Monozygotic 24-year-old twins presented with discordant ovarian function. One had had premature ovarian failure at the age of 14 years, whereas her sister had normal ovaries and three naturally conceived children. After unsuccessful egg-donation therapy, the sterile twin received a transplant of ovarian cortical tissue from her sister by means of a minilaparotomy. Within three months after transplantation, the recipient's cycles resumed and serum gonadotropin levels fell to the normal range. During the second cycle, she conceived, and her pregnancy progressed uneventfully. At 38 weeks' gestation, she delivered a healthy-appearing female infant.

Stiffness is a mechanical property of vital importance to any material system and is typically considered a static quantity. Recent work, however, has shown that novel materials with programmable stiffness can enhance the performance and simplify the design of engineered systems, such as morphing wings, robotic grippers, and wearable exoskeletons. For many of these applications, the ability to program stiffness with electrical activation is advantageous because of the natural compatibility with electrical sensing, control, and power networks ubiquitous in autonomous machines and robots. The numerous applications for materials with electrically driven stiffness modulation has driven a rapid increase in the number of publications in this field. Here, a comprehensive review of the available materials that realize electroprogrammable stiffness is provided, showing that all current approaches can be categorized as using electrostatics or electrically activated phase changes, and summarizing the advantages, limitations, and applications of these materials. Finally, a perspective identifies state‐of‐the‐art trends and an outlook of future opportunities for the development and use of materials with electroprogrammable stiffness.

The force, speed, dexterity, and compact size required of prosthetic hands present extreme design challenges for engineers. Current prosthetics rely on high-quality motors to achieve adequate precision, force, and speed in a small enough form factor with the trade-off of high cost. We present a simple, compact, and cost-effective continuously variable transmission produced via projection stereolithography. Our transmission, which we call an elastomeric passive transmission (EPT), is a polyurethane composite cylinder that autonomously adjusts its radius based on the tension in a wire spooled around it. We integrated six of these EPTs into a three-dimensionally printed soft prosthetic hand with six active degrees of freedom. Our EPTs provided the prosthetic hand with about three times increase in grip force without compromising flexion speed. This increased performance leads to finger closing speeds of ~0.5 seconds (average radial velocity, ~180 degrees second−1) and maximum fingertip forces of ~32 newtons per finger.

From January 1998 through August, 2001, 108 women with a preoperative diagnosis of suspected ovarian dermoid cyst underwent surgical treatment at the University of Miami. Fifty-three patients underwent laparoscopic cystectomy (n ϭ 32, 61%) or laparoscopic oophorectomy (n ϭ 21, 39%) and another 55 patients had laparotomy for ovarian cystectomy or oophorectomy.Laparoscopy was performed using three or four trocars, at least one of which was placed at the umbilicus. During laparoscopic cystectomy, after separation from the ovary, the cyst was placed into an impermeable bag. The bag was removed using the largest trocar port. When the opening of the bag was completely out of the port, the contents of the cysts were drained in the bag before complete removal. If spillage occurred, lavage of the peritoneal cavity was performed until the irrigation was clear.The mean age of patients was significantly lower (27.6 years; range, 7-46 years) for the 55 women who underwent laparotomy compared with those who had laparoscopy (33.5 years; range, 19-55 years) (P Ͻ0.001). Otherwise, the two groups were comparable. Chronic pain was the most common presenting complaint (69%). Four patients presented with acute pelvic pain and 22% of patients had no symptoms. Nearly one third of patients had more than one presenting symptom.Dermoid cysts tended to be larger in women who had laparotomy (mean cyst diameter 9.75 cm) compared with the women who underwent laparoscopy (mean cyst diameter 6.52 cm) (P ϭ 0.007). Fourteen percent of the patients had bilateral cysts. Spillage of the cyst contents was much more frequent in women who underwent laparoscopy (31.4%) compared with those who had laparotomy (4.1%) (P ϭ 0.0004). The mean operating room time was significantly less for laparotomy procedures than for laparoscopy (88 minutes vs 118 minutes) (P ϭ 0.0008), but mean blood loss was greater in laparotomy procedures compared with laparoscopy (119 mL and 72 mL, respectively; P ϭ 0.002).Intraoperative laparoscopy complications included uterine perforation in two women, enterotomy in one patient, and cystotomy in one laparotomy patient. There were more postoperative complications in laparotomy patients (n ϭ 8) than in the laparoscopic group (n ϭ 2). In the laparoscopic group, one patient had a postoperative wound infection and one woman developed a hernia. Among laparotomy patients, there were four postoperative wound infections, one urinary tract infection, two postoperative fevers, and one death. The woman who died was obese with a 24-cm partially infracted dermoid cyst and died the day after surgery of cardiac arrhythmia. Nine (17%) patients undergoing laparoscopy were converted to laparotomy, four because of the large size of the mass and five as a result of adhesions. Nine patients with pain and cyst torsion underwent laparotomy.Laparoscopy was significantly more commonly associated with dermoid cyst spillage, even when adjustments were made for cyst size, oophorectomy, and cystectomy. No patient in this series developed peritonitis. EDITORIAL C...

Materials with electroprogrammable stiffness and adhesion can enhance the performance of robotic systems, but achieving large changes in stiffness and adhesive forces in real time is an ongoing challenge. Electroadhesive clutches can rapidly adhere high stiffness elements, although their low force capacities and high activation voltages have limited their applications. A major challenge in realizing stronger electroadhesive clutches is that current parallel plate models poorly predict clutch force capacity and cannot be used to design better devices. Here, we use a fracture mechanics framework to understand the relationship between clutch design and force capacity. We demonstrate and verify a mechanics-based model that predicts clutch performance across multiple geometries and applied voltages. On the basis of this approach, we build a clutch with 63 times the force capacity per unit electrostatic force of state-of-the-art electroadhesive clutches. Last, we demonstrate the ability of our electroadhesives to increase the load capacity of a soft, pneumatic finger by a factor of 27 times compared with a finger without an electroadhesive.

Underwater swimmers present unique opportunities for using bodily reconfiguration for self propulsion. Origamiinspired designs are low-cost, fast to fabricate, robust, and can be used to create compliant mechanisms useful in energy efficient underwater locomotion. In this paper, we demonstrate an origami-inspired robot that can change its body shape to ingest and expel water, creating a jet that propels it forward similarly to cephalopods. We use the magic ball origami pattern, which can transform between ellipsoidal (low volume) and spherical (high volume) shapes. A custom actuation mechanism contracts the robot to take in fluid, and the inherent mechanics of the magic ball returns the robot to its natural shape upon release. We describe the design and control of this robot and verify its locomotion in a water tank. The resulting robot is able to move forward at 6.7 cm/s (0.2 body lengths/s), with a cost of transport of 2.0.

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Discontinuous carbide formation along the grain boundaries was found to be a desirable condition for obtaining ASTM-recommended strength and ductility levels in a sintered alloy containing 0.3% carbon by weight and meeting the requirements of the ASTM Specification for Cast Cobalt-Chromium-Molybdenum Alloy for Surgical Implant Applications (F 75–82). Excessive carbides in the grain boundaries of this alloy caused a severe reduction in ductility, while relatively carbide-free grain boundaries produced acceptable ductility but a marked reduction in the ultimate and 0.2% yield strengths. This behavior was also true for an ASTM F75 alloy with a lower carbon level (0.24% by weight). However, the latter alloy failed to meet the strength levels specified in ASTM Specification F 75–82. Subsequent aging of similar specimens led to carbide precipitation within the grains and dissolution of grain boundary particles, which caused an immediate loss of ductility. In addition, there was evidence for the precipitation of intermetallic, topologically close-packed (TCP) phases, which have been shown to have deleterious effects on the room-temperature ductilities of cobalt-base alloys. This phenomenon occurs in alloys with both high (0.3%) and low (0.24%) carbon contents. The precipitate population and the severity of ductility loss were time and temperature dependent.