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For given machine tool settings of a universal hypoid gear generator, the tooth contact patterns are computed for the coast and drive side of a hypoid gear drive. Each contact pattern is replaced by a determined tooth-bearing ellipse. The position, shape, and inclination of each bearing ellipse is calculated. By the help of these data, an influence function is designed that describes the influence of supplemental kinematic flank correction motions (modified motions) on the gear-tooth contact. Examples show the influence of helical motion and modified roll. An evaluation function permits the calculation of modified motions which improve the tooth contact either at coast and drive side simultaneously, or only at one of the sides. For a given pair of start-bearing ellipses at coast and drive side, and for given importance weights to the sides, we describe how modified motions can be computed that best fit a given target pair of bearing ellipses. [DOI: 10.1115/1.1625403]

A study was conducted to analyze a number of experimental effects that occur in tapping-mode atomic force microscopy. These include the apparent hysteresis effects in force probes, frequency sweeps, and imaging distortions. Results indicated that the experimental effects can be minimized to one common cause, the existence of more than on stable state of the tip vibration for certain parameters.

Infant botulism (IB) is an intestinal toxemia that manifests as descending paralysis, constipation, and, in some cases, respiratory failure. Laboratory-confirmed IB cases are rare, and recent data in Israel are lacking. We conducted a national multicenter retrospective study of laboratory-confirmed IB cases reported in Israel during 2007–2021. A total of 8 cases were reported during the study period. During 2019–2021, incidence may have increased because of a cluster of 5 cases. Infant median age for diagnosis was 6.5 months, older than previously reported (3 months). Most cases occurred during March–July. Honey consumption was reported in 1 case, and possible environmental risk factors (living nearby rural or construction areas, dust exposure, and having a father who works as a farmer) were reported in 6 cases. Although IB is rare, its incidence in Israel may have increased over recent years, and its epidemiology and risk factors differ from cases reported previously in Israel.

Abstract Low pressure histotripsy is likely to facilitate current treatments that require extremely high pressures. An ultrasound guided focused ultrasound system was designed to accommodate a rotating imaging transducer within a low frequency therapeutic transducer that operates at a center frequency of 105 kHz. The implementation of this integrated system provides real-time therapeutic and volumetric imaging functions, that are used here for low-cost, low-energy 3D volumetric ultrasound histotripsy using nanodroplets. A two-step approach for low pressure histotripsy is implemented with this dual-array. Vaporization of nanodroplets into gaseous microbubbles was performed via the 1D rotating imaging probe. The therapeutic transducer is then used to detonate the vaporized nanodroplets and trigger potent mechanical effects in the surrounding tissue. Rotating the imaging transducer creates a circular vaporized nanodroplet shape which generates a round lesion upon detonation. This contrasts with the elongated lesion formed when using a standard 1D imaging transducer for nanodroplet activation. Optimization experiments show that maximal nanodroplet activation can be achieved with a 2-cycle excitation pulse at a center frequency of 3.5 MHz, and a peak negative pressure of 3.4 MPa (a mechanical index of 1.84). Vaporized nanodroplet detonation was achieved by applying a low frequency treatment at a center frequency of 105 kHz and mechanical index of 0.9. In ex-vivo samples, the rotated nanodroplet activation method yielded the largest lesion area, with a mean of 4.7 ± 0.5 mm2, and a rounded shape. In comparison, standard fixed transducer nanodroplet activation resulted in an average lesion area of 2.6 ± 0.4 mm2, and an elongated shape. This hybrid system enables to achieve volumetric low energy histotripsy, and thus facilitates the creation of precise, large-volume mechanical lesions in tissues, while reducing the pressure threshold required for standard histotripsy by over an order of magnitude.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.chb.2008.09.001 Byline: Petter Bae BradtzA[bar]g, Anxo Cereijo Roibas