Infestation and distribution of chigger mites on Brown rat (Rattus norvegicus) in Yunnan Province, Southwest China

Chigger mites is a group of arthropods and some of them are vectors of scrub typhus. As a common synanthropic rodent species, the Brown rat (Rattus norvegicus) often harbors lots of ectoparasites including chigger mites. According to some "data mining" strategies, the present study took the advantage of the abundant original data from a long-term field ecological investigation between 2001 and 2015 to make a detailed analysis of chigger mites on R. norvegicus in Yunnan Province, Southwest of China. From 18 of 33 investigated counties, only 1414 chigger mites were collected from 1113 Brown rats with relatively low infestations. The 1414 individual chigger mites were identified as comprising 61 species, 11 genera and 2 subfamilies of the family Trombiculidae with a high species diversity (S=61, H'=3.13). Of 61 mite species, there were four main species, Walchia ewingi, Ascoschoengastia indica, W. koi and A. rattinorvegici, which accounted for 44.41% of the total mites. All the chigger mites were of aggregated distribution among different individuals of R. norvegicus. The Brown rats in the outdoor habitats harbored much more individuals and species of chigger mites with a higher mean abundance (MA=1.46) and mean intensity (MI=12.53) than in the indoor habitats (P<0.05). The overall infestation of the rats was significantly higher in the mountainous landscapes than in the flatland landscapes (P<0.001). The species similarity (C_ss) of the mites on the male and female rats reached 64.44% with sex biased infestations. The male rats harbored more species and individuals of the mites than the female rats. The adult rats harbored more species and individuals of the mites than the juvenile rats. The species abundance distribution of the mites was successfully fitted by Preston's lognormal model with ŝ(R)=15e^{-[0.31(R-1)]2} (α=0.31, R²=0.95). On the basis of fitting the theoretical curve by Preston's model, the total mite species on R. norvegicus was estimated to be 86 species, and 25 rare mite species were missed in the sampling field investigation. The curve tendency of the species-plot relationship indicates that R. norvegicus have a great potential to harbor many species of chigger mites, and more species of the mites would be collected if more rats are sampled.

DFT study on the [4+4] domino cycloaddition of ynones with benzylidenepyrazolones to access eight-membered cyclic ethers: effects of DBUvs.Et3N

The difference in the catalytic activity of bases is primarily attributed to their electron-donating ability (t-BuO⁻> DBU > Et₃N).

Designing Mechanical Metamaterials with Kirigami-Inspired, Hierarchical Constructions for Giant Positive and Negative Thermal Expansion

Advanced mechanical metamaterials with unusual thermal expansion properties represent an area of growing interest, due to their promising potential for use in a broad range of areas. In spite of previous work on metamaterials with large or ultralow coefficient of thermal expansion (CTE), achieving a broad range of CTE values with access to large thermally induced dimensional changes in structures with high filling ratios remains a key challenge. Here, design concepts and fabrication strategies for a kirigami-inspired class of 2D hierarchical metamaterials that can effectively convert the thermal mismatch between two closely packed constituent materials into giant levels of biaxial/uniaxial thermal expansion/shrinkage are presented. At large filling ratios (>50%), these systems offer not only unprecedented negative and positive biaxial CTE (i.e., -5950 and 10 710 ppm K^-1 ), but also large biaxial thermal expansion properties (e.g., > 21% for 20 K temperature increase). Theoretical modeling of thermal deformations provides a clear understanding of the microstructure-property relationships and serves as a basis for design choices for desired CTE values. An Ashby plot of the CTE versus density serves as a quantitative comparison of the hierarchical metamaterials presented here to previously reported systems, indicating the capability for substantially enlarging the accessible range of CTE.

Feasibility and efficacy of left bundle branch area pacing in patients indicated for cardiac resynchronization therapy

AIMS

The present study was to evaluate the feasibility and clinical outcomes of left bundle branch area pacing (LBBAP) in cardiac resynchronization therapy (CRT)-indicated patients.

METHODS AND RESULTS

LBBAP was performed via transventricular septal approach in 25 patients as a rescue strategy in 5 patients with failed left ventricular (LV) lead placement and as a primary strategy in the remaining 20 patients. Pacing parameters, procedural characteristics, electrocardiographic, and echocardiographic data were assessed at implantation and follow-up. Of 25 enrolled CRT-indicated patients, 14 had left bundle branch block (LBBB, 56.0%), 3 right bundle branch block (RBBB, 12.0%), 4 intraventricular conduction delay (IVCD, 16.0%), and 4 ventricular pacing dependence (16.0%). The QRS duration (QRSd) was significantly shortened by LBBAP (intrinsic 163.6 ± 29.4 ms vs. LBBAP 123.0 ± 10.8 ms, P < 0.001). During the mean follow-up of 9.1 months, New York Heart Association functional class was improved to 1.4 ± 0.6 from baseline 2.6 ± 0.6 (P < 0.001), left ventricular ejection fraction (LVEF) increased to 46.9 ± 10.2% from baseline 35.2 ± 7.0% (P < 0.001), and LV end-diastolic dimensions (LVEDD) decreased to 56.8 ± 9.7 mm from baseline 64.1 ± 9.9 mm (P < 0.001). There was a significant improvement (34.1 ± 7.4% vs. 50.0 ± 12.2%, P < 0.001) in LVEF in patients with LBBB.

CONCLUSION

The present study demonstrates the clinical feasibility of LBBAP in CRT-indicated patients. Left bundle branch area pacing generated narrow QRSd and led to reversal remodelling of LV with improvement in cardiac function. LBBAP may be an alternative to CRT in patients with failure of LV lead placement and a first-line option in selected patients such as those with LBBB and heart failure.

MAGGIC Risk Model Predicts Adverse Events and Left Ventricular Remodeling in Non-Ischemic Dilated Cardiomyopathy

Purpose

We aimed to study the Meta-analysis Global Group in Chronic Heart Failure (MAGGIC) risk model’s prognostic value and relationship with left ventricular remodeling in dilated cardiomyopathy.

Patients and Methods

Dilated cardiomyopathy patients were prospectively recruited and underwent clinical assessments. MAGGIC risk score was calculated. Patients were followed up for adverse events and echocardiography. Primary endpoints were all-cause mortality and first rehospitalization due to heart failure. Secondary endpoint was left ventricular remodeling defined as a decline in left ventricular ejection fraction >10% or an increase in left ventricular end-diastolic diameter >10%. Survival status was examined using Cox regression analysis. The model’s ability to discriminate adverse events and left ventricular remodeling was calculated using a receiver operating characteristics curve.

Results

In total, 114 patients were included (median follow-up time = 31 months). The risk score was independently related to adverse events (2-year all-cause mortality: hazard ratio [HR] = 1.122; 95% confidence interval [CI], 1.043–1.208; 1-year first rehospitalization due to heart failure: HR = 1.094; 95% CI, 1.032–1.158; 2-year first rehospitalization due to heart failure: HR = 1.088; 95% CI, 1.033–1.147, all P < 0.05). One-year change in left ventricular end-diastolic diameter was correlated with the risk score (r = 0.305, P = 0.002). The model demonstrated modest ability in discriminating adverse events and left ventricular remodeling (all areas under the curve were 0.6–0.7).

Conclusion

The MAGGIC risk score was related to adverse events and left ventricular remodeling in dilated cardiomyopathy.

Controllably facile design of electrophoretic-induced film-forming of nano tungsten oxide (VI) and their anti-wetting functionalization

There is keen interest for designing promising tungsten oxide (VI, WO₃) films or coatings due to their wide applications in fields of energy, engineering, etc. Thus, this paper firstly introduce a novel convenient method of electrophoretic assembly technique (EAT) in an optimal stable suspension of isopropyl alcohol, PEG-1000 and polyethyleneimine for designing the promising anti-wetting functional WO₃ (VI) films with relative rough structures and uniform distribution in mild conditions. The product possess a high crystallinity and pureness by x-ray powder diffraction analysis. The EAT dynamic behaviours of WO₃ (VI) nanoparticles are investigated in detail. Moreover, obtained films shows excellent anti-wetting properties after suface modification, and the hydrophobic studies results demonstrate that product have a high static water CA of approximate 169° and keep nearly stable even after ultralong exposure time (360 d), and show outstanding properties of anti-soaking, impacting-proof, and moisture resistance even in high relative humidity (90%). These breakthroughs will substantially push forward the convenient processing of other anti-wetting functional coatings with wide potential applications.

Real-time three-dimensional transesophageal echocardiographic guidance versus fluoroscopic guidance for transvenous temporary cardiac pacemaker implantation during transcatheter aortic valve implantation surgeries

Background

Fluoroscopic guidance is the traditional method for the implantation of transvenous temporary cardiac pacemakers (TVTPs). This study aimed to compare the time, effectiveness, and safety of real-time three-dimensional transesophageal echocardiography (3D TEE) with those of fluoroscopy in guiding TVTP implantation.

Methods

The records of patients who underwent transcatheter aortic valve implantation (TAVI) guided by real-time 3D TEE or fluoroscopy between July 1, 2016, and June 30, 2020, were retrospectively analyzed. TVTPs were implanted by anesthesiologists via the right internal jugular vein (IJV) in the real-time 3D TEE-guided group (3D TEE group), and by interventional cardiologists via the femoral vein in the fluoroscopy-guided group (fluoro group).

Results

A total of 143 patients (3D TEE-group n=79, and fluoro group n=64) were included. No statistical differences were observed in the baseline characteristics of the two groups. TVTPs were successfully implanted in all of the patients. The needle-to-pace time was significantly shorter in 3D TEE group than in fluoro group (5.2±2.9 vs. 8.5±4.6 min, P<0.001). Further, the incidence of access complications was significantly lower in 3D TEE group than in fluoro group (3.8% vs. 12.5%, P<0.05). One patient in fluoro group who suffered cardiac perforation underwent drainage via pericardiocentesis. No patients in either group died because of TVTP placement. The total complication rates were significantly lower in 3D TEE group than in fluoro group (19.0% vs. 39.1%, P<0.05). No statistically significant differences existed between groups in terms of pacing threshold, the incidence of permanent pacemaker insertion after surgery, the length of postoperative intensive care unit (ICU) stay, or the duration of postoperative hospitalization.

Conclusions

Real-time 3D TEE-guided can be used to effectively, quickly, and safely guide TVTP implantation. The procedure can be performed by properly trained anesthesiologists. Therefore, real-time 3D TEE is a suitable option for guiding perioperative TVTP implantation in patients undergoing cardiac surgery.

Alternate recurrent coronary artery spasm and stress cardiomyopathy: a case report

Background

Coronary artery spasm (CAS) and stress cardiomyopathy (SC) have different characteristic clinical manifestations in the case of suspicious myocardial infarction with nonobstructive coronary arteries. Established recurrence rates of both conditions have been reported, however, alternate recurrent CAS and SC in the same individual have not been described.

Case presentation

A 59-year-old man suffered from atypical chest pain in the first episode, acute heart attack in the second and third episodes (totally 3 times over a period of approximately 5 years). During the first episode, he visited our hospital with mild paroxysmal chest pain without obvious inducement for approximately 2 years. He was underdiagnosed at that time without other obvious findings except the poor R wave progression in V1–3 leads revealed in electrocardiogram. At 4 months after the first episode, he suffered from a heart attack (the second episode) and was diagnosed with SC based on the coronary angiography (CAG) and left ventriculography findings of nonobstructive coronary arteries combined with a classic apical ballooning shape. At 31 months after the second episode, he suffered another heart attack (the third episode) and was diagnosed with CAS based on the CAG results of recoverable severe multivessel stenoses. During the episodes, partial reversible nature of apical hypokinesis was observed in echocardiogram. In retrospect, the patient suffered silent CAS in the first episode, SC in the second episode, and severe multivessel CAS in the third episode.

Conclusion

The unusual presentations observed in this case have not been reported. This case suggests that cardiologists should be aware of the possibility of alternate recurrent CAS and SC in the same individual. Provocative tests for spasm and cardiac magnetic resonance imaging might help gain more insights into this issue.

Prognostic Value of Cardiac Magnetic Resonance–Derived Right Ventricular Remodeling Parameters in Pulmonary Hypertension

Background

Cardiac right ventricular remodeling plays a substantial role in pathogenesis, progression, and prognosis of pulmonary hypertension. Cardiac magnetic resonance is considered an excellent tool for evaluation of right ventricle. However, value of right ventricular remodeling parameters derived from cardiac magnetic resonance in predicting adverse events is controversial.

Methods

The Pubmed (MEDLINE), Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure platform (CNKI), China Science and Technology Journal Database (VIP), and Wanfang databases were systematically searched until November 2019. Studies reporting hazard ratios (HRs) for all-cause death and composite end point of pulmonary hypertension were included. Univariate HRs were extracted from the included studies to calculate pooled HRs of each right ventricular remodeling parameter.

Results

Eight studies with 1120 patients examining all-cause death (female: 44%–92%, age: 40–67 years old, follow-up time: 27–48 months) and 10 studies with 604 patients examining composite end point (female: 60%–83%, age: 29–57 years old, follow-up time: 10–68 months) met the criteria. Right ventricular ejection fraction was the only parameter which could predict both all-cause death (pooled HR=0.95; P =0.014) and composite end point (pooled HR=0.95; P <0.001), although right ventricular end-diastolic volume index (pooled HR=1.01; P <0.001), right ventricular end-systolic volume index (pooled HR=1.01, P =0.045), and right ventricular mass index (pooled HR=1.03, P =0.032) only predicted composite outcome. Similar results were observed when we conducted the meta-analysis among patients with World Health Organization type I of pulmonary hypertension.

Conclusions

Cardiac magnetic resonance–derived right ventricular remodeling parameters have independent prognostic value for all-cause death and composite end point of patients with pulmonary hypertension. Right ventricular ejection fraction was the strongest prognostic factor among all the right ventricular remodeling parameters. Right ventricular mass index, right ventricular end-diastolic volume index, and right ventricular end-systolic volume index also demonstrated prognostic value.

Overexpression of FNTB and the activation of Ras induce hypertrophy and promote apoptosis and autophagic cell death in cardiomyocytes

Farnesyltransferase (FTase) is an important enzyme that catalyses the modification of protein isoprene downstream of the mevalonate pathway. Previous studies have shown that the tissue of the heart in the suprarenal abdominal aortic coarctation (AAC) group showed overexpression of FTaseβ (FNTB) and the activation of the downstream protein Ras was enhanced. FTase inhibitor (FTI) can alleviate myocardial fibrosis and partly improve cardiac remodelling in spontaneously hypertensive rats. However, the exact role and mechanism of FTase in myocardial hypertrophy and remodelling are not fully understood. Here, we used recombinant adenovirus to transfect neonatal rat ventricular cardiomyocytes to study the effect of FNTB overexpression on myocardial remodelling and explore potential mechanisms. The results showed that overexpression of FNTB induces neonatal rat ventricular myocyte hypertrophy and reduces the survival rate of cardiomyocytes. FNTB overexpression induced a decrease in mitochondrial membrane potential and increased apoptosis in cardiomyocytes. FNTB overexpression also promotes autophagosome formation and the accumulation of autophagy substrate protein, LC3II. Transmission electron microscopy (TEM) and mCherry‐GFP tandem fluorescent‐tagged LC3 (tfLC3) showed that FNTB overexpression can activate autophagy flux by enhancing autophagosome conversion to autophagolysosome. Overactivated autophagy flux can be blocked by bafilomycin A1. In addition, salirasib (a Ras farnesylcysteine mimetic) can alleviate the hypertrophic phenotype of cardiomyocytes and inhibit the up‐regulation of apoptosis and autophagy flux induced by FNTB overexpression. These results suggest that FTase may have a potential role in future treatment strategies to limit the adverse consequences of cardiac hypertrophy, cardiac dysfunction and heart failure.

New Insights into the Stability of Anhydrous 2H-Imidazolium Fluoride and its High Dissolution Capability toward a Strongly Hydrogen-Bonded Compound

Fluorides have been widely applied in pharmaceutical, medicinal, and materials science as well as in fine chemical manufacturing. The performance of fluorides, however, can be markedly affected by the water content. One previous study (Maiti, A.; et al. Phys. Chem. Chem. Phys. 2008, 10, 5050) suggested that anhydrous 1,3-dimethylimidazolium fluoride ([DMIm]F) was unstable since the fluoride undergoes a self-decomposition reaction. Herein we first show quantum-chemical calculation evidence that although gas-phase [DMIm]F is unstable, the bulk phase of anhydrous [DMIm]F is quite stable. We then demonstrate the successful synthesis of the anhydrous [DMIm]F compound via the reaction between 1,3-dimethylimidazolium iodide and silver fluoride. Importantly, we find that anhydrous [DMIm]F possesses a high dissolution capability toward 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), although it is known that TATB is hardly dissolved in many common organic solvents. Our Born-Oppenheimer molecular dynamics (BOMD) simulations further show that the high dissolving ability of anhydrous [DMIm]F toward TATB can be attributed to the chemical reaction between the F^- anion and the TATB molecules, which disrupts the strong hydrogen-bonding interaction among the TATB molecules. Alternatively, water molecules in hydrous [DMIm]F tend to form a hydration layer around the F^- anion, thereby preventing F^- from reacting with the TATB molecule. This result explains why TATB is barely dissolved in hydrous [DMIm]F.

Controllable Electrically Guided Nano-Al/MoO3 Energetic-Film Formation on a Semiconductor Bridge with High Reactivity and Combustion Performance

Film-forming techniques and the control of heat release in micro-energetic chips or devices create challenges and bottlenecks for the utilization of energy. In this study, promising nano-Al/MoO3 metastable intermolecular composite (MIC) chips with an uniform distribution of particles were firstly designed via a convenient and high-efficiency electrophoretic deposition (EPD) technique at room temperature and under ambient pressure conditions. The mixture of isopropanol, polyethyleneimine, and benzoic acid proved to be an optimized dispersing agent for EPD. The kinetics of EPD for oxidants (Al) and reductants (MoO3) were systematically investigated, which contributed to adjusting the equivalence ratio of targeted energetic chips after changing the EPD dynamic behaviors of Al and MoO3 in suspension. In addition, the obtained nano-Al/MoO3 MIC energetic chips showed excellent heat-release performance with a high heat release of ca. 3340 J/g, and were successfully ignited with a dazzling flame recorded by a high-speed camera. Moreover, the fabrication method here is fully compatible with a micro-electromechanical system (MEMS), which suggests promising potential in designing and developing other MIC energetic chips or devices for micro-ignition/propulsion applications.

Endothelial Scaffolding Protein ENH (Enigma Homolog Protein) Promotes PHLPP2 (Pleckstrin Homology Domain and Leucine-Rich Repeat Protein Phosphatase 2)-Mediated Dephosphorylation of AKT1 and eNOS (Endothelial NO Synthase) Promoting Vascular Remodeling

OBJECTIVE

A decrease in nitric oxide, leading to vascular smooth muscle cell proliferation, is a common pathological feature of vascular proliferative diseases. Nitric oxide synthesis by eNOS (endothelial nitric oxide synthase) is precisely regulated by protein kinases including AKT1. ENH (enigma homolog protein) is a scaffolding protein for multiple protein kinases, but whether it regulates eNOS activation and vascular remodeling remains unknown. Approach and Results: ENH was upregulated in injured mouse arteries and human atherosclerotic plaques and was associated with coronary artery disease. Neointima formation in carotid arteries, induced by ligation or wire injury, was greatly decreased in endothelium-specific ENH-knockout mice. Vascular ligation reduced AKT and eNOS phosphorylation and nitric oxide production in the endothelium of control but not ENH-knockout mice. ENH was found to interact with AKT1 and its phosphatase PHLPP2 (pleckstrin homology domain and leucine-rich repeat protein phosphatase 2). AKT and eNOS activation were prolonged in VEGF (vascular endothelial growth factor)-induced ENH- or PHLPP2-deficient endothelial cells. Inhibitors of either AKT or eNOS effectively restored ligation-induced neointima formation in ENH-knockout mice. Moreover, endothelium-specific PHLPP2-knockout mice displayed reduced ligation-induced neointima formation. Finally, PHLPP2 was increased in the endothelia of human atherosclerotic plaques and blood cells from patients with coronary artery disease.

CONCLUSIONS

ENH forms a complex with AKT1 and its phosphatase PHLPP2 to negatively regulate AKT1 activation in the artery endothelium. AKT1 deactivation, a decrease in nitric oxide generation, and subsequent neointima formation induced by vascular injury are mediated by ENH and PHLPP2. ENH and PHLPP2 are thus new proatherosclerotic factors that could be therapeutically targeted.

Opportunities for holistic waste stream valorization from food waste treatment facilities: a review

Difficult-to-biodegrade fractions (DBFs) generated from the biological treatment of food waste (FW) account for approximately 30% of the actual waste. These wastes are difficult to degrade or are considered indigestible residues of the aerobic and anaerobic fermentation treatment of FW treatment facilities. The currently applied disposal routes for DBFs exert environmental pressure and underutilize waste as resources. Therefore, these challenges must be overcome. An innovative strategy for the enhancement of the energy value and beneficial products from FW and the associated DBFs is proposed in this review. We propose conceptual future optimization routes for FW and DBFs via three types of technology integration. Pyrolysis techniques thoroughly treat DBFs to produce various value-added bio-energy products, such as pyrogenic bio-char, syngas, and bio-oil. Anaerobic digestion treats FW while utilizing pyrolysis products for robust performance enhancement and bio-methane upgrade. This holistic route offers conceptual information and proper direction as crucial knowledge for real application to harness the inherent resources of waste streams generated from FW treatment facilities.

Downregulation of Cypher induces apoptosis in cardiomyocytes via Akt/p38 MAPK signaling pathway

Background: Dilated cardiomyopathy (DCM) is considered as the most common form of non-ischemic cardiomyopathy with a high mortality worldwide. Cytoskeleton protein Cypher plays an important role in maintaining cardiac function. Genetic studies in human and animal models revealed that Cypher is involved in the development of DCM. However, the underlying molecular mechanism is not fully understood. Accumulating evidences suggest that apoptosis in myocytes may contribute to DCM. Thus, the purpose of this study is to define whether lack of Cypher in cardiomyocytes can elevate apoptosis signaling and lead to DCM eventually. Methods and Results: Cypher-siRNA sufficiently inhibited Cypher expression in cardiomyocytes. TUNEL-positive cardiomyocytes were increased in both Cypher knockdown neonatal rat cardiomyocytes and Cypher knockout mice hearts, which were rare in the control group. Flow cytometry further confirmed that downregulation of Cypher significantly increased myocytes apoptosis in vitro. Cell counting kit-8 assay revealed that Cypher knockdown in H9c2 cells significantly reduced cell viability. Cypher knockdown was found to increase cleaved caspase-3 expression and suppress p21, ratio of bcl-2 to Bax. Cypher-deficiency induced apoptosis was linked to downregulation of Akt activation and elevated p-p38 MAPK accumulation. Pharmacological activation of Akt with SC79 attenuated apoptosis with enhanced phosphorylation of Akt and reduced p-p38 MAPK and Bax expression. Conclusions: Downregulation of Cypher participates in the promotion of cardiomyocytes apoptosis through inhibiting Akt dependent pathway and enhancing p38 MAPK phosphorylation. These findings may provide a new potential therapeutic strategy for the treatment of DCM.

Theoretical investigation on the Cu(i)-catalyzed N-carboxamidation of indoles with isocyanates to form indole-1-carboxamides: effects of solvents

The solvents act as the hydrogen-bond acceptor to facilitate intermolecular addition, and then play the proton-shuttle to assist H1⁺-shift. The stronger electron-donating property of solvent is favorable for the present Cu(i)-catalyzed reactions.

A novel RNA aptamer-modified riboswitch as chemical sensor

In this study, a novel label- and immobilization-free RNA aptamer-modified riboswitch-based biosensor was developed by using RNA aptamer modified secondary-structural scaffolds to control the identity of the ribosomal binding sequence (RBS). In the developed sensor, the duplex RNA aptamers-modified cis-repressor sequence is introduced upstream to the RBS of the indicating gene (gfp gene), leading to formatting an RNA bubble due to the none-complementary state of the RNA aptamers in the hairpin structure of the cis-repressor sequence. Without the presence of the target molecule, the ribosome cannot identify the RBS of the indicating gene as the RBS is hidden by the introduced cis-repressor, consequently, the indicating gene in the sensor would not be expressed, demonstrating the absence of the target. On the contrary, with the presence of the target molecule, the binding of aptamer with the target would induce the enlargement of the RNA bubble, leading to the separation of the cis-repressor sequence and RBS. Hence, the indicating gene would be expressed, manifesting the existence of the target. In addition, the developed sensor can quantitatively report the target concentrations by measuring the gfp gene-encoded GFP (green fluorescent protein) concentration. The approach proposed in this study can be used to construct sensors for detecting various chemicals by introducing the corresponding aptamers, therefore, this strategy can potentially provide a new set of analytical tools in the field of analytical chemistry.

Electro-mechanically controlled assembly of reconfigurable 3D mesostructures and electronic devices based on dielectric elastomer platforms

The manufacture of 3D mesostructures is receiving rapidly increasing attention, because of the fundamental significance and practical applications across wide-ranging areas. The recently developed approach of buckling-guided assembly allows deterministic formation of complex 3D mesostructures in a broad set of functional materials, with feature sizes spanning nanoscale to centimeter-scale. Previous studies mostly exploited mechanically controlled assembly platforms using elastomer substrates, which limits the capabilities to achieve on-demand local assembly, and to reshape assembled mesostructures into distinct 3D configurations. This work introduces a set of design concepts and assembly strategies to utilize dielectric elastomer actuators as powerful platforms for the electro-mechanically controlled 3D assembly. Capabilities of sequential, local loading with desired strain distributions allow access to precisely tailored 3D mesostructures that can be reshaped into distinct geometries, as demonstrated by experimental and theoretical studies of ∼30 examples. A reconfigurable inductive–capacitive radio-frequency circuit consisting of morphable 3D capacitors serves as an application example.

2D Mechanical Metamaterials with Widely Tunable Unusual Modes of Thermal Expansion

Most natural materials expand uniformly in all directions upon heating. Artificial, engineered systems offer opportunities to tune thermal expansion properties in interesting ways. Previous reports exploit diverse design principles and fabrication techniques to achieve a negative or ultralow coefficient of thermal expansion, but very few demonstrate tunability over different behaviors. This work presents a collection of 2D material structures that exploit bimaterial serpentine lattices with micrometer feature sizes as the basis of a mechanical metamaterials system capable of supporting positive/negative, isotropic/anisotropic, and homogeneous/heterogeneous thermal expansion properties, with additional features in unusual shearing, bending, and gradient modes of thermal expansion. Control over the thermal expansion tensor achieved in this way provides a continuum-mechanics platform for advanced strain-field engineering, including examples of 2D metamaterials that transform into 3D surfaces upon heating. Integrated electrical and optical sources of thermal actuation provide capabilities for reversible shape reconfiguration with response times of less than 1 s, as the basis of dynamically responsive metamaterials.

Precise Cross-Dimensional Regulation of the Structure of a Photoreversible DNA Nanoswitch

In this study, an accurately and digitally regulated allosteric nanoswitch based on the conformational control of two DNA hairpins was developed. By switching between UV irradiation and blue light conditions, the second molecular beacon (H#2) would bind/separate with a repression sequence (RES) via the introduced PTG molecules (a photosensitive azobenzene derivative), resulting in the target aptamer sequence in the first molecular beacon (H#1) not being able/being able to hold the stem-loop configuration, hence losing/regaining the ability to bind with the target. Importantly, we successfully monitor conformation changes of the nanoswitch by an elegant mathematical model for connecting K_i (the dissociation constant between RES and H#2) with K_d (the overall equilibrium constant of the nanoswitch binding the target), hence realizing "observing" DNA structure across dimensions from "structural visualization" to digitization and, accurately, digitally regulating DNA structure from digitization to "structural visualization".