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At least 19 recordsLinked to original sources
PubMed1976

Laparoscopic sterilization with an elasticated silicone ring.

A method of laparoscopic sterilization using an elasticated silicone ring is described. It was used in 155 patients over a period of 13 months by 12 gynaecologists. There were 12 complications specifically related to the method and only one of them required laparotomy. One tubal patency was discovered, but no pregnancy occurred in a total follow-up period of 81-25 years. Many patients had pain in the first 24 hours after operation but only 3 per cent had pain after three months.

Adult↗
PubMed2006

Transmission of high-data-rate optical signals through a micrometer-scale silicon ring resonator.

The effects of a micrometer-scale silicon ring resonator with a FWHM of 0.078 nm (9.6 GHz) on a nonreturn to zero amplitude-modulated optical signal with a modulation rate of 10 Gbps are experimentally investigated. By transmitting the optical signal through the device, significant spectral distortion and side band attenuation is introduced, as characterized by amplitude Bode plots, and a power penalty of 0.8 dB is observed. Carrier wavelengths within the transmission resonance, but detuned from the center wavelength, are investigated as well. Numerical simulations further support the experimental results.

Journal Article↗
PubMed1979

Female sterilization using an elasticated silicone ring.

This paper presents the experience, in a District General Hospital, of using an elasticated silicone ring applied to the Fallopian tubes by the laparoscope. It is concluded that this is a safe and effective method of female sterilization, with good patient acceptance.

Adult↗
PubMed2006

Carrier-induced optical bistability in silicon ring resonators.

We demonstrate optical bistability in a micrometer-sized silicon ring resonator based on the free-carrier dispersion effect in silicon. We measure the transfer function of the resonator showing a hysteresis loop with an input optical power of less than 10 mW. The influence of the thermal optical effect, which is minimized in the experiment by use of nanosecond pulses, is evaluated theoretically. Applications include sequential logic operations for all-optical routing.

Journal Article↗
PubMed2000

Two-membered silicon rings on the dehydroxylated surface of silica

We present extensive modeling of the amorphous silica surface, aimed at connecting its structural and chemical features. beta-cristobalite surfaces are initially studied to model the hydroxylated surfaces. A model reconstruction of the (111) surface is used to define a path leading to the formation of two-membered silicon rings upon dehydroxylation. Subsequently, a realistic model of the amorphous dehydroxylated (dry) surface is produced, by full ab initio annealing of an initial model generated by classical simulation. The presence of surface two-membered silicon rings emerges naturally. A calculation of IR activity yields an associated peak doublet in agreement with experimental data.

Journal Article↗
PubMed1996

Outcome of Silicone Ring Vertical Gastroplasty in Patients Aged 50 Years and Older.

BACKGROUND: The authors studied the results Of silicone ring vertical gastroplasty (SRVG) in Patients aged 50 years and older. METHODS: The early and late Postoperative results in 28 patients aged.50 Years or older undergoing SRVG were reviewed retrospectively, The results were compared to those of 370 Patients Younger than 50 years operated during the same period. RESULTS: There was no Postoperative mortality among patients aged 50 years and older. There was a significantly higher incidence Of Pulmonary embolus and wound infection among patients aged 50 years and older (P < 0.05). The weight loss did not differ significantly between the two studied age groups. CONCLUSION: SRVG may performed on patients aged 50 years or older with acceptable complication rate and favorable postoperative results.

Journal Article↗
PubMed2006

Ringed silicon rubber attachment prevents laparoscopic surgeon's thumb.

BACKGROUND: This investigation, using the nerve conduction study, aimed to quantify the degree of laparoscopic surgeon's thumb, and to evaluate the effect of the ringed silicon rubber attachment (RSRA) developed by the authors. METHODS: For the study, 26 residents or students performed surgical tasks (grasping and dissecting) using both the laparoscopic forceps with RSRA and the conventional instrument. The paresthesia was evaluated with a severity score obtained by interview and measurement of sensory nerve conduction velocity (SCV). RESULTS: The mean severity score was 2.57 +/- 0.58 m/s for the conventional forceps and 1.05 +/- 0.80 m/s for the forceps with RSRA (p < 0.01). For the grasping task with the conventional forceps, the mean SCV was 58.3 +/- 2.81 m/s before and 54.8 +/- 2.83 m/s after the task (p < 0.01), whereas for the dissecting task, the corresponding values were 57.5 +/- 2.46 m/s and 56.1 +/- 2.93 m/s (p < 0.01). For the grasping task with the RSRA, the mean SCV was 57.1 +/- 3.33 m/s before and 55.9 +/- 3.18 m/s after the task (p < 0.01), whereas for the dissecting task, the corresponding values were 55.7 +/- 4.59 m/s and 55.8 +/- 3.50 m/s (nonsignificant difference). CONCLUSIONS: Laparoscopic surgeon's thumb was induced by compression of the lateral digital nerve. The RSRA significantly reduced the degree of paresthesia.

Adult↗
PubMed1992

Direct imaging of the tricuspid valve annular motions by fiberoptic cardioscopy in dogs with tricuspid regurgitation. II. Does flexible ring annuloplasty preserve the annular motions?

Applying the technology of direct imaging by fiberoptic cardioscopy in a working-heart condition, we studied the tricuspid valve annular motions with flexible rings in nine dogs with chronic tricuspid regurgitation. Three annuloplasty studies with a totally flexible polytetrafluoroethylene ring, an elastic silicone ring, and a rigid metal ring were compared with a nonannuloplasty study. The annuloplasty was performed by reducing tricuspid valve annular area to 65% of that of nonannuloplasty condition. The anuli were observed and recorded on a videotape in real time. The three rings effectively reduced and remodeled the dilated anuli and improved the valve coaptation. The patterns of annular motions with the polytetrafluoroethylene and silicone ring were similar to that of normal anulus; the free wall anulus contracted centripetally, and the septal anulus moved toward the free wall side during systole. Pliability of both the anteroseptal and posteroseptal commissures with the flexible rings made these motions possible. The polytetrafluoroethylene ring followed a natural undulation of the anulus, whereas the silicone and rigid metal rings forced the annular planes to horizontal ones. Percent reductions of tricuspid valve annular area were 25%, 21%, and 23% in the nonannuloplasty, polytetrafluoroethylene, and silicone ring studies, respectively, without significant differences in annular contraction. In contrast, rigid metal rings completely disturbed the annular motions. These findings indicated that the two flexible rings did preserve the physiologic annular motions to the degree that the anuli had in the chronic tricuspid regurgitation condition. Especially, the totally flexible polytetrafluoroethylene ring preserved not only the annular motions but also the natural undulation, which resulted in reinforcing the valve coaptation. We believe that the flexible ring, especially a totally flexible one, is superior to the rigid ring in the aspect of reinforcing the valve coaptation to prevent further regurgitation.

Animals↗
PubMed2000

Pentosanpolysulfate coating of silicone reduces encrustation.

BACKGROUND AND PURPOSE: A significant problem associated with catheterization in the urinary tract is the encrustation of the catheter materials. One approach to reducing encrustation is to alter the surface properties of the catheters. We evaluated the effectiveness of coating with pentosanpolysulfate (PPS), a semisynthetic polysaccharide similar to heparin, in reducing encrustation and the foreign-body inflammatory response to silicone stents in the bladders of male New Zealand White rabbits. MATERIALS AND METHODS: Sixteen rabbits were divided into three groups to receive placement in their bladders of uncoated (N = 7), PPS-coated (N = 7), or sham matrix-processed silicone rings (N = 2) via open cystotomy. After 50 days of maintenance on normal food and water, all rabbits were sacrificed, and the air-dried, unfixed silicone ring surfaces were examined by scanning electron microscopy. Bladders and remaining silicone rings were removed and preserved separately. Silicone rings, cleaned of all encrustation, were stained with toluidene blue to determine the presence or absence of PPS coating on the surface. RESULTS: Histologic examination revealed normal tissue in bladder sections exposed to coated silicone rings and an inflammatory response in sections from bladders having uncoated silicone rings. Coating with PPS was associated with an eightfold reduction in the amount of encrustation of silicone and a marked reduction in the inflammatory response of the bladder wall to the foreign body. CONCLUSIONS: A PPS coating may be useful in reducing the encrustation of long-term indwelling silicone stents or catheters in the human urinary tract.

Animals↗
PubMed1987

Long-term results of silicone elastomer ring vertical gastroplasty for the treatment of morbid obesity.

This article reviews 305 silicone elastomer ring vertical gastroplasties that were used to treat morbid obesity. All patients underwent surgery 2 or more years ago. The average weight loss was 101 pounds, 35.7% of initial total body weight, or 60.8% of excess body weight. Fourteen patients failed to lose an adequate amount of weight and in four (1.3%) of these patients the surgery failed because the gastric partition disrupted; in these cases, another operation was required. There were no pulmonary emboli, gastric perforations, or deaths in this series. Banding of the vertical gastroplasty stoma with silicone elastomer rings is safe and effective and offers distinct technical advantages over other methods of banding.

Adolescent↗
PubMed1991

Silicone Elastomere Ring Vertical Gastroplasty: extended follow-up.

Statistically significant long-term data have been noticeably scarce in the evaluation of various bariatric procedures. Bariatric patients who lost weight frequently experience drastic life-style changes and often exhibit denial to the extent that follow-up is impaired. In this study, a cohort of 100 consecutive patients who underwent silicone elastomere ring vertical gastroplasty is evaluated at 46-55 months post-surgery with 90% follow-up. Results indicate that the 24-month figure of 36% loss of the preoperative weight level deteriorates to 32% at 46-55 months, and the failure rate increases slightly to 25% (or less), primarily due to anatomic failure of the procedure. Failure due to lack of patient compliance occurs but is less common than previously thought. Silicone elastomere ring vertical gastroplasty remains one of the safest of the effective procedures available to the bariatric surgeon.

Journal Article↗
PubMed2002

Synthesis of gamma-methylene oxacycles and alpha- and beta-alkylidene lactones via silicon-assisted ring opening of cyclopropyl carbinols.

Cyclopropyl carbinols bearing a (tert-butyldiphenylsilyl)methyl substituent undergo silicon-assisted regioselective ring cleavage and the resulting beta-silyl carbocation is intramolecularly trapped with hydroxy and ester functions to generate gamma-methylene oxacycles and alpha- and beta-alkylidene lactones without the cleavage of the silicon function.

Journal Article↗
PubMed2002

A dynamic mechanical method for determining the silicone elastomer solubility of drugs and pharmaceutical excipients in silicone intravaginal drug delivery rings.

The silicone elastomer solubilities of a range of drugs and pharmaceutical excipients employed in the development of silicone intravaginal drug delivery rings (polyethylene glycols, norethisterone acetate, estradiol, triclosan, oleyl alcohol, oxybutynin) have been determined using dynamic mechanical analysis. The method involves measuring the concentration-dependent decrease in the storage modulus associated with the melting of the incorporated drug/excipient, and extrapolation to zero change in storage modulus. The study also demonstrates the effect of drug/excipient concentrations on the mechanical stiffness of the silicone devices it 37 degrees C.

Biocompatible Materials↗
PubMed1988

Laparoscopic sterilization. A comparison of current techniques.

Current techniques of laparoscopic sterilization--bipolar electrocoagulation, endocoagulation, silicone ring, Hulka clip and Filshie clip--were analyzed from a large pool of international data. Technical difficulties have been encountered much less with electrocoagulation than with the silicone ring, Hulka clip or Filshie clip. There have been fewer technical failures with bipolar electrocoagulation and endocoagulation than with the ring or clip. Surgical complications have been the fewest with bipolar electrocoagulation and endocoagulation but have been more serious (electrical burns). The Hulka and Filshie clips have had lower complication rates than has the silicone ring. The greater technical difficulties and failures and greater surgical complications with clips and rings have been due to technical problems in applying them in cases of tuboperitoneal pathology. The pregnancy rates from method failure have been acceptably low with all the methods. Ectopic pregnancies are a serious problem with bipolar electrocoagulation and endocoagulation. The pregnancy rates after reversal surgery have been highest with the Hulka and Filshie clip. Electrical methods seem to be preferable in women with pelvic adhesions and tubal pathology. Clips seem to be preferable in women who may be candidates for future sterilization reversal.

Electrocoagulation↗