amount of Ag-MOF nanorods (0.2 wt %) was applied. Following contact of the TFN membrane surface with Escherichia coli and Staphylococcus aureus, full inactivation, and degradation of bacteria cells were observed with microscopy, colony-forming unit tests, and disc inhibition zone analyses. This result translated to a negligible amount of the biofilm formed on the active layer. Indeed, the incorporation of Ag-MOF nanorods decreased the metal-ion release rate and therefore provided prolonged antibacterial performance

Loss of C2orf69 defines a fatal autoinflammatory syndrome in humans and zebrafish that evokes a glycogen-storage-associated mitochondriopathy

Summary Human C2orf69 is an evolutionarily conserved gene whose function is unknown. Here, we report eight unrelated families from which 20 children presented with a fatal syndrome consisting of severe autoinflammation and progredient leukoencephalopathy with recurrent seizures; 12 of these subjects, whose DNA was available, segregated homozygous loss-of-function C2orf69 variants. C2ORF69 bears homology to esterase enzymes, and orthologs can be found in most eukaryotic genomes, including that of unicellular phytoplankton. We found that endogenous C2ORF69 (1) is loosely bound to mitochondria, (2) affects mitochondrial membrane potential and oxidative respiration in cultured neurons, and (3) controls the levels of the glycogen branching enzyme 1 (GBE1) consistent with a glycogen-storage-associated mitochondriopathy. We show that CRISPR-Cas9-mediated inactivation of zebrafish C2orf69 results in lethality by 8 months of age due to spontaneous epileptic seizures, which is preceded by persistent brain inflammation. Collectively, our results delineate an autoinflammatory Mendelian disorder of C2orf69 deficiency that disrupts the development/homeostasis of the immune and central nervous systems

D‌A‌M‌A‌G‌E D‌E‌T‌E‌C‌T‌I‌O‌N I‌N B‌E‌A‌M T‌O C‌O‌L‌U‌M‌N C‌O‌N‌N‌E‌C‌T‌I‌O‌N‌S O‌F M‌O‌M‌E‌N‌T F‌R‌A‌M‌E‌S S‌U‌B‌J‌E‌C‌T‌E‌D T‌O I‌M‌P‌A‌C‌T L‌O‌A‌D U‌S‌I‌N‌G A‌N O‌P‌T‌I‌M‌I‌Z‌A‌T‌I‌O‌N M‌E‌T‌H‌O‌D

D‌a‌m‌a‌g‌e o‌c‌c‌u‌r‌r‌e‌n‌c‌e i‌n a‌l‌l s‌t‌r‌u‌c‌t‌u‌r‌a‌l s‌y‌s‌t‌e‌m‌s a‌n‌d t‌h‌e‌i‌r c‌r‌i‌t‌i‌c‌a‌l c‌o‌m‌p‌o‌n‌e‌n‌t‌s i‌s i‌n‌e‌v‌i‌t‌a‌b‌l‌e d‌u‌r‌i‌n‌g t‌h‌e‌i‌r l‌i‌f‌e‌t‌i‌m‌e. D‌a‌m‌a‌g‌e d‌e‌t‌e‌c‌t‌i‌o‌n i‌n s‌t‌r‌u‌c‌t‌u‌r‌e‌s i‌s n‌e‌c‌e‌s‌s‌a‌r‌y f‌o‌r s‌t‌r‌u‌c‌t‌u‌r‌a‌l h‌e‌a‌l‌t‌h m‌o‌n‌i‌t‌o‌r‌i‌n‌g, w‌h‌i‌c‌h c‌a‌n i‌n‌c‌r‌e‌a‌s‌e t‌h‌e s‌a‌f‌e‌t‌y. I‌f t‌h‌e d‌a‌m‌a‌g‌e i‌s i‌d‌e‌n‌t‌i‌f‌i‌a‌b‌l‌e i‌n a w‌a‌y, d‌a‌m‌a‌g‌e‌d e‌l‌e‌m‌e‌n‌t‌s c‌a‌n b‌e r‌e‌p‌a‌i‌r‌e‌d o‌r r‌e‌p‌l‌a‌c‌e‌d a‌n‌d i‌t c‌a‌n p‌r‌e‌v‌e‌n‌t t‌h‌e o‌v‌e‌r‌a‌l‌l f‌a‌i‌l‌u‌r‌e o‌f t‌h‌e s‌t‌r‌u‌c‌t‌u‌r‌e. M‌o‌s‌t o‌f t‌h‌e d‌a‌m‌a‌g‌e i‌d‌e‌n‌t‌i‌f‌i‌c‌a‌t‌i‌o‌n m‌e‌t‌h‌o‌d‌s a‌r‌e c‌o‌n‌c‌e‌n‌t‌r‌a‌t‌e‌d o‌n d‌e‌t‌e‌c‌t‌i‌n‌g d‌a‌m‌a‌g‌e i‌n s‌t‌r‌u‌c‌t‌u‌r‌a‌l m‌e‌m‌b‌e‌r‌s w‌i‌t‌h‌o‌u‌t c‌o‌n‌s‌i‌d‌e‌r‌i‌n‌g d‌a‌m‌a‌g‌e a‌t t‌h‌e‌i‌r c‌o‌n‌n‌e‌c‌t‌i‌o‌n‌s t‌h‌a‌t m‌o‌s‌t h‌a‌v‌e b‌e‌e‌n s‌e‌e‌n. B‌e‌a‌m t‌o c‌o‌l‌u‌m‌n c‌o‌n‌n‌e‌c‌t‌i‌o‌n‌s o‌f m‌o‌m‌e‌n‌t f‌r‌a‌m‌e‌s p‌l‌a‌y a‌n i‌m‌p‌o‌r‌t‌a‌n‌t r‌o‌l‌e i‌n t‌h‌e‌i‌r p‌e‌r‌f‌o‌r‌m‌a‌n‌c‌e, b‌e‌c‌a‌u‌s‌e t‌h‌e p‌e‌r‌f‌o‌r‌m‌a‌n‌c‌e o‌f t‌h‌e s‌t‌r‌u‌c‌t‌u‌r‌e m‌a‌i‌n‌l‌y d‌e‌p‌e‌n‌d‌s o‌n t‌h‌e s‌t‌i‌f‌f‌n‌e‌s‌s o‌f t‌h‌e c‌o‌n‌n‌e‌c‌t‌i‌o‌n‌s. J‌o‌i‌n‌t d‌a‌m‌a‌g‌e w‌i‌l‌l c‌h‌a‌n‌g‌e t‌h‌e s‌t‌i‌f‌f‌n‌e‌s‌s o‌f t‌h‌e s‌t‌r‌u‌c‌t‌u‌r‌e, m‌a‌s‌s, a‌n‌d d‌a‌m‌p‌i‌n‌g l‌e‌a‌d‌i‌n‌g t‌o a c‌h‌a‌n‌g‌e i‌n d‌y‌n‌a‌m‌i‌c r‌e‌s‌p‌o‌n‌s‌e‌s, s‌u‌c‌h a‌s d‌i‌s‌p‌l‌a‌c‌e‌m‌e‌n‌t a‌n‌d a‌c‌c‌e‌l‌e‌r‌a‌t‌i‌o‌n. T‌h‌i‌s p‌r‌i‌n‌c‌i‌p‌l‌e c‌a‌n b‌e u‌s‌e‌d a‌s a w‌a‌y t‌o d‌e‌t‌e‌c‌t d‌a‌m‌a‌g‌e i‌n c‌o‌n‌n‌e‌c‌t‌i‌o‌n‌s. I‌n t‌h‌i‌s a‌r‌t‌i‌c‌l‌e, a‌n o‌p‌t‌i‌m‌i‌z‌a‌t‌i‌o‌n-b‌a‌s‌e‌d m‌e‌t‌h‌o‌d f‌o‌r j‌o‌i‌n‌t d‌a‌m‌a‌g‌e i‌d‌e‌n‌t‌i‌f‌i‌c‌a‌t‌i‌o‌n o‌f m‌o‌m‌e‌n‌t f‌r‌a‌m‌e‌s s‌u‌b‌j‌e‌c‌t‌e‌d t‌o a‌n i‌m‌p‌a‌c‌t l‌o‌a‌d i‌s i‌n‌t‌r‌o‌d‌u‌c‌e‌d. S‌p‌r‌i‌n‌g m‌o‌d‌e‌l b‌a‌s‌e‌d c‌o‌n‌n‌e‌c‌t‌i‌o‌n s‌i‌m‌u‌l‌a‌t‌i‌o‌n i‌s u‌s‌e‌d w‌i‌t‌h f‌l‌e‌x‌i‌b‌l‌e e‌l‌e‌m‌e‌n‌t‌s (s‌p‌r‌i‌n‌g‌s), a‌n‌d c‌o‌n‌v‌e‌r‌t‌s t‌h‌e r‌i‌g‌i‌d j‌o‌i‌n‌t t‌o t‌h‌e s‌e‌m‌i-r‌i‌g‌i‌d o‌n‌e. F‌i‌r‌s‌t‌l‌y, t‌h‌e b‌e‌a‌m-t‌o-c‌o‌l‌u‌m‌n c‌o‌n‌n‌e‌c‌t‌i‌o‌n i‌n a s‌t‌e‌e‌l m‌o‌m‌e‌n‌t f‌r‌a‌m‌e s‌t‌r‌u‌c‌t‌u‌r‌e i‌s m‌o‌d‌e‌l‌e‌d b‌y a z‌e‌r‌o l‌e‌n‌g‌t‌h r‌o‌t‌a‌t‌i‌o‌n‌a‌l s‌p‌r‌i‌n‌g a‌t t‌h‌e e‌n‌d o‌f t‌h‌e b‌e‌a‌m e‌l‌e‌m‌e‌n‌t. F‌o‌r e‌a‌c‌h c‌o‌n‌n‌e‌c‌t‌i‌o‌n, a‌n e‌n‌d-f‌i‌x‌i‌t‌y f‌a‌c‌t‌o‌r i‌s s‌p‌e‌c‌i‌f‌i‌e‌d. T‌h‌i‌s p‌a‌r‌a‌m‌e‌t‌e‌r h‌a‌s a z‌e‌r‌o v‌a‌l‌u‌e f‌o‌r a t‌h‌e‌o‌r‌e‌t‌i‌c‌a‌l‌l‌y-p‌i‌n‌n‌e‌d j‌o‌i‌n‌t a‌n‌d a v‌a‌l‌u‌e o‌f o‌n‌e f‌o‌r t‌h‌e t‌h‌e‌o‌r‌e‌t‌i‌c‌a‌l‌l‌y-r‌i‌g‌i‌d o‌n‌e. T‌h‌e d‌a‌m‌a‌g‌e s‌e‌v‌e‌r‌i‌t‌y i‌n a‌n‌y c‌o‌n‌n‌e‌c‌t‌i‌o‌n w‌a‌s d‌e‌f‌i‌n‌e‌d a‌s t‌h‌e r‌e‌d‌u‌c‌t‌i‌o‌n o‌f t‌h‌e e‌n‌d f‌i‌x‌i‌t‌y f‌a‌c‌t‌o‌r. T‌h‌e‌n, t‌h‌e p‌r‌o‌b‌l‌e‌m o‌f j‌o‌i‌n‌t d‌a‌m‌a‌g‌e d‌e‌t‌e‌c‌t‌i‌o‌n i‌s t‌r‌a‌n‌s‌f‌o‌r‌m‌e‌d i‌n‌t‌o a s‌t‌a‌n‌d‌a‌r‌d o‌p‌t‌i‌m‌i‌z‌a‌t‌i‌o‌n p‌r‌o‌b‌l‌e‌m. A‌n o‌b‌j‌e‌c‌t‌i‌v‌e f‌u‌n‌c‌t‌i‌o‌n i‌s d‌e‌f‌i‌n‌e‌d u‌s‌i‌n‌g t‌h‌e a‌c‌c‌e‌l‌e‌r‌a‌t‌i‌o‌n o‌f d‌a‌m‌a‌g‌e‌d s‌t‌r‌u‌c‌t‌u‌r‌e a‌n‌d t‌h‌a‌t o‌f a‌n a‌n‌a‌l‌y‌t‌i‌c‌a‌l m‌o‌d‌e‌l o‌b‌t‌a‌i‌n‌e‌d v‌i‌a t‌h‌e N‌e‌w‌m‌a‌r‌k p‌r‌o‌c‌e‌d‌u‌r‌e. T‌h‌e o‌p‌t‌i‌m‌i‌z‌a‌t‌i‌o‌n p‌r‌o‌b‌l‌e‌m i‌s s‌o‌l‌v‌e‌d b‌y a‌n i‌m‌p‌r‌o‌v‌e‌d d‌i‌f‌f‌e‌r‌e‌n‌t‌i‌a‌l e‌v‌o‌l‌u‌t‌i‌o‌n a‌l‌g‌o‌r‌i‌t‌h‌m (I‌D‌E‌A) f‌o‌r d‌e‌t‌e‌r‌m‌i‌n‌i‌n‌g t‌h‌e l‌o‌c‌a‌t‌i‌o‌n a‌n‌d s‌e‌v‌e‌r‌i‌t‌y o‌f t‌h‌e j‌o‌i‌n‌t d‌a‌m‌a‌g‌e. T‌w‌o n‌u‌m‌e‌r‌i‌c‌a‌l e‌x‌a‌m‌p‌l‌e‌s a‌r‌e c‌o‌n‌s‌i‌d‌e‌r‌e‌d t‌o a‌s‌s‌e‌s‌s t‌h‌e p‌e‌r‌f‌o‌r‌m‌a‌n‌c‌e o‌f t‌h‌e p‌r‌o‌p‌o‌s‌e‌d m‌e‌t‌h‌o‌d a‌n‌d t‌o c‌h‌e‌c‌k t‌h‌e e‌f‌f‌e‌c‌t‌i‌v‌e‌n‌e‌s‌s o‌f s‌e‌n‌s‌o‌r p‌l‌a‌c‌e‌m‌e‌n‌t i‌n d‌a‌m‌a‌g‌e d‌e‌t‌e‌c‌t‌i‌o‌n. T‌h‌e r‌e‌s‌u‌l‌t‌s d‌e‌m‌o‌n‌s‌t‌r‌a‌t‌e t‌h‌e h‌i‌g‌h e‌f‌f‌i‌c‌i‌e‌n‌c‌y o‌f t‌h‌e p‌r‌o‌p‌o‌s‌e‌d m‌e‌t‌h‌o‌d f‌o‌r d‌e‌t‌e‌c‌t‌i‌n‌g t‌h‌e l‌o‌c‌a‌t‌i‌o‌n a‌n‌d s‌e‌v‌e‌r‌i‌t‌y o‌f j‌o‌i‌n‌t d‌a‌m‌a‌g‌e, c‌o‌n‌s‌i‌d‌e‌r‌i‌n‌g n‌o‌i‌s‌e e‌f‌f‌e‌c‌t‌s. B‌e‌s‌i‌d‌e‌s, a‌n i‌n‌a‌p‌p‌r‌o‌p‌r‌i‌a‌t‌e l‌o‌c‌a‌t‌i‌o‌n o‌f s‌e‌n‌s‌o‌r‌s c‌a‌u‌s‌e‌s s‌o‌m‌e e‌r‌r‌o‌r‌s i‌n d‌a‌m‌a‌g‌e d‌e‌t‌e‌c‌t‌i‌o‌n p‌r‌o‌c‌e‌d‌u‌r‌e, a‌n‌d t‌h‌e m‌e‌t‌h‌o‌d c‌a‌n‌n‌o‌t e‌a‌s‌i‌l‌y i‌d‌e‌n‌t‌i‌f‌y t‌h‌e d‌a‌m‌a‌g‌e

Simulation of Contaminant Transport through the Vadose Zone: A Continuum Mechanical Approach within the Framework of the Extended Theory of Porous Media (eTPM)

The simulation of contaminant transport through the vadose zone enjoys high significance for decision makers and contaminated site planners since the vadose zone can serve as a filter, but many contaminants can be transported from this region to aquifers. The intention of this paper is to utilize the extended Theory of Porous Media (eTPM) to develop a ternary model for the simulation of contaminant transport in the vadose zone whose application is subsequently shown via a numerical example. The simulation was conducted for 140 days, during which the contamination source was removed after 25 days. The results indicate that the contaminant reached the water table after 76 days. The concentration of the contaminant reaching the groundwater was 17% less than that of the contaminant source

Subsurface Silicon Processing by Microsphere Focusing of Ultrafast Infrared Laser

Attention on applications of femtosecond lasers in semiconductor materials processing is ever growing. There has been an increasing research momentum especially towards multi-photon absorption based silicon (Si) processing with infrared lasers in the last decade. Since Si is transparent at wavelengths >1.1 mu m, the processing inside Si is triggered by the nonlinear optical phenomenon of two or more photon absorption which requires laser amplitude to reach and pass beyond threshold conditions. A method that utilizes back-reflection at the Si-air interface was developed and demonstrated to be useful for subsurface processing of Si at the micro-scale. In previous studies, pixels of such processed regions were limited to 5-10 mu m size despite use of high numerical aperture lenses due to strong refraction of light in Si. In order to deem the laser processing of Si useful for photonic applications, pixel size needed to be reduced down to a micron or below. In this work, we demonstrate subsurface modification of Si using microsphere based focusing of a 1.5 mu m wavelength ultrafast laser pulses in Si

Uncertainty with Varying Subsurface Permeabilities Reduced Using Coupled Random Field and Extended Theory of Porous Media Contaminant Transport Models

To maximize the usefulness of groundwater flow models for the protection of aquifers and abstraction wells, it is necessary to identify and decrease the uncertainty associated with the major parameters such as permeability. To do this, there is a need to develop set of estimates representing subsurface heterogeneity or representative soil permeability estimates. Here, we use a coupled Random Field and extended Theory of Porous Media (eTPM) simulation to develop a robust model with a good predictive ability that reduces uncertainty. The coupled model is then validated with a physical sandbox experiment. Uncertainty is reduced by using 500 realisations of the permeability parameter using the eTPM approach. A multi-layer contaminant transport scenario with varying permeabilities, similar to what could be expected with shallow alluvial sediments, is simulated. The results show that the contaminant arrival time could be strongly affected by random field realizations of permeability compared with a modelled homogenous permeability parameter. The breakthrough time for heterogeneous permeabilities is shorter than the homogeneous condition. Using the 75% confidence interval (CI), the average contaminant concentration shows 4.4% variation from the average values of the considered area and 8.9% variation in the case of a 95% confidence interval

Loose nanofiltration membranes functionalized with in situ-synthesized metal organic framework for water treatment

In this study, modified loose nanofiltration membranes were prepared by in-situ decoration with Zeolitic Imidazolate Framework-7 (ZIF-7) on the surface of porous polyethersulfone substrates functionalized with co-deposited sulfobetaine methacrylate (SBMA) zwitterion (ZW) and polydopamine (PDA). With the aid of ZW/PDA active layer co-deposition under mild conditions, ZIF-7 metal organic framework (MOF) nanocrystals were successfully formed and anchored onto the membrane surface via both non-covalent and covalent bonds to simultaneously achieve the desired selectivity and productivity of the loose nanofiltration membranes. The characterization results confirmed the successful deposition of the ZW/PDA active layer and the consequent decoration with ZIF-7 nanocrystals. The average water contact angle decreased notably from 81.4 to 51.43 degrees upon the formation of ZIF-7. This membrane showed high rejection (~99.9%) of methyl blue and Congo red dyes and high water flux with dye solutions (around 40 L m-2h-1) at a very low applied pressure of 1.5 bar. Moreover, the filtration experiments revealed that functionalized membranes exhibited a significant reduction in fouling and biofouling propensity. Notably, the MOF-SBMA/PDA membrane displayed favorable antifouling behavior associated with a significant ability to recover flux upon simple physical cleaning. The combination of these two properties is possibly the most promising feature of the membrane proposed in this study