Making informed future decisions about solar radiation modification (SRM; also known as solar geoengineering)—approaches such as stratospheric aerosol injection (SAI) that would cool the climate by ...reflecting sunlight—requires projections of the climate response and associated human and ecosystem impacts. These projections, in turn, will rely on simulations with global climate models. As with climate-change projections, these simulations need to adequately span a range of possible futures, describing different choices, such as start date and temperature target, as well as risks, such as termination or interruptions. SRM modeling simulations to date typically consider only a single scenario, often with some unrealistic or arbitrarily chosen elements (such as starting deployment in 2020), and have often been chosen based on scientific rather than policy-relevant considerations (e.g., choosing quite substantial cooling specifically to achieve a bigger response). This limits the ability to compare risks both between SRM and non-SRM scenarios and between different SRM scenarios. To address this gap, we begin by outlining some general considerations on scenario design for SRM. We then describe a specific set of scenarios to capture a range of possible policy choices and uncertainties and present corresponding SAI simulations intended for broad community use.
The article reviews the relationship between technology and geography from a social science perspective. Especially, the everyday use of technology is discussed as a form of "geography-making". ...Making use of technology means that an interaction between lay users and experts (the designer of an abstract system and its user interface) takes place which basically implies the use and translation of differing spatial symbolisations: mainly numerical/algorithmic, deictic, and toponymical terms.
Capacitance and charge transfer rates of self-assembled monolayers of ω-(4′-methyl-biphenyl-4-yl)-alkanethiols (CH
3–C
6H
4–C
6H
4–(CH
2)
n
–SH,
n=0–6) adsorbed on polycrystalline gold were ...investigated. For
n=1–6 the reciprocal capacity exhibits a linear dependence on the length of the alkane spacer. Its change of 0.054±0.0036 cm
2 μF
−1 per CH
2 group and the calculated dielectric constant of
ε=2.5 agrees well with the values of
n-alkane thiols.
ε of the aromatic tail group is around 5 which is substantially larger than the bulk value of biphenyl. Measurements of the charge transfer rate yield an exponential dependence on the number of methylene units but reveal significant differences from alkanethiols. Transfer rates are more than a factor of 100 larger than those for alkane thiols of comparable length and the tunneling constant of 1.48±0.15 Å
−1 is higher compared to the value of about 1 Å
−1 for pure alkane thiols. In contrast to the film structure which alternates with the number of CH
2 units, no odd–even-effect is observed either for the capacity or for the charge transfer rate. However, the structural differences are reflected in the exchange kinetics. Exposure of the biphenyl monolayers to a hexadecane thiol solution reveals a significant dependence of the exchange rate on
n. SAMs with
n=even are displaced more easily compared to
n=odd with differences being largest for shorter spacer chains.
Spatially selective deposition of electrically charged microparticles onto integrated circuits that generate electrical fields in programmable patterns using electrodes on their surface was ...previously limited to a pixel pitch of 100
μm. Now, we demonstrate spatially selective deposition onto pixels of 45
μm pitch in experiments on a test chip allowing arbitrary patterns, but being of limited size and of fixed characteristics, complemented by COMSOL simulations. Experiments on a prototype high voltage CMOS chip demonstrate the feasibility of miniaturisation in the first place, imply simulations of interest that cannot be tested experimentally and, conversely, complement the simplified simulation models by reality checks. Using COMSOL for the optimisation of the setup parameters, particles of decreasing average diameter in a number of aerosol and electrical field geometries are simulated with particular attention to minimising contamination (deposition of particles on undesirable locations). Combining these results, the average particle diameter is decreased from 10
μm to less than 3
μm and the deposition voltage is reduced from 100
V to 30
V, when using pixels with a pitch of 45
μm. Optimising these parameters allows for more than quadrupling the spot density compared to the previous chip, on which combinatorial particle deposition with minimal contamination is achieved. Peptide arrays, having been previously shown to be a major application for this method, benefit in particular, as the increase in density from 10,000
pixels/cm
2 to approximately 50,000
pixels/cm
2 promises a significant decrease in cost-per-peptide and amount of test specimens required.
We built high voltage complementary metal oxide semiconductor (CMOS) chips that generate electrical fields on their surface, such that electrically charged microparticles (diameter 10–20
μm on ...average) can be addressed on distinct pixel electrodes according to arbitrary field patterns. Each pixel contains a memory cell in canonical low-voltage CMOS-technology controlling a high voltage (30–100
V) potential area on the top metal layer. Particle transfer with minimal contaminations in less than 10
s for a complete chip was observed for pixels of 100
μm
×
100
μm down to 65
μm
×
65
μm. This allows a new way to create surface modifications on top of CMOS chips without need for additional masks or stamps. Using suitable particles, a chemically modified chip surface, and compatible chemistry, this method can be utilized for self-aligned high-density biopolymer arrays, e.g., peptide arrays. Transfer of microparticles loaded with amino acids for combinatorial peptide synthesis is demonstrated. Successful synthesis of different peptides (octamers) was proven by immunostaining. Based on results obtained by a chip containing pixel areas of different characteristics, a chip for biological applications with 16,384
pixels (10,000
pixel/cm
2) was built. Good homogeneity of peptide synthesis over the chip area was verified by immunostaining.
The article reviews the relationship between technology and geography from a social science perspective. Especially, the everyday use of technology is discussed as a form of “geography-making”. ...Making use of technology means that an interaction between lay users and experts (the designer of an abstract system and its user interface) takes place which basically implies the use and translation of differing spatial symbolisations: mainly numerical/algorithmic, deictic, and toponymical terms.
ABSTRACT
Some of the most important features of modern societies are the specialisation of knowledge, the development of technology and its ubiquitous integration in everyday practices. Apparently, ...the routine use of complex transport, communication and retail systems can only work out as long as a continuous encoding and decoding of spatial information takes place. In this paper different modes of system‐user‐interaction and the involved spatial concepts will be examined. The outcome is a framework of three conceptual types of interaction (or translation) between the geography of the system and the geography of the user's lifeworld. First, the user learns about the internal spatial code of the system to achieve ‘white‐box‐transparency’. Second, efforts in interface‐design show the attempt for ‘lifeworld‐simulation’ by replicating the individual's spatial perception. Third, common geographical imaginations, names of cities, regions or nations, can serve as a ‘third language’ which both the system and the user can refer to.
Glass slides have been modified with a multifunctional poly(ethylene glycol) (PEG)-based polymer with respect to array applications in the growing field of proteome research. We systematically ...investigated the stepwise synthesis of the PEG films starting from self-assembled alkyl silane monolayers via monolayer peroxidation and subsequent graft polymerization of PEG methacrylate (PEGMA). Chemical composition was examined by X-ray photoelectron spectroscopy (XPS); infrared spectroscopy provided information about order and composition of the films as well; film thickness was determined by ellipsometry; using fluorescence microscopy and again XPS, the amount of proteins adsorbed on the slides was investigated. The novel support material allows a versatile modification of the amino group surface density up to 40
nmol/cm
2 for the linkage of probe molecules. Further on, we carried out standard peptide synthesis based on the well-established 9-fluorenylmethoxycarbonyl (Fmoc) chemistry, which was monitored by UV/Vis quantification of the Fmoc deblocking and mass spectrometry. The polymer coating is stable with respect to a wide range of chemical and thermal conditions, and prevents the glass surface from unspecific protein adsorption. Finally, we applied our modified glass slides in immunoassays and thus examined specific interactions of monoclonal antibodies with appropriate peptide epitopes.
Arrays promise to advance biology by allowing parallel screening for many different binding partners. Meanwhile, lithographic methods enable combinatorial synthesis of > 50,000 oligonucleotides per ...cm(2), an advance that has revolutionized the whole field of genomics. A similar development is expected for the field of proteomics, provided that affordable, very high-density peptide arrays are available. However, peptide arrays lag behind oligonucleotide arrays. This review discusses recent developments in the field with an emphasis on methods that lead to very high-density peptide arrays.
Combinatorial synthesis of peptides on solid supports (1), either as spots on cellulose membranes (2) or with split-pool-libraries on polymer beads (3), substantially forwarded research in the field ...of peptide-protein interactions. Admittedly, these concepts have specific limitations, on one hand the number of synthesizable peptide sequences per area, on the other hand elaborate decoding/encoding strategies, false-positive results and sequence limitations. We recently established a method to produce high-density peptide arrays on microelectronic chips (4). Solid amino acid microparticles were charged by friction and transferred to defined pixel electrodes onto the chip's surface, where they couple to a functional polymer coating simply upon melting (Fig. 16.1 A-D,F). By applying standard Fmoc chemistry according to Merrifield, peptide array densities of up to 40,000 spots per square centimetre were achieved (Fig. 16.1G). The term "Merrifield synthesis" describes the consecutive linear coupling and deprotecting of L-amino acids modified with base-labile fluorenylmethoxy (Fmoc) groups at the N-terminus and different acid-sensitive protecting groups at their side chains. Removing side chain protecting groups takes place only once at the very end of each synthesis and generates the natural peptide sequence thereby.
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