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PubMed1978

A randomized study of 12-mm and 15.9 mm cannulas in midtrimester abortion by laminaria and vacuum curettage.

We evaluated the adequacy of a new large-bore vacuum cannula system for midtrimester abortion by randomly allocating patients to be treated with a standard 12-mm vacuum system or the new 15.9-mm system. Cervical dilataion was accomplished by overnight placement of laminaria tents. Blood loss was similar for the two treatment groups and was significantly greater at gestational ages 17 to 18 weeks than for abortions at 16 weeks or less. Operating time was slightly less in the large-cannula group. When the 12-mm cannula was used beyond 13 weeks' gestation, forceps were usually needed to empty the uterus completely. The large-cannula system was able to empty the uterus through 16 weeks, but at 17 and 18 weeks it offered no advantage over the smaller system and forceps were always needed. Complications were minimal. We caution against forcible cervical dilatation to 16 mm and urge the use of laminaria instead. Our findings, together with published reports of the safety of late dilatations and evacuation, would appear to justify wider clinical trials by experienced investigators.

Abortion, Induced↗

PubMed1993

Evaluation of a one-piece poly(methyl methacrylate) intraocular lens with a 7 mm biconvex optic and a total diameter of 10 mm.

To find out how large the total diameter of an open-loop intraocular lens (IOL) should be, we studied 90 consecutive implantations of a one-piece poly(methyl methacrylate) IOL with a 7 mm biconvex optic and a total diameter of 10 mm (Adatomed 75 ST). The lens design made implantation simple, even through a small capsulorhexis. In 85% of the cases, the IOL remained well centered. One case with asymmetric placement of the IOL showed a decentration of more than 1 mm. In 14% of the eyes slight decentrations occurred because the capsular bag was too large. Contact between the iris and IOL was found in 15%. In 4% there were folds in the posterior capsule, and in 35% there was a small space between the IOL and the posterior capsule because the capsular bag was too large. Although the ST lens has a small total diameter, it remained at a distance from the iris in most cases. In-the-bag implantation through a continuous central capsulorhexis is mandatory to avoid secondary displacement; nevertheless, slight decentrations cannot be excluded. For a large capsular bag, the total diameter of an IOL should exceed 10 mm. Clinical results, cellular reaction on the lens surface (26.6%), biocompatibility, and visual performance are comparable to those of other well-approved poly(methyl methacrylate) IOLs.

Adult↗

PubMed1994

Astigmatic changes after cataract surgery with 5.1 mm and 3.5 mm sutureless incisions.

We evaluated postoperative keratometric astigmatism in 80 eyes that had phacoemulsification and intraocular lens implantation through sutureless corneal incisions. The eyes were separated into two groups based on the use of rigid ovoid or foldable silicone lenses inserted through 5.1 mm corneal lip incisions or 3.5 mm lip incisions, respectively. In the early postoperative period (one to three months), vector analysis showed less induced astigmatism in the 3.5 mm group than in the 5.1 mm group. Uncorrected visual acuity during the postoperative period was also better in the smaller incision group.

Adult↗

PubMed1991

Optical quality testing of monofocal intraocular lens implants with a 3 mm and a 4 mm aperture.

The optical quality of 81 monofocal poly(methyl methacrylate) intraocular lenses (IOLs) from eight U.S. firms was tested using a 3 mm aperture, as recommended by the American National Standards Institute Z80.7 standard for IOLs, and a 4 mm aperture. The use of the larger aperture had no effect on the measurements of refractive power and astigmatism. When examined with the 3 mm aperture, the average resolving power of the IOLs was 81% of the diffraction limit; when examined with the 4 mm aperture, the average resolving power was 67% of the diffraction limit. Use of the larger aperture would ensure that a larger area of the IOL had been examined. Incorporating the larger aperture into the ANSI minimum resolution requirement would not appreciably affect the rejection rate for currently manufactured monofocal lenses.

Lenses, Intraocular↗

PubMed1996

Effect of 3.0 mm tunnel and 6.0 mm corneoscleral incisions on the blood-aqueous barrier.

PURPOSE: To study of the effect of silicone intraocular lens (IOL) implantation using a 3.0 mm tunnel incision with that of implantation though a 6.0 mm corneoscleral incision after phacoemulsification in human eyes. SETTING: Department of Ophthalmology, University of Köln, Germany. METHODS: In a prospective, randomized clinical study, 50 patients with senile cataract had phacoemulsification and IOL implantation through a 3.0 mm tunnel or a 6.0 mm corneoscleral incision. To assess blood-aqueous barrier (BAB) disruption, preoperative and postoperative sodium fluorescein concentrations in the anterior chamber were measured with the Fluorotron Master II. Diclofenac sodium 0.1% was applied to the operative eyes five times a day for 5 days. The contralateral eyes served as controls. RESULTS: There was no significant between-group difference in sodium fluorescein concentrations in the 5 days after surgery. CONCLUSION: The findings underline our clinical impression that BAB disruption 5 days after surgery does not differ significantly with the type and length of scleral incision used for IOL implantation.

Analysis of Variance↗

PubMed2001

New charge transfer salts based on bis(ethylenedithio)tetrathiafulvalene (ET) and ferro- or antiferromagnetic oxalato-bridged dinuclear anions: syntheses, structures and magnetism of ET5[MM'(C2O4)(NCS)8] with MM' = Cr(III)Fe(III), Cr(III)Cr(III).

Electrochemical combination of the magnetic dinuclear anion [MM'(C2O4)(NCS)8](4-) (MM' = Cr(III)Cr(III), Cr(III)Fe(III)) with the ET organic pi-donor (ET = BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) gives rise to two new isostructural molecular hybrid salts ET5[MM'(C2O4)(NCS)8], with MM' = CrCr (1), CrFe (2). The molecular structure of compound 1 has been determined by single crystal X-ray diffraction. The particular arrangement of the organic units consists of an unprecedented two-dimensional organic sublattice nearly similar to that observed in kappa-phase structures. For both compounds, the magnetic susceptibility measurements indicate (i) the ET radicals do not contribute to the magnetic moment probably due to the presence of strong antiferromagnetic interaction between them, and (ii) in the anion, the magnetic coupling is antiferromagnetic for 1 (J = -3.65 cm(-1)) and ferromagnetic for 2 (J = 1.14 cm(-1), J being the parameter of the exchange Hamiltonian H = -2JS1S2). The field dependence of the magnetization of compound 2 at 2.0 K gives further evidence of the S = 4 ground-state arising from the interaction between S = 3/2 Cr(III) and S = 5/2 Fe(III). EPR measurements confirm the nature of the magnetic interactions and the absence of any contribution from the organic part, as observed from the static magnetic measurement. Conductivity measurements and electronic band structure calculations show that both salts are semiconductors with low activation energies.

Journal Article↗

PubMedDate not supplied

Syndesmosis fixation: analysis of shear stress via axial load on 3.5-mm and 4.5-mm quadricortical syndesmotic screws.

The effect of shear stress on a fixated distal syndesmosis of the ankle was evaluated with a servohydraulic materials-testing machine. Eighteen syndesmoses were fixated in a quadricortical technique using 3.5-mm cortical and 4.5-mm cortical stainless steel screws. A shear stress was applied via an axial load in an attempt to simulate weightbearing. The 4.5-mm quadricortical screws produced a higher yield load and peak load (484.3 +/- 93.8 N and 597.7 +/- 81.4 N) when compared with the 3.5-mm quadricortical syndesmotic screws (412.8 +/- 55 N, P = .033 and 511.2 +/- 64.4 N). These findings suggest that a larger diameter screw provides greater resistance to an applied shear stress at the distal syndesmosis.

Ankle Injuries↗

PubMed2002

Comparison of polyethylene wear with femoral heads of 22 mm and 32 mm. A prospective, randomised study.

In this prospective, randomised study, we have compared the wear rate of cemented, acetabular polyethylene cups articulating with either a 22 mm or a 32 mm cobalt-chromium head. We evaluated 89 patients who had a total of 484 radiographs. The mean follow-up period was 71.4 months (SD 29.1). All the radiographs were digitised and electronically measured. The linear wear rate was significantly higher during the first two years and decreased after this period to a constant value. We suggest that this is partly due to a 'run-in' process caused by irregularities between surfaces of the cup and head and an initial plastic deformation of the polyethylene. The mean volumetric wear was 120.3 mm/year for the 32 mm head, which was significantly higher than the 41.5 mm3/year for the 22 mm heads. The mean linear wear rate was not significantly different. We were, however, unable to find radiological signs of osteolysis in the patients who had higher wear rates.

Acetabulum↗

PubMed2005

High-energy quasi-phase-matched optical parametric oscillation in a periodically poled MgO:LiNbO3 device with a 5 mm x 5 mm aperture.

Fabrication of a 5 mm thick periodically poled MgO-doped LiNbO3 device with a 32.1 microm period for mid-infrared generation was demonstrated. The periodic structure was evaluated by measurement of second-harmonic generation with the d31 coefficient. Optical parametric oscillation using this device with an uncoated 5 mm x 5 mm aperture and a 36 mm effective length realized a high-energy output of 77 mJ for both signal (wavelength 1.83 microm) and idler (2.54 microm) waves with a 72% slope efficiency at 110 mJ pumping of a Q-switched Nd:YAG laser with a 12 ns pulse duration.

Journal Article↗

PubMed2001

[Surgery of femoral neck fractures--higher rate of osteosynthesis failure with the use of 4,5 mm screws compared to 6,5 mm screws].

BACKGROUND: Displaced femoral neck fractures are usually treated with screw osteosynthesis or primary hip replacement (unipolar or bipolar). MATERIAL AND METHOD: In this retrospective study we compared the rate of early failure during two consecutive years using two different screw implants each year. The patient groups were demographically similar, and the relationships between the use of hip replacement and screws as primary treatment were similar in the two groups. In the first group (group A), two screws with a shaft and outer thread diameter both of 6.5 mm were used. In the second group (group B), two screws with shaft diameter of 4.5 mm and outer thread diameter of 7.3 mm were used. The number of patients operated with screws were 191 the first year and 177 the following year. RESULTS: The number of patients reoperated with a hip replacement within the first 100 days was 16 (8%) in group A and 29 (16%) in group B (risk difference 0.08; 95% CI 0.013-0.147). INTERPRETATION: We recommend that when two screws are used for fixation of femoral neck fractures, they should have a shaft diameter of at least 6.5 mm.

Aged↗

PubMed2002

Comparison of hemodynamic performance of Medtronic Hall 21 mm versus St. Jude Medical 23 mm prostheses in pigs.

BACKGROUND AND AIM OF THE STUDY: The ideal prosthesis for aortic valve replacement in the small annulus remains controversial, and has yet to be defined. In previous studies, the Medtronic Hall (MH) tilting disc valve showed superior hemodynamic performance in the hemodynamically optimum orientation compared to the St. Jude Medical (SJM) bileaflet valve, especially in smaller-sized valves. Using an animal model, the hemodynamics of 21 mm MH and 23 mm SJM valves, both of which have shown identical performance in previous clinical studies, were compared. METHODS: A rotation device holding either a MH or a SJM aortic valve was implanted into eight pigs. The device allowed rotation of the implanted valve without reopening the aorta. In different orientations (best and worst orientation hemodynamically as defined previously), transvalvular pressure gradients and ventricular dimensions were measured using transesophageal echocardiography at constant hemodynamic conditions. RESULTS: In the optimum hemodynamic orientation, pressure gradients of the MH valve (6.3+/-1.7 mmHg) corresponded to those obtained with the SJM valve (6.3+/-3.7 mmHg), whereas in the worst orientation the MH showed a tendency towards higher gradients (14.0+/-2.9 versus 10.3+/-4.0 mmHg) (p = not significant). A significant increase in left ventricular enddiastolic diameter was observed for both valve designs with rotation from the optimal into the worst orientation. CONCLUSION: In the optimum hemodynamic orientation, the 21 mm MH valve matched the hemodynamic performance of the 23 mm SJM valve. Thus, implantation of the MH valve might be an alternative to root enlargement and implantation of a larger SJM valve in patients with a small aortic annulus, though optimum orientation is required.

Animals↗

PubMed1988

Comparison of the terminal ballistics of full metal jacket 7.62-mm M80 (NATO) and 5.56-mm M193 military bullets: a study in ordnance gelatin.

Great controversy has surrounded the replacement of the 7.62-mm caliber by the reduced 5.56-mm caliber as the standard U.S. military rifle. Although its relevance to human wounding can be debated, the terminal ballistics of military small arms in ordnance gelatin remains a convenient medium for comparative testing. In the present study, 7- by 10- by 24-in. (18 by 25 by 61 cm) blocks of 20% ordnance gelatin were fired upon from a range of 19 ft (6 m) under high-speed cinemagraphic surveillance. The tendency of the M193 5.56-mm full metal jacket projectile to break up in soft tissue simulant was confirmed as a fundamental difference from the 7.62-mm M80 NATO ball.

Bone and Bones↗

PubMed1979

Accuracy of 100 mm x 100 mm mirror optic camera technique as compared to normal chest radiography technique.

Full size and 100 mm x 100 mm mirror optic camera (photofluorographic) chest films of 121 patients were read by a team of four radiologists. Altogether 2781 diagnostic statements were reported, 968 of which were of primary importance, and only these statements were analysed. Error rates with the standard technique varied between 16 and 31% and with the 100 mm x 100 mm technique between 21 and 38%. The difference in error rates between the techniques used was not statistically significant but there were significant differences between the individual radiologists.

Clinical Competence↗

PubMed1995

Comparison of the holding power of 3.5-mm cortical versus 4.0-mm cancellous orthopedic screws in the pelvis of immature dogs (cadavers).

A 3.5-mm cortical orthopedic screw was compared with a 4.0-mm cancellous screw for maximal load to failure in the pelvis of immature dogs. The pelvis from young cadavers (7 to 13 months old) was divided into hemipelves and used for testing of the 2 screw types. Two sites in each hemipelvis were used, mid-shaft of the ilium and mid-sacrum, including the wing of the ilium. The screws were extracted, and maximal load to failure and mode of failure were recorded. Maximal load to failure per millimeter of engaged thread was calculated. In either pelvic site, the 4.0-mm cancellous screw required a significantly (P < 0.05) higher pullout force per millimeter of engaged screw threads than did the 3.5-mm cortical bone screw.

Animals↗

PubMed1984

Experience of thin cutaneous melanomas (less than 0.76 mm and less than 0.85 mm thick) in a large plastic surgery unit: a 5 to 17 year follow-up.

The detailed histological findings of 728 melanoma patients treated at Frenchay Hospital during the period 1967 to 1978 have been fully reviewed and analysed. Of these, 75 patients with lesions less than 0.76 mm thick and 15 with lesions greater than 0.75 mm and less than 0.85 mm thick have been identified using a computerised data base. The general practitioners of all the patients in the series have been approached and the clinical histories found in nearly every case (69/75 and 15/15) thus providing a follow-up period of 5 to 17 years. A number of fatal melanomata have been found in these two groups. The histopathological features have been related to the known prognosis in an attempt to characterise the lethal lesions. No statistically significant relationship could be found between prognosis and any histological feature, including specifically the amount of regression within the lesion. However, it was found that assessment of the ratio of the uninvolved dermis beneath the tumour to tumour thickness itself might prove helpful in future case evaluation.

Adolescent↗

PubMed2005

The 22-mm vs the 32-mm femoral head in cemented primary hip arthroplasty long-term clinical and radiological follow-up study.

A retrospective clinical and radiological analysis was performed on 117 patients (138 hips) with a mean age of 75 years and a mean follow-up of 11 years. The prostheses used were 2 similar monoblock femoral components with 22- and 32-mm head sizes; their effects on the wear of the high-density polyethylene cup were studied. Wear of component was determined by evaluating the standardized initial and follow-up radiographs. The mean rate of linear wear was higher in the 22-mm femoral head, whereas the volumetric wear was higher in the 32-mm femoral head. In both groups, volumetric wear was significantly correlated with cup lysis. Increasing body weight in both groups was associated with more volumetric wear. The radiological evidence of prosthetic loosening did not correlate well with clinical evaluation of the hip.

Aged↗

PubMed2004

Comparison of higher-order aberrations after LASEK with a 6.0 mm ablation zone and a 6.5 mm ablation zone with blend zone.

PURPOSE: To compare the higher-order aberrations (HOAs) after laser-assisted subepithelial keratectomy (LASEK) using a conventional optical zone and a larger zone with a blend zone. SETTING: Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea. METHODS: In this prospective study, 19 patients with a manifest refraction of -3.00 to -8.25 diopters (D) were treated with LASEK using a conventional (6.0 mm) optical zone in 1 eye and a larger (6.5 mm) zone with 8.0 mm blend zone in the other eye. The patients were followed for 3 months. Pupil size, best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), manifest refraction, corneal topography, pachymetry, and wavefront aberration were examined preoperatively; BCVA, UCVA, manifest refraction, and wavefront aberration were measured 1 and 3 months postoperatively. The Hartmann-Shack aberrometer (WaveScan(R), Visx) was used to measure the overall wavefront aberrations in scotopic pupils. RESULTS: There were no significant differences in preoperative pupil size, BCVA, UCVA, and manifest refraction between the 2 groups or in postoperative BCVA, UCVA, and refraction. Higher-order aberrations increased at 1 and 3 months in both eyes compared with preoperatively. At 3 months, in a scotopic pupil, the mean root-mean-square wavefront error of the HOAs was 0.41 +/- 0.14 in the eyes treated with the larger optical zone and 0.61 +/- 0.28 in those treated with the conventional optical zone. There was a significant difference between optical zones (P =.006). The difference was more pronounced in the treatment of myopia greater than -5.0 D (P =.001). CONCLUSIONS: In the scotopic condition, HOAs after LASEK using a large optical zone with blend zone ablation were smaller than those associated with conventional ablation zone treatment. The larger zone with blend zone treatment may be a good surgical alternative for better visual outcomes in scotopic conditions.

Adult↗

PubMed2000

A cylindrical micro-ultrasonic motor (stator transducer size: 1.4 mm in diameter and 5.0 mm long)

Ultrasonic motors are suitable for a micro-actuator because of a direct drive, no brake and their simple construction. In order to fabricate micro-ultrasonic motors, a piezoelectric thin film is essential. In this study, a hydrothermal method was adopted to deposit a PZT thin film. The dimensions of the stator transducer were: outer diameter, 1.4 mm; inner diameter, 1.2 mm; and length, 5.0 mm. The resonance frequency of the stator transducer was 227 kHz, and the vibration amplitude was 58 nmp-p at an input voltage of 4.0 Vp-p. The maximum revolution speed was 680 rpm, and the maximum starting torque was 0.67 microNm. The experimental conditions were 20 Vp-p and 5.3 mN pre-load. The motor property versus scale was investigated using an equivalent circuit. The calculated results indicated that the output torque of the 100 microns diameter motor was 27 nNm.

Journal Article↗