Man-made rotary nanomotors: a review of recent developments.

The development of rotary nanomotors is an essential step towards intelligent nanomachines and nanorobots. In this article, we review the concept, design, working mechanisms, and applications of state-of-the-art rotary nanomotors made from synthetic nanoentities. The rotary nanomotors are categorized according to the energy sources employed to drive the rotary motion, including biochemical, optical, magnetic, and electric fields. The unique advantages and limitations for each type of rotary nanomachines are discussed. The advances of rotary nanomotors is pivotal for realizing dream nanomachines for myriad applications including microfluidics, biodiagnosis, nano-surgery, and biosubstance delivery.

Parallel fabrication of magnetic tunnel junction nanopillars by nanosphere lithography.

We present a new method for fabricating magnetic tunnel junction nanopillars that uses polystyrene nanospheres as a lithographic template. Unlike the common approaches, which depend on electron beam lithography to sequentially fabricate each nanopillar, this method is capable of patterning a large number of nanopillars simultaneously. Both random and ordered nanosphere patterns have been explored for fabricating high quality tunneling junctions with magnetoresistance in excess of 100%, employing ferromagnetic layers with both out-of-plane and in-plane easy axis. Novel voltage induced switching has been observed in these structures. This method provides a cost-effective way of rapidly fabricating a large number of tunnel junction nanopillars in parallel.

Electric Tweezers.

Electric tweezers utilize DC and AC electric fields through voltages applied on patterned electrodes to manipulate nanoentities suspended in a liquid. Nanowires with a large aspect ratio are particularly suitable for use in electric tweezers for patterning, assembling, and manipulation. Despite operating in the regime of extremely small particle Reynolds number (of order 10-5), electric tweezers can manipulate nanowires with high precision to follow any prescribed trajectory, to rotate nanowires with controlled chirality, angular velocity and rotation angle, and to assemble nanowires to fabricate nanoelectromechanical system (NEMS) devices such as nanomotors and nano-oscillators. Electric tweezers have also been used to transport in a highly controlled manner drug-carrying functionalized nanowires for cell-specific drug delivery.

Urological complications in 1,223 kidney transplantations.

INTRODUCTION: Urological complications after kidney transplantation may lead to graft loss. In this study, we retrospectively reviewed urological complications in 1,223 kidney transplantations that were performed at our institution. MATERIALS AND METHODS: The occurrence of urological complications such as urine leakage, ureteral obstruction and vesicoureteral reflux (VUR) according to the different way of urinary tract reconstruction, ureteroneocystostomy (U-C) and ureteroureterostomy (U-U), was studied. RESULTS: Urological complications were encountered in 92 (7.5%) cases, including urine leakage (n = 43, 3.5%), ureteral obstruction (n = 35, 2.9%) and VUR (n = 14, 1.1%). 75 cases (7.9%) were in the U-C group and 17 cases (6.2%) in the U-U group. 91 recipients were successfully treated, and 1 patient lost the graft due to kidney pelvis and ureteral necrosis. There was no recipient loss due to these complications. For recipients with urological complications, the 1- and 3-year survival rates were 90 and 88% for recipients and 87 and 82% for grafts, respectively. CONCLUSIONS: After U-U, the same number of overall incidences of urological complications is observed as after U-C; however, a decrease in the number of incidences of urine leakage is apparent. Therefore, U-U is a good first option with a greater success rate of resolving ureteral stenosis with endourology and no risk of VUR.

Treatment of urinary fistula after kidney transplantation.

Urinary fistula is a common complication after kidney transplantation and may lead to graft loss and patient death. Its current incidence ranges from 1.2% to 8.9%. From December 1993 to April 2007, 1223 kidney transplant procedures were performed by our kidney transplantation team. In 948 recipients (group 1), we performed an extravesical ureteroneocystostomy, and in 275 recipients (group 2), a terminoterminal ureteroureterostomy (UU). We observed urinary fistulas in 43 patients (3.5%), with mean onset at 6 days (range, 3-20 days) posttransplantation. Urinary fistula was significantly more common in group 1 compared with group 2 (4.1% and 1.5%, respectively; P < .05). The distal ureteral necrosis was the major frequent cause of urinary fistula (n = 34; 76.7%), which required either a second ureteroneocystostomy or UU using the native ureter. Of these 21 fistulas, including 10 recurrent fistulaes, were successfully treated with pedicled omentum covering the anastomotic stoma. Conservative treatment with a stent and Foley catheter drainage for 1 to 2 weeks was successful in 8 patients. All patients with a urinary fistula regained normal graft function except 1 in whom transplant nephrectomy was necessary because of pelvic and ureteral necrosis. There was no recipient loss secondary to urinary fistula. In conclusion, UU can decrease the incidence of urinary fistula after kidney transplantation. Most urinary fistulas require surgical management; and pedicled omentum is useful to repair the fistula.

Magnetic bistability and controllable reversal of asymmetric ferromagnetic nanorings.

Magnetization reversals through the formation of a vortex state and the rotation of an onion state are two processes with comparable probabilities for symmetric magnetic nanorings with a radius of about 50 nanometers. This magnetic bistability is the manifestation of the competition between the exchange energy and the magnetostatic energy in nanomagnets. The relative probability of the two processes in symmetric nanorings is dictated by the ring geometry and cannot be altered after fabrication. In this work, we report a novel type of nanorings--asymmetric nanorings. By tuning the asymmetry, we can control the fraction of the vortex formation process from about 40% to nearly 100% by utilizing the direction of the external magnetic field. The observed results have been accounted for by the dependence of the domain-wall energy on the local cross-section area for which we have provided theoretical calculations.

A study on the serum pregnancy zone protein levels in pregnant women and patients with gynecological tumors.

In this study, the serum levels of the pregnancy zone protein (PZP) were determined by PZP-single radial immunodiffusion in 708 cases of normal pregnancy, 207 with abnormal pregnancy and 188 with gynecological tumors. The results indicated that serum PZP levels in the normal pregnancy was detectable 5 weeks after gestation. It increased with the advance of gestational weeks, and reached a peak level in week 40. The serum PZP levels in 81.7% of patients with threatened abortion but not aborted were within the normal range, and also mostly in those with pregnancy-induced hypertension, intrauterine growth retardation (IUGR), anencephalus and ectopic pregnancy; the serum PZP levels in 51.6% of patients with invasive moles and 80.0% with choriocarcinoma, respectively, were lower than in normal controls. In gynaecological tumors, the serum PZP levels were significantly higher in patients with ovarian carcinomas than in those with other ovarian tumors (P < 0.01), and in those with endometrial or cervical carcinoma than in those with uterine myomas (P < 0.01). These results suggest that measuring the serum PZP levels may be used as an important reference index to observe threatened abortion and to identify trophoblastic diseases and gynecological tumors.

[Determination catecholamines levels in amniotic fluid, maternal and umbilical blood].

Catecholamines (CA) levels of amniotic fluid, maternal and umbilical blood were determined by HPLC. The results showed that epinaphrine (E) and dopamine (DA) levels of pregnancy were significantly different as compared with non-pregnant women (P > 0.05), where as norepinephrine (NE) levels were significantly decreased (P < 0.05). In vaginal delivery, CA levels of pregnant women were significantly higher than those of non and late-pregnant women (P < 0.01). Plasma CA levels of umbilical artery were higher than those of umbilical vein (P < 0.001); NE of CA was 3.3 times, E 4.7 times and DA 2.1 times. NE and E levels of umbilical artery in cesarean section were significantly lower than those of in vaginal delivery. In fetal distress, plasma NE and E levels of umbilical artery were higher significantly than those of the normal fetus. CA levels of amniotic fluid increased with advance of gestational weeks, significantly in fetal distress, even more than the upper limit of 95%. The incidence of newborn asphyxia was about 60.0%.

[Determination of catecholamine levels in umbilical artery and amniotic fluid in the diagnosis of fetal distress].

Catecholamine (CA) levels of umbilical artery were determined by high performance liquid chromatography (HPLC) in 11 normal term delivery babies and 30 infants with intrauterine fetal distress, and CA in their amniotic fluid which was collected after delivery was also determined. Results showed that CA levels, mainly norepinephrine (NE) and epinephrine (E), in umbilical artery of distressed babies were significantly higher than that of normal infants. The degree of increase was related to the occurrence of neonatal asphyxia, and was negatively correlated with Apgar score. The correlation coefficiency between NE, E and Apgar score was rNE = -0.639, P < 0.01, and rE = -0.459, P < 0.05, respectively. The increase of CA level was an early signal of fetal hypoxia. We believe that CA level in umbilical artery and amniotic fluid was a good index for early diagnosis of fetal distress.

[Clinical significance in determining pregnancy zone protein].

Serum pregnancy zone protein (PZP) levels were determined by PZP-single radial immunodiffusion in 708 normal pregnancies, 207 pregnancies with complication, and 188 cases with gynecological tumors. The results indicated that serum PZP could be detected at the fifth week of normal pregnancy, up to peak level at the 40th week. 81.5% women with threatened abortion who had a good prognosis had normal PZP levels. The PZP levels of women with pregnancy-induced hypertension (PIH), intrauterine growth retardation (IUGR), anencephalus and ectopic pregnancy were within the normal range. However, 51.6% and 80.0% serum PZP levels in patients with malignant mole and choriocarcinoma, respectively, were below the normal level; PZP levels in cases with ovarian cancer were significantly higher than that of patients with ovarian benign tumors (P < 0.05); and PZP in endometrial carcinoma and cervical cancer were significantly higher than that in myoma of uterus (P < 0.05). This study showed that the measurement of serum PZP levels might be an important prognostic reference index for predicting the outcome of threatened abortion and identifying benign trophoblastic tumors and gynecological tumors.

[Significance of composite scoring of biochemical monitoring in fetal distress].

Urinary E/C ratio, maternal urinary meconial index (UMI), human placental lactogen (hPL) and pregnancy specific beta-1 glycoprotein (SP1) were determined by biochemical and immunologic method. The accuracy of composite scoring method was compared with that of individual index. The results show that composite scoring method was better than the single index in predicting and diagnosis of fetal distress.

[Significance of detecting meconium-like substance in maternal urine in perinatal monitoring].

Urinary meconium index (UMI) was determined in 538 cases of pregnant women by spectrophotometry (265 cases were in late pregnancies 229 in the first stage of delivery, and 44 in the second stage). The results indicated that most of those having positive UMI were high-risk pregnancies (P less than 0.01). The UMI index of the meconium contaminated amniotic fluid was higher than the non-contaminated amniotic fluid (P less than 0.01), and patients with lower Apgar score had higher rate of positive UMI. In consecutive measuring, , We found that the rate of neonatal asphyxia was highest in those with a UMI of falling type, and then in the rising type. It showed that measurement of maternal UMI is of value in monitoring high-risk pregnancies.

[Clinical significance of urine estriol-125I-radioimmunoassay in obstetric monitoring].

This paper reported the determination of urine E3 in 326 normal pregnancies from 28 to 41 gestational weeks, and 80 abnormal pregnancies by E3-125I-RIA. The results showed that E3 levels in normal pregnancies increased with advance of gestational weeks with their peaks at the 38th week and decreased gradually after the 40th week. There was a positive correlation between urine E3 and the 12 hour urine E/C ratio (r = 0.798, P less than 0.001). In monitoring the high-risk pregnancies, we found 92.3% with E3 less than or equal to 10 mg/L in severe PIH, 23.5% in mild and moderate PIH, 37.9% in post-term pregnancy and 78.9% in intrauterine growth retardation (IUGR). It indicated that measurement of urine E3 using E3 125I-RIA is a better index for detecting and screening placenta 1 function.

[Dibutyryl cyclic adenosine monophosphate (DBc-AMP) in the treatment of recurrent malignant gliomas--report of 7 patients].

It has been demonstrated, by experiments, that DBc-AMP can induce biochemical and morphological changes in cultured glioma cells. In this paper, seven recurrent malignant glioma patients, who had received operation, radiotherapy and chemotherapy, were treated with DBc-AMP by injecting into the tumor feeding artery in 1 patient and directly into the tumor cavities in 6 patients. The results showed that although no improvement of symptoms was observed except the case by intraarterial injection, the IgG and IgA levels were elevated and tumor volume was reduced as shown by enhancement CT scan in 4 patients. It suggests that this method be a better adjuvant therapy for recurrent malignant gliomas.