Hourglass structures

Figure2.1 The hourglass structure of the IMRD format (adapted from Hill et al., 1982).

Browse through three articles in Chemical Research in Toxicology or the Journal of Agricultural and Food Chemistry. For each article, copy and paste into a text document one sentence from each IMRD section that is consistent with the hourglass structure. Examine each group of four sentences. Is the hourglass structure apparent in these four sentences Explain. 

Most Methods sections follow a conventional organizational pattern. The pattern typically Involves two or three separate steps, each of which corresponds to a move, as shown in hgure 3.1. In accord with a common title for this section— Materials and Methods—the moves describe first the materials and then the methods (experimental and/or numerical) that were used in the work. Because these moves describe specific information, the Methods section is in the narrowest part of the IMRD hourglass structure. 

Is the last paragraph (P5) accessible to a scientific audience (as opposed to an expert audience), thereby completing the hourglass structure What larger implications do the authors present ... 

The second move of the poster Introduction previews the specific accomplishments of the work and is often given its own subheading (e.g.. Research Objectives or Goals). The focus should be on research goals that have been achieved and are presented in the poster. Move 2 has a narrower focus than move 1 hence, the poster Introduction follows the broad-to-narrow hourglass structure. As a test to see if your Introduction addresses moves 1 and 2 sufficiently, ask yourself if a viewer, after reading only your Introduction, could answer the following questions (1) What research area is addressed (2) Why is this area important (3) What specific accomplishments will the authors present in their poster ... 

Aquaporins comprise six transmembrane a-helices, and five interhelical loop regions (A-E) that form the extracellular and cytoplasmic vestibules. Loops B and E are hydrophobic loops which contain the highly, although not completely, conserved Asn-Pro-Ala (NPA) motif, which overlaps the middle of the lipid bilayer of the membrane, forming a 3D hourglass structure through which water flows. Two constrictions in the channel act as selectivity Alters. 

Figure 4 The modified stalk mechanism of membrane fusion and inverted phase formation, (a) planar lamellar (La) phase bilayers (b) the stalk intermediate the stalk is cylindrically-symmetrical about the dashed vertical axis (c) the TMC (trans monolayer contact) or hemifusion structure the TMC can rupture to form a fusion pore, referred to as interlamellar attachment, ILA (d) (e) If ILAs accumulate in large numbers, they can rearrange to form Qn phases, (f) For systems close to the La/H phase boundary, TMCs can also aggregate to form H precursors and assemble Into H domains. The balance between Qn and H phase formation Is dictated by the value of the Gaussian curvature elastic modulus of the bIlayer (reproduced from (25) with permission of the Biophysical Society) The stalk in (b) is structural unit of the rhombohedral phase (b ) electron density distribution for the stalk fragment of the rhombohedral phase, along with a cartoon of a stalk with two lipid monolayers merged to form a hourglass structure (reproduced from (26) with permission of the Biophysical Society).

Fig. 34 Microscopic images of a typical silicalite-1 crystal in two different orientations. The hourglass structure is made visible by using the shearing mechanism of the microscope. The length scale in the x,y, and z directions is shown in micrometers...

The poster text is divided into the same general IMRD sections as the journal article Introduction, Methods, Results, and Discussion. Similarly, most posters include an Acknowledgments section, some have an abbreviated References section, and all have a title and author list. Most posters do not include an abstract, in part because of space limitations and in part because an abstract already appears in the conference proceedings. Like the journal article, the IMRD structure of the poster follows an hourglass shape. The top (Introduction) and bottom (Discussion) sections have a broader focus, while the middle sections (Methods and Results) have a narrower focus. Each section of the poster can be divided into individual moves or steps that guide viewers in a conventional way through the content of each section. These moves are analyzed in the next part of the chapter. 

Jung J, Preston G M, Smith B, Guggino W, Agre P. 1994. Molecular structure of the water channel through aquaporin CHIP. The hourglass model. J Biol Chem 269 14648-14654. 

The seed coat is the outermost tissue layer which protects the embryonic structure and consists of approximately 7-8 % of the total dry weight in the mature bean with a protein content of 5% (db) (3 and 4). Two external anatomical features include the hilum and micropyle which each have a role in water absorption. The major components in the seed coat structure include a waxy cuticle layer, palisade cell layer, hourglass cells and thick cell-walled parenchyma cells. The cuticle is the outermost portion of the seed coat and its... 

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