bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Accommodation Training on Accommodation and Depth of Focus in an Eye Implanted with a Crystalens Intraocular Lens
Authors: Tahir Humza J. , Tong Jian L. , Geissler Sydney , Vedamurthy Indu , Schor Clifton M. 
Published: October 2010

Purpose:
To investigate objective measures of the effects of accommodative training of a pseudophakic eye implanted with a Crystalens AT-52SE (eyeonics Inc) intraocular lens (IOL) on reading performance, accommodation, and depth of focus.

Methods:
Objective dynamic measures of accommodation, pupil size, and depth of focus were quantified from wavefront measures before and after 1 week of accommodative training that began 29 months after implantation of an accommodating IOL in one patient. Depth of focus was estimated from 50% cut-off of peak performance levels for defocus curves that were computed from the image quality metric VSOTF based on ocular wavefront aberrations.

Results:
The patient reported improved near vision reading performance after completing the training procedure. After training, there was a shift in conjugate focus in the hyperopic direction, yet the depth of focus increased significantly for near objects. Simulated retinal images and the calculated modulation transfer function of the eye both demonstrated improved quality for near vision after training.

Conclusions:
The subjective report of improved near vision after training was correlated with improvement of objective measures. Depth of focus increased for near objects with attempts to accommodate after training. This change was linked to increases in aberrations and pupil size and occurred despite the conjugate focus shifting in the hyperopic direction. These results demonstrate that accommodative training may be useful in improving near vision in patients with accommodating IOLs.
A New Coordinate System Convention in Schematic Eye Modeling
Authors: Simpson Michael J. 
Published: October 2010

Purpose:To discuss standardizing methods for presenting results from schematic eye calculations where light is entering the eye and forming an image on the retina.Methods:Published methods, measurement equipment, and software were evaluated.Results:The methods already used by ray tracing software are proposed, where everything is viewed from behind the eye and a conventional (x,y) coordinate system is used for images and plots. For meaningful evaluation in comparison to the image, any representations of the cornea, pupil, imaging wavefront, point spread function (PSF), and spot diagram are rotated by 180° about the optical axis for display to match the image orientation of a standard text chart. If a Zernike sag surface is used for a corneal surface of a schematic eye, this is also defined from the rear; however, care must be taken to ensure that the ordering of the Zernike terms is correct.Conclusions:Simulated images can be viewed from behind the eye and oriented so that text has a normal appearance. This requires a rotation of the imaging wavefront and PSF by 180° about the optical axis.
Effect of Incident Light Wavelength and Corneal Edema on Light Scattering and Penetration: Laboratory Study of Human Corneas
Authors: Peyrot Donald A. , Aptel Florent , Crotti Caroline , Deloison Florent , Lemaire Simon , Marciano Tal , Bancelin Stéphane , Alahyane Fatima , Kowalczuk Laura , Savoldelli Michèle , Legeais Jean-Marc , Plamann Karsten 
Published: October 2010

Purpose:
The outcome of ultrashort pulse laser surgery of the cornea is strongly influenced by the light scattering properties of the tissue, for which little data are available. The purpose of the present study is to provide quantitative values for light scattering and its relation to the degree of edema.

Methods:
An experimental optical measuring setup based on confocal geometry was used to measure the unscattered and scattered fractions of light transmitted by eye bank corneas presenting various degrees of edema. From these measurements, the effective light penetration depth in the cornea was calculated as a function of wavelength.

Results:
Corneal transparency depends on the pathological state of the cornea and on wavelength. It may be predicted as a function of corneal thickness, ie, the degree of edema. In healthy and edematous cornea, the percentage of scattered light decreases with increasing wavelength. The total penetration depths at the wavelengths of ∼1050 nm (which is used in typical clinical systems) and 1650 nm (which is recommended for future devices) are comparable; however, the former is limited by scattering, which degrades the laser beam quality, whereas the latter is only limited by optical absorption, which may be compensated for.

Conclusions:
The use of longer wavelengths should help improve the surgical outcome in ultrashort pulse laser surgery of the cornea when working on pathological tissue. A wavelength of approximately 1650 nm appears to be a good compromise, as it allows for reduced light scattering while keeping optical absorption reasonably low.
LASIK for −6.00 to −12.00 D of Myopia with up to 3.00 D of Cylinder Using the ALLEGRETTO WAVE: 3- and 6-Month Results with the 200- and 400-Hz Platforms
Authors: Stonecipher Karl G. , Kezirian Guy M. , Stonecipher Megan 
Published: October 2010

Purpose:
To report the refractive results after LASIK for high myopia and cylinder at one center with one surgeon comparing two laser platforms.

Methods:

A total of 206 eyes of 121 patients were treated for −6.00 to −12.00 diopters (D) of spherical equivalent refractive error with up to 3.00 D of cylinder. All eyes underwent LASIK with the ALLEGRETTO WAVE 200-Hz (n=141) or 400-Hz (n=65) laser (Alcon Laboratories Inc) between 2003 and 2009. Corneal flaps were created with the IntraLase femtosecond laser (Abbott Medical Optics) at an intended thickness of 100 or 110
μ
m in all cases.

Results:

At 3- and 6-month follow-up in the 200-Hz group, 77% (109/141) and 86% (121/141) of eyes, respectively, were within ±0.50 D of intended correction. In the 400-Hz group, 98.5% (64/65) and 100% (65/65) of eyes were within ±0.50 D of intended correction at 3 and 6 months postoperatively. At 3- and 6-month follow-up, 84% (119/141) and 77% (109/141) of eyes, respectively, in the 200-Hz group and 80% (52/65) and 92% (60/65) of eyes, respectively, in the 400-Hz group had 20/20 or better uncorrected distance visual acuity. At 6-month follow-up, refractive predictability and visual acuity were statistically superior in eyes in the 400-Hz group (chi square,
P
<.01). No eyes underwent retreatment as a secondary procedure during the time of analysis.

Conclusions:
LASIK with the ALLEGRETTO WAVE 200- and 400-Hz laser is effective and predictable for the treatment of high myopia with astigmatism in appropriately selected patients. The acuity and predictability of refractive results may be slightly better when using the 400-Hz platform.
LASIK for Mixed Astigmatism Using the ALLEGRETTO WAVE: 3- and 6-Month Results with the 200- and 400-Hz Platforms
Authors: Stonecipher Karl G. , Kezirian Guy M. , Stonecipher Kody 
Published: October 2010

Purpose:
To report the refractive results after LASIK for mixed astigmatism at one center with one surgeon comparing two laser platforms.

Methods:
A total of 137 eyes of 69 patients were treated with LASIK for mixed astigmatism up to 3.33 diopters (D) using either the ALLEGRETTO WAVE 200- or 400-Hz laser (Alcon Laboratories Inc) between April 2006 and December 2009. The degree of astigmatism was higher in the 400-Hz group. Corneal flaps were created with the IntraLase femtosecond laser (Abbott Medical Optics) in all cases.

Results:
The refractive outcomes with both laser systems were statistically similar. At 6 months, 78% of eyes had 20/20 or better uncorrected distance visual acuity (UDVA) with all but one eye achieving 20/30 or better UDVA. At 6 months, 10% of eyes treated with the 200-Hz system lost one line of corrected distance visual acuity (CDVA) whereas no eyes treated with the 400-Hz system lost any lines of CDVA. Residual astigmatism was <0.50 D for all eyes treated with both platforms.

Conclusions:
Both laser platforms provided predictable and effective treatment of mixed astigmatism in the patient populations treated, with over 90% of eyes achieving UDVA of 20/25 or better 6 months after surgery.
Technical Aspects of the WaveLight FS200 Femtosecond Laser
Authors: Mrochen Michael , Wüllner Christian , Krause Johannes , Klafke Mario , Donitzky Christof , Seiler Theo 
Published: October 2010

Purpose:
To demonstrate the feasibility and technical features of the WaveLight FS200 femtosecond laser (WaveLight GmbH) in refractive and corneal laser surgery.

Methods:
The reproducibility of femtosecond laser–created flap dimensions and channels used for corneal ring segment implantation were measured by means of an optical coherence tomography system in porcine corneas. The increase in the intraocular pressure (IOP) during applanation with the corneal interface was measured by means of an IOP sensor. The possibility of creating a channel for gas diffusion within the stroma was investigated to minimize opaque bubble layer formation.

Results:
The technical features, such as optical design, pulse energy, and scanning algorithms at a high repetition rate, allow reproducibility for tissue cutting with a standard deviation of <10 μm in depth and 0.1 mm laterally. Intraocular pressure increases up to 150 mmHg during applanation. The use of a gas channel minimizes the creation of an opaque bubble layer during the femtosecond laser procedure.

Conclusions:
The WaveLight FS200 femtosecond laser provides a high reproducibility for cutting three-dimensional tissue structures. The IOP increase is comparable to other microkeratomes and femtosecond lasers. The minimized opaque bubble layers allow the surgeon to perform an excimer laser treatment immediately after FS200 flap creation.
Correlation Among Ocular Spherical Aberration, Corneal Spherical Aberration, and Corneal Asphericity Before and After LASIK for Myopic Astigmatism with the SCHWIND Amaris Platform
Authors: Mosquera Samuel Arba , de Ortueta Diego 
Published: October 2010

Purpose:
To determine the spherical wave aberration of the human eye based on corneal topography.

Methods:
Based on the pre- and postoperative status of 146 consecutive eyes (median patient age 36 years), the correlations between spherical aberration and asphericity and between corneal and ocular spherical aberrations were determined using simple linear regression methods. The asphericity (Q) values for which spherical aberration equals zero as well as the reference Q values for which corneal spherical aberration equals ocular spherical aberration have been determined. Patients underwent LASIK using the AMARIS excimer laser platform (SCHWIND eye-tech-solutions). All ablations were based on aspheric aberration-neutral profiles.

Results:

Corneal and ocular spherical aberrations correlate well with Q value and the value
p
·
R
−3
in patients before and after LASIK for myopic astigmatism. A Q value of −0.19 to −0.27 can provide zero ocular spherical aberration in patients before and after LASIK for myopic astigmatism. Ocular spherical aberration is induced at a rate of half the induced corneal spherical aberration. A reference Q value of −0.12 to +0.01 can provide corneal spherical aberration equal to ocular spherical aberration in patients before and after LASIK for myopic astigmatism.

Conclusions:
Ocular and corneal wave aberrations are two different concepts that are not interchangeable. As for spherical aberration, a simple static model with a reference cornea deviating from a Cartesian oval can provide a 2:1 correspondence between corneal and ocular spherical aberration.
Narrow- and Open-Angle Measurements with Anterior-Segment Optical Coherence Tomography and Pentacam™
Authors: Mou Dapeng , Fu Jing , Li Shuning , Wang Lan , Wang Xiaozhen , Wu Gewei , Qing Guoping , Peng Yi , Wang Ningli 
Published: October 2010

Background and Objective:
To assess the agreement of the Pentacam (Oculus, Wetzlar, Germany) and anterior-segment optical coherence tomography (AS-OCT) in measuring open and narrow angles.

Patients and Methods:
Prospective observational case series in which 39 healthy normal subjects (39 eyes) and 25 patients with narrow angles (37 eyes) were enrolled between May and September 2008. The anterior chamber measurements were performed by AS-OCT and the Pentacam.

Results:

There was no significant difference in the open-angle measurements between the Pentacam and AS-OCT (
P
> .05). However, in patients with narrow angles, the average values of nasal and temporal anterior chamber angles taken by the Pentacam were larger than those of AS-OCT (25.5° ± 5.66° and 25.77° ± 5.15° vs 13.40° ± 6.81° and 12.13° ± 6.47°;
P
< .001).

Conclusion:
Both AS-OCT and the Pentacam can reliably measure anterior chamber angles in healthy normal subjects. The difference in measuring narrow angles by the two instruments was due to inability to view the angle recess or the scleral spur with the Pentacam.
Temperature and brain death determination: need for updated criteria
Authors: Meyer Michael A. 
Published: October 2010

For an excellent review on the diagnosis of brain death, the interested reader is directed to the review of <a href="/journals/index.php/ni/article/view/ni.2010.e2" target="_blank">Machado</a> appearing in this journal; the author reviews all aspects of brain death and cites nine different references where the minimum temperature for brain death exams appear to have been at least 32°C. Given the new data listed above, it is clearly time for a reconsideration of the how we approach the exam for diagnosis of brain death – normal or near normal temperatures of 36°C and above are very reasonable starting points.
Cell-cell adhesion proteins in melanocytic pilomatrix carcinoma
Authors: Soler Alejandro Peralta , Kindel Susan E , McCloskey Gayle , Burchette James L 
Published: October 2010

Tumors of the matrix of rigid structures include matrical tumors of the hairs, nails, and teeth. These tumors share similar phenotypical and signaling features. Although benign matrical hair tumors are among the most common of these tumors, hair matrix tumors containing pigmented melanocytes are very rare. The malignant variant called melanocytic pilomatrix carcinoma contains benign colonizing dendritic melanocytes admixed with the carcinomatous follicular matrical cells. We studied the expression of cadherins and β-catenin in melanocytic pilomatrix carcinoma because cadherin/catenin-dependent cell-cell adhesion and signals play a critical role in the development of hair and hair tumors. We examined the expression of E- and P-cadherin and the multifunctional protein β-catenin in two cases of melanocytic pilomatrix carcinoma by immunohistochemistry. E- and P-cadherin are expressed at the cell membrane. In contrast, β-catenin is distributed uniformly in the nucleus and cytoplasm of all tumor cells. The diffuse nuclear and cytoplasmic β-catenin expression found in melanocytic pilomatrix carcinomas is indicative of transcriptional activation and β-catenin-induced cell transformation. This is the first report of cadherin/catenin expression in melanocytic pilomatrix carcinoma. Although the study is limited by the number of these rare tumors, the data add information for the understanding of disease mechanisms in hair matrical tumors. Matrical tumors of the hairs share phenotypical features with other matrical tumors and show nuclear translocation of β-catenin, suggesting a transcriptional activating rather than a cellcell adhesion function.
Proprioceptive Sensory Feedback
Authors: Grey MJ 
Published: October 2010

Abstract

Proprioceptors are sensors that provide information about orientation of the body relative to the body's orientation with respect to gravity, movement of the body relative to the external medium and movements and forces in localised regions of the body. Muscle spindles are primarily responsible for position and movement sense, Golgi tendon organs provide the sense of force and the vestibular system provides the sense of balance. Feedback from proprioceptors feedback is essential for the accurate execution of movement execution. For voluntary limb movements in primates, proprioceptive feedback can regulate the generation of motor command by correcting errors using negative feedback loops; providing timing cues about an ongoing movement to initiate commands required at a later time within a movement sequence; and by providing signals used in the planning of movements by providing information about starting limb position to set parameters of feedforward commands. Proprioceptive feedback is also required to modify motor commands slowly in response to alterations in the biomechanical properties of the limbs.

Key Concepts:

Proprioception is a peripherally derived kinaesthetic sense.

Position and movement sense is provided by muscle spindles.

Muscle tension is sensed by Golgi tendon organs.

The centrally derived sense of effort gives information about force and heaviness of objects.

Proprioceptors project to the motor cortex via the dorsal columns and to the cerebellum via spinocerebellar tracts.

Proprioceptive information is used in the spinal regulation of rhythmic movements.
Complement: Measurement
Authors: North Jonathan 
Published: October 2010

AbstractThe complement system comprises a group of serum proteins and cell membrane receptors that function primarily to fight infection. Clinically, measurement of complement pathway activity and individual component levels is of value in (i) cases of suspected immunodeficiency with deficiencies of soluble components, including lectins, and of receptors leading to particular patterns of infection and (ii) conditions that involve complement activation such as systemic lupus erythematosis and renal translantion. This article describes functional and immunochemical methods that can be established in‐house or are available commercially. Until recently, measurement of complement in clinical situations has been aimed at identifying deficiency, of either level or function or activation. Mutations resulting in increased function have been identified for one component and this has opened a new area of research with clinical implications.Key Concepts:Correct sample collection and storage is essential for measurement of complement.Immunochemical measurement of circulating complement components can be performed by commercial assays, usually ELISA.Functional complement assays are required to detect deficiencies that do not affect immunochemical levels.Functional complement assays require buffers that are of the correct ionic strength and provide the requisite ions as well as being of the correct pH.Biosensor assays allow affinity and kinetic studies of complement component interaction.
Plant Embryogenesis (Zygotic and Somatic)
Authors: Harada John J , Belmonte Mark F , Kwong Raymond W 
Published: October 2010

AbstractZygotic embryogenesis in higher plants describes the developmental period in which the zygote undergoes a series of differentiation events, leading to the formation of a mature embryo. Establishment of the major embryonic organs and shoot and root apical meristems occur though partitioning events along the apical–basal axis, and many of these events are guided by the hormoneauxin. Formation of the three embryonic tissue systems occurs along a radial axis perpendicular to the apical–basal axis. The mature zygotic embryo is generally developmentally arrested, metabolically quiescent and enclosed within maternal tissues of the seed. Somatic cells can be induced to divert from their normal fate and develop into embryos in a process termed somatic embryogenesis.Auxinand other plant hormones appear to play critical roles in inducing embryogenic competence. Zygotic and somatic embryogenesis represent parallel developmental programs in which cells acquire embryogenic cell fate and develop into mature embryos.Key Concepts:Embryo development can be divided into two phases: the morphogenesis phase in which the basic body plan of the embryo is established, and the maturation phase in which the embryo becomes tolerant of desiccation and accumulates storage macromolecules such as lipids, proteins and starch.During its development, the embryo is divided into distinct domains along its apical–basal and radial axes.Plant embryo formation represents a series of partitioning events in which organs and tissues are formed from larger domains.Cell fate within the embryo is largely dependent on the position of the cell within the embryo body.Plant cells are totipotent and have the ability to regenerate a fully differentiated organism.Somatic embryos follow similar developmental patterns to their zygotic counterparts, and they occur naturally or are induced in culture.Establishment of embryogenic competence occurs before the formation of the somatic embryo.
Electroporation
Authors: Nickoloff Jac A 
Published: October 2010

Abstract

Electroporation is a simple, rapid and efficient technique for introducing DNA, RNA, proteins and other bioactive molecules into cells and tissues. Electroporation involves the creation of transient, electrically induced membrane pores through which molecules pass into cytoplasmic and nuclear compartments. Because electroporation involves a physical process acting on cell membranes, it is effective with a wide range of cell types including bacterial, fungal, plant and animal cells. Electroporation is used to transiently or stably increase gene expression through transfection of plasmid‐borne gene expression cassettes or decrease gene expression using antisense RNA, small interfering RNA or short hairpin RNA systems. Recent advances have led to new techniques for tissue and organ electroporation in living animals. These techniques are increasingly used in clinical applications including gene therapy, cancer drug delivery and vaccination.

Key Concepts:

Gene transfer is fundamental to molecular genetic analysis in bacteria, plant and animal cells.

Electroporation introduces a wide variety of bioactive molecules into cells, including DNA, RNA, siRNA, proteins, drugs and dyes.

Electroporation creates transient membrane pores through which molecules pass into cytoplasmic and nuclear compartments.

Electroporation is used to transiently or stably upregulate or downregulate gene expression.

Electroporation is used to make stable genetic changes to chromosomes including gene knockout and knockin.

Electroporation of molecules into tissues and organs of living organisms is driving novel clinical applications including gene therapy, drug delivery and vaccination.

The cytotoxic effects of electroporation are being used in tissue ablation including direct killing of tumours.
Kovalevsky, Alexander Onufrevitch
Authors: Ulett Mark A 
Published: October 2010

Abstract

Russian embryologist and invertebrate zoologist Alexander Onufrevitch Kovalvsky (1840–1901) was one of the founders of cellular and evolutionary embryology. His acclaimed scientific work focused on embryological and invertebrate anatomy of amphioxus, ascidians and other invertebrates. The innovation of this work was to trace the history of adult tissues cell‐by‐cell from the original egg‐cell. Based on these studies, Kovalevsky proposed an evolutionary theory of germ layers and argued that the process of gastrulation is homologous among all animals. Along with his friend and colleague Ilja Iljich Metschnikoff, Kovalevsky published detailed descriptions of most major invertebrate groups. His combination of detailed embryological observations and evolutionary considerations make Kovalevsky one of the founders of an approach now called evolutionary developmental biology.

Key Concepts:

Kovalevsky was one of the founders of cellular and evolutionary embryology.

Kovalevsky was an embryologist and invertebrate zoologist.