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In this study, loose nanofiltration membranes made of polysulfone dissolved in co-solvents PolarClean and gamma-Valerolactone were prepared via slot die coating (SDC) on a roll-to-roll (R2R) system by directly coating them onto a support layer or free standing. A solution flow rate of 20 mL/min, substrate speed of 17.1 mm/s, and coating gap of 0.1 mm resulted in the formation of membranes without structural defects. Pre-wetting the support layer with dope solution minimized shrinkage of membrane layer thickness and improved interfacial adhesion. Membrane samples produced using SDC exhibited properties and performance consistent with bench-scale doctor blade extruded samples; pre-wetted and uncompressed samples (SDC-3) exhibited the highest rejection of bovine serum albumin (99.20% ± 1.31%) and along with adequate mean permeability during filtration (70.5 ± 8.33 LMH/bar). This study shows that combining sustainable materials development with SDC provides a holistic approach to membrane separations to bridge materials discovery and membrane formation.

 

Membranes serve as important components for modern manufacturing and purification processes but are conventionally associated with excessive solvent usage. Here, for the first time, a procedure for fabricating large area polysulfone membranes is demonstrated via the combination of direct ink writing (DIW) with non-solvent induced phase inversion (NIPS). The superior control and precision of this process allows for complete utilization of the polymer dope solution during membrane fabrication, thus enabling a significant reduction in material usage. Compared to doctor blade fabrication, a 63% reduction in dope solution volume was achieved using the DIW technique for fabricating similarly sized membranes. Cross flow filtration analysis revealed that, independent of the manufacturing method (DIWvs.doctor blade), the membranes exhibited near identical separation properties. The separation properties were assessed in terms of bovine serum albumin (BSA) rejection and permeances (pressure normalized flux) of pure water and BSA solution. This new manufacturing strategy allows for the reduction of material and solvent usage while providing a large toolkit of tunable parameters which can aid in advancing membrane technology.

 

Plasma cell-free DNA (cfDNA) is a noninvasive biomarker for cell death of all organs. Deciphering the tissue origin of cfDNA can reveal abnormal cell death because of diseases, which has great clinical potential in disease detection and monitoring. Despite the great promise, the sensitive and accurate quantification of tissue-derived cfDNA remains challenging to existing methods due to the limited characterization of tissue methylation and the reliance on unsupervised methods. To fully exploit the clinical potential of tissue-derived cfDNA, here we present one of the largest comprehensive and high-resolution methylation atlas based on 521 noncancer tissue samples spanning 29 major types of human tissues. We systematically identified fragment-level tissue-specific methylation patterns and extensively validated them in orthogonal datasets. Based on the rich tissue methylation atlas, we develop the first supervised tissue deconvolution approach, a deep-learning-powered model, cfSort , for sensitive and accurate tissue deconvolution in cfDNA. On the benchmarking data, cfSort showed superior sensitivity and accuracy compared to the existing methods. We further demonstrated the clinical utilities of cfSort with two potential applications: aiding disease diagnosis and monitoring treatment side effects. The tissue-derived cfDNA fraction estimated from cfSort reflected the clinical outcomes of the patients. In summary, the tissue methylation atlas and cfSort enhanced the performance of tissue deconvolution in cfDNA, thus facilitating cfDNA-based disease detection and longitudinal treatment monitoring. 

(1) Different methods have been applied to fabricate polymeric membranes with non-solvent induced phase separation (NIPS) being one of the mostly widely used. In NIPS, a solvent or solvent blend is required to dissolve a polymer or polymer blend. N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF) and other petroleum-derived solvents are commonly used to dissolve some petroleum-based polymers. However, these components may have negative impacts on the environment and human health. Therefore, using greener and less toxic components is of great interest for increasing membrane fabrication sustainability. The chemical structure of membranes is not affected by the use of different solvents, polymers, or by the differences in fabrication scale. On the other hand, membrane pore structures and surface roughness can change due to differences in diffusion rates associated with different solvents/co-solvents diffusing into the non-solvent and with differences in evaporation time. (2) Therefore, in this review, solvents and polymers involved in the manufacturing process of membranes are proposed to be replaced by greener/less toxic alternatives. The methods and feasibility of scaling up green polymeric membrane manufacturing are also examined. 

Even as end-to-end encrypted communication becomes more popular, private messaging remains a challenging problem due to metadata leakages, such as who is communicating with whom. Most existing systems that hide communication metadata either (1) do not scale easily, (2) incur significant overheads, or (3) provide weaker guarantees than cryptographic privacy, such as differential privacy or heuristic privacy. This paper presents XRD (short for Crossroads), a metadata private messaging system that provides cryptographic privacy, while scaling easily to support more users by adding more servers. At a high level, XRD uses multiple mix networks in parallel with several techniques, including a novel technique we call aggregate hybrid shuffle. As a result, XRD can support 2 million users with 228 seconds of latency with 100 servers. This is 13.3x and 4x faster than Atom and Pung, respectively, which are prior scalable messaging systems with cryptographic privacy. 

Magnetic resonance imaging (MRI) has unique advantages for guiding interventions, but the narrow space is a major challenge. This study evaluates the feasibility of a remote‐controlled hydrostatic actuator system for MRI‐guided targeted needle placement.

The effects of the hydrostatic actuator system on MR image quality were evaluated. Using a reference step‐and‐shoot method (SS) and the proposed actuator‐assisted method (AA), two operators performed MRI‐guided needle placement in targets (n = 12) in a motion phantom.

The hydrostatic actuator system exhibited negligible impact on MR image quality. In dynamic targets, AA was significantly more accurate and precise than SS, with mean ± SD needle‐to‐target error of 1.8 ± 1.0 mm (operator 1) and 1.3 ± 0.5 mm (operator 2). AA reduced the insertion time by 50% to 80% and total procedure time by 25%, compared to SS.

The proposed hydrostatic actuator system may improve accuracy and reduce procedure time for MRI‐guided targeted needle placement during motion.