An experimental design for the control and assembly of magnetic microwheels.

Superparamagnetic colloidal particles can be reversibly assembled into wheel-like structures called microwheels (µwheels), which roll on surfaces due to friction and can be driven at user-controlled speeds and directions using rotating magnetic fields. Here, we describe the hardware and software to create and control the magnetic fields that assemble and direct µwheel motion and the optics to visualize them. Motivated by portability, adaptability, and low-cost, an extruded aluminum heat-dissipating frame incorporating open optics and audio speaker coils outfitted with high magnetic permeability cores was constructed. Open-source software was developed to define the magnitude, frequency, and orientation of the magnetic field, allowing for real-time joystick control of µwheels through two-dimensional (2D) and three-dimensional (3D) fluidic environments. With this combination of hardware and software, µwheels translate at speeds up to 50 µm/s through sample sizes up to 5 × 5 × 5 cm3 using 0.75 mT-2.5 mT magnetic fields with rotation frequencies of 5 Hz-40 Hz. Heat dissipation by aluminum coil clamps maintained sample temperatures within 3 °C of ambient temperature, a range conducive for biological applications. With this design, µwheels can be manipulated and imaged in 2D and 3D networks at length scales of micrometers to centimeters.

Non reciprocal skewed rolling of a colloidal wheel due to induced chirality.

We use a rotating magnetic field to assemble an oblate cluster of paramagnetic colloidal particles. If the field is rotating about a horizontal axis, the cluster acts as a colloidal wheel rolling across the supporting glass surface. The motion is reversible upon switching the direction of rotation. Surprisingly, the reversibility is lost if the axis of field rotation is tilted with respect to the surface. The wheel then rolls in a direction that is not perpendicular to the field rotation axis. We explain the skewed rotation with an interplay between a magnetic driving torque, magnetic anisotropy and an anisotropy in the hydrodynamic mobility tensor in the vicinity of a surface. The opposing forward and backward drive induce opposite chirality in the degrees of freedom of the mechanically achiral colloidal wheel.

Stage IVB endometrial cancer confined to the abdomen: is chemotherapy superior to radiotherapy?

PURPOSE: To determine the impact of clinical variables and adjuvant therapy on survival in patients with Stage IVB endometrial cancer (EC) confined to abdomen. METHODS AND METHODS: A total of 65 patients were included. Curative chemotherapy was defined as using only chemotherapy (platin based) or sandwich therapy. Patients receiving only radiotherapy had standard pelvic radiotherapy and extended-field radiotherapy when necessary. RESULTS: The optimal cytoreduction was achieved in 89.3% of patients. With a median follow-up of 18 months, two-year progression free survival (PFS) and overall survival (OS) were calculated as 33.4% and 42.2%, respectively. Optimal cytoreduction provided more longer PFS and OS compared to suboptimal cytoreduction. In univariate analysis, curative chemotherapy instead of radiotherapy improved the two-year PFS and two-year OS. Type of adjuvant therapy, tumor grade, and peritoneal cytology were found as the independent prognostic factors for PFS. Peritoneal cytology, adnexal involvement, and adjuvant therapy were independent prognostic factor for OS. CONCLUSION: Curative chemotherapy significantly improved both two-year PFS and OS in patients with Stage IVB endometrial disease confined to abdomen over only radiotherapy.

Surface-enabled propulsion and control of colloidal microwheels.

Propulsion at the microscale requires unique strategies such as the undulating or rotating filaments that microorganisms have evolved to swim. These features however can be difficult to artificially replicate and control, limiting the ability to actuate and direct engineered microdevices to targeted locations within practical timeframes. An alternative propulsion strategy to swimming is rolling. Here we report that low-strength magnetic fields can reversibly assemble wheel-shaped devices in situ from individual colloidal building blocks and also drive, rotate and direct them along surfaces at velocities faster than most other microscale propulsion schemes. By varying spin frequency and angle relative to the surface, we demonstrate that microwheels can be directed rapidly and precisely along user-defined paths. Such in situ assembly of readily modified colloidal devices capable of targeted movements provides a practical transport and delivery tool for microscale applications, especially those in complex or tortuous geometries.

The importance of age and menopausal status in endometrial complex hyperplasia with atypia.

The effects of menopausal status and age on the intra-operative and post-operative pathology results of patients operated on with a pre-operative diagnosis of complex hyperplasia with atypia (CHA) were assessed. A hundred and eleven patients diagnosed in our centre between January 1993 and March 2013 were included. Cancer was detected in the paraffin blocks (PBs) of 52 (46.8%) patients. Among these, 50 patients had stage-IA disease. In 31.1% of the pre-menopausal patients and 66% of the post-menopausal patients, PB revealed cancer (p < 0.0001). The results of frozen section (FS) and PB were concordant in 51% and 70% in the pre-menopausal and post-menopausal patients, respectively (p = 0.041). In the patients operated on with a pre-operative diagnosis of CHA, the probability of detecting cancer in PB increases with increasing age and menopause. The reliability of FS is limited in younger and pre-menopausal patients.

Undifferentiated uterine carcinoma: analysis of eighteen cases.

Analysis of the surgicopathological characteristics and clinical follow-up of patients with undifferentiated uterine carcinoma (UUC) was conducted. A total of 18 cases operated between January 1993 and December 2013 were included. Among 1,690 patients with endometrial cancer, 18 patients (1.1%) had UUC. Lymph node involvement was detected in 70.6%; depth of myometrial invasion was ≥ 0.5 in 55.6%; lymphovascular space invasion was detected in 99.3%; cervical stromal invasion was positive in 27.8%; omental and adnexal involvement were detected in 11.8% and 38.9%, respectively. The median follow-up time of the 12 patients evaluated in the survival analysis was 66 months. In the follow-up period, recurrence or progression during adjuvant therapy were observed in four patients (33.3%) and two patients (16.6%) died of the disease. UUC manifests as an aggressive tumour. In conclusion, a high rate of survival could be achieved with complete staging surgery, including an extensive lymphadenectomy with the contribution of adjuvant therapy.

Outcomes after early or midfollicular phase LH supplementation in previous inadequate responders.

Second cycle outcomes of 75 patients who had previous inadequate ovarian response with recombinant FSH (rFSH)-only ovarian stimulation during gonadotrophin-releasing hormone analogue (GnRHa) down-regulated cycles were evaluated retrospectively. In these second cycles, both rFSH and human menopausal gonadotrophin (HMG) in GnRHa long down-regulation were given to all patients, HMG initiated either on day 1 (group A, n=37) or day 5-6 of the ovarian stimulation (group B, n=38). Total HMG dose was higher (1198+/-514 IU versus 726+/-469 IU; P<0.001), cumulative rFSH consumption was lower (1823+/-804 IU versus 2863+/-1393 IU; P=0.001) and duration of stimulation was shorter (8.94+/-1.15 days versus 10.37+/-1.80 days; P<0.001) in group A than in group B. No significant differences were found regarding fertilization, implantation or pregnancy rates and embryo quality between the groups. Further analysis by supplementary HMG dose (75 IU versus 150 IU) revealed that total gonadotrophin and HMG consumption was lower in 75 IU-supplemented subgroups. Notably, pregnancy rate was higher in patients where 75 IU HMG was supplemented on day 5-6 of ovarian stimulation, which deserves further evaluation.

Dehydroepiandrosterone supplementation improves ovarian response and cycle outcome in poor responders.

The effect of dehydroepiandrosterone (DHEA) supplementation on cycle outcome was assessed in patients with poor ovarian response. In total, 19 poor responder patients who were scheduled to undergo a second intracytoplasmic sperm injection (ICSI)/embryo transfer cycle were enrolled and first ICSI/embryo transfer cycles were taken as the control group. All subjects were given DHEA supplementation (25 mg t.i.d.) for at least 3 months prior to their second ICSI/embryo transfer cycle. In both cycles a fixed dose of rFSH (300 IU/day) and human menopausal gonadotrophin (HMG) (75 or 150 IU/day) along with a flexible gonadotrophin-releasing hormone (GnRH) antagonist protocol were administered. A favourable decrease was noted in mean day 3 serum oestradiol concentrations after DHEA supplementation (75.14 +/- 28.93 versus 43.07 +/- 11.77; P < 0.01). Increased number of >17 mm follicles (3 +/- 0.7 versus 1.9 +/- 1.3; P < 0.05), MII oocytes (4 +/- 1.8 versus 2.1 +/- 1.8; P < 0.05), top quality day 2 (2.2 +/- 0.8 versus 1.3 +/- 1.1; P < 0.05) and day 3 embryos (1.9 +/- 0.8 versus 0.7 +/- 0.6; P < 0.05) were achieved in DHEA-supplemented cycles. Cycle cancellation rates were reduced (5.3% versus 42.1%; P < 0.01), and the pregnancy rate per patient and clinical pregnancy rate per embryo transfer (47.4% versus 10.5%; P < 0.01 and 44.4% versus 0%; P < 0.01) were improved after DHEA supplementation. DHEA supplementation might enhance ovarian response, reduce cycle cancellation rates and increase embryo quality in poor responders.

Focused RF hyperthermia using magnetic fluids.

Heat therapies such as hyperthermia and thermoablation are very promising approaches in the treatment of cancer. Compared with available hyperthermia modalities, magnetic fluid hyperthermia (MFH) yields better results in uniform heating of the deeply situated tumors. In this approach, fluid consisting of superparamagnetic particles (magnetic fluid) is delivered to the tumor. An alternating (ac) magnetic field is then used to heat the particles and the corresponding tumor, thereby ablating it. However, one of the most serious shortcomings of this technique is the unwanted heating of the healthy tissues. This results from the magnetic fluid diffusion from the tumor to the surrounding tissues or from incorrect localization of the fluids in the target tumor area. In this study, the authors demonstrated that by depositing appropriate static (dc) magnetic field gradients on the alternating (ac) magnetic fields, focused heating of the magnetic particles can be achieved. A focused hyperthermia system was implemented by using two types of coils: dc and ac coils. The ac coil generated the alternating magnetic field responsible for the heating of the magnetic particles; the dc coil was used to superimpose a static magnetic field gradient on the alternating magnetic field. In this way, focused heating of the particles was obtained in the regions where the static field was dominated by the alternating magnetic field. In vitro experiments showed that as the magnitude of the dc solenoid currents was increased from 0 to 1.8 A, the specific absorption rate (SAR) of the superparamagnetic particles 2 cm apart from the ac solenoid center decreased by a factor of 4.5, while the SAR of the particles at the center was unchanged. This demonstrates that the hyperthermia system is capable of precisely focusing the heat at the center. Additionally, with this approach, shifting of the heat focus can be achieved by applying different amounts of currents to individual dc solenoids. In vivo experiments were performed with adult rats, where magnetic fluids were injected percutaneously into the tails (with homogeneous fluid distribution inside the tails). Histological examination showed that, as we increased the dc solenoid current from 0.5 to 1.8 A, the total burned volume decreased from 1.6 to 0.2 cm3 verifying the focusing capability of the system. The authors believe that the studies conducted in this work show that MFH can be a much more effective method with better heat localization and focusing abilities.

Measuring local RF heating in MRI: Simulating perfusion in a perfusionless phantom.

PURPOSE: To overcome conflicting methods of local RF heating measurements by proposing a simple technique for predicting in vivo temperature rise by using a gel phantom experiment. MATERIALS AND METHODS: In vivo temperature measurements are difficult to conduct reproducibly; fluid phantoms introduce convection, and gel phantom lacks perfusion. In the proposed method the local temperature rise is measured in a gel phantom at a timepoint that the phantom temperature would be equal to the perfused body steady-state temperature value. The idea comes from the fact that the steady-state temperature rise in a perfused body is smaller than the steady-state temperature increase in a perfusionless phantom. Therefore, when measuring the temperature on a phantom there will be the timepoint that corresponds to the perfusion time constant of the body part. RESULTS: The proposed method was tested with several phantom and in vivo experiments. Instead, an overall average of 30.8% error can be given as the amount of underestimation with the proposed method. This error is within the variability of in vivo experiments (45%). CONCLUSION: With the aid of this reliable temperature rise prediction the amount of power delivered by the scanner can be controlled, enabling safe MRI examinations of patients with implants.