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root/group/trunk/matt_papers/MWTCC03/poster.tex
Revision: 552
Committed: Mon Jun 9 21:19:02 2003 UTC (21 years, 3 months ago) by mmeineke
Content type: application/x-tex
File size: 19679 byte(s)
Log Message:
First completed rough draft (spell checked even).

File Contents

# User Rev Content
1 mmeineke 546 %% this is my poster for the Midwest Theoretical Conference
2    
3    
4     \documentclass[10pt]{scrartcl}
5     %%
6     %
7     % This is a poster template with latex macros and using
8     % the University of Florida Logo. For further information
9     % on making postscript, resizeing, and printing the poster file
10     % please see web site
11     % http://www.phys.ufl.edu/~pjh/posters/poster_howto_UF.html
12     %
13     % N.B. This format is cribbed from one obtained from the University
14     % of Karlsruhe, so some macro names and parameters are in German
15     % Here is a short glosary:
16     % Breite: width
17     % Hoehe: height
18     % Spalte: column
19     % Kasten: box
20     %
21     % All style files necessary are part of standard TeTeX distribution
22     % On the UF unix cluster you should not need to import these files
23     % specially, as they will be automatically located. If you
24     % run on a local PC however, you will need to locate these files.
25     % At UF try /usr/local/TeTeX...
26     %
27     % P. Hirschfeld 2/11/00
28     %
29     % The recommended procedure is to first generate a ``Special Format" size poster
30     % file, which is relatively easy to manipulate and view. It can be
31     % resized later to A0 (900 x 1100 mm) full poster size, or A4 or Letter size
32     % as desired (see web site). Note the large format printers currently
33     % in use at UF's OIR have max width of about 90cm or 3 ft., but the paper
34     % comes in rolls so the length is variable. See below the specifications
35     % for width and height of various formats. Default in the template is
36     % ``Special Format", with 4 columns.
37     %%
38     %%
39     %% Choose your poster size:
40     %% For printing you will later RESIZE your poster by a factor
41     %% 2*sqrt(2) = 2.828 (for A0)
42     %% 2 = 2.00 (for A1)
43     %%
44     %%
45 mmeineke 551 \def\breite{390mm} % Special Format.
46 mmeineke 546 \def\hoehe{319.2mm} % Scaled by 2.82 this gives 110cm x 90cm
47     \def\anzspalten{4}
48     %%
49     %%\def\breite{420mm} % A3 LANDSCAPE
50     %%\def\hoehe{297mm}
51     %%\def\anzspalten{4}
52     %%
53     %% \def\breite{297mm} % A3 PORTRAIT
54     %% \def\hoehe{420mm}
55     %% \def\anzspalten{3}
56     %%
57     %% \def\breite{210mm} % A4 PORTRAIT
58     %% \def\hoehe{297mm}
59     %% \def\anzspalten{2}
60     %%
61     %%
62     %% Procedure:
63     %% Generate poster.dvi with latex
64     %% Check with Ghostview
65     %% Make a .ps-file with ``dvips -o poster.ps poster''
66     %% Scale it with poster_resize poster.ps S
67     %% where S is scale factor
68     %% for Special Format->A0 S= 2.828 (= 2^(3/2)))
69     %% for Special Format->A1 S= 2 (= 2^(2/2)))
70     %%
71     %% Sizes (European:)
72     %% A3: 29.73 X 42.04 cm
73     %% A1: 59.5 X 84.1 cm
74     %% A0: 84.1 X 118.9 cm
75     %% N.B. The recommended procedure is ``Special Format x 2.82"
76     %% which gives 90cm x 110cm (not quite A0 dimensions).
77     %%
78     %% --------------------------------------------------------------------------
79     %%
80     %% Load the necessary packages
81     %%
82 mmeineke 549 \usepackage{palatino}
83 mmeineke 546 \usepackage[latin1]{inputenc}
84     \usepackage{epsf}
85     \usepackage{graphicx,psfrag,color,pstcol,pst-grad}
86     \usepackage{amsmath,amssymb}
87     \usepackage{latexsym}
88     \usepackage{calc}
89     \usepackage{multicol}
90 mmeineke 550 \usepackage{wrapfig}
91 mmeineke 546 %%
92     %% Define the required numbers, lengths and boxes
93     %%
94     \newsavebox{\dummybox}
95     \newsavebox{\spalten}
96     %\input psfig.sty
97    
98     %%
99     %%
100     \newlength{\bgwidth}\newlength{\bgheight}
101     \setlength\bgheight{\hoehe} \addtolength\bgheight{-1mm}
102     \setlength\bgwidth{\breite} \addtolength\bgwidth{-1mm}
103    
104     \newlength{\kastenwidth}
105    
106     %% Set paper format
107     \setlength\paperheight{\hoehe}
108     \setlength\paperwidth{\breite}
109     \special{papersize=\breite,\hoehe}
110    
111     \topmargin -1in
112     \marginparsep0mm
113     \marginparwidth0mm
114     \headheight0mm
115     \headsep0mm
116    
117    
118     %% Minimal Margins to Make Correct Bounding Box
119     \setlength{\oddsidemargin}{-2.44cm}
120     \addtolength{\topmargin}{-3mm}
121     \textwidth\paperwidth
122     \textheight\paperheight
123    
124     %%
125     %%
126     \parindent0cm
127     \parskip1.5ex plus0.5ex minus 0.5ex
128     \pagestyle{empty}
129    
130    
131    
132     \definecolor{ndgold}{rgb}{0.87,0.82,0.59}
133     \definecolor{ndgold2}{rgb}{0.96,0.91,0.63}
134 mmeineke 547 \definecolor{ndblue}{rgb}{0,0.1875, 0.6992}
135 mmeineke 546 \definecolor{recoilcolor}{rgb}{1,0,0}
136     \definecolor{occolor}{rgb}{0,1,0}
137     \definecolor{pink}{rgb}{0,1,1}
138    
139    
140    
141    
142    
143     \def\UberStil{\normalfont\sffamily\bfseries\large}
144     \def\UnterStil{\normalfont\sffamily\small}
145     \def\LabelStil{\normalfont\sffamily\tiny}
146     \def\LegStil{\normalfont\sffamily\tiny}
147    
148     %%
149     %% Define some commands
150     %%
151     \definecolor{JG}{rgb}{0.1,0.9,0.3}
152    
153     \newenvironment{kasten}{%
154     \begin{lrbox}{\dummybox}%
155     \begin{minipage}{0.96\linewidth}}%
156     {\end{minipage}%
157     \end{lrbox}%
158     \raisebox{-\depth}{\psshadowbox[framearc=0.05,framesep=1em]{\usebox{\dummybox}}}\\[0.5em]}
159     \newenvironment{spalte}{%
160     \setlength\kastenwidth{1.2\textwidth}
161     \divide\kastenwidth by \anzspalten
162     \begin{minipage}[t]{\kastenwidth}}{\end{minipage}\hfill}
163    
164    
165    
166 mmeineke 551
167 mmeineke 546 \def\op#1{\hat{#1}}
168     \begin{document}
169     \bibliographystyle{plain}
170     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
171     %%% Background %%%
172     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
173 mmeineke 551 {\newrgbcolor{gradbegin}{0.0 0.01875 0.6992}%
174 mmeineke 546 \newrgbcolor{gradend}{1 1 1}%{1 1 0.5}%
175     \psframe[fillstyle=gradient,gradend=gradend,%
176     gradbegin=gradbegin,gradmidpoint=0.1](\bgwidth,-\bgheight)}
177     \vfill
178     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
179     %%% Header %%%
180     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
181     \hfill
182     \psshadowbox[fillstyle=solid,fillcolor=ndgold2]{\makebox[0.95\textwidth]{%
183     \hfill
184 mmeineke 547 \parbox[c]{2cm}{\includegraphics[width=8cm]{ndLogoScience1a.eps}}
185 mmeineke 546 \hfill
186     \parbox[c]{0.8\linewidth}{%
187     \begin{center}
188 mmeineke 547 \color{ndblue}
189 mmeineke 546 \textbf{\Huge {A Mesoscale Model for Phospholipid Simulations}}\\[0.5em]
190     \textsc{\LARGE \underline{Matthew~A.~Meineke}, and J.~Daniel~Gezelter}\\[0.3em]
191     {\large Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA\\
192     {\tt\ mmeineke@nd.edu}
193     }
194     \end{center}}
195     \hfill}}\hfill\mbox{}\\[1.cm]
196     %\vspace*{1.3cm}
197     \begin{lrbox}{\spalten}
198     \parbox[t][\textheight]{1.3\textwidth}{%
199     \vspace*{0.2cm}
200     \hfill
201     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
202     %%% first column %%%
203     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
204     \begin{spalte}
205     \begin{kasten}
206     %
207     %
208     % This begins the first "kasten" or box
209     %
210     %
211     \begin{center}
212     {\large{\color{red} \underline{ABSTRACT} } }
213     \end{center}
214    
215     {\color{ndblue}
216    
217     A mesoscale model for phospholipids has been developed for molecular
218     dynamics simulations of lipid bilayers. The model makes several
219     simplifications to both the water and the phospholipids to reduce the
220     computational cost of each force evaluation. The water was represented
221     by the soft sticky dipole model of Ichiye \emph{et
222     al}.\cite{liu96:new_model,liu96:monte_carlo,chandra99:ssd_md} The
223     simplifications to the phospholipids included the reduction of atoms
224     in the tail groups to beads representing $\mbox{CH}_{2}$ and
225     $\mbox{CH}_{3}$ unified atoms, and the replacement of the head groups
226     with a single point mass containing a centrally located dipole. The
227 mmeineke 552 model was then used to simulate micelle formation from a configuration
228     of randomly placed phospholipids which was simulated for times in
229     excess of 20 nanoseconds.
230 mmeineke 546
231     }
232     \end{kasten}
233    
234 mmeineke 550
235     \begin{kasten}
236     \section{{\color{red}\underline{Introduction \& Background}}}
237     \label{sec:intro}
238 mmeineke 546
239 mmeineke 551 %% \subsection{{\color{ndblue}Motivation}}
240 mmeineke 550 \label{sec:motivation}
241 mmeineke 546
242 mmeineke 550
243     Simulations of phospholipid bilayers are, by necessity, quite
244     complex. The lipid molecules are large, and contain many
245     atoms. Additionally, the head groups of the lipids are often
246     zwitterions, and the large separation between charges results in a
247     large dipole moment. Adding to the complexity are the number of water
248     molecules needed to properly solvate the lipid bilayer, typically 25
249     water molecules for every lipid molecule. These factors make it
250     difficult to study certain biologically interesting phenomena that
251     have large inherent length or time scale.
252    
253     \end{kasten}
254    
255     \begin{kasten}
256     \subsection{{\color{ndblue}Ripple Phase}}
257    
258     \begin{wrapfigure}{o}{60mm}
259     \centering
260     \includegraphics[width=40mm]{ripple.epsi}
261     \end{wrapfigure}
262    
263     \mbox{}
264     \begin{itemize}
265     \item The ripple (~$P_{\beta'}$~) phase lies in the transition from the gel to fluid phase.
266     \item Periodicity of 100 - 200 $\mbox{\AA}$\cite{Cevc87}
267     \item Current simulations have box sizes ranging from 50 - 100 $\mbox{\AA}$ on a side.\cite{saiz02,lindahl00,venable00}
268     \end{itemize}
269    
270     \label{sec:ripplePhase}
271    
272     \end{kasten}
273    
274    
275     \begin{kasten}
276     \subsection{{\color{ndblue}Diffusion \& Formation Dynamics}}
277     \begin{itemize}
278    
279     \item
280     Drug Diffusion
281     \begin{itemize}
282     \item
283     Some drug molecules may spend appreciable amounts of time in the
284     membrane
285    
286     \item
287     Long time scale dynamics are need to observe and characterize their
288     actions
289     \end{itemize}
290    
291     \item
292     Bilayer Formation Dynamics
293     \begin{itemize}
294     \item
295     Current lipid simulations indicate\cite{Marrink01}:
296     \begin{itemize}
297     \item Aggregation can happen as quickly as 200 ps
298    
299     \item Bilayers can take up to 20 ns to form completely
300     \end{itemize}
301    
302     \end{itemize}
303     \end{itemize}
304     \end{kasten}
305    
306     \begin{kasten}
307 mmeineke 552 \subsection{{\color{ndblue}System Simplifications}}
308 mmeineke 550 \begin{itemize}
309     \item Unified atoms with fixed bond lengths replace groups of atoms.
310 mmeineke 552 \item Replace charge distributions with dipoles.(Eq.~\ref{eq:dipole}
311     vs. Eq.~\ref{eq:coloumb})
312 mmeineke 550 \begin{itemize}
313     \item Relatively short range, $\frac{1}{r^3}$, interactions allow
314     the application of computational simplification algorithms,
315 mmeineke 552 i.e. neighbor lists.
316 mmeineke 550 \end{itemize}
317     \end{itemize}
318     \begin{equation}
319     V^{\text{dp}}_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},
320     \boldsymbol{\Omega}_{j}) = \frac{1}{4\pi\epsilon_{0}} \biggl[
321     \frac{\boldsymbol{\mu}_{i} \cdot \boldsymbol{\mu}_{j}}{r^{3}_{ij}}
322     -
323     \frac{3(\boldsymbol{\mu}_i \cdot \mathbf{r}_{ij}) %
324     (\boldsymbol{\mu}_j \cdot \mathbf{r}_{ij}) }
325     {r^{5}_{ij}} \biggr]
326     \label{eq:dipole}
327     \end{equation}
328     \begin{equation}
329     V^{\text{ch}}_{ij}(\mathbf{r}_{ij}) = \frac{q_{i}q_{j}}%
330     {4\pi\epsilon_{0} r_{ij}}
331     \label{eq:coloumb}
332     \end{equation}
333     \end{kasten}
334    
335    
336    
337 mmeineke 546 \end{spalte}
338     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
339     %%% second column %%%
340     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
341     \begin{spalte}
342    
343    
344 mmeineke 550 \begin{kasten}
345     \subsection{{\color{ndblue}Reduction in calculations}}
346     Unified water and lipid models and decrease the number of interactions
347     needed between two molecules.
348    
349     \begin{center}
350     \includegraphics[width=50mm,angle=-90]{reduction.epsi}
351     \end{center}
352 mmeineke 546 \end{kasten}
353    
354    
355 mmeineke 550 \begin{kasten}
356     \section{{\color{red}\underline{Models}}}
357     \label{sec:model}
358 mmeineke 552 \subsection{{\color{ndblue}The Water Model}}
359 mmeineke 550 \label{sec:waterModel}
360 mmeineke 546
361 mmeineke 550 The waters in the simulation were modeled after the Soft Sticky Dipole
362     (SSD) model of Ichiye.\cite{liu96:new_model} Where:
363 mmeineke 546
364 mmeineke 550 \begin{wrapfigure}[10]{o}{60mm}
365     \begin{center}
366     \includegraphics[width=40mm]{ssd.epsi}
367     \end{center}
368     \end{wrapfigure}
369     \mbox{}
370     \begin{itemize}
371 mmeineke 552 \item $\sigma$ is the Lennard-Jones length parameter
372     \item $\boldsymbol{\mu}_i$ is the dipole vector of molecule $i$
373 mmeineke 550 \item $\mathbf{r}_{ij}$ is the vector between molecules $i$ and $j$
374 mmeineke 552 \item $\boldsymbol{\Omega}_i$ and $\boldsymbol{\Omega}_j$ are the Euler angles of molecule $i$ or $j$ respectively
375 mmeineke 550 \end{itemize}
376    
377     It's potential is as follows:
378     \begin{equation}
379     V_{s\!s\!d} = V_{L\!J}(r_{i\!j}) + V_{d\!p}(r_{i\!j},\Omega_{i},\Omega_{j})
380     + V_{s\!p}(r_{i\!j},\Omega_{i},\Omega_{j})
381 mmeineke 552 \label{eq:ssdPot}
382 mmeineke 550 \end{equation}
383 mmeineke 552 Where $V_{d\!p}(r_{i\!j}$ is given in Eq.~\ref{eq:dipole}, and $V_{L\!J}(r_{i\!j})$ is the Lennard-Jones potential:
384     \begin{equation}
385     V_{\text{LJ}} =
386     4\epsilon_{ij} \biggl[
387     \biggl(\frac{\sigma_{ij}}{r_{ij}}\biggr)^{12}
388     - \biggl(\frac{\sigma_{ij}}{r_{ij}}\biggr)^{6}
389     \biggr]
390     \label{eq:lennardJonesPot}
391     \end{equation}
392 mmeineke 550
393     \end{kasten}
394    
395 mmeineke 552 \begin{kasten}
396     \subsection{{\color{ndblue}Soft Sticky Potential}}
397     \label{sec:SSeq}
398 mmeineke 550
399 mmeineke 552 Hydrogen bonding in the SSD model is described by the
400     $V_{\text{sp}}$ term in Eq.~\ref{eq:ssdPot}. Its form is as follows:
401     \begin{equation}
402     V_{\text{sp}}(\mathbf{r}_{i\!j},\boldsymbol{\Omega}_{i},
403     \boldsymbol{\Omega}_{j}) =
404     v^{\circ}[s(r_{ij})w_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},
405     \boldsymbol{\Omega}_{j})
406     +
407     s'(r_{ij})w^{x}_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},
408     \boldsymbol{\Omega}_{j})]
409     \label{eq:spPot}
410     \end{equation}
411     Where $v^\circ$ scales the strength of the interaction.
412     $w_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},\boldsymbol{\Omega}_{j})$
413     and
414     $w^{x}_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},\boldsymbol{\Omega}_{j})$
415     are responsible for the tetrahedral potential and a correction to the
416     tetrahedral potential respectively. They are,
417     \begin{equation}
418     w_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},\boldsymbol{\Omega}_{j}) =
419     \sin\theta_{ij} \sin 2\theta_{ij} \cos 2\phi_{ij}
420     + \sin \theta_{ji} \sin 2\theta_{ji} \cos 2\phi_{ji}
421     \label{eq:spPot2}
422     \end{equation}o
423     and
424     \begin{equation}
425     \begin{split}
426     w^{x}_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},\boldsymbol{\Omega}_{j}) =
427     &(\cos\theta_{ij}-0.6)^2(\cos\theta_{ij} + 0.8)^2 \\
428     &+ (\cos\theta_{ji}-0.6)^2(\cos\theta_{ji} + 0.8)^2 - 2w^{\circ}
429     \end{split}
430     \label{eq:spCorrection}
431     \end{equation}
432     The angles $\theta_{ij}$ and $\phi_{ij}$ are defined by the spherical
433     coordinates of the position of molecule $j$ in the reference frame
434     fixed on molecule $i$ with the z-axis aligned with the dipole moment.
435     The correction
436     $w^{x}_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},\boldsymbol{\Omega}_{j})$
437     is needed because
438     $w_{ij}(\mathbf{r}_{ij},\boldsymbol{\Omega}_{i},\boldsymbol{\Omega}_{j})$
439     vanishes when $\theta_{ij}$ is $0^\circ$ or $180^\circ$. Finally, the
440     potential is scaled by the switching function $s(r_{ij})$,
441     which scales smoothly from 0 to 1.
442     \begin{equation}
443     s(r_{ij}) =
444     \begin{cases}
445     1& \text{if $r_{ij} < r_{L}$}, \\
446     \frac{(r_{U} - r_{ij})^2 (r_{U} + 2r_{ij}
447     - 3r_{L})}{(r_{U}-r_{L})^3}&
448     \text{if $r_{L} \leq r_{ij} \leq r_{U}$},\\
449     0& \text{if $r_{ij} \geq r_{U}$}.
450     \end{cases}
451     \label{eq:spCutoff}
452     \end{equation}
453 mmeineke 550
454 mmeineke 552 \end{kasten}
455 mmeineke 550
456 mmeineke 552
457 mmeineke 546 \end{spalte}
458     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
459     %%% third column %%%
460     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
461     \begin{spalte}
462    
463 mmeineke 552 \begin{kasten}
464     \subsection{{\color{ndblue}Hydrogen Bonding in SSD}}
465     \label{sec:hbonding}
466 mmeineke 546
467 mmeineke 552 The SSD model's $V_{s\!p}(r_{i\!j},\Omega_{i},\Omega_{j})$
468     recreates the hydrogen bonding network of water.
469     \begin{center}
470     \begin{minipage}{100mm}
471     \begin{minipage}[t]{48mm}
472     \begin{center}
473     \includegraphics[width=48mm]{iced_final.eps}\\
474     SSD Relaxed on a diamond lattice
475     \end{center}
476     \end{minipage}
477     \hspace{4mm}%
478     \begin{minipage}[t]{48mm}
479     \begin{center}
480     \includegraphics[width=48mm]{dipoled_final.eps}\\
481     Stockmayer Spheres relaxed on a diamond lattice
482     \end{center}
483     \end{minipage}
484     \end{minipage}
485 mmeineke 546
486 mmeineke 552 \end{center}
487    
488 mmeineke 546
489 mmeineke 552 \end{kasten}
490    
491    
492     \begin{kasten}
493    
494     \subsection{{\color{ndblue}The Lipid Model}}
495     \label{sec:lipidModel}
496    
497     \begin{center}
498     \includegraphics[width=25mm,angle=-90]{lipidModel.epsi}
499     \end{center}
500    
501     \begin{itemize}
502     \item Head group replaced by a single Lennard-Jones sphere containing a dipole at its center
503     \item Atoms in the tail chains modeled as unified groups of atoms
504     \item Tail group interaction parameters based on those of TraPPE\cite{Siepmann1998}
505     \end{itemize}
506    
507     The total potential is given by:
508     \begin{equation}
509     V_{\text{lipid}} =
510     \sum_{i}V_{i}^{\text{internal}}
511     + \sum_i \sum_{j>i} \sum_{\text{$\alpha$ in $i$}}
512     \sum_{\text{$\beta$ in $j$}}
513     V_{\text{LJ}}(r_{\alpha_{i}\beta_{j}})
514     +\sum_i\sum_{j>i}V_{\text{dp}}(r_{1_i,1_j},\Omega_{1_i},\Omega_{1_j})
515     \end{equation}
516     Where
517     \begin{equation}
518     V_{i}^{\text{internal}} =
519     \sum_{\text{bends}}V_{\text{bend}}(\theta_{\alpha\beta\gamma})
520     + \sum_{\text{torsions}}V_{\text{tors.}}(\phi_{\alpha\beta\gamma\zeta})
521     + \sum_{\alpha} \sum_{\beta>\alpha}V_{\text{LJ}}(r_{\alpha \beta})
522     \end{equation}
523     The bend and torsion potentials were of the form:
524     \begin{equation}
525     V_{\text{bend}}(\theta_{\alpha\beta\gamma})
526     = k_{\theta}\frac{(\theta_{\alpha\beta\gamma} - \theta_0)^2}{2}
527     \label{eq:bendPot}
528     \end{equation}
529     \begin{equation}
530     V_{\text{tors.}}(\phi_{\alpha\beta\gamma\zeta})
531     = c_1 [1+\cos\phi_{\alpha\beta\gamma\zeta}]
532     + c_2 [1 - \cos(2\phi_{\alpha\beta\gamma\zeta})]
533     + c_3 [1 + \cos(3\phi_{\alpha\beta\gamma\zeta})]
534     \label{eq:torsPot}
535     \end{equation}
536    
537    
538     \end{kasten}
539    
540     \begin{kasten}
541    
542     \section{{\color{red}\underline{Initial Results}}}
543     \label{sec:results}
544     \subsection{{\color{ndblue}50 lipids randomly arranged in water}}
545     \label{sec:r50}
546    
547     \begin{center}
548     \begin{minipage}{130mm}
549     \begin{minipage}[t]{40mm}
550     \begin{itemize}
551     \item $N_{\mbox{lipids}} = 25$
552     \end{itemize}
553     \end{minipage}
554     \begin{minipage}[t]{40mm}
555     \begin{itemize}
556     \item $N_{\mbox{H}_{2}\mbox{O}} = 1386$
557     \end{itemize}
558     \end{minipage}
559     \begin{minipage}[t]{40mm}
560     \begin{itemize}
561     \item T = 300 K
562     \end{itemize}
563     \end{minipage}
564     \end{minipage}
565     \end{center}
566    
567     \end{kasten}
568    
569     \begin{kasten}
570    
571     \subsection{{\color{ndblue}Simulation Snapshots}}
572     \label{sec:r50snapshots}
573    
574     \begin{center}
575     \includegraphics[width=105mm]{r50-montage.eps}
576     \end{center}
577    
578     \end{kasten}
579    
580    
581 mmeineke 546 \end{spalte}
582     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
583     %%% fourth column %%%
584     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
585     \begin{spalte}
586    
587 mmeineke 552 \begin{kasten}
588    
589     \subsection{{\color{ndblue}Position and Angular Correlations}}
590     \label{sec:r50corr}
591 mmeineke 546
592 mmeineke 552 \begin{center}
593     \begin{minipage}{110mm}
594     \begin{minipage}[t]{55mm}
595     \begin{center}
596     \includegraphics[width=36mm,angle=-90]{r50-HEAD-HEAD.epsi}\\
597     The self correlation of the head groups
598     \end{center}
599     \end{minipage}
600     \begin{minipage}[t]{55mm}
601     \begin{center}
602     \includegraphics[width=36mm,angle=-90]{r50-CH2-CH2.epsi}\\
603     The self correlation of the tail beads.
604     \end{center}
605     \end{minipage}
606     \end{minipage}
607     \end{center}
608     \begin{equation}
609     g(r) = \frac{V}{N_{\text{pairs}}}\langle \sum_{i} \sum_{j > i}
610     \delta(|\mathbf{r} - \mathbf{r}_{ij}|) \rangle
611     \label{eq:gofr}
612     \end{equation}
613     \begin{equation}
614     g_{\gamma}(r) = \langle \sum_i \sum_{j>i}
615     (\cos \gamma_{ij}) \delta(| \mathbf{r} - \mathbf{r}_{ij}|) \rangle
616     \label{eq:gammaofr}
617     \end{equation}
618 mmeineke 546
619 mmeineke 552 \end{kasten}
620 mmeineke 546
621    
622 mmeineke 552 \begin{kasten}
623    
624     \subsection{{\color{red}\underline{Discussion}}}
625     \label{sec:discussion}
626    
627     The initial results show much promise for the model. The
628     system of 50 lipids was able to form micelles quickly, however
629     bilayer formation was not seen on the time scale of the
630     current simulation. Current simulations are exploring the
631     phase space of the model when the tail beads are larger than
632     the head group. This should help to drive the system toward a
633     bilayer rather than a micelle. Work is also being done on the
634     simulation engine to allow for the box size of the system to
635     be adjustable in all three dimensions to allow for constant
636     pressure.
637    
638     \end{kasten}
639    
640    
641 mmeineke 546 \begin{kasten}
642     \begin{center}
643     {\large{\color{red} \underline{Acknowledgments}}}
644     \end{center}
645    
646     The authors would like to acknowledge Charles Vardeman, Christopher
647     Fennell, and Teng lin for their contributions to the simulation
648     engine. MAM would also like to extend a special thank you to Charles
649 mmeineke 552 Vardeman for his help with the \TeX formatting of this
650     poster. Computation time was provided on the Notre Dame Bunch-of-Boxes (B.o.B.)
651 mmeineke 546 cluster under NSF grant DMR 00 79647. The authors acknowledge support
652     under NSF grant CHE-0134881.
653    
654     \end{kasten}
655    
656     \vspace{0.5cm}
657     \begin{kasten}
658     {\small
659     \bibliography{poster}
660     }
661     \end{kasten}
662     \end{spalte}
663     }
664     \end{lrbox}
665     \resizebox*{0.98\textwidth}{!}{%
666     \usebox{\spalten}}\hfill\mbox{}\vfill
667     \end{document}