Robust topology optimization of three-dimensional photonic-crystal band-gap structures.

We perform full 3D topology optimization (in which "every voxel" of the unit cell is a degree of freedom) of photonic-crystal structures in order to find optimal omnidirectional band gaps for various symmetry groups, including fcc (including diamond), bcc, and simple-cubic lattices. Even without imposing the constraints of any fabrication process, the resulting optimal gaps are only slightly larger than previous hand designs, suggesting that current photonic crystals are nearly optimal in this respect. However, optimization can discover new structures, e.g. a new fcc structure with the same symmetry but slightly larger gap than the well known inverse opal, which may offer new degrees of freedom to future fabrication technologies. Furthermore, our band-gap optimization is an illustration of a computational approach to 3D dispersion engineering which is applicable to many other problems in optics, based on a novel semidefinite-program formulation for nonconvex eigenvalue optimization combined with other techniques such as a simple approach to impose symmetry constraints. We also demonstrate a technique for robust topology optimization, in which some uncertainty is included in each voxel and we optimize the worst-case gap, and we show that the resulting band gaps have increased robustness to systematic fabrication errors.

Design of photonic crystals with multiple and combined band gaps.

We present and use an algorithm based on convex conic optimization to design two-dimensional photonic crystals with large absolute band gaps. Among several illustrations we show that it is possible to design photonic crystals which exhibit multiple absolute band gaps for the combined transverse electric and magnetic modes. The optimized crystals show complicated patterns which are far different from existing photonic crystal designs. We employ subspace approximation and mesh adaptivity to enhance computational efficiency. For some examples involving two band gaps, we demonstrate the tradeoff frontier between two different absolute band gaps.

Correlation between brow lift outcomes and aesthetic ideals for eyebrow height and shape in females.

This study correlates brow lift outcomes published in the plastic surgical literature with aesthetic criteria for ideal female eyebrow height and shape. Aesthetic criteria were determined by testing the opinions of 11 cosmetic surgeons and 9 cosmetologists. Eyebrow height and shape were altered with computer graphics to isolate those changes as the only variables of appearance. Plastic surgeons and cosmetologists preferred (p = 0.01) medial eyebrows below or at the supraorbital rim and disliked the medial eyebrow above the rim. Both groups preferred (p = 0.01) eyebrow shape to have an apex lateral slant. One hundred preoperative and 100 postoperative photographs from 16 frequently referenced articles on brow lifts were evaluated. There was a significant (p = 0.0008) increase in the number of medial eyebrows elevated above the rim. The number of medial apex eyebrows increased, and the number of flat brows decreased (p = 0.01). There was no significant increase in the number of apex lateral eyebrows. Three conclusions are made about female eyebrows: (1) The medial eyebrow should be located at or below the supraorbital rim but not above it. (2) Eyebrow shape should have an apex lateral slant. (3) Standard open and endoscopic brow lift operations frequently result in unsatisfactory eyebrow height and shape, judged by these criteria.

A classification of plagiocephaly utilizing a three-dimensional computer analysis of cranial base landmarks.

Plagiocephaly is a term commonly used to describe congenital forehead asymmetry. Previous classification systems based on the various etiologies of dysmorphic crania have been used in an effort to categorize the patients into groups and to assist in treatment planning. The system most commonly used today was described by Bruneteau and Mulliken in 1992. The authors separated frontal plagiocephaly into three types: synostotic, compensational, and deformational. The present study was undertaken in order to define a simple system for classifying plagiocephaly based on Bruneteau and Mulliken's system using the patients' preoperative craniofacial computed tomography scans. The involvement of the entire coronal ring in synostotic plagiocephaly led to the choice of 20 skull base landmarks as the basis of the analysis. Nine lateral landmarks (the superior orbital fissure, the optic foramen, the zygomatic arch, the greater palatine foramen, the foramen ovale, the mastoid tip, the hypoglossal canal, the external auditory canal, and the internal auditory canal) and two midline landmarks (the crista galli and the internal occipital protuberance) were used. The changes that occurred in these landmarks were analyzed in 30 patients. The results demonstrated that Bruneteau and Mulliken's classification system underestimated the number of different subtypes of plagiocephaly. As a result, three major types of frontal plagiocephaly and several different subtypes based on the different etiologies were described. Type I plagiocephaly includes plagiocephaly resulting from cranial suture synostosis. Type II includes those with a nonsynostotic etiology. Type III describes patients with craniofacial microsomia-associated plagiocephaly. Statistical analysis was unavailable because of the small number of patients in each subtype. With a larger number of patients, we hope to refine this system for use by the surgeon in preoperative diagnosis and surgical planning. The analysis is unique in its ability to quantitate changes from normal on the x-, y-, and z-coordinates, and therefore allows for identification of both horizontal (frontal bone deviation) and vertical (ear shear) growth disturbances.

Serial quantitation of hyaluronan and sulfated glycosaminoglycans in fetal sheep skin.

Fetal wounds are abundant in hyaluronic acid (HA), but little is known as to the total HA content of fetal tissues as a function of gestational age. Previous studies demonstrated scarless healing prior to approximately 130 days gestation, after which disorganized collagen deposition became prevalent. Glycosaminoglycans (GAGs) have been shown to play an important role in wound healing, cytodifferentiation, and morphogenesis. In this study, we examined the HA and GAG content of fetal sheep skin of increasing gestational age. We found that the total amount of HA and GAGs declined from a high at 80 days gestation (528 +/- 9 micrograms/gm) to a low at 130 days (174 +/- 11). Analysis of the various GAG species revealed that HA comprised the largest fraction (75-96%). The sulfated GAGs, Heparan Sulfate (HS) and Dermatan Sulfate (DS), were not present in the extracellular matrix until 120 days gestation. Both the trough of HA content and the appearance of sulfated GAGs in the extracellular fraction correspond to the appearance of scarring in fetal sheep wound repair.

Differential effect of platelet-activating factor (PAF) receptor antagonists on peptide and PAF-stimulated prostaglandin release in unilateral ureteral obstruction.

Unilateral ureteral obstruction (UUO) results in increased renal resistance as well as in exaggerated prostaglandin (PG) release from the obstructed hydronephrotic kidney (HNK). We have reported previously that platelet-activating factor (PAF) dose-dependently stimulates the release of PGs from both the HNK and unobstructed contralateral kidney (CLK), with CLK release being 10% that of the HNK. In the present report, we studied the interaction of PAF with its receptor by examining the effects of PAF-receptor antagonists on the release of PGs from the isolated perfused rabbit HNK and CLK stimulated by PAF; angiotensin II (AII), and bradykinin (BK) were also used as agonists. In the HNK, kadsurenone (3 microM) inhibited PAF-stimulated PGE2 and thromboxane B2 (TxB2) release by 28.2 and 62.5% respectively. CV-3988 (20 microM) and triazolam (5 microM) also preferentially diminished PAF-stimulated TxB2 release. In addition, all three drugs significantly diminished BK- and AII-stimulated TxB2 release, while CV-3988 was the only antagonist to affect peptide-stimulated PGE2 release. While effective against agonist-stimulated PG synthesis, these drugs had no direct effect on arachidonic acid metabolism to PGs. Furthermore, in the CLK, CV-3988 had no effect on BK- or AII-stimulated PGE2 release, whereas it totally inhibited PAF-stimulated release of PGE2. These results show that PAF-receptor antagonists in the HNK preferentially inhibit TxB2 release whether stimulated by PAF, AII or BK; in the CLK only PAF-stimulated PG release is affected. This biochemical difference may be of physiological significance and explain some of the functional differences between the HNK and CLK. Therefore, PAF may be an important mediator of some of the biochemical and functional changes associated with UUO.

The isolation, mapping and transcription in vitro of a beta 0-thalassaemia globin gene.

The red blood cell precursors of a patient with homozygous beta 0-thalassaemia have previously been shown to contain nuclear, but not cytoplasmic, beta-globin-specific transcripts. We describe the isolation of a beta-globin gene from this patient as a recombinant bacteriophage chromosome. Restriction-enzyme cleavage-site mapping experiments demonstrate no detectable deletions, insertions or major rearrangements in this thalassaemia gene. Two different techniques show that the gene isolated is transcribed as efficiently in vitro as the normal beta-globin gene.