There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.

Large-scale pattern growth of graphene films for stretchable transparent electrodes

Multilayer films of organic compounds on solid surfaces have been studied for more than 60 years because they allow fabrication of multicomposite molecular assemblies of tailored architecture. However, both the Langmuir-Blodgett technique and chemisorption from solution can be used only with certain classes of molecules. An alternative approach—fabrication of multilayers by consecutive adsorption of polyanions and polycations—is far more general and has been extended to other materials such as proteins or colloids. Because polymers are typically flexible molecules, the resulting superlattice architectures are somewhat fuzzy structures, but the absence of crystallinity in these films is expected to be beneficial for many potential applications.

https://science.sciencemag.org/content/sci/277/5330/1232.full.pdf

Fuzzy Nanoassemblies: Toward Layered Polymeric Multicomposites

Cool, or simple and cheap? Why not both?

Sir: Direct electrochemical methods for reduction of NAD(P) to NAD(P)H have not proved sufficiently selective for reduction at the 4-position to give high turnover numbers (TN) for these cofactors.l-3 A combined electrochemicallenzymatic method based on cathodic reduction of lipoamide and lipoamide dehydrogenase (LipDH, EC 1.6.4.3) catalyzed reduction of NAD gave TN 900,4 and hydrogenase-catalyzed reduction of MV2+ by Hz combined with lipoamide dehydrogenase or ferredoxin reductase (FDR, EC 1.6.99.4) catalyzed reduction of NAD(P) gave similar values.5 Nthough the use of electrochemically generated MVl+ to produce NADPH from NADP via reaction with FDR has been reported previously,6'7 application of this redox cycle to regeneration of NAD(P)H for practical organic synthesis has not been described; here we report such a procedure. Reactions were performed under argon in a 1-L threenecked flask containing a magnetic stirring bar and a working electrode of 10 m of coiled tungsten wire8 (0.020-in. diameter, -160-cm2 surface area). The counter electrode was a 2 x 5-in. section of 80-mesh platinum gauze and was separated from the working solution in a glass tube sealed to a fine-porosity sintered glass frit inserted through the center neck of the flask. The reference electrode (SCE) was isolated from the working solution in the same manner. The total charge passed during electrolyses was determined by graphical integration of the recorded current-time curve. Current efficiency was calculated by subtraction of the integrated background currente from the total in-

Enzyme-catalyzed organic synthesis: electrochemical regeneration of NAD(P)H from NAD(P) using methyl viologen and flavoenzymes

Electromagnetic radiation valves are provided. In one system, a transparent, elastomeric article is provided having a contoured surface including protrusions and intervening indentations. The contoured surface is placed adjacent a transparent plate and a void pattern defined by indentations of the contoured surface is filled with an opaque fluid. The protrusions decrease in cross-sectional area in the direction in which they extend away from the bulk of the elastomeric article, thus compression of the elastomeric protrusions against the transparent plate results in an increase in surface area in elastomeric protrusions against the transparent plate due to deformation of the protrusions, and the opaque fluid is displaced from the voids. Increased transmission of the electromagnetic radiation results. In another system, a similar elastomeric article includes an array of corner cubes that are totally internally reflective of the electromagnetic radiation. Increased deformation of the protrusions of the transparent plate results in decreased total internal reflection of light, due to the progressive destruction of the corner-cube geometry, and the passage of light is increased with compression.

Elastomeric light valves

This paper describes a physical-organic study of the effect of uncharged, polar, functional groups on the rate of charge transport by tunneling across self-assembled monolayer (SAM)-based large-area junctions of the form Ag(TS)S(CH2)(n)M(CH2)(m)T//Ga2O3/EGaIn. Here Ag(TS) is a template-stripped silver substrate, -M- and -T are "middle" and "terminal" functional groups, and EGaIn is eutectic gallium-indium alloy. Twelve uncharged polar groups (-T = CN, CO2CH3, CF3, OCH3, N(CH3)2, CON(CH3)2, SCH3, SO2CH3, Br, P(O)(OEt)2, NHCOCH3, OSi(OCH3)3), having permanent dipole moments in the range 0.5 < μ < 4.5, were incorporated into the SAM. A comparison of the electrical characteristics of these junctions with those of junctions formed from n-alkanethiolates led to the conclusion that the rates of charge tunneling are insensitive to the replacement of terminal alkyl groups with the terminal polar groups in this set. The current densities measured in this work suggest that the tunneling decay parameter and injection current for SAMs terminated in nonpolar n-alkyl groups, and polar groups selected from common polar organic groups, are statistically indistinguishable.

/pdf/the-rate-of-charge-tunneling-is-insensitive-to-polar-4sav4bqs9z.pdf

The rate of charge tunneling is insensitive to polar terminal groups in self-assembled monolayers in Ag(TS)S(CH2)(n)M(CH2)(m)T//Ga2O3/EGaIn junctions.

This paper describes the application of reduction photolithography, using arrays of microlenses and gray scale masks, to generate arrays of micropatterns having multilevel and curved features in ph...

George M. Whitesides

Papers

Cool, or simple and cheap? Why not both?

Enzyme-catalyzed organic synthesis: electrochemical regeneration of NAD(P)H from NAD(P) using methyl viologen and flavoenzymes

Elastomeric light valves

The rate of charge tunneling is insensitive to polar terminal groups in self-assembled monolayers in Ag(TS)S(CH2)(n)M(CH2)(m)T//Ga2O3/EGaIn junctions.

Reduction photolithography using microlens arrays: applications in gray scale photolithography.