Responses of Defect-Rich Zr-Based Metal-Organic Frameworks toward NH3 Adsorption.

Understanding structural responses of metal-organic frameworks (MOFs) to external stimuli such as the inclusion of guest molecules and temperature/pressure has gained increasing attention in many applications, for example, manipulation and manifesto smart materials for gas storage, energy storage, controlled drug delivery, tunable mechanical properties, and molecular sensing, to name but a few. Herein, neutron and synchrotron diffractions along with Rietveld refinement and density functional theory calculations have been used to elucidate the responsive adsorption behaviors of defect-rich Zr-based MOFs upon the progressive incorporation of ammonia (NH3) and variable temperature. UiO-67 and UiO-bpydc containing biphenyl dicarboxylate and bipyridine dicarboxylate linkers, respectively, were selected, and the results establish the paramount influence of the functional linkers on their NH3 affinity, which leads to stimulus-tailoring properties such as gate-controlled porosity by dynamic linker flipping, disorder, and structural rigidity. Despite their structural similarities, we show for the first time the dramatic alteration of NH3 adsorption profiles when the phenyl groups are replaced by the bipyridine in the organic linker. These molecular controls stem from controlling the degree of H-bonding networks/distortions between the bipyridine scaffold and the adsorbed NH3 without significant change in pore volume and unit cell parameters. Temperature-dependent neutron diffraction also reveals the NH3-induced rotational motions of the organic linkers. We also demonstrate that the degree of structural flexibility of the functional linkers can critically be affected by the type and quantity of the small guest molecules. This strikes a delicate control in material properties at the molecular level.

Paediatric glaucoma in Hong Kong: a multicentre retrospective analysis of epidemiology, presentation, clinical interventions, and outcomes.

PURPOSE: To document the epidemiology, presentation, clinical interventions, and outcomes of paediatric glaucoma in Hong Kong. METHODS: This multicentre territory-wide retrospective study was performed by reviewing charts of patients with paediatric glaucoma in six clusters of the Hong Kong Hospital Authority and The Chinese University of Hong Kong from 2006 to 2015. RESULTS: This study included 150 eyes of 98 patients with paediatric glaucoma (presenting age: 5.2±5.7 years). Of them, 35 eyes (23.3%) had primary congenital glaucoma, 22 eyes (14.7%) had juvenile open-angle glaucoma, and 93 eyes (62.0%) had secondary glaucoma. The most prevalent types of secondary glaucoma were lens-related after cataract extraction (18.0%), Axenfeld-Rieger anomaly (5.3%), uveitis (5.3%), Sturge-Weber syndrome (4.7%), and traumatic (3.3%). The most common clinical presentations were parental concerns (20.7%) including cloudy cornea (12.7%) and tearing/photophobia (8.0%), followed by poor visual acuity (18.0%), high intraocular pressure (13.3%), and strabismus (6.0%). The follow-up duration was 8.46±6.51 years. Furthermore, 63.2% of eyes with primary glaucoma and 45.2% of eyes with secondary glaucoma were treated surgically. The final visual acuity was 0.90±0.98 LogMAR; intraocular pressure was 18.4±6.6 mm Hg; and number of glaucoma medications was 2.22±1.61. CONCLUSION: Primary congenital glaucoma was most prevalent, followed by juvenile open-angle glaucoma and aphakic glaucoma. Most eyes with primary glaucoma required surgical treatment. Parental concerns were important clinical presentations. Basic assessments by healthcare providers to identify glaucoma signs (eg, poor visual acuity, high intraocular pressure, and strabismus) warranted prompt referral to an ophthalmologist.

A qualitative study exploring factors influencing clinical decision-making for influenza-like illness in Solapur city, Maharashtra, India.

The co-existence of different types of medical systems (medical pluralism) is a typical feature of India's healthcare system. For conditions such as influenza-like illness (ILI), where non-specific disease signs/symptoms exist, clinical reasoning in the context of medical pluralism becomes crucial. Recognising this need, we undertook a qualitative study, which explored factors underpinning clinical decisions on diagnosis and management of ILI. The study involved semi-structured interviews including clinical vignettes with 20 healthcare practitioners (working within allopathy, homeopathy and Ayurveda) working in the private healthcare sector in Solapur city, India. An inquiry was conducted into criteria influencing the diagnosis, treatment, referral to specialist care and role of treatment guidelines for ILI. Thematic analysis was used to identify aspects relating to ILI diagnosis, treatment and referral. The diagnosis of influenza was based largely on clinical symptoms suggestive of influenza in the absence of other diagnoses. Referral for laboratory tests was only initiated if illness did not resolve, generally after 2-3 consultations. Antibiotics were often prescribed for persistent illness, with antivirals rarely considered. Some differences between practitioners from different medical systems were observed in relation to treatment and referral in case of persistent illness. A combination of analytical and intuitive clinical reasoning was used by the participants and clinical decisions were based on both social and clinical factors. Clinical decision-making was rarely a linear process and respondents felt that broad guidelines on influenza that allowed doctors to account for the sociocultural context within which they practised medicine would be helpful.

The Feasibility of Electrochemical Ammonia Synthesis in Molten LiCl-KCl Eutectics.

Molten LiCl and related eutectic electrolytes are known to permit direct electrochemical reduction of N2 to N3- with high efficiency. It had been proposed that this could be coupled with H2 oxidation in an electrolytic cell to produce NH3 at ambient pressure. Here, this proposal is tested in a LiCl-KCl-Li3 N cell and is found not to be the case, as the previous assumption of the direct electrochemical oxidation of N3- to NH3 is grossly over-simplified. We find that Li3 N added to the molten electrolyte promotes the spontaneous and simultaneous chemical disproportionation of H2 (H oxidation state 0) into H- (H oxidation state -1) and H+ in the form of NH2- /NH2 - /NH3 (H oxidation state +1) in the absence of applied current, resulting in non-Faradaic release of NH3 . It is further observed that NH2- and NH2 - possess their own redox chemistry. However, these spontaneous reactions allow us to propose an alternative, truly catalytic cycle. By adding LiH, rather than Li3 N, N2 can be reduced to N3- while stoichiometric amounts of H- are oxidised to H2 . The H2 can then react spontaneously with N3- to form NH3 , regenerating H- and closing the catalytic cycle. Initial tests show a peak NH3 synthesis rate of 2.4×10-8  mol cm-2 s-1 at a maximum current efficiency of 4.2 %. Isotopic labelling with 15 N2 confirms the resulting NH3 is from catalytic N2 reduction.

Unexpected synergistic and antagonistic antibiotic activity against Staphylococcus biofilms.

Objectives: To evaluate putative anti-staphylococcal biofilm antibiotic combinations used in the management of periprosthetic joint infections (PJIs). Methods: Using the dissolvable bead biofilm assay, the minimum biofilm eradication concentration (MBEC) was determined for the most commonly used antimicrobial agents and combination regimens against staphylococcal PJIs. The established fractional inhibitory concentration (FIC) index was modified to create the fractional biofilm eradication concentration (FBEC) index to evaluate synergism or antagonism between antibiotics. Results: Only gentamicin (MBEC 64 mg/L) and daptomycin (MBEC 64 mg/L) were observed to be effective antistaphylococcal agents at clinically achievable concentrations. Supplementation of gentamicin with daptomycin, vancomycin or ciprofloxacin resulted in a similar or lower MBEC than gentamicin alone (FBEC index 0.25-2). Conversely, when rifampicin, clindamycin or linezolid was added to gentamicin, there was an increase in the MBEC of gentamicin relative to its use as a monotherapy (FBEC index 8-32). Conclusions: This study found that gentamicin and daptomycin were the only effective single-agent antibiotics against established Staphylococcus biofilms. Interestingly the addition of a bacteriostatic antibiotic was found to antagonize the ability of gentamicin to eradicate Staphylococcus biofilms.

Engineered core-shell magnetic nanoparticle for MR dual-modal tracking and safe magnetic manipulation of ependymal cells in live rodents.

Tagging recognition group(s) on superparamagnetic iron oxide is known to aid localisation (imaging), stimulation and separation of biological entities using magnetic resonance imaging (MRI) and magnetic agitation/separation (MAS) techniques. Despite the wide applicability of iron oxide nanoparticles in T 2-weighted MRI and MAS, the quality of the images and safe manipulation of the exceptionally delicate neural cells in a live brain are currently the key challenges. Here, we demonstrate the engineered manganese oxide clusters-iron oxide core-shell nanoparticle as an MR dual-modal contrast agent for neural stem cells (NSCs) imaging and magnetic manipulation in live rodents. As a result, using this engineered nanoparticle and associated technologies, identification, stimulation and transportation of labelled potentially multipotent NSCs from a specific location of a live brain to another by magnetic means for self-healing therapy can therefore be made possible.

Structural Studies of Bulk to Nanosize Niobium Oxides with Correlation to Their Acidity.

Hydrated niobium oxides are used as strong solid acids with a wide variety of catalytic applications, yet the correlations between structure and acidity remain unclear. New insights into the structural features giving rise to Lewis and Brønsted acid sites are presently achieved. It appears that Lewis acid sites can arise from lower coordinate NbO5 and in some cases NbO4 sites, which are due to the formation of oxygen vacancies in thin and flexible NbO6 systems. Such structural flexibility of Nb-O systems is particularly pronounced in high surface area nanostructured materials, including few-layer to monolayer or mesoporous Nb2O5·nH2O synthesized in the presence of stabilizers. Bulk materials on the other hand only possess a few acid sites due to lower surface areas and structural rigidity: small numbers of Brønsted acid sites on HNb3O8 arise from a protonic structure due to the water content, whereas no acid sites are detected for anhydrous crystalline H-Nb2O5.

THE EFFECT OF ETHNICITY ON THE INCIDENCE OF POSTOPERATIVE NAUSEA AND VOMITING IN MODERATE TO HIGH RISK PATIENTS UNDERGOING GENERAL ANESTHESIA IN SOUTH AFRICA: A CONTROLLED OBSERVATIONAL STUDY.

BACKGROUND: We conducted this prospective controlled observational study to compare the effect of ethnicity on the risk of postoperative nausea and vomiting (PONV) between moderate to high-risk African and non-African patients undergoing general anesthesia. METHODS: Using Apfel score risk factors and predicted length of surgery (>30 minutes), 89 moderate to high risk patients undergoing general anesthesia were recruited in a university hospital between March 2009 and November 2010. Thirty patients in the non-African group and 59 patients in the African group were allocated using an ethnicity self identification questionnaire. Intraoperative anesthesia was standardized. PONV was assessed at 0 minutes, 15 minutes, 90 minutes, 180 minutes, and 24 hours. Generalized linear mixed effects models was used to determine the effect of ethnicity on PONV. RESULTS: Despite similar Apfel scores, cumulative incidence of postoperative nausea was higher in the non-African group at 0 minutes (46.67% vs 22.03%, P = 0.019), 15 minutes (70% vs 23.73%, p<0.001) and 90 minutes (36.67% vs 16.95%, P = 0.04). The non-African group had more episodes of vomiting over 24 hours (13.33% vs 1.69%, P = 0.055). Non-Africans had a 25 times higher reported nausea incidence than Africans over 24 hours. CONCLUSION: The incidence of PONV in non-Africans is significantly higher than in Africans. Non-African ethnicity is an independent risk factor for PONV. Current risk prediction models may be limited in multi-ethnic populations and further investigations are warranted to examine ethnicity as a risk factor.

Decarboxylation of Lactones over Zn/ZSM-5: Elucidation of the Structure of the Active Site and Molecular Interactions.

Herein, we report the catalytic decarboxylation of γ-valerolactone (GVL) over Zn/ZSM-5 to butene, followed by aromatization at high yield with co-feeding of water. An evaluation of the catalytic performance after prolonged periods of time showed that a water molecule is essential to maintain the decarboxylation and aromatization activities and avoid rapid catalyst deactivation. Synchrotron X-ray powder diffraction and Rietveld refinement were then used to elucidate the structures of adsorbed GVL and immobilized Zn species in combination with EXAFS and NMR spectroscopy. A new route for the cooperative hydrolysis of GVL by framework Zn-OH and Brønsted acidic sites to butene and then to aromatic compounds has thus been demonstrated. The structures and fundamental pathways for the nucleophilic attack of terminal Zn-OH sites are comparable to those of Zn-containing enzymes in biological systems.

Hospital Authority audit of the outcome of endoscopic resection of superficial upper gastro-intestinal lesions in Hong Kong.

OBJECTIVES: To review the short-term outcome of endoscopic resection of superficial upper gastro-intestinal lesions in Hong Kong. DESIGN: Historical cohort study. SETTING: All Hospital Authority hospitals in Hong Kong. PATIENTS: This was a multicentre retrospective study of all patients who underwent endoscopic resection of superficial upper gastro-intestinal lesions between January 2010 and June 2013 in all government-funded hospitals in Hong Kong. MAIN OUTCOME MEASURES: Indication of the procedures, peri-procedural and procedural parameters, oncological outcomes, morbidity, and mortality. RESULTS: During the study period, 187 lesions in 168 patients were resected. Endoscopic mucosal resection was performed in 34 (18.2%) lesions and endoscopic submucosal dissection in 153 (81.8%) lesions. The mean size of the lesions was 2.6 (standard deviation, 1.8) cm. The 30-day morbidity rate was 14.4%, and perforations and severe bleeding occurred in 4.3% and 3.2% of the patients, respectively. Among patients who had dysplasia or carcinoma, R0 resection was achieved in 78% and the piecemeal resection rate was 11.8%. Lateral margin involvement was 14% and vertical margin involvement was 8%. Local recurrence occurred in 9% of patients and 15% had residual disease. The 2-year overall survival rate and disease-specific survival rate was 90.6% and 100%, respectively. CONCLUSION: Endoscopic mucosal resection and endoscopic submucosal dissection were introduced in low-to-moderate-volume hospitals with acceptable morbidity rates. The short-term survival was excellent. However, other oncological outcomes were higher than those observed in high-volume centres and more secondary procedures were required.

Elucidating the genetic basis of crystalline biofilm formation in Proteus mirabilis.

Proteus mirabilis forms extensive crystalline biofilms on urethral catheters that occlude urine flow and frequently complicate the management of long-term-catheterized patients. Here, using random transposon mutagenesis in conjunction with in vitro models of the catheterized urinary tract, we elucidate the mechanisms underpinning the formation of crystalline biofilms by P. mirabilis. Mutants identified as defective in blockage of urethral catheters had disruptions in genes involved in nitrogen metabolism and efflux systems but were unaffected in general growth, survival in bladder model systems, or the ability to elevate urinary pH. Imaging of biofilms directly on catheter surfaces, along with quantification of levels of encrustation and biomass, confirmed that the mutants were attenuated specifically in the ability to form crystalline biofilms compared with that of the wild type. However, the biofilm-deficient phenotype of these mutants was not due to deficiencies in attachment to catheter biomaterials, and defects in later stages of biofilm development were indicated. For one blocking-deficient mutant, the disrupted gene (encoding a putative multidrug efflux pump) was also found to be associated with susceptibility to fosfomycin, and loss of this system or general inhibition of efflux pumps increased sensitivity to this antibiotic. Furthermore, homologues of this system were found to be widely distributed among other common pathogens of the catheterized urinary tract. Overall, our findings provide fundamental new insight into crystalline biofilm formation by P. mirabilis, including the link between biofilm formation and antibiotic resistance in this organism, and indicate a potential role for efflux pump inhibitors in the treatment or prevention of P. mirabilis crystalline biofilms.

Three-dimensional graphene based passively mode-locked fiber laser.

We present an all-fiber passively mode-locked fiber laser incorporating three-dimensional (3D) graphene as a saturable absorber (SA) for the first time to the best of our knowledge. The 3D graphene is synthesized by template-directed chemical vapor deposition (CVD). The SA is then simply formed by sandwiching the freestanding 3D graphene between two conventional fiber connectors without any deposition process. It is demonstrated that such 3D graphene based SA is capable to produce high quality mode-locked pulses. A passively mode-locked fiber laser is constructed and stable output pulses with a fundamental repetition rate of ~9.9 MHz and a pulse width of ~1 ps are generated from the fiber laser. The average output power of the laser is ~10.5 mW while the output pulse is operating at single pulse region. The results imply that the freestanding 3D graphene can be applied as an effective saturable absorption material for passively mode-locked lasers.

Rationalization of interactions in precious metal/ceria catalysts using the d-band center model.

A correlation between ceria reducibility and the precious-metal d-band center is reported for ceria-supported precious-metal catalysts. The results could provide the missing link to fully explain the occurrence of strong metal-support interaction (SMSI) and hydrogen spillover in catalysts that consist of dispersed metals in contact with reducible metal oxides.

Neural stem cells harvested from live brains by antibody-conjugated magnetic nanoparticles.

It stems from the magnetism: The extraction of stem/progenitor cells from the brain of live animals is possible using antibodies conjugated to magnetic nanoparticles (Ab-MNPs). The Ab-MNPs are introduced to a rat's brain with a superfine micro-syringe. The stem cells attach to the Ab-MNPs and are magnetically isolated and removed. They can develop into neurospheres and differentiate into different types of cells outside the subject body. The rat remains alive and healthy.

Imprinting in the schizophrenia candidate gene GABRB2 encoding GABA(A) receptor ß(2) subunit.

Schizophrenia is a complex genetic disorder, the inheritance pattern of which is likely complicated by epigenetic factors yet to be elucidated. In this study, transmission disequilibrium tests with family trios yielded significant differences between paternal and maternal transmissions of the disease-associated single-nucleotide polymorphism (SNP) rs6556547 and its haplotypes. The minor allele (T) of rs6556547 was paternally undertransmitted to male schizophrenic offsprings, and this parent-of-origin effect strongly suggested that GABRB2 is imprinted. 'Flipping' of allelic expression in heterozygotes of SNP rs2229944 (C/T) in GABRB2 or rs2290732 (G/A) in the neighboring GABRA1 was compatible with imprinting effects on gene expression. Clustering analysis of GABRB2 mRNA expressions suggested that imprinting brought about the observed two-tiered distribution of expression levels in controls with heterozygous genotype at the disease-associated SNP rs1816071 (A/G). The deficit of upper-tiered expressions accounted for the lowered expression levels in the schizophrenic heterozygotes. The occurrence of a two-tiered distribution furnished support for imprinting, and also pointed to the necessity of differentiating between two kinds of heterozygotes of different parental origins in disease association studies on GABRB2. Bisulfite sequencing revealed hypermethylation in the neighborhood of SNP rs1816071, and methylation differences between controls and schizophrenia patients. Notably, the two schizophrenia-associated SNPs rs6556547 and rs1816071 overlapped with a CpG dinucleotide, thereby opening the possibility that CpG methylation status of these sites could have an impact on the risk of schizophrenia. Thus multiple lines of evidence pointed to the occurrence of imprinting in the GABRB2 gene and its possible role in the development of schizophrenia.

Sequence Variant in the TRIM39-RPP21 Gene Readthrough is Shared Across a Cohort of Arabian Foals Diagnosed with Juvenile Idiopathic Epilepsy.

Juvenile idiopathic epilepsy (JIE) is a self-limiting neurological disorder with a suspected genetic predisposition affecting young Arabian foals of the Egyptian lineage. The condition is characterized by tonic-clonic seizures with intermittent post-ictal blindness, in which most incidents are sporadic and unrecognized. This study aimed to identify genetic components shared across a local cohort of Arabian foals diagnosed with JIE via a combined whole genome and targeted resequencing approach: Initial whole genome comparisons between a small cohort of nine diagnosed foals (cases) and 27 controls from other horse breeds identified variants uniquely shared amongst the case cohort. Further validation via targeted resequencing of these variants, that pertain to non-intergenic regions, on additional eleven case individuals revealed a single 19bp deletion coupled with a triple-C insertion (Δ19InsCCC) within the TRIM39-RPP21 gene readthrough that was uniquely shared across all case individuals, and absent from three additional Arabian controls. Furthermore, we have confirmed recent findings refuting potential linkage between JIE and other inherited diseases in the Arabian lineage, and refuted the potential linkage between JIE and genes predisposing a similar disorder in human newborns. This is the first study to report a genetic variant to be shared in a sub-population cohort of Arabian foals diagnosed with JIE. Further evaluation of the sensitivity and specificity of the Δ19InsCCC allele within additional cohorts of the Arabian horse is warranted in order to validate its credibility as a marker for JIE, and to ascertain whether it has been introduced into other horse breeds by Arabian ancestry.

Achieving Ultrahigh-Rate Planar and Dendrite-Free Zinc Electroplating for Aqueous Zinc Battery Anodes.

Despite being one of the most promising candidates for grid-level energy storage, practical aqueous zinc batteries are limited by dendrite formation, which leads to significantly compromised safety and cycling performance. In this study, by using single-crystal Zn-metal anodes, reversible electrodeposition of planar Zn with a high capacity of 8 mAh cm-2 can be achieved at an unprecedentedly high current density of 200 mA cm-2 . This dendrite-free electrode is well maintained even after prolonged cycling (>1200 cycles at 50 mA cm- 2 ). Such excellent electrochemical performance is due to single-crystal Zn suppressing the major sources of defect generation during electroplating and heavily favoring planar deposition morphologies. As so few defect sites form, including those that would normally be found along grain boundaries or to accommodate lattice mismatch, there is little opportunity for dendritic structures to nucleate, even under extreme plating rates. This scarcity of defects is in part due to perfect atomic-stitching between merging Zn islands, ensuring no defective shallow-angle grain boundaries are formed and thus removing a significant source of non-planar Zn nucleation. It is demonstrated that an ideal high-rate Zn anode should offer perfect lattice matching as this facilitates planar epitaxial Zn growth and minimizes the formation of any defective regions.