A digital microfluidic device integrated with electrochemical sensor and 3D matrix for detecting soluble PD-L1.

PD1/PD-L1 checkpoint inhibitors are at the forefront of cancer immunotherapies. However, the overall response rate remains only 10-30%. Even among initial responders, drug resistance often occurs, which can lead to prolonged use of a futile therapy in the race with the fatal disease. It would be ideal to closely monitor key indicators of patients' immune responsiveness, such as circulating PD-L1 levels. Traditional PD-L1 detection methods, such as ELISA, are limited in sensitivity and rely on core lab facilities, preventing their use for the regular monitoring. Electrochemical sensors exist as an attractive candidate for point-of-care tool, yet, streamlining multiple processes in a single platform remains a challenge. To overcome this challenge, this work integrated electrochemical sensor arrays into a digital microfluidic device to combine their distinct merits, so that soluble PD-L1 (sPD-L1) molecules can be rapidly detected in a programmed and automated manner. This new platform featured microscale electrochemical sensor arrays modified with electrically conductive 3D matrix, and can detect as low as 1 pg/mL sPD-L1 with high specificity. The sensors also have desired repeatability and can obtain reproducible results on different days. To demonstrate the functionality of the device to process more complex biofluids, we used the device to detect sPD-L1 molecules secreted by human breast cancer cell line in culture media directly and observed 2X increase in signal compared with control experiment. This novel platform holds promise for the close monitoring of sPD-L1 level in human physiological fluids to evaluate the efficacy of PD-1/PD-L1 immunotherapy.

Development of a tightly regulated copper-inducible transient gene expression system in Nicotiana benthamiana incorporating a suicide exon and Cre recombinase.

Chemical-inducible gene expression systems are commonly used to regulate gene expression for functional genomics in various plant species. However, a convenient system that can tightly regulate transgene expression in Nicotiana benthamiana is still lacking. In this study, we developed a tightly regulated copper-inducible system that can control transgene expression and conduct cell death assays in N. benthamiana. We tested several chemical-inducible systems using Agrobacterium-mediated transient expression and found that the copper-inducible system exhibited the least concerns regarding leakiness in N. benthamiana. Although the copper-inducible system can control the expression of some tested reporters, it is not sufficiently tight to regulate certain tested hypersensitive cell death responses. Using the MoClo-based synthetic biology approach, we incorporated the suicide exon HyP5SM/OsL5 and Cre/LoxP as additional regulatory elements to enhance the tightness of the regulation. This new design allowed us to tightly control the hypersensitive cell death induced by several tested leucine-rich repeat-containing proteins and their matching avirulence factors, and it can be easily applied to regulate the expression of other transgenes in transient expression assays. Our findings offer new approaches for both fundamental and translational studies in plant functional genomics.

miRNA analysis reveals novel dysregulated pathways in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Its complex pathogenesis and phenotypic heterogeneity hinder therapeutic development and early diagnosis. Altered RNA metabolism is a recurrent pathophysiologic theme, including distinct microRNA (miRNA) profiles in ALS tissues. We profiled miRNAs in accessible biosamples, including skin fibroblasts and whole blood and compared them in age- and sex-matched healthy controls versus ALS participants with and without repeat expansions to chromosome 9 open reading frame 72 (C9orf72; C9-ALS and nonC9-ALS), the most frequent ALS mutation. We identified unique and shared profiles of differential miRNA (DmiRNA) levels in each C9-ALS and nonC9-ALS tissues versus controls. Fibroblast DmiRNAs were validated by quantitative real-time PCR and their target mRNAs by 5-bromouridine and 5-bromouridine-chase sequencing. We also performed pathway analysis to infer biological meaning, revealing anticipated, tissue-specific pathways and pathways previously linked to ALS, as well as novel pathways that could inform future research directions. Overall, we report a comprehensive study of a miRNA profile dataset from C9-ALS and nonC9-ALS participants across two accessible biosamples, providing evidence of dysregulated miRNAs in ALS and possible targets of interest. Distinct miRNA patterns in accessible tissues may also be leveraged to distinguish ALS participants from healthy controls for earlier diagnosis. Future directions may look at potential correlations of miRNA profiles with clinical parameters.

Foot Reflexology: Recent Research Trends and Prospects.

Foot reflexology is a non-invasive complementary therapy that is increasingly being accepted by modern people in recent years. To understand the research trends and prospects of foot reflexology in the past 31 years, this study used the Web of Science core collection as the data source and two visualization tools, COOC and VOSviewer, to analyze the literature related to the field of foot reflexology from 1991 to 2021. This study found that the number of articles published in the field of foot reflexology has been increasing year by year, and the top three journals with the most articles are Complementary Therapies in Clinical Practice, Therapies in Medicine, and the Journal of Alternative and Complementary Medicine. The top three most prolific authors are Wyatt, Sikorskii, and Victorson, and the core institutions in the field of foot reflexology are Michigan State University, Northwestern University, Tehran University of Medical Sciences, and the University of Exeter. Foot reflexology has been shown to have a moderating effect on anxiety, fatigue, and cancer, and is a topic of ongoing and future research. This study uses this bibliometric analysis of foot reflexology literature to provide an overview of prior knowledge and a reference direction for modern preventive medicine.

Extracellular Vesicles in Serum and Central Nervous System Tissues Contain microRNA Signatures in Sporadic Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a terminalneurodegenerative disease. Clinical and molecular observations suggest that ALS pathology originates at a single site and spreads in an organized and prion-like manner, possibly driven by extracellular vesicles. Extracellular vesicles (EVs) transfer cargo molecules associated with ALS pathogenesis, such as misfolded and aggregated proteins and dysregulated microRNAs (miRNAs). However, it is poorly understood whether altered levels of circulating extracellular vesicles or their cargo components reflect pathological signatures of the disease. In this study, we used immuno-affinity-based microfluidic technology, electron microscopy, and NanoString miRNA profiling to isolate and characterize extracellular vesicles and their miRNA cargo from frontal cortex, spinal cord, and serum of sporadic ALS (n = 15) and healthy control (n = 16) participants. We found larger extracellular vesicles in ALS spinal cord versus controls and smaller sized vesicles in ALS serum. However, there were no changes in the number of extracellular vesicles between cases and controls across any tissues. Characterization of extracellular vesicle-derived miRNA cargo in ALS compared to controls identified significantly altered miRNA levels in all tissues; miRNAs were reduced in ALS frontal cortex and spinal cord and increased in serum. Two miRNAs were dysregulated in all three tissues: miR-342-3p was increased in ALS, and miR-1254 was reduced in ALS. Additional miRNAs overlapping across two tissues included miR-587, miR-298, miR-4443, and miR-450a-2-3p. Predicted targets and pathways associated with the dysregulated miRNAs across the ALS tissues were associated with common biological pathways altered in neurodegeneration, including axon guidance and long-term potentiation. A predicted target of one identified miRNA (N-deacetylase and N-sulfotransferase 4; NDST4) was likewise dysregulated in an in vitro model of ALS, verifying potential biological relevance. Together, these findings demonstrate that circulating extracellular vesicle miRNA cargo mirror those of the central nervous system disease state in ALS, and thereby offer insight into possible pathogenic factors and diagnostic opportunities.

Epidermal Growth Factor Receptor Mutations Carried in Extracellular Vesicle-Derived Cargo Mirror Disease Status in Metastatic Non-small Cell Lung Cancer.

In non-small cell lung cancer (NSCLC), identifying the presence of sensitizing and resistance epidermal growth factor receptor (EGFR) mutations dictates treatment plans. Extracellular vesicles (EVs) are emerging as abundant, stable potential liquid biopsy targets that offer the potential to quantify EGFR mutations in NSCLC patients at the RNA and protein level at multiple points through treatment. In this study, we present a systematic approach for serial mutation profiling of 34 EV samples from 10 metastatic NSCLC patients with known EGFR mutations through treatment. Using western blot and droplet digital PCR (ddPCR), sensitizing (exon 19 deletion, L858R) mutations were detected in EV-Protein, and both sensitizing and resistance (T790M) mutations were quantified in EV-RNA. EGFR mutations were detected in EV-Protein from four patients at multiple time points through treatment. Using EV-RNA, tumor biopsy matched sensitizing mutations were detected in 90% of patients and resistance mutations in 100% of patients. Finally, mutation burden in EV-RNA at each time point was compared to disease status, described as either stable or progressing. For 6/7 patients who were longitudinally monitored through treatment, EV mutation burden mirrored clinical trajectory. When comparing mutation detection between EV-RNA and ctDNA using ddPCR, EVs had a better detection rate for exon 19 deletions and the L858R point mutation. In conclusion, this study demonstrates that integrating EV analysis into liquid biopsy mutation screening has the potential to advance beyond the current standard of care "rule in" test. The multi-analyte testing allows future integration of EGFR mutation monitoring with additional EV-markers for a comprehensive patient monitoring biomarker.

Women's Cognition and Attitude with Eco-Friendly Menstrual Products by Consumer Lifestyle.

With rapid technology developments and the convenient and fast pace of life in recent years, many people are using disposable products, which cause environmental and ecological damages. A variety of eco-friendly menstrual products have been launched on the market, and "menstrual pads" now have a large market share in Taiwan's menstrual product industry. This study interviewed experts and collected questionnaires for qualitative and quantitative investigation and analysis. The results show that women have positive and open concepts regarding sustainability, as well as a good understanding of their body and are very interested in the performance and usage efficiency of products. The results also indicate that consumers purchase based on their lifestyles; most women collected enough product information before purchasing while overcoming the difficulties in dealing with the environment and learning to adapt them, and the majority of consumers attach importance to comfort, volume, and duration of blood absorption. The results suggest that the government and private enterprises should increase and improve sanitation education and sanitary facilities and guide the approach and serve as an important reference index for the promotion of eco-friendly menstrual products for environmental benefits.

On-Chip Biogenesis of Circulating NK Cell-Derived Exosomes in Non-Small Cell Lung Cancer Exhibits Antitumoral Activity.

As the recognition between natural killer (NK) cells and cancer cells does not require antigen presentation, NK cells are being actively studied for use in adoptive cell therapies in the rapidly evolving armamentarium of cancer immunotherapy. In addition to utilizing NK cells, recent studies have shown that exosomes derived from NK cells also exhibit antitumor properties. Furthermore, these NK cell-derived exosomes exhibit higher stability, greater modification potentials and less immunogenicity compared to NK cells. Therefore, technologies that allow highly sensitive and specific isolation of NK cells and NK cell-derived exosomes can enable personalized NK-mediated cancer therapeutics in the future. Here, a novel microfluidic system to collect patient-specific NK cells and on-chip biogenesis of NK-exosomes is proposed. In a small cohort of non-small cell lung cancer (NSCLC) patients, both NK cells and circulating tumor cells (CTCs) were isolated, and it is found NSCLC patients have high numbers of NK and NK-exosomes compared with healthy donors, and these concentrations show a trend of positive and negative correlations with bloodborne CTC numbers, respectively. It is further demonstrated that the NK-exosomes harvested from NK-graphene oxide chip exhibit cytotoxic effect on CTCs. This versatile system is expected to be used for patient-specific NK-based immunotherapies along with CTCs for potential prognostic/diagnostic applications.

Dual-Isolation and Profiling of Circulating Tumor Cells and Cancer Exosomes from Blood Samples with Melanoma Using Immunoaffinity-Based Microfluidic Interfaces.

Melanoma is among the most aggressive cancers, and its rate of incidence continues to grow. Early detection of melanoma has been hampered due to the lack of promising markers for testing. Recent advances in liquid biopsy have proposed noninvasive alternatives for cancer diagnosis and monitoring. Circulating tumor cells (CTCs) and cancer-exosomes are gaining influence as promising biomarkers because of their cancer-associated molecular markers and signatures. However, technologies that offer the dual-isolation of CTCs and exosomes using a single sample have not been thoroughly developed. The dual-utilization OncoBean (DUO) device is conjugated with melanoma specific antibodies, MCAM and MCSP, enabling simultaneous CTC and exosome isolations. Using blood samples from patients, CTCs and exosomes are specifically isolated from a single sample and then undergo molecular profiling for comprehensive study. Melanoma patients have 0-17CTCs mL-1 and 299 µg exosomal protein mL-1 while healthy donors display fewer than 2CTCs and 75.6 µg of exosomes mL-1, respectively. It is also demonstrated that both markers express melanoma-associated genes using multiplex qRT-PCR to test for expression pattern of a 96 gene panel. The dual isolation and molecular characterization will allow for further research into melanoma to identify viable markers for disease progression and treatment efficacy.

Tumour-reprogrammed stromal BCAT1 fuels branched-chain ketoacid dependency in stromal-rich PDAC tumours.

Branched-chain amino acids (BCAAs) supply both carbon and nitrogen in pancreatic cancers, and increased levels of BCAAs have been associated with increased risk of pancreatic ductal adenocarcinomas (PDACs). It remains unclear, however, how stromal cells regulate BCAA metabolism in PDAC cells and how mutualistic determinants control BCAA metabolism in the tumour milieu. Here, we show distinct catabolic, oxidative and protein turnover fluxes between cancer-associated fibroblasts (CAFs) and cancer cells, and a marked reliance on branched-chain α-ketoacid (BCKA) in PDAC cells in stroma-rich tumours. We report that cancer-induced stromal reprogramming fuels this BCKA demand. The TGF-ß-SMAD5 axis directly targets BCAT1 in CAFs and dictates internalization of the extracellular matrix from the tumour microenvironment to supply amino-acid precursors for BCKA secretion by CAFs. The in vitro results were corroborated with circulating tumour cells (CTCs) and PDAC tissue slices derived from people with PDAC. Our findings reveal therapeutically actionable targets in pancreatic stromal and cancer cells.

Simultaneous Single Cell Gene Expression and EGFR Mutation Analysis of Circulating Tumor Cells Reveals Distinct Phenotypes in NSCLC.

While cancer cell populations are known to be highly heterogeneous within a tumor, the current gold standard of tumor profiling is through a tumor biopsy. These biopsies are invasive and prone to missing these clones due to spatial heterogeneity, and this bulk analysis approach can miss information from rare subpopulations. To noninvasively investigate tumor cell heterogeneity, a streamlined workflow is developed to scrutinize rare cells, such as circulating tumor cells (CTCs), for simultaneous analysis of mutations and gene expression profiles at the single cell level. This powerful workflow overcomes low-input limitations of single cell analysis techniques. The utility of this multiplexed workflow to unravel inter- and intra-patient heterogeneity is demonstrated using non-small-cell lung cancer (NSCLC) CTCs (n = 58) from six epidermal growth factor receptor (EGFR) mutant positive NSCLC patients. CTCs are isolated using a high-throughput microfluidic technology, the Labyrinth, and their EGFR mutation status and gene expression profiles are characterized.

Real-world gaseous and particulate emissions from Euro IV to VI medium duty diesel trucks.

This study offers emission factors for earlier and late technology medium duty diesel particulate filter (DPF) -equipped trucks, operating on real-world conditions. The analysis includes levels of nitrous oxide (N2O) emissions as well as the impacts of DPF regenerations on emission levels. The real-driving gaseous and particulate emissions, as well as fuel consumption of 14 Euro IV, Euro V, and Euro VI medium duty diesel trucks were analysed and the efficiency of different emission control technologies were assessed. Measurements were conducted using portable emission measurement systems (PEMS) over a wide range of driving and operating conditions. Distance-based integration of emission rates over 500 m sections was considered for statistical analysis, providing a large dataset of emission factors to be used for network link-based traffic and emissions modelling. In terms of emissions performance, nitrogen oxides (NOx) levels were in general above the corresponding Euro standard limits, while carbon monoxide (CO), total hydrocarbons (THC) and particulate matter (PM) levels were within limits. Selective catalytic reduction (SCR) -equipped Euro V vehicles were seen to emit more than their non-SCR-equipped counterparts. NOx and fuel consumption were positively correlated with road gradient over the -6% to 6% gradient range. The emission levels of ammonia (NH3) were measured significantly lower than the respective Euro VI provisions for heavy duty engines, while the N2O levels were found to contribute approximately 1% to the respective total greenhouse gases levels. DPF regeneration events in real world seem to have a measurable impact mostly on THC and PM emissions, increasing baseline levels by 8.1% and 29%, respectively, for Euro VI vehicles.

Microfluidic device for high-throughput affinity-based isolation of extracellular vesicles.

Immunoaffinity based EV isolation technologies use antibodies targeting surface markers on EVs to provide higher isolation specificity and purity compared to existing approaches. One standing challenge for researchers is how to release captured EVs from the substrate to increase downstream and biological studies. The strong binding between the antibody and antigen or the antibody and substrate is commonly unbreakable without operating at conditions outside of the critical physiological range, making the release of EVs problematic. Additionally, immuno-affinity approaches are usually low-throughput due to their low flow velocity to ensure adequate time for antibody-antigen binding. To overcome these limitations, we modified the OncoBean chip, a previously reported circulating tumor cell isolation microfluidic device. The OncoBean chip is a radial flow microfluidic device with bean-shape microposts functionalized with biotin-conjugated EPCAM antibody through biotin-avidin link chemistry. It was demonstrated that the high surface area and varying shear rate provided by the bean-shaped posts and the radial flow design in the chip, enabled efficient capture of CTCs at high flow rate. We replace the anti-EPCAM with antibodies that recognize common EV surface markers to achieve high-throughput EV isolation. Moreover, by incorporating desthiobiotin-conjugated antibodies, EVs can be released from the device after capture, which offers a significant improvement over the existing isolation. The released EVs were found to be functional by confirming their uptake by cells using flow cytometry and fluorescent microscopy. We believe the proposed technology can facilitate both the study of EVs as cell-to-cell communicators and the further identification of EV markers.

Isolation and Profiling of Circulating Tumor-Associated Exosomes Using Extracellular Vesicular Lipid-Protein Binding Affinity Based Microfluidic Device.

Extracellular vesicles (EVs) are emerging as a potential diagnostic test for cancer. Owing to the recent advances in microfluidics, on-chip EV isolation is showing promise with respect to improved recovery rates, smaller necessary sample volumes, and shorter processing times than ultracentrifugation. Immunoaffinity-based microfluidic EV isolation using anti-CD63 is widely used; however, anti-CD63 is not specific to cancer-EVs, and some cancers secrete EVs with low expression of CD63. Alternatively, phosphatidylserine (PS), usually expressed in the inner leaflet of the lipid bilayer of the cells, is shown to be expressed on the outer surface of cancer-associated EVs. A new exosome isolation microfluidic device (new ExoChip), conjugated with a PS-specific protein, to isolate cancer-associated exosomes from plasma, is presented. The device achieves 90% capture efficiency for cancer cell exosomes compared to 38% for healthy exosomes and isolates 35% more A549-derived exosomes than an anti-CD63-conjugated device. Immobilized exosomes are then easily released using Ca2+ chelation. The recovered exosomes from clinical samples are characterized by electron microscopy and western-blot analysis, revealing exosomal shapes and exosomal protein expressions. The new ExoChip facilitates the isolation of a specific subset of exosomes, allowing the exploration of the undiscovered roles of exosomes in cancer progression and metastasis.

Multiplex isolation and profiling of extracellular vesicles using a microfluidic DICE device.

Profiling of extracellular vesicles (EVs) is an emerging area in the field of liquid biopsies because of their innate significance in diseases and abundant information reflecting disease status. However, unbiased enrichment of EVs and thorough profiling of EVs is challenging. In this paper, we present a simple strategy to immobilize and analyze EVs for multiple markers on a single microfluidic device and perform differentiated immunostaining-based characterization of extracellular vesicles (DICE). This device, composed of four quadrants with a single inlet, captures biotinylated EVs efficiently and facilitates multiplexed immunostaining to profile their extracellular proteins, allowing for a multiplexed approach for non-invasive cancer diagnostics in the future. From controlled sample experiments using cancer cell line derived EVs and specific fluorescence staining with lipophilic dyes, we identified that the DICE device is capable of isolating biotinylated EVs with 84.4% immobilization efficiency. We extended our study to profile EVs of 9 clinical samples from non-small cell lung cancer (NSCLC) patients and healthy donors and found that the DICE device successfully facilitates immunofluorescent staining for both the NSCLC patients and the healthy control. This versatile and simple method to profile EVs could be extended to EVs of any biological origin, promoting discoveries of the role of EVs in disease diagnostics and monitoring.

Evaluation of Real-World Gaseous Emissions Performance of Selective Catalytic Reduction and Diesel Particulate Filter Bus Retrofits.

This study reports on the results of gaseous pollutants emission measurements of double-decker buses in an urban road network, using portable emission measurement systems (PEMS). Measured vehicles were tested by following in-service buses on regular routes. Six Euro II and Euro III buses were retrofitted with diesel particulate filters (DPF) and selective catalytic reduction (SCR) or a combined SCR+DPF (SCRT) device. Substantial and statistically significant technology impacts were observed for several pollutants. Optimized SCR and SCRT retrofit technology reduced real-world NO x emissions by approximately 70%, on average. Retrofit DPF slightly reduced NO x emissions but increased direct NO2 emissions by more than a factor of 8, on average. SCRT led to about 70% lower NO2 levels than DPF alone, but for some vehicles higher NO2 levels were observed as compared with the "no retrofit" situation, warranting further investigation. None of the SCR systems were found to lead to a substantial increase in NH3 emissions after operation optimization. High NH3 and N2O emissions were occasionally observed while experience with the system calibration was being accumulated. Observed average N2O emission levels for "DPF+SCR" technology were relatively high at 182 mg/kg fuel, corresponding to 1.5% of total greenhouse gas emissions. The study shows that SCR retrofit programs can be effective for NO x reduction of transit buses but that proper calibration and regular emission monitoring are required.

Directed Self-Assembly of Star-Block Copolymers by Topographic Nanopatterns through Nucleation and Growth Mechanism.

Exploring the ordering mechanism and dynamics of self-assembled block copolymer (BCP) thin films under confined conditions are highly essential in the application of BCP lithography. In this study, it is aimed to examine the self-assembling mechanism and kinetics of silicon-containing 3-arm star-block copolymer composed of polystyrene (PS) and poly(dimethylsiloxane) blocks as nanostructured thin films with perpendicular cylinders and controlled lateral ordering by directed self-assembly using topographically patterned substrates. The ordering process of the star-block copolymer within fabricated topographic patterns with PS-functionalized sidewall can be carried out through the type of secondary (i.e., heterogeneous) nucleation for microphase separation initiated from the edge and/or corner of the topographic patterns, and directed to grow as well-ordered hexagonally packed perpendicular cylinders. The growth rate for the confined microphase separation is highly dependent upon the dimension and also the geometric texture of the preformed pattern. Fast self-assembly for ordering of BCP thin film can be achieved by lowering the confinement dimension and also increasing the concern number of the preformed pattern, providing a new strategy for the design of BCP lithography from the integration of top-down and bottom-up approaches.

A Meta-analysis of Corticosteroid Injection for Trigger Digits Among Patients With Diabetes.

A majority of patients with diabetes have trigger digits. Initial management of symptomatic trigger digits commonly involves corticosteroid injection. However, varying outcomes have been reported for patients with diabetes who receive corticosteroid injections. The authors conducted a meta-analysis to evaluate the effect of diabetes on outcome after corticosteroid injection for trigger digit. PubMed and other Internet databases were searched for the period 1977 to 2015. Five articles, involving 381 diabetic digits and 449 non-diabetic digits, were included in the meta-analysis. The authors found treatment failure rates of 78% for patients with insulin-dependent diabetes, 47% for patients with non-insulin-dependent diabetes, and 49% for patients without diabetes when a single injection of corticosteroid was administered for trigger digit. After 3 injections, the failure rates were 57%, 39%, and 30%, respectively. The pooled data showed that patients with insulin-dependent diabetes and patients with non-insulin-dependent diabetes had worse prognoses after corticosteroid injection for trigger digit than patients without diabetes. Furthermore, the patients with insulin-dependent diabetes had a trend toward multiple digit involvement and much worse treatment outcomes than the patients with non-insulin-dependent diabetes. The authors conclude that more aggressive treatment, such as surgical intervention, should be considered for those patients expected to have high failure rates after injection. [Orthopedics. 2018; 41(1):e8-e14.].

let-7 Modulates Chromatin Configuration and Target Gene Repression through Regulation of the ARID3B Complex.

Let-7 is crucial for both stem cell differentiation and tumor suppression. Here, we demonstrate a chromatin-dependent mechanism of let-7 in regulating target gene expression in cancer cells. Let-7 directly represses the expression of AT-rich interacting domain 3B (ARID3B), ARID3A, and importin-9. In the absence of let-7, importin-9 facilitates the nuclear import of ARID3A, which then forms a complex with ARID3B. The nuclear ARID3B complex recruits histone demethylase 4C to reduce histone 3 lysine 9 trimethylation and promotes the transcription of stemness factors. Functionally, expression of ARID3B is critical for the tumor initiation in let-7-depleted cancer cells. An inverse association between let-7 and ARID3A/ARID3B and prognostic significance is demonstrated in head and neck cancer patients. These results highlight a chromatin-dependent mechanism where let-7 regulates cancer stemness through ARID3B.

Morphological Evolution of Gyroid-Forming Block Copolymer Thin Films with Varying Solvent Evaporation Rate.

In this study, we aim to examine the morphological evolution of block copolymer (BCP) nanostructured thin films through solvent evaporation at different rates for solvent swollen polystyrene-block-poly(l-lactide) (PS-PLLA). Interesting phase transitions from disorder to perpendicular cylinder and then gyroid can be found while using a partially selective solvent for PS to swell PS-PLLA thin film followed by solvent evaporation. During the transitions, gyroid-forming BCP thin film with characteristic crystallographic planes of (111)G, (110)G, and (211)G parallel to air surface can be observed, and will gradually transform into coexisting (110)G and (211)G planes, and finally transforms to (211)G plane due to the preferential segregation of constituted block to the surface (i.e., the thermodynamic origin for self-assembly) that affects the relative amount of each component at the air surface. With the decrease on the evaporation rate, the disorder phase will transform to parallel cylinder and then directly to (211)G without transition to perpendicular cylinder phase. Most importantly, the morphological evolution of PS-PLLA thin films is strongly dependent upon the solvent removal rate only in the initial stage of the evaporation process due to the anisotropy of cylinder structure. Once the morphology is transformed back to the isotropic gyroid structure after long evaporation, the morphological evolution will only relate to the variation of the surface composition. Similar phase transitions at the substrate can also be obtained by controlling the ratio of PLLA-OH to PS-OH homopolymers to functionalize the substrate. As a result, the fabrication of well-defined nanostructured thin films with controlled orientation can be achieved by simple swelling and deswelling with controlled evaporation rate.