Preparation and characterisation of chemisorbents based on heteropolyacids supported on synthetic mesoporous carbons and silica

The preparation of chemisorbents based on tungsto- and molybdophosphoric acids supported on two types of synthetic mesoporous carbons and two types of mesoporous silica is described. Strong solid acids with good accessibility to acid sites may potentially be effective adsorbents for the removal of basic molecular impurities, such as amines, from ultrapure manufacturing environments. Prepared materials were characterised by scanning electron microscopy, nitrogen adsorption, Fourier-transform infrared spectroscopy, powder X-ray diffraction, and equilibrium ammonia uptake. Composites of SBA-15 with heteropolyacids were synthesised. It was shown that the inclusion of HPAs into SBA-15 results in the loss of long range order. Adsorbents based on the HPAs impregnated into the supports with the open-pore morphology (Novacarb and SBA-15) were found to be promising materials. A composite of tungstophosphoric acid with sol–gel SiO₂ was found to have the highest ammonia uptake.     

The Lrat−/− Rat: CRISPR/Cas9 Construction and Phenotyping of a New Animal Model for Retinitis Pigmentosa

Purpose: We developed and phenotyped a pigmented knockout rat model for lecithin retinol acyltransferase (LRAT) using CRISPR/Cas9. The introduced mutation (c.12delA) is based on a patient group harboring a homologous homozygous frameshift mutation in the LRAT gene (c.12delC), causing a dysfunctional visual (retinoid) cycle. Methods: The introduced mutation was confirmed by DNA and RNA sequencing. The expression of Lrat was determined on both the RNA and protein level in wildtype and knockout animals using RT-PCR and immunohistochemistry. The retinal structure and function, as well as the visual behavior of the Lrat^−/− and control rats, were characterized using scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), electroretinography (ERG) and vision-based behavioral assays. Results: Wildtype animals had high Lrat mRNA expression in multiple tissues, including the eye and liver. In contrast, hardly any expression was detected in Lrat^−/− animals. LRAT protein was abundantly present in wildtype animals and absent in Lrat^−/− animals. Lrat^−/− animals showed progressively reduced ERG potentials compared to wildtype controls from two weeks of age onwards. Vison-based behavioral assays confirmed reduced vision. Structural abnormalities, such as overall retinal thinning, were observed in Lrat^−/− animals. The retinal thickness in knockout rats was decreased to roughly 80% by four months of age. No functional or structural differences were observed between wildtype and heterozygote animals. Conclusions: Our Lrat^−/− rat is a new animal model for retinal dystrophy, especially for the LRAT-subtype of early-onset retinal dystrophies. This model has advantages over the existing mouse models and the RCS rat strain and can be used for translational studies of retinal dystrophies.     

Synthesis and Evaluation of Functionalized Aryl and Biaryl Isothiocyanates against Human MCF-7 Cells

Organic isothiocyanates (ITCs) are a class of anticancer agents which naturally result from the enzymatic degradation of glucosinolates produced by Brassica vegetables. Previous studies have demonstrated that the structure of an ITC impacts its potency and mode(s) of anticancer properties, opening the way to preparation and evaluation of synthetic, non-natural ITC analogues. This study describes the preparation of a library of 79 non-natural ITC analogues intended to probe further structure-activity relationships for aryl ITCs and second-generation, functionalized biaryl ITC variants. ITC candidates were subjected to bifurcated evaluation of antiproliferative and antioxidant response element (ARE)-induction capacity against human MCF-7 cells. The results of this study led to the identification of (1) several key structure-activity relationships and (2) lead ITCs demonstrating potent antiproliferative properties.     

Optimization of Multiple Reservoir Networks for Sedimentation Control

An optimal control methodology is developed to evaluate reservoir management policies that minimize sediment scour and deposition in multiple-reservoir river networks. Consideration is given to adverse effects occurring in both reservoirs and rivers of a hydraulic network. The sedimentation problem is formulated as a discrete-time optimal control problem in which a successive approximation linear quadratic regulator optimization scheme is coupled with the U.S. Army Corps of Engineers HEC-6 sediment transport simulation model. Operational constraints imposed on reservoir storage levels and releases are accommodated using either a bracket or hyperbolic penalty function method. The resulting model also allows the user to evaluate policies that alternatively maximize sedimentation or consider adverse effects only at specified locations. Comparisons of the computational efficiencies between the successive approximation linear quadratic regulator and differential dynamic programming methodology and between different penalty functions are performed. Capabilities of the model are demonstrated through applications to a hypothetical three-reservoir network and the Yazoo Basin river-reservoir network in Mississippi.     

Using gene expression to assess the status of fish from anthropogenically influenced estuarine wetlands

The diverse mixture of contaminants frequently present in estuaries complicates their assessment by routine chemical or biological analyses. We investigated the use of gene expression to assess contaminant exposure and the condition of southern California estuarine fish. Liver gene expression, plasma estradiol concentrations, and gonad histopathology were used to study biological condition in longjaw mudsuckers (Gillichthys mirabilis). Metals, legacy organochlorine pesticides, PCBs, and contaminants of emerging concern were detected in sediments and whole fish. Overall gene expression patterns were characteristic to each of four sites investigated in this study. Differentially expressed genes belonged to several functional categories including xenobiotic metabolism, detoxification, disease, and stress responses. In general, plasma estradiol concentrations were similar among fish from all areas. Some fish gonads had pathologic changes (e.g., infection, inflammation) that could indicate weakened immune systems and chronic stress. The differential expression of some genes involved in stress responses correlated with the prevalence of histologic gonad lesions. This study indicates that gene expression is a promising tool for assessing the biological condition of fish exposed to environmental contaminants.     

Craniocervical junction tuberculosis: a rare but dangerous disease

BACKGROUND: Mycobacterium tuberculosis of the cervical spine is a rare but dangerous manifestation of extra-pulmonary tuberculosis. The clinical picture ranges from early, nonspecific, insidious symptoms to severe neurological complications and death, attributed to craniocervical junction instability and cervicomedullary compression. The different lines of management include antituberculous medication with traction and external fixation or adjunctive surgery (debridement and stabilization) in patients with severe or persistent neurological complications and/or vertebral instability. METHODS: We describe two patients with advanced craniocervical junction tuberculosis. The early clinical picture was nonspecific in Case 1 and obscured by psychiatric illness in Case 2. The detailed clinical and radiological findings, and the management, will be described. Involvement of the occipital condyles and foramen magnum, which has not been reported previously, will be demonstrated. RESULTS: Both cases underwent transoral biopsy, aspiration, and debridement of retropharyngeal abscess (granuloma). Histological and tissue culture studies proved the abscesses were tuberculous and anti-tuberculous medications were started. Case 1 showed complete resolution of the clinical and radiological findings. Case 2 developed cardiorespiratory arrest while in a halo jacket. He was resuscitated but remained quadriplegic and semiconscious; he developed nosocomial gram negative pneumonia. He was referred back to his local hospital where he died 1 year later. CONCLUSIONS: Tuberculosis is an infrequent but notable cause of cervicomedullary compression. It should be suspected in patients with infective spondylitis who are immunocompromised or reside in an area highly endemic for tuberculosis. Management strategies include antituberculosis medication, transoral biopsy and drainage of the abscess, traction and external fixation, posterior decompression, and internal fixation, according to the clinical and radiological findings.     

Polymer electrolyte membranes from fluorinated polyisoprene-block-sulfonated polystyrene: Microdomain orientation by external field

In this study, block copolymer ionomers of the cesium salt (20 mol %) of fluorinated polyisoprene-block-sulfonated polystyrene were spin cast into membranes and annealed under an electric field of ∼40 V/μm at 130 °C for 24 h. The effect of this treatment was a 2.5 times increase in the ionic conductivity as measured by electrochemical impedance spectroscopy, under all humidity conditions measured. This can be attributed to the increased connectivity of the ionic domains of the block copolymers. This E-field alignment technique may thus find application in the fabrication of nanostructured polyelectrolytes with enhanced charge transport capacity.     

Use of cover crops in short rotation hardwood plantations to control erosion

This study was designed to test whether the cultivation of cover crops between tree rows in short-rotation woody crop (SRWC) plantations could reduce erosion. Sweetgum (Liquidambar styraciflua L.) seedlings were planted as the SRWC at a 1.5×3 m spacing. Four cover crops, annual ryegrass (Lolium multiflorum L. a winter annual grass); tall fescue (Festuca arundinacea L. a cool-season perennial grass); crimson clover (Trifolium incarnatum L. a winter annual legume); and Interstate sericea lespedeza [Lespedeza cuneata (Dumont) G. Don. a summer growing-perennial legume], were tested at two different strip widths (1.22 and 2.44 m) in comparison with complete competition control. Erosion was measured from 1 August, 1995 to 8 March, 1997 (585 days) by sediment accumulation near the fence where 72 PVC pipes were inserted into soil on a 4.65 m² (50 ft³) grid area of each plot. The total rainfall recorded during this period was 2422.91 mm (95.3 in.). All cover crops reduced erosion over the complete competition free plot (control), although tall fescue performed poorly at the narrow strip width. There were no significant differences between grasses and legumes for erosion control. Winter annual crops provided significantly more erosion protection than summer growing-perennials. With the exception of tall fescue, narrow strip widths performed as well as wider strip widths. The results indicate that cover crops ryegrass, crimson clover, lespedeza and tall fescue controlled about 64, 61, 51 and 37% soil erosion respectively as compared to the control during the critical early years of stand development in SRWC hardwood plantations.     

Role of mismatch repair in the Escherichia coli UVM response

Mutagenesis at 3,N4-ethenocytosine (epsilonC), a nonpairing mutagenic lesion, is significantly enhanced in Escherichia coli cells pretreated with UV, alkylating agents, or H2O2. This effect, termed UVM (for UV modulation of mutagenesis), is distinct from known DNA damage-inducible responses, such as the SOS response, the adaptive response to alkylating agents, or the oxyR-mediated response to oxidative agents. Here, we have addressed the hypothesis that UVM results from transient depletion of a mismatch repair activity that normally acts to reduce mutagenesis. To test whether the loss of mismatch repair activities results in the predicted constitutive UVM phenotype, E. coli cells defective for methyl-directed mismatch repair, for very-short-patch repair, or for the N-glycosylase activities MutY and MutM were treated with the UVM-inducing agent 1-methyl-3-nitro-1-nitrosoguanidine, with subsequent transfection of M13 viral single-stranded DNA bearing a site-specific epsilonC lesion. Survival of the M13 DNA was measured as transfection efficiency, and mutation fixation at the lesion was characterized by multiplex sequencing technology. The results showed normal UVM induction patterns in all the repair-defective strains tested. In addition, normal UVM induction was observed in cells overexpressing MutH, MutL, or MutS. All strains displayed UVM reactivation, the term used to describe the increased survival of epsilonC-containing DNA in UVM-induced cells. Taken together, these results indicate that the UVM response is independent of known mismatch repair systems in E. coli and may thus represent a previously unrecognized misrepair or misreplication pathway.