Inducing and Switching the Handedness of Polyacetylenes with Topologically Chiral [2]Catenane Pendants.

To explore the chirality induction and switching of topological chirality, poly[2]catenanes composed of helical poly(phenylacetylenes) (PPAs) main chain and topologically chiral [2]catenane pendants are described for the first time. These poly[2]catenanes with optically active [2]catenanes on side chains were synthesized by polymerization of enantiomerically pure topologically chiral [2]catenanes with ethynyl polymerization site and/or point chiral moiety. The chirality information of [2]catenane pendants was successfully transferred to the main chain of polyene backbones, leading to preferred-handed helical conformations, while the introduction of point chiral units has negligible effect on the overall helices. More interestingly, attributed to unique dynamic feature of the [2]catenane pendants, these polymers revealed dynamic response behaviors to solvents, temperature, and sodium ions, resulting in the fully reversible switching on/off of the chirality induction. This work provides not only new design strategy for novel chiroptical switches with topologically chiral molecules but also novel platforms for the development of smart chiral materials.

Correlation between differences in intraoperative jumping gaps and soft tissue changes around immediate implant placement and provisionalization in the maxillary anterior region.

OBJECTIVES: This study aims to evaluate the correlation between differences in intraoperative jumping gaps and soft tissue changes around immediate implant placement and provisionalization (IIPP) in the maxillary anterior region. Results will provide a basis for clinical evaluation of the change trend and long-term stability of the labial soft tissue contours of patients with different jumping gaps. METHODS: Thirty-two patients with single tooth loss in the maxillary aesthetic area were enrolled, and they all received immediate implant placement and restoration. All patients were divided into three groups: A, B, and C according to the size of the jumping gap, group A: horizontal defect dimension (HDD) ≤2 mm; group B: 2 mm3 mm. Geomagic studio 2013 was used to quantitatively analyze the contour volume of the soft tissue around the implant and the level of the labial gingival margin. The pink esthetic score (PSE) was used for the final aesthetic evaluation. RESULTS: All implants had osseointegration within 6 months after the surgery. The average thickness of soft tissue contour volume changed by 0.62 mm±0.15 mm, and the average PES was 11.09±0.99. The changes in the gingival mucosa levels in the three groups at 6 months after operation were 0.45 mm±0.11 mm, 0.40 mm±0.12 mm, and 0.35 mm± 0.11 mm, respectively. The changes in the average thickness of the soft tissue contour volume in the three groups at 6 months after the operation were 0.77 mm±0.16 mm, 0.63 mm±0.17 mm, and 0.54 mm±0.11 mm. A moderate negative correlation was found between the jumping gap size and the gingival mucosa level, and the average thickness changed. No significant correlation was found between size of jumping gap and PES. CONCLUSIONS: Although the contour volume of the labial soft tissue continuously decreased within 6 months after IIPP in the maxillary anterior region, the surgical procedure can achieve a satisfactory aesthetic effect, and the level of soft tissue around the implant can be well maintained.

Associations of Urinary Phytoestrogen Concentrations with Nonalcoholic Fatty Liver Disease among Adults.

Phytoestrogens can alleviate some pathological processes related to nonalcoholic fatty liver disease (NAFLD). However, there are limited and contradictory studies on the relationships between phytoestrogens (especially single phytoestrogen) and NAFLD. The purpose of this study was to explore the relationships between urinary phytoestrogen concentrations and NAFLD in American adults. This cross-sectional study used the data of the National Health and Nutrition Examination Survey from 1999 to 2010, and 2294 adults were finally enrolled in this study. The concentrations of phytoestrogens were measured in urine samples, and urinary phytoestrogens were divided into tertiles according to the concentration distributions. The diagnosis of NAFLD was determined by the United States fatty liver index. The main analysis used a multivariate logistic regression model. The fully adjusted models included gender, age, race, education, marriage, poverty, body mass index, waist circumference, smoking, diabetes, hypertension, total cholesterol, high-density lipoprotein cholesterol, triglycerides, and other five phytoestrogens. In the fully adjusted model, the urinary enterolactone (ENL) concentration was negatively correlated with NAFLD (OR of Tertile 3 : 0.48, 95% CI 0.25-0.94). When stratified by age and gender, the urinary ENL concentration was negatively correlated with NAFLD in males aged 40-59 years (OR of Tertile 3 : 0.08, 95% CI 0.01-0.82), while the urinary equol concentration was positively correlated with NAFLD in such population (OR of Tertile 3 : 4.27, 95% CI 1.02-17.85). In addition, a negative correlation between enterodiol (END) concentration and NAFLD was observed in males aged 60 years or over (OR of Tertile 2 : 0.18, 95% CI 0.05-0.69). Collectively, in middle-aged males, urinary ENL may be associated with a lower risk of NAFLD, while urinary equol may be related to a higher risk. In addition, urinary END has a possible relationship with a reduced risk of NAFLD in elder males. Definitely, clinical randomized controlled trials are needed to further verify the conclusions.

Highly Sensitive Strain Sensors Based on Molecules-Gold Nanoparticles Networks for High-Resolution Human Pulse Analysis.

High-performance flexible strain sensors are key components for the next generation of wearable health monitoring devices. Here, the authors have fabricated a novel strain sensor based on gold nanoparticles (AuNPs) interconnected by flexible and responsive molecular linkers. The combination of conductive AuNPs (25 nm in diameter) with tetra(ethylene glycol) dithiol (SH-TEG-SH) linkers yields a covalent 3D network which can be directly deposited onto prepatterned flexible supports exposing interdigitated Au electrodes. The electrically insulating nature of the linkers effectively defines the tunneling modulated charge transfer through the AuNPs network. When compressive/tensile strain is applied, the molecular linkers adopt a compressed/stretched conformation thus decreasing/increasing the interparticle distance, ultimately yielding an exponential increase/decrease of the tunneling current when voltage is applied. The strain sensor displays state-of-the-art performances including a highly sensitive response to both tensile and compressive strain, as quantified by a high gauge factor (GF≈126) combined with other superior sensing properties like high flexibility, short response time (16.1 ms), and good robustness (>2000 cycles). Finally, the applicability of the device for health monitoring is demonstrated: high-resolution artery pulse waves are acquired by placing the strain sensor onto the skin allowing the extraction of important physical parameters for human-health assessment.

Designing of CuS growing on Bi2WO6 nanosheet heterostructures based on a photoelectrochemical aptasensor for detecting ofloxacin.

Bi2WO6 (BW) was compounded with different contents of copper sulfide (CuS) by a two-step procedure. The chemical composition and morphology of the materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results of photoelectrochemical (PEC) tests showed that CuS can improve the PEC performance of semiconductor materials and it has the best performance when the CuS mass fraction is 5%. Therefore, CuS/BW-5% nanocomposite has been constructed as ofloxacin (OFL) drug PEC aptasensors by binding of aptamer receptors. The PEC aptasensor based on CuS/BW-5% has a linear relationship for OFL of 1-12,000 nM and a determination limit of 0.35 nM. Since the photoelectron potential generated by CuS/BW-5% heterojunction reduces the combination of photogenerated electrons and holes CuS/BW-5% has a better photoelectrocatalytic performance. Graphical abstract Schematic presentation of a photoelectrochemical aptasensor based on CuS/Bi2WO6 for the determination of OFL.

Molecular Springs: Integration of Complex Dynamic Architectures into Functional Devices.

Molecular/supramolecular springs are artificial nanoscale objects possessing well-defined structures and tunable physicochemical properties. Like a macroscopic spring, supramolecular springs are capable of switching their nanoscale conformation as a response to external stimuli by undergoing mechanical spring-like motions. This dynamic action offers intriguing opportunities for engineering molecular nanomachines by translating the stimuli-responsive nanoscopic motions into macroscopic work. These nanoscopic objects are reversible dynamic multifunctional architectures which can express a variety of novel properties and behave as adaptive nanoscopic systems. In this Minireview, we focus on the design and structure-property relationships of supramolecular springs and their (self-)assembly as a prerequisite towards the generation of novel dynamic materials featuring controlled movements to be readily integrated into macroscopic devices for applications in sensing, robotics, and the internet of things.

Molecule-Graphene Hybrid Materials with Tunable Mechanoresponse: Highly Sensitive Pressure Sensors for Health Monitoring.

The development of pressure sensors is crucial for the implementation of electronic skins and for health monitoring integrated into novel wearable devices. Tremendous effort is devoted toward improving their sensitivity, e.g., by employing microstructured electrodes or active materials through cumbersome processes. Here, a radically new type of piezoresistive pressure sensor based on a millefeuille-like architecture of reduced graphene oxide (rGO) intercalated by covalently tethered molecular pillars holding on-demand mechanical properties are fabricated. By applying a tiny pressure to the multilayer structure, the electron tunnelling ruling the charge transport between successive rGO sheets yields a colossal decrease in the material's electrical resistance. Significantly, the intrinsic rigidity of the molecular pillars employed enables the fine-tuning of the sensor's sensitivity, reaching sensitivities as high as 0.82 kPa-1 in the low pressure region (0-0.6 kPa), with short response times (≈24 ms) and detection limit (7 Pa). The pressure sensors enable efficient heartbeat monitoring and can be easily transformed into a matrix capable of providing a 3D map of the pressure exerted by different objects.

Real-Time Monitoring the Dynamics of Coordination-Driven Self-Assembly by Fluorescence-Resonance Energy Transfer.

It is quite challenging to investigate the dynamics of coordination-driven self-assembly due to the existence of multiple intermediates and many possible processes. By taking advantage of the high sensitivity and efficiency of fluorescence-resonance energy transfer (FRET), FRET was successfully employed to real-time monitor the dynamic behavior of coordination-driven self-assembly. The Förster energy transfer efficiencies and kinetic aspects of a series of discrete, well-defined metallacycles have been determined. Moreover, the dynamic characteristics of these supramolecular assemblies, such as the dynamic ligand exchange, anion-induced disassembly and reassembly, and stability in different solvents, have been investigated by using FRET.

A naphthalimide-based fluorescent probe for highly selective detection of histidine in aqueous solution and its application in in vivo imaging.

A naphthalimide-based fluorescent ensemble probe NPC for selectively detecting His in aqueous solution (10 mM HEPES, pH 7.4) has been reported. Moreover, the application of NPC in in vivo (both in Hela cells and in C. elegans) fluorescence imaging was carried out as well.

A naphthalimide-based fluorescence "turn-on" probe for the detection of Pb(2+) in aqueous solution and living cells.

An easily available naphthalimide-based fluorescent probe NPA for Pb(2+) detection was successfully developed. NPA exhibited an obvious fluorescence turn-on response toward Pb(2+) in aqueous solution and in living cells. Moreover, a series of model compounds were rationally designed and synthesized in order to explore the sensing mechanism and binding mode of NPA with Pb(2+) .

A naphthalimide-based bifunctional fluorescent probe for the differential detection of Hg²âº and Cu²âº in aqueous solution.

A novel fluorescent probe NPM based on naphthalimide was designed and synthesized. Interestingly, NPM exhibited highly selective fluorescence turn-on for Hg(2+) and turn-off for Cu(2+) in aqueous solution (10 mM HEPES, pH 7.5). Its fluorescence intensity enhanced in a linear fashion with the concentration of Hg(2+) and decreased in a nearly linear fashion with the concentration of Cu(2+). Thus NPM could be potentially used for the quantification of Hg(2+) and Cu(2+) in aqueous solution. A series of model compounds were rationally designed and synthesized in order to explore the sensing mechanisms and binding modes of NPM with Hg(2+) and Cu(2+).