A convenient method for preparation of monofluorocarboxylic acids

Monofluoro esters were prepared by the reaction of hydroxy esters with N,N-diethyl-1,1,2,3,3,3-hexafluoro propylamine (PPDA). Saponification of these monofluoroesters with enzyme (lipase MY) was attempted to give their corresponding monofluorocarboxylic acids in moderate yields.     

Study of the Effect of Fluorine Atom(s) on Fluoromethylated Imines in the Tandem Mannich–Michael-type Reaction

Differences in chemical behavior between non-fluorinated and fluorinated methylimines in the tandem Mannich–Michael-type reaction are described based on NMR and computational studies.     

Protein Tyrosine Phosphatase Receptor Type Z in Central Nervous System Disease

Gliomas are among the most common tumors of the central nervous system and include highly malignant subtypes, such as glioblastoma, which are associated with poor prognosis. Effective treatments are therefore urgently needed. Despite the recent advances in neuroimaging technologies, differentiating gliomas from other brain diseases such as multiple sclerosis remains challenging in some patients, and often requires invasive brain biopsy. Protein tyrosine phosphatase receptor type Z (PTPRZ) is a heavily glycosylated membrane protein that is highly expressed in the central nervous system. Several reports analyzing mouse tumor models suggest that PTPRZ may have potential as a therapeutic target for gliomas. A soluble cleaved form of PTPRZ (sPTPRZ) in the cerebrospinal fluid is markedly upregulated in glioma patients, making it another promising diagnostic biomarker. Intriguingly, PTPRZ is also involved in the process of remyelination in multiple sclerosis. Indeed, lowered PTPRZ glycosylation by deletion of the glycosyltransferase gene leads to reduced astrogliosis and enhanced remyelination in mouse models of demyelination. Here, we review the expression, molecular structure, and biological roles of PTPRZ. We also discuss glioma and demyelinating diseases, as well as the pathological role of PTPRZ and its application as a diagnostic marker and therapeutic target.     

Surface shape measurement for a multilayered object by synthesis ofoptical coherence function

An interferometric system is proposed by synthesis of the optical coherence function for measuring surface shapes of multiple planes in a multilayered transparent object. By stepwise optical frequency modulation of a laser source, the system synthesizes the optical coherence function into a delta function-like peak at an arbitrary depth, and the depth of the peak can be adjusted by changing the frequency modulation parameter. In this way, the interference of a reference with the reflection at each target surface can be selectively extracted, and the shapes of the target surfaces can then be obtained by means of fringe analysis such as the Fourier transform (FT) method. An experimental demonstration is presented and performance degradation factors are discussed     

Synthesis and properties of trifluoromethylated chiral dopants for ferroelectric liquid crystals

The synthesis and specific properties of a new family of chiral dopants for ferroelectric liquid crystals, which are derived from a series of trifluorinated dihydrofuranones and tetrahydrofurans, are described. On the basis of the structural features of designed materials and the MOPAC-PM 3 calculations, a discussion of the response time-structure relationships is given. Optically active trifluoromethylated materials with a tetrahydrofuran tail unit were found to be superior chiral dopants for preparing ferroelectric liquid crystalline compositions.     

Investigation on Static Stability of Sheet Pile Quay Wall Improved by Cement Treated Sea-Side Ground from Centrifuge Model Tests

The static stability of sheet pile quay walls on a thick clay deposit against horizontal loads was studied through a series of centrifuge model tests. In the tests, an overconsolidated Kaolin clay layer was prepared over a layer of dense Toyoura sand in a rectangular container. The model quay wall was set to the bottom of the sand layer. The sea-side area adjacent to the quay wall was improved with cement-treated Kawasaki clay. Under 50 g centrifugal acceleration, the clay deposit was consolidated and horizontal line loads of about 0 to 70 kN/m were applied to the quay wall. The width and the depth of the improved area were varied and its performance was compared with that of a quay wall embedded in unimproved ground. Results of the study indicated that the improved ground provided significant resistance against horizontal loading. In addition, a numerical model to estimate the mechanical behavior of the sheet pile quay wall is presented. The outcomes of the numerical model show good agreement with the centrifuge test results.     

Enhancing mechanical behaviors of collapsible soil using two biopolymers

This study aims to investigate the possibility of using biopolymer (environmental friendly material) to enhance the mechanical behaviors of collapsible soil. Two types of biopolymers were (xanthan gum and guar gum) used in this study due to their stable behaviors under severe conditions and their availability with reasonable prices. The experimental program focused on three major soil properties, i.e. compaction characterizations, collapsible potential and shear parameters. These three properties are essential in process of soil improvement. Different biopolymer concentrations were used in this study and the experimental program was performed at two curing periods (soon after mixing the soil with the biopolymer and after one week curing time). Shear parameters were measured for the treated specimens under both soaked and unsoaked conditions, while a collapsible potential test was performed under different mixing conditions (wet mix and dry mix). A numerical model was built to predict the behavior of the treated collapsible soil after and before water immersing. The results indicated that the ability of both xanthan gum and guar gum can be used as improvement materials for collapsible soil treatment. The collapsible potential has been reduced from 9% to 1% after mixing the soil with 2% biopolymer concentration in the wet case. After one week curing, the cohesion has been increased from 8.5 kPa to 105 kPa by increasing the xanthan gum concentration from zero to 2%, leading to an overall improvement in soil shear strength. It also proves that the guar gum is superior to the xanthan gum. The shear strength of soil can be increased by about 30% when using the guar gum in comparison with the xanthan gum at the same conditions; however, the collapsible potential of soil material will be reduced by about 20%.     

CuCN and Trimethylsilyl Chloride-Catalyzed Regiospecific Grignard Reactions to CF3-Containing Allylic Derivatives

CF₃-containing allylic alcohol derivatives were treated with an appropriate Grignard reagent in the presence of catalytic amounts of CuCN and trimethylsilyl chloride (TMSCl) to furnish products via the clean anti-S_N2′ mechanism. Experimental results as well as ab initio computational analyses unambiguously demonstrated the important roles of TMSCl as a Lewis basic additive for smooth promotion of reductive elimination and inhibition of the “Cu···F” elimination leading to undesired byproduct formation.