Ultracompact Vernier-effect-improved sensor by a single microfiber-knot resonator.

Fiber-optic sensors are an indispensable element of modern sensing technologies by virtue of their low cost, excellent electromagnetic immunity, and remote sensing capability. Optical Vernier effect is widely used to enhance sensitivity of fiber-optic sensors but requires bulky and complex cascaded interferometers. Here we propose and experimentally demonstrate an ultracompact (∼2 mm by ∼2 mm) Vernier-effect-improved sensor by only using a single microfiber-knot resonator. With the Vernier effect achieved by controlling the optical beating with the spectral ripple of a super light emitting diode (SLED), we show ∼20x sensitivity enhancement for quantitative temperature monitoring. Our sensor creates a new practical method to realize Vernier effect in fiber-optic sensors and beyond.

Distribution Pattern of Mangrove Fish Communities in China.

Mangroves are among the most productive marine and coastal ecosystems and play an important role in maintaining the stability and diversity of fish communities. To explore the structure of mangrove fish communities in China, we compiled previous studies, monographs, and two databases on 54 mangrove areas published in the past 30 years. Mangrove fish communities in China comprised Osteichthys (597 species) and Chondrichthyes (14 species), representing 611 species in 344 genera, 117 families, and 28 orders. Perciformes were the predominant taxon, with 350 species in 52 families, accounting for 57% of the total species richness. Reef fish accounted for 29.62%. With regard to feeding groups, there were 328 carnivorous species (53.68%), 214 omnivorous species (35.02%), 41 herbivorous species (6.71%), and 28 detritivores species (4.58%). Classified by body size, 57.61% were small-sized, 24.22% medium-sized, and 18.17% were large-sized fishes. A total of 5.23% (32 species) of these mangrove fish are currently on IUCN red lists, i.e., 2 species are critically endangered, 4 are endangered, 12 are vulnerable, and 14 are near threatened. Cluster analyses shows that Chinese mangroves fish were divided into two categories, i.e., coastal mangrove and island mangrove type. This is closely related to the distribution of reef fish. Moreover, the number of fish species showed a strong positive correlation with mangrove area, but not with latitude. The main reasons may be the subtropical and tropical geographic locations, as well as the characteristics of the South China Sea and the Taiwan Warm Current. The size and integrity of mangrove area are crucial to the local ecosystems; thus, protecting and restoring mangroves is of great significance to large-scale ecosystem-stability and local biodiversity.

Studying the Role of a Single Mutation of a Family 11 Glycoside Hydrolase Using High-Resolution X-ray Crystallography.

XynII is a family 11 glycoside hydrolase that uses the retaining mechanism for catalysis. In the active site, E177 works as the acid/base and E86 works as the nucleophile. Mutating an uncharged residue (N44) to an acidic residue (D) near E177 decreases the enzyme's optimal pH by ~ 1.0 unit. D44 was previously suggested to be a second proton carrier for catalysis. To test this hypothesis, we abolished the activity of E177 by mutating it to be Q, and mutated N44 to be D or E. These double mutants have dramatically decreased activities. Our high-resolution crystallographic structures and the microscopic pKa calculations show that D44 has similar position and pKa value during catalysis, indicating that D44 changes electrostatics around E177, which makes it prone to rotate as the acid/base in acidic conditions, thus decreases the pH optimum. Our results could be helpful to design enzymes with different pH optimum.

Functionalized Carbon Nanotube-Embedded Poly(vinyl alcohol) Microspheres for Efficient Removal of Tumor Necrosis Factor-α.

Tumor necrosis factor (TNF)-α has an important role in the pathogenesis of autoimmune and inflammatory diseases such as rheumatoid and septic arthritis. Removal of excess tumor necrosis factor-α (TNF-α) is a promising treatment. In this study, a series of functionalized carbon nanotube-embedded poly(vinyl alcohol) (PVA) nanocomposite adsorbents were prepared for TNF-α removal for the first time. The resulting nanocomposites were characterized by scanning electron microscopy and Raman spectroscopy, which demonstrated that carbon nanotubes were well-dispersed on the surface of PVA macroporous microspheres. Adsorption tests showed that the carboxylated carbon nanotube-embedded composite microspheres (PVA/MWCNTs-COOH) possessed much better adsorption capacity for TNF-α in both simulated serum solution and rat plasma compared to the aminated (PVA/MWCNTs-NH2) and raw carbon nanotube-embedded microspheres (PVA/MWCNTs-raw). In addition, the effects on hemolytic activity, the anticoagulant property, and the components of blood were negligible, indicating the excellent blood compatibility of composite beads. Our findings suggest that the carboxylated carbon nanotube-embedded composite microspheres may be potentially useful for the treatment of autoimmune and inflammatory diseases by removing TNF-α from the blood.

Bead-type polystyrene/nano-CaCO3 (PS/nCaCO3) composite: a high-performance adsorbent for the removal of interleukin-6.

A novel nano-CaCO3 (nCaCO3) particle composite-derived polystyrene (PS) resin was successfully synthesized by a suspension polymerization method. The nCaCO3 reinforced PS material (PS/nCaCO3) possessed a structure with abundant mesopores of high porosity, high specific surface area (828.3 m2 g-1) and large pore volume (1.83 cm3 g-1). It was revealed that the incorporation of nCaCO3 into the PS matrix enhanced both the mechanical strength which can prevent the fragmentation and its adsorption capacity for interleukin-6 (IL-6, MW = 24.0 kDa) from human plasma. The adsorption isotherm could be described by the Langmuir model and classified as S-3 type, showing an IL-6 uptake of up to 25.6 ng g-1 at an equilibrium concentration of about 500 ng L-1. The adsorption capacity for IL-6 of PS/nCaCO3 is not only significantly higher than that of PS (without nCaCO3), but also superior to those of currently available adsorbents that are under clinical studies (e.g., CytoSorb™ towards cytokines). In addition, the PS/nCaCO3 adsorbent also had good hemocompatibility and showed no leakage of nCaCO3 in the plasma in a flowing model system. Therefore, the synthesized PS/nCaCO3 nano-composite has a great potential to be used as an efficient adsorbent for the removal of interleukin-6 (IL-6) from blood of inflammatory and auto-immune disease patients through hemoperfusion.

Preparation of nano-CaCO3/polystyrene nanocomposite beads for efficient bilirubin removal.

A novel nano-CaCO3/polystyrene nanocomposite adsorbent (NPS-8) was synthesized for efficient bilirubin removal from human plasma. A comparison with the polystyrene adsorbent (PS-8), which was without the incorporation of nano-CaCO3, revealed that NPS-8 had superior bilirubin adsorption capacity and mechanical strength. The resulting nano-CaCO3 reinforced PS-8 (NPS-8) was tested by transmission electron microscopy (TEM), scanning electron microscopy (SEM), mechanical strength test, and bilirubin adsorption assays. The adsorption results indicated that NPS-8 displayed better adsorption capacity for bilirubin (91%) than that of PS-8 (75.88%). The mechanical strength of NPS-8 was significantly greater than that of PS-8. In addition, both PS-8 and NPS-8 possessed good blood compatibility properties (a negligible hemolytic activity and platelet adhesion). Therefore, a conclusion could be drawn that NPS-8 has a high potential as an efficient bilirubin adsorbent for blood purification in clinical practice. At the same time, the success of organic-inorganic nanocomposite adsorbents might provide a new insight into the improvement of adsorbents in hemoperfusion.

High performance of a unique mesoporous polystyrene-based adsorbent for blood purification.

A multi-functional polystyrene based adsorbent (NKU-9) with a unique mesoporous and a high surface area was prepared by suspension polymerization for removal of therapeutic toxins in blood purification. The adsorbent produced had an almost equal amount of mesopore distribution in the range from 2 to 50 nm. The adsorption of serum toxins with different molecular weights were examined by in vitro adsorption assays and compared with some clinical currently used adsorbents such as HA-330, Cytosorb and BL-300 which are produced by China, America and Japan, respectively. Test results indicated that the adsorption rate for pentobarbital by NKU-9 was 81.24% which is nearly as high as HA-330 (81.44%). The latter adsorbent is currently used for acute detoxification treatment in China. To reach adsorption equilibrium, NKU-9 was faster than HA-330, which implies short treatment time. For the removal of middle molecular toxins such as ß2-microglobulin (98.88%), NKU-9 performed better adsorptive selectivity than Cytosorb (92.80%). In addition, NKU-9 showed high performance for the removal of albumin-bound toxins (e.g., bilirubin), and its adsorption rate for total bilirubin (80.79%) in plasma was 8.4% higher than that of anion exchange resin BL-300 which is currently used to eliminate bilirubin in clinic. Therefore, our results indicate that the newly developed adsorbent with a wide distribution and almost equal amount of mesopores is a multifunctional adsorbent for high efficient removal of serum toxins with different molecular weights which might be an excellent blood purification adsorbent especially to treat diseases that conventional medical methods are low or not efficient.

Wagging motion of hydrogen-bonded wire in the excited-state multiple proton transfer process of 7-hydroxyquinoline·(NH3)3 cluster.

In this work, the dynamics of hydrogen bonds (as well as the hydrogen-bonded wire) in excited-state tautomerization of 7-hydroxyquinoline·(NH3)3 (7HQ·(NH3)3) cluster has been investigated by using time-dependent density functional theory (TDDFT). It shows that upon an excitation, the hydrogen bond between -OH group in 7-hydroxyquinoline (7HQ) and NH3 moiety would extremely strengthened in S1 state, which could effectively facilitate the releasing of the proton from the phenolic group of 7HQ moiety to the hydrogen-bonded wire and the forming an Eigen-like cationic wire (NH3···NH4(+)···NH3) in the cluster. To fulfill the different optimal angles of NH4(+) in the wire, a wagging motion of hydrogen-bonded wire would occur in excited state. Moreover, the wagging motion of the hydrogen-bonded wire would effectively promote excited-state proton transfer reaction. As the results, an excited-state multiple proton transfer (ESMPT) mechanism containing two concerted and asymmetrical processes has been proposed for the proton transfer dynamics of 7HQ·(NH3)3 cluster.