A high-surface-area silicoaluminophosphate material rich in Brnsted acid sites as a matrix in catalytic cracking

A transparent gel-like mesoporous silicoaluminophosphate material (SAP) with a Si/Al molar ratio of 20 was synthesized by hydrothermal method. The physicochemical features of SAP were characterized by XRD, XRF, BET, SEM and FT-IR spectroscopy of pyridine adsorption techniques. The results indicated that incorporation of phosphorus (P) into aluminasilica system altered the basic textural characteristics of aluminasilica. Especially after hydrothermal treatment, the material with large special surface area (up to 492 m 2 /g) exhibited a good performance on hydrothermal stability. Moreover, the phosphorus modifier can not only increase the amount of Bro¨nsted acidic sites (up to 48.44 μmol/g) and the percentage of weak acidic sites in total acidic sites, but also regulate the acid type, such as the ratio of B/L (Bro¨nsted acid/Lewis acid) increases to 1.15. The performances of samples as matrices for the catalytic cracking of heavy vacuum gas oil (VGO) were investigated. At 520 C, the catalysts showed much higher gasoline and diesel oil yields achieving to 45.59 wt% and 19.20 wt%, respectively, and lower coke selectivity (2.86%) than conventional FCC matrices, such as kaolin and amorphous silica-alumina.

The Relative Prevalence of Typhoid and Malaria in Febrile Patients in Freetown, Sierra Leone

Malaria and typhoid fever are debilitating diseases responsible for the deaths of thousands of lives annually. Over the last decade both diseases have received increasing attention with particular focus on malaria. However, recent reports indicate an increasing co-infection rate between mala- ria and typhoid fever. Familiar signs and symptoms of both diseases have led to the belief in some communities that it’s a new disease. In this study, we investigated the relationship between mala- ria and typhi O and H antigens among patients reporting with fever. Patients reporting with fever from April 2013-March 2014 were recruited for the study. Our results showed that there was no association between having malaria and typhoid fever infection. However, having fever was asso- ciated with having both diseases. Also, fever among patients was more likely to be caused by Sal- monella typhi O and H antigens than plasmodium parasites. Infections of both diseases were higher in wet season than in dry season. The study recommends that malaria and typhoid fever intervention programs are increased in endemic areas. Also attention should be paid to typhoid fever infection rates in the country.

House dust mite disrupts the airway epithelial barrier by affecting the expression of thymic stromal lymphopoietin through inducing Atg5

To the Editor:Asthma is a complex chronic inflammatory lung disease,and its pathogenesis is not fully understood.It is believed that airway epithelium primarily acts as a defensive barrier to protect the lung from allergens,avoiding the asthma.The integrity of the airway epithelial barrier is dependent on tight junctions comprised of zona occludens(ZO)1 to 3,occludin,and claudin 1 to 5,and adherens junctions mainly formed by E-cadherin,b-catenin,and junctional adhesion molecule,which maintain apicobasal polarity of bronchial epithelial cells.

Spatio-temporal distribution of gaseous pollutants from multiple sources in industrial buildings with different flow patterns

Energy consumption of industrial buildings has remained continuously high,and the environmental quality requirements are also constantly improving.Only by improving industrial environmental control technology based on the transport mechanism of the pollution,can the energy consumption of industrial building environmental control be further reduced,and the environmental quality of industrial buildings can be improved as well.Therefore,after verifying the numerical simulation by experiments,this study uses a self-label method to investigate the spatio-temporal distribution of gaseous pollutants from multiple time-series sources in industrial plants with different length-span ratios.The results show that,the polluted flow in plants with different aspect ratios have different flow patterns:(i)the,,Back-mixingw flow pattern occurs when the ratio of ventilation rate 6 and polluted flow rate at the exhaust height b is less than 1,i.e.,G/L_(p)<1,and(ii)the"One-way"flow pattern occurs when G/L_(p)>1.For plants with the"Back-mixing"pattern,the following source pollutants enter a density stratified environment induced by the retained pre-source pollutants.The flow of following source pollutants released at the same intensity as the precursor source can reach the roof,while those with low velocity and density difference may be blocked during the ascending process.The maximum height zm of the flow of the following source is related to both the initial Froude number Fr_(o)of the following source and the unsteady vertical density gradient of the fluid in the indoor environment dpa/dz.For plants with the,,One-way,/pattern,the flow from the following source enters into an environment with approximately uniform density.Under the condition of positive buoyancy,design parameters of ventilation corresponding to the vicinity of G/L_(p)=1 may be the optimal solution for safety and energy conservation.