Open arrow

A symbol used to indicate a retrosynthetic step is an open arrow written from prod uct to suitable precursors or fragments of those precursors... 

Figure 5 Free energy surface at l l(Fig. 5a) [22, 24, 28] and 1 3 (Fig. 5b) [23, 24, 33] stoichiometries in the vicinity of disordered state ( f=0.0) at T—. 7Q and 1.6, respectively. The solid line in left-hand (right-hand) figure indicates the kinetic path evolving towards the L q LI2 ordered phase when the system is quenched from T—2.5 (3.0) down to 1.70 (1.60), while the broken lines are devolving towards disordered phase. The open arrows on the contour surface designate the direction of the decrease of free energy, and the arrows on the kinetic path indicate the direction of time evolution or devolution.

Figure 42-12. Structure of human proinsulin. Insulin and C-peptide molecules are connected at two sites by dipeptide links. An initial cleavage by a trypsin-like enzyme (open arrows) followed by several cleavages by a car-boxypeptidase-like enzyme (solid arrows) results in the production of the heterodimeric (AB) insulin molecule (light blue) and the C-peptide.

In the epidermis, one observes an accumulation of calcium in the tricellular junction (arrow head) and in the tangential wall (open arrow). In young flax hypocotyl, the calcium-signal intensities were lower than in mature flax hypocotyl (conq)are A and C). 

The initial step in creating a synthetic plan involves a retrosynthetic analysis. The structure of the molecule is dissected step by step along reasonable pathways to successively simpler compounds until molecules that are acceptable as starting materials are identified. Several factors enter into this process, and all are closely interrelated. The recognition of bond disconnections allows the molecule to be broken down into key intermediates. Such disconnections must be made in such a way that it is feasible to form the bonds by some synthetic process. The relative placement of potential functionality strongly influences which bond disconnections are preferred. To emphasize that these disconnections must correspond to transformations that can be conducted in the synthetic sense, they are sometimes called antisynthetic transforms, i.e., the reverse of synthetic steps. An open arrow symbol, = , is used to indicate an antisynthetic transform. 

Basic two-phase model of fluidized bed. Open arrows indicate movement of solids. (Adapted from Fluidization Engineering by D. Kunii and O. Levenspiel. Copyright 1969. Reprinted by permission of John Wiley and Sons, Inc.)... 

Fig. 13.5. Hydrophobicity analysis of the predicted amino acid sequence from a metalloprotease component of H-gal-GP (MEP3) showing two potential transmembrane domains (indicated by open arrows). B41 and B47 indicate the relative positions of two N-terminal sequences determined from bands present when H-gal-GP is reduced.

Fig. 18. Top transition coordinates (with symmetry species) of conformational transition states of cyclohexane (top and side views). Hydrogen displacements are omitted. The displacement amplitudes given are towards the C2v-symmetric boat form, and towards >2-symmetric twist forms (from left), respectively. Inversion of these displacements leads to the chair and an equivalent T>2-form, respectively. Displacements of obscured atoms are given as open arrows, obscured displacements as an additional top. See Fig. 17 for perspective conformational drawings. Bottom pseudorotational normal coordinates (with symmetry species) of the Cs- and C2-symmetric transition states. The phases of the displacement amplitudes are chosen such that a mutual interconversion of both forms results. The two conformations are viewed down the CC-bonds around which the ring torsion angles - 7.3 and - 13.1° are calculated (Fig. 17). The displacement components perpendicular to the drawing plane are comparatively small. - See text for further details.

Fig. 1. Schematic for /zSR and fiLCR experiments. For pSR the muon spin polarization vector starts off in the x direction (open arrow). It then precesses about an effective field (the vector sum of the external field and the internal hyperfine field), which is normally approximately the z direction. The muons are detected in the M counter, and positrons from muon decay are detected in the L or R counters. For pLCR, the muon spin polarization is initially along the external field or t axis (solid arrow). The positron rates in the F and B counters are measured as a function of external field. A sharp decrease in the asymmetry of the F and B counting rates signifies a level crossing.

Fig. 16. Parallel superpleated /J-structure proposed for Ure2p amyloid-like fibrils, from Kajava et al. (2004). (A) Ribbon diagram o( a dimer of Saccharnmyces cermnsiae l Jre2p C-terminal domains (PDB ID code 1G6W), generated with Pymol (DeLano, 2002). The monomers are colored in light and dark gray and are viewed down the twofold symmetry axis. The N- and C-termini are indicated, and residue 137 is denoted by an open arrow.

Events Exchanges of information that happen when initiated by the sender to signal a state change (shown with an open arrow —> )... 

Pictorially, input and output properties can be shown with solid arrows, as distinguished from the open arrows of events. (The shadow emphasizes that this is a component—that is, something intended to be implemented according to a component architecture. But it s only for dramatic effect and can be omitted.)... 

Figure 4. A schematic of endocytotic pathways in a cell. P = pinocytosis Ex = Exocytosis R = receptor C = clathrin CP, CV = coated pit and coated vesicle E = endosome L = lysosome. Open arrow indicates recycling of clathrin and receptors. Solid arrows indicate pathways. See the text for discussion...

Figure 5. Isolate islands with different e under the infinite- and zero-torque conditions. The shear modulus of the substrate phase is twice that of the film (p = 2p), and all the interface energies are identical to each other. Large open arrow heads mark triple j unctions, and small solid ones indicate islands on the top of a main island.

Figure 2-26 Some of the possibilities for hydrogen bonding of side chain groups in proteins. Oxygen atoms can and frequently do form up to three hydrogen bonds at once. Open arrows point from H-atoms and toward electron donor pairs.

Figure 27-20 (A) Hypothetical replisome for concurrent replication of leading and lagging strands by a dimeric polymerase associated with helicase dnaB and a primosome. Open arrows indicate directions of movement of DNA, which is forming a loop as the polymerase fills a gap to complete an Okazaki fragment. The primase will then form a new primer and a new loop. From Komberg and Baker.265 (B) Electron micrograph of the primosome bound to covalently closed ( )X174 duplex replicative form. These enzymatically synthesized duplexes invariably contain a single primosome with one or two associated small DNA loops. From A. Komberg in Hubscher and Spadari,266 pp. 9,10.

Fig. 20.1. Generalized scheme of the main pathways of aerobic and anaerobic carbohydrate degradation in parasitic flatworms. The aerobic pathway is indicated by open arrows, whereas the anaerobic pathway (malate dismutation) is indicated by solid arrows. Abbreviations AcCoA, acetyl-CoA ASCT, acetateisuccinate CoA-transferase C, cytochrome c CI-CIV, complexes I—IV of the respiratory chain CITR, citrate FRD, fumarate reductase FUM, fumarate MAL, malate Methylmal-CoA, methylmalonyl-CoA OXAC, oxaloacetate PEP, phosphoenolpyruvate PROP, propionate Prop-CoA, propionyl-CoA PYR, pyruvate RQ, rhodoquinone SDH, succinate dehydrogenase SUCC, succinate Succ CoA, succinyl CoA UQ, ubiquinone.

Fig. 20.3. Schematic representation of the main pathways in the lipid metabolism of parasitic flatworms. Boxed substrates are supplied by the host. Pathways present in mammalian systems but absent in parasitic flatworms are shown by open arrows. Abbreviations DAG, diacylglycerol CDP-DAG, cytidine diphosphodiacylglycerol Farnesyl PP, farnesyl pyrophosphate Geranyl PP, geranylpyrophosphate Geranylgeranyl PP, geranylgeranylpyrophosphate FlMG-CoA, hydroxymethylglutaryl-CoA TAG, triacylglycerol PA, phosphatidic acid PC, phosphatidylcholine PE, phosphatidylethanolamine PI, phosphatidylinositol PS, phosphatidylserine.

The cAMP second messenger pathway. Key proteins include hormone receptors (Rec), a stimulatory G protein (Gs), catalytic adenylyl cyclase (AC), phosphodiesterases (PDE) that hydrolyze cAMP, cAMP-dependent kinases, with regulatory (R) and catalytic (C) subunits, protein substrates (S) of the kinases, and phosphatases (P ase), which remove phosphates from substrate proteins. Open arrows denote regulatory effects. 

The Ca2+-phosphoinositide signaling pathway. Key proteins include hormone receptors (R), a G protein (G), a phosphoinositide-specific phospholipase C (PLC), protein kinase C substrates of the kinase (S), calmodulin (CaM), and calmodulin-binding enzymes (E), including kinases, phosphodiesterases, etc. (PIP2, phosphatidylinositol-4,5-bisphosphate DAG, diacylglycerol. Asterisk denotes activated state. Open arrows denote regulatory effects.)... 

Scheme 8.1 Retrosynthesis in synthetic organic chemistry to determine suitable synthons and hence prepare the target molecule from suitable synthetic equivalents. The retrosynthetic steps are indicated by open arrows.

Fig. 2 Electron micrograph of synapses. The image shows synapses formed by cultured cortical neurons from mouse. Note abundant synaptic vesicles in nerve terminals adjacent to synaptic junctions that are composed of presynaptic active zones and postsynaptic densities (open arrows point to postsynaptic densities of synaptic junctions synapse on the right contains two junctions). In addition to synaptic vesicles, two of the nerve terminals contain LDCVs (closed arrows). Calibration bar = 500 nm. (Image courtesy of Dr. Xinran Liu, UT Southwestern).

Fig. 5 GPCR regulation of exocytosis downstream of Ca2+-entry. (a) Sequence of steps leading from recruitment to maturation of synaptic vesicles from a reserve pool (RP) to a readily-releasable pool (RRP) displaying slow (asynchronous) and fast (synchronous highly Ca2+-sensitive pool, HCSP synaptotagmin 1 (SYT 1) supported) components, (b) Protein-protein interactions of SNARES (SYX, syntaxin SYB, synaptobrevin and SNAP-2s-7S complex) and major putative regulatory proteins. Phosphoproteins are shown in shaded boxes (phosphorylation sites for PKA and PKC are indicated where known) with phosphorylation-dependent interactions depicted by arrows (increase indicated by filled arrows decrease indicated by open arrows). Circle-end connectors indicate a phosphorylation-independent or as yet unspecified interaction. Potential effects of interactions at various points of the sequence in A are discussed in the text.

Figure 2. Fluxes of sulfur in higher plants. Open arrows fluxes of sulfate closed arrows synthesis and translocation of reduced sulfur compound. CYS, cysteine MET, methionine, GSH, reduced glutathione X-SH, carrier-bound sulfide.

Figure 10.13 Schematic representation of an adsorbed fragment of a PDMS chain [113]. The solid arrows denote the anisotropic motion of chain units during the lifetime in the adsorbed state. The open arrows denote the adsorption-desorption of chain units. The length of the adsorption-desorption jumps is possibly in the order of...

Photoinduced electron transport and the coupled phosphorylation reactions as they are postulated to occur in chloroplasts are presented schematically in Figure 2. Not all investigators agree on the details of this scheme, and some even question the sequence of the intermediates. The numbers and locations of the phosphorylation sites also remain to be identified precisely. However, the scheme is a reasonable approximation based on available information. Reactions that occur in the light are represented by the open arrows and the solid arrows represent electron transfers that occur in the dark. 

Figure 2. Schematic of photoinduced electron transport and phosphorylation reactions considered to occur in chloroplast lamellae [from Moreland and Hilton (2)]. Open arrows indicate light reactions solid arrows indicate dark reactions and the narrow dashed line represents the cyclic pathway. Abbreviations used PS I, photosystem I PS II, photosystem II Y, postulated electron donor for photosystem II Q, unknown primary electron acceptor for photosystem II PQ, plastoquinones cyt b, b-type cytochromes cyt f, cytochrome f PC, plastocyanin P700, reaction center chlorophyll of photosystem I FRS, ferredoxin-reducing substance Fd, ferredoxin Fp, ferredoxin-NADP oxidoreductase FeCy, ferricyanide asc, ascorbate and DPIP, 2,6-dichloropheno-lindophenol. The numbers la, lb, 2, 3, and 4 indicate postulated sites of action by...

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