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At least 163 records · Page 9Linked to original sources
PubMed2004

Ten-year follow-up of a ciliary sulcus-fixated silicone phakic posterior chamber intraocular lens.

In 1992, a ciliary sulcus-fixated, silicone, phakic posterior chamber intraocular lens (PPC IOL) (Adatomed, Fyodorov type) was implanted in both eyes of a 42-year-old white woman to correct high myopia (right eye, -17.0 diopters [D]; left eye, -11.5 D). In the right eye, localized cortical opacification was present in the anterior part of the natural lens preoperatively but did not progress during a 10-year follow-up period. With Scheimpflug photography, it was possible to detect a space between the natural lens and the IOL that was not evident on slitlamp examination. Maintenance of space between an IOL and the natural lens appears to be an important factor in preventing cataract formation after PPC IOL implantation.

Cataract↗
PubMed1992

Development of life support requirements for long-term space flight.

When humans move out into the solar system to stay for long durations, the most immediate challenge will be the provision of a life-supporting environment in locations that are naturally devoid of food, air, and water. Life support systems must provide these commodities in all phases of space flight--during intravehicular activity (IVA) and during extra-vehicle activity (EVA). Systems that support human life must provide: overall reliability in the space environment, allowing maintenance and component replacement in space; reduced resupply mass of consumables and spares; for planetary surfaces, the ability to utilize local resources for increased self sufficiency; and the minimized mass power and volume requirements necessary for all space flight systems. This paper will discuss the melding of these technical requirements in such a way as to meet the human needs of space flight.

Ecological Systems, Closed↗
PubMed2003

Transiently beneficial insertions could maintain mobile DNA sequences in variable environments.

The maintenance of mobile DNA sequences in clonal organisms has been seen as a paradox. If selfish mobile sequences spread through genomes only by overreplication in transposition, then sexuality is necessary for their spread through populations. The persistence of bacterial transposable elements without obvious dominant selectable markers has previously been explained by horizontal transfer. However, advantageous insertions of mobile DNAs are known in bacteria. Here we model maintenance of an otherwise selfish mobile DNA element in a clonal species in which selection for null mutations occurs during one of two temporally alternating environments. Large areas of parameter space permit maintenance of mobile DNAs where, without selection, they would have gone extinct. Horizontal transfer diminishes, rather than enhances, mean copy number. In finite populations, effective population sizes are greatly reduced by selective sweeps, and mean copy number can be increased as the reduced variance in copy number results in reduced selection.

Clone Cells↗
PubMedDate not supplied

[Prevention of psychoemotional disorders on a prolonged space flight by psychological support means].

A number of supportive and rehabilitative measures forming so-called psychological support can be used to prevent potential psychoemotional disorders in crewmembers during prolonged space missions. The use of these measures in the Salyut--6--Soyuz 96--185-day space flights has shown their efficiency in terms of expansion of the "psychological living space" and maintenance of a high emotional and working tone of crewmembers.

Aerospace Medicine↗
PubMedDate not supplied

The swaged crown: its modern applications.

The authors makes no claim for originating the technique of construction and the use of the swaged crown. He was introduced to the swaged crown over a quarter-century ago by the late Dr. Benjamin Weiss, and orthodontist, and his technician, Sanford Pollock. Clinical adaptations of the swaged crown followed. The swaged crown has proved to be a versatile solution to a number of clinical problems occurring in the primary, mixed, and early adult dentitions. It provides simplicity of use, strength, and durability of appliances, and virtual freedom from decalcification and caries for the covered teeth. Chair-time procedures are kept to a minimum, and laboratory costs are reasonable. All appliances require supervision and maintenance by the dentist. When swaged crowns are used, the time and effort involved in such supervision and maintenance are kept at a minimum. This time is considerable less than that required, when even well fitted orthodontic bands are used, instead of swaged crowns.

Chromium↗
PubMed1999

Anterior interbody fusion of the cervical spine with coralline hydroxyapatite.

STUDY DESIGN: A nonrandomized, retrospective human study of patients requiring anterior discectomy and reconstruction from C3 to T1. The pattern of incorporation, presence or absence of disc space collapse, maintenance of correction, and clinical outcomes were considered. OBJECTIVE: To determine the efficacy of coralline hydroxyapatite as a bone replacement in anterior interbody fusions of the cervical spine used in conjunction with rigid plate fixation. SUMMARY OF THE BACKGROUND DATA: Autograft is the gold standard for anterior interbody fusion of the cervical spine. Reported complication and morbidity rates with the use of autograft are as high as 21%. Using allograft instead of autograft presents numerous problems including lower rates of fusion. Other bone substitutes such as ceramics and polymethylmethacrylate are ineffective for fusion. METHODS: Twenty-six skeletally mature patients underwent anterior decompression, stabilization, microdiscectomy, and reconstruction with Pro Osteon 200 (Interpore Cross International, Irvine, CA) coralline hydroxyapatite and AO anterior cervical locking plates. Iliac crest autograft, local bone, and allograft were not used. RESULTS: The minimum follow-up period was 2 years (average, 30 months). There was no evidence of plate breakage, screw breakage, resorption of the implant, or pseudarthrosis. Two patterns of incorporation were identified. The implant incorporated totally in 100% of the disc spaces. Average hospital stay was 1.6 days. The average decrease in pain was 75.8%. There was no evidence of nonunion. CONCLUSIONS: The use of Pro Osteon 200 with rigid anterior plating seems promising as a bone replacement in the cervical spine. The incorporation rate is exceedingly high, and the complication rate nonexistent.

Adult↗
PubMed1998

Maintenance of acidic lateral intercellular spaces by endogenous fixed buffers in MDCK cell epithelium.

The lateral intercellular spaces (LIS) of MDCK cell epithelia grown on permeable supports are about 0.4 pH units acidic to the bathing solutions, presumably because of buffering by the fixed negative charges on the surface of the lateral cell membranes. To test the hypothesis that fixed buffers are responsible for the acidity, a theoretical and experimental approach was developed for the determination of the concentration and pK of the fixed buffer constituted by the glycocalyx. The pH of the solution in the LIS was measured by ratiometric fluorescence microscopy while the buffer concentration or composition of the bathing solutions was altered. In addition, the divalent cation Sr2+ was added to the perfusion solutions to displace protons from the fixed buffer sites for the determination of the fixed buffer properties. We conclude that the LIS contain 3.7 mm of pK 6.2 fixed buffer and that this buffer is responsible for the acidic microenvironment in the LIS.

Animals↗