High-level expression and characterization of a new κ-carrageenase from marine bacterium Pedobacter hainanensis NJ-02

A novel κ-carrageenase gene (CgkB) has been cloned from Pedobacter hainanensis NJ-02 and expressed heterologously in Escherichia coli BL21 (DE3). It consisted of 1935 bp and encoded 644 amino acid residues with a molecular weight of 71·61 kDa. The recombinant enzyme showed maximal activity of 2458 U mg^-1 at 40°C and pH 8·0. Additionally, it could retain more than 70% of its maximal activity after being incubated at pH of 5·5-10·0 below 40°C. K⁺ and a broad range of NaCl can activate the enzyme. The K_m and V_max of CgkB was 2·4 mg ml^-1 and 126 mmol mg^-1  min^-1 . The ESI-MS analysis of hydrolysates indicated that the enzyme can endolytically depolymerize the carrageenan into tetrasaccharides and hexasaccharides. The results indicated that the enzyme with high activity could be a valuable enzyme tool to produce carrageenan oligosaccharides with various activities.

SIGNIFICANCE AND IMPACT OF THE STUDY

Enzymatic preparation of carrageenan oligosaccharides has drawn increased attention due to their various physiological activities. It is urgent to explore enzyme tools with higher activity and better stability. In this work, a novel κ-carrageenase was identified and characterized from marine bacterium Pedobacter hainanensis NJ-02. The enzyme with high activity could be a valuable tool to produce carrageenan oligosaccharides with various activities.

Novel MBTPS2 missense mutation causes a keratosis follicularis spinulosa decalvans phenotype: mutation update and review of the literature

Keratosis follicularis spinulosa decalvans (KFSD) is an X-linked condition characterized by keratotic follicular papules and progressive alopecia, which is caused by mutations in the MBTPS2 gene. We carried out a genetic study on a child who was suspected clinically to have KFSD. Sanger sequencing was performed to detect mutations in the entire coding region of MBTPS2. A novel missense mutation (c.599C>T) was identified in the patient, confirming a diagnosis of KFSD. We reviewed related cases with MBTPS2 mutations for evidence of genotype-phenotype correlations.

A One-Step Rapid Assembly of Thin Film Coating Using Green Coordination Complexes for Enhanced Removal of Trace Organic Contaminants by Membranes

We report a fast, simple, and green coating method using the coordination complex of tannic acid (TA) and ferric ion (Fe³⁺) to enhance the removal of trace organic contaminants (TrOCs) by polyamide membranes. The entire coating process can be completed in less than 2 min; quartz crystal microbalance characterization revealed that a TA-Fe thin film formed in merely 10-20 s. Coating this TA-Fe thin film on a commercial nanofiltration membrane (NF270) reduced its effective pore size from 0.44 to 0.40 nm. The TA-Fe-coated NF270 showed significantly increased rejection of both NaCl and trace organic contaminants. In comparison with the more-time-consuming polydopamine coating (e.g., 0.5 h), the TA-Fe coating presented greater resistance to TrOC permeation (i.e., lower permeability of TrOCs). The advantages of the fast coating process, greatly improved rejection performance, and use of green accessible materials make TA-Fe a highly promising coating material for large-scale applications.

Gestational diabetes care and outcomes for refugee women: a population-based cohort study

AIM

To determine the prevalence of adverse clinical outcomes, the rates of healthcare utilization, and the incidence of post-partum Type 2 diabetes in refugees with gestational diabetes (GDM), compared with other immigrants and non-immigrants.

METHODS

A population-based cohort study was conducted using healthcare databases in Ontario, Canada. Over 40 000 women with GDM having singleton live births between 2002 and 2014 were identified. We identified GDM adverse outcomes such as macrosomia, pre-eclampsia and respiratory distress syndrome. Antenatal and newborn healthcare utilization were ascertained. Women were then followed for diagnosis of diabetes post-partum.

RESULTS

Both refugees and other immigrants had a lower rate than non-immigrants of many adverse GDM outcomes, including pre-eclampsia [relative risk (RR) 0.65, 95% confidence interval (95% CI) 0.44-0.95 and 0.61, 95% CI 0.52-0.72, respectively], preterm birth (RR 0.87, 95% CI 0.75-0.995 and 0.85, 95% CI 0.80-0.91, respectively), and respiratory distress syndrome (RR 0.83, 95% CI 0.70-0.97 and 0.78, 95% CI 0.72-0.84, respectively). However, refugees were less likely to attend well-baby care in time for the first routine vaccination (RR 0.92, 95% CI 0.88-0.95). Incidence of post-partum diabetes was high in all groups, but refugee women were at increased risk (hazard ratio 1.23, 95% CI 1.11-1.37).

CONCLUSIONS

Despite different circumstances leading to migration, refugees have a similar 'healthy immigrant effect' to other immigrants, with respect to adverse GDM outcomes. However, newborns of refugees were less likely to have well-baby care, and refugee women were also at especially high risk of developing diabetes post-partum. These are both important public health issues.

Simultaneous Remote Observations of Intense Reconnection Effects by DMSP and MMS Spacecraft During a Storm Time Substorm

During a magnetic storm on 23 June 2015, several very intense substorms took place, with signatures observed by multiple spacecraft including DMSP and Magnetospheric Multiscale (MMS). At the time of interest, DMSP F18 crossed inbound through a poleward expanding auroral bulge boundary at 23.5 h magnetic local time (MLT), while MMS was located duskward of 22 h MLT during an inward crossing of the expanding plasma sheet boundary. The two spacecraft observed a consistent set of signatures as they simultaneously crossed the reconnection separatrix layer during this very intense reconnection event. These include (1) energy dispersion of the energetic ions and electrons traveling earthward, accompanied with high electron energies in the vicinity of the separatrix; (2) energy dispersion of polar rain electrons, with a high-energy cutoff; and (3) intense inward convection of the magnetic field lines at the MMS location. The high temporal resolution measurements by MMS provide unprecedented observations of the outermost electron boundary layer. We discuss the relevance of the energy dispersion of the electrons, and their pitch angle distribution, to the spatial and temporal evolution of the boundary layer. The results indicate that the underlying magnetotail magnetic reconnection process was an intrinsically impulsive and the active X-line was located relatively close to the Earth, approximately at 16-18 R_E.

Updated review of genetic reticulate pigmentary disorders

Reticulate pigmentary disorders are a group of disorders characterized by hyper- and/or hypopigmented macules with varying sizes and amounts of pigment. Some of the disorders are heritable, such as Dowling-Degos disease, dyschromatosis universalis hereditaria, dyschromatosis symmetrica hereditaria, reticulate acropigmentation of Kitamura and X-linked reticulate pigmentary disorder. Although each condition possesses unique phenotypic characteristics and the prognosis for each is somewhat different, there is a large degree of overlap between the disorders and therefore they are difficult to differentiate in the clinical setting. This updated review provides a clinical and molecular delineation of these genetic reticulate pigmentary disorders and aims to establish a concise diagnostic strategy to allow clinical dermatologists to make an accurate diagnosis, as well as to provide useful information for clinical and genetic counselling.

A highly selective surface coating for enhanced membrane rejection of endocrine disrupting compounds: Mechanistic insights and implications

We designed a highly selective surface coating to achieve enhanced rejection of endocrine disrupting compounds (EDCs) by nanofiltration membranes. A commercial NF90 membrane was first coated with polydopamine (PDA) followed by in situ immobilization of silver nanoparticles (AgNPs). This PDA/AgNPs coating greatly improved EDC rejection at the expense of slight water permeability loss (4-10%). This improvement in rejection can be attributed to a combination of enhanced size exclusion and suppressed hydrophobic interaction. A resistance-in-series analysis further reveals that the coating was highly permeable to water but highly resistant to EDCs, leading to an EDC selectivity that was an order of magnitude greater than those of the bare PDA coating and the base membrane NF90. The current study provides important insights into the design of highly selective coatings for effective retention of targeted trace organic contaminants.

Enhanced polarization-sensitive terahertz emission from vertically grown graphene by a dynamical photon drag effect

Improving terahertz (THz) emission from graphene is a challenge for graphene-based THz photonics as graphene demonstrates a weak light-matter interaction. With a unique ultra-black surface structure, vertically grown graphene (VGG) is proposed to enhance the light-matter interaction and further enhance THz emission. Herein, enhanced THz radiation is observed by THz time-domain emission spectroscopy from VGG compared with single-layer graphene. The radiated THz amplitude shows a linear dependence on pump power, which demonstrates a second order nonlinear effect. Considering the symmetry of VGG on a substrate, we can exclude the optical rectification effect and photogalvanic effect (PGE) by the D_6h point group with centrosymmetry. Thus we analyze the transient photocurrent related to THz emission only by the photon drag effect (PDE). The polarization-sensitive THz radiation signals are wave-vector reliant and demonstrate cos 2φ and sin 2φ dependence on the polarization angles of the pump laser. This is consistent with the theoretical analysis of PDE. Our results show the enhanced, ultrafast, broadband THz radiation property of VGG, which paves the way for high performance THz emitters and THz detectors based on graphene materials.

Research on Optimizing Parameters of Thermal Bonding Technique for PMMA Microfluidic Chip

The thermal bonding method is an advanced processing technology, which can bond a variety of polymer sheets on request. This work aims to analyze the effect of applied loading, heating temperature and duration on the depth loss of the PMMA microfluidic chip after bonding. Several experiments were designed by us and the results were analyzed by orthogonal experimental method. Finally optimal applied loading, heating temperature and duration were obtained and in the optimal case, the bonded microfluidic chip has small depth loss and enough strength.

Skin involvement as the first symptom of rapidly progressive ALK-positive systemic anaplastic large cell lymphoma

Systemic anaplastic large cell lymphomas (sALCLs) comprise a heterogeneous group of relatively rare T-cell non-Hodgkin lymphomas that are characterized by CD30 expression. Anaplastic lymphoma kinase (ALK)-positive ALCL is a type of sALCL that commonly involves lymph nodes and extranodal sites. Skin involvement usually presents as tumours, nodules and ulcers. We describe an unusual case of ALK-positive ALCL in an 11-year-old Chinese boy, who initially presented with skin eruption with rapid progression and poor prognosis. This case emphasizes the value of clinical factors to predict the prognosis of ALK-positive sALCL, and we recommend close collaboration between dermatologists, pathologists and haematologists/oncologists to assure the correct diagnosis and treatment.

Transition and post-transition metal ions in borate glasses: Borate ligand speciation, cluster formation, and their effect on glass transition and mechanical properties

A series of transition and post-transition metal ion (Mn, Cu, Zn, Pb, Bi) binary borate glasses was studied with special consideration of the cations impact on the borate structure, the cations cross-linking capacity, and more generally, structure-property correlations. Infrared (IR) and Raman spectroscopies were used for the structural characterization. These complementary techniques are sensitive to the short-range order as in the differentiation of tetrahedral and trigonal borate units or regarding the number of non-bridging oxygen ions per unit. Moreover, vibrational spectroscopy is also sensitive to the intermediate-range order and to the presence of superstructural units, such as rings and chains, or the combination of rings. In order to clarify band assignments for the various borate entities, examples are given from pure vitreous B₂O₃ to meta-, pyro-, ortho-, and even overmodified borate glass compositions. For binary metaborate glasses, the impact of the modifier cation on the borate speciation is shown. High field strength cations such as Zn²⁺ enhance the disproportionation of metaborate to polyborate and pyroborate units. Pb²⁺ and Bi³⁺ induce cluster formation, resulting in PbO_n- and BiO_n-pseudophases. Both lead and bismuth borate glasses show also a tendency to stabilize very large superstructural units in the form of diborate polyanions. Far-IR spectra reflect on the bonding states of modifier cations in glasses. The frequency of the measured cation-site vibration band was used to obtain the average force constant for the metal-oxygen bonding, F_M-O. A linear correlation between glass transition temperature (T_g) and F_M-O was shown for the metaborate glass series. The mechanical properties of the glasses also correlate with the force constant F_M-O, though for cations of similar force constant the fraction of tetrahedral borate units (N₄) strongly affects the thermal and mechanical properties. For paramagnetic Cu- and Mn-borate glasses, N₄ was determined from the IR spectra after deducing the relative absorption coefficient of boron tetrahedral versus boron trigonal units, α = α₄/α₃, using NMR literature data of the diamagnetic glasses.