SQUID-on-tip with single-electron spin sensitivity for high-field and ultra-low temperature nanomagnetic imaging.

Scanning nanoscale superconducting quantum interference devices (nanoSQUIDs) are of growing interest for highly sensitive quantitative imaging of magnetic, spintronic, and transport properties of low-dimensional systems. Utilizing specifically designed grooved quartz capillaries pulled into a sharp pipette, we have fabricated the smallest SQUID-on-tip (SOT) devices with effective diameters down to 39 nm. Integration of a resistive shunt in close proximity to the pipette apex combined with self-aligned deposition of In and Sn, has resulted in SOTs with a flux noise of 42 nΦ0 Hz-1/2, yielding a record low spin noise of 0.29 µB Hz-1/2. In addition, the new SOTs function at sub-Kelvin temperatures and in high magnetic fields of over 2.5 T. Integrating the SOTs into a scanning probe microscope allowed us to image the stray field of a single Fe3O4 nanocube at 300 mK. Our results show that the easy magnetization axis direction undergoes a transition from the 〈111〉 direction at room temperature to an in-plane orientation, which could be attributed to the Verwey phase transition in Fe3O4.

Imaging of super-fast dynamics and flow instabilities of superconducting vortices.

Quantized magnetic vortices driven by electric current determine key electromagnetic properties of superconductors. While the dynamic behavior of slow vortices has been thoroughly investigated, the physics of ultrafast vortices under strong currents remains largely unexplored. Here, we use a nanoscale scanning superconducting quantum interference device to image vortices penetrating into a superconducting Pb film at rates of tens of GHz and moving with velocities of up to tens of km/s, which are not only much larger than the speed of sound but also exceed the pair-breaking speed limit of superconducting condensate. These experiments reveal formation of mesoscopic vortex channels which undergo cascades of bifurcations as the current and magnetic field increase. Our numerical simulations predict metamorphosis of fast Abrikosov vortices into mixed Abrikosov-Josephson vortices at even higher velocities. This work offers an insight into the fundamental physics of dynamic vortex states of superconductors at high current densities, crucial for many applications.Ultrafast vortex dynamics driven by strong currents define eletromagnetic properties of superconductors, but it remains unexplored. Here, Embon et al. use a unique scanning microscopy technique to image steady-state penetration of super-fast vortices into a superconducting Pb film at rates of tens of GHz and velocities up to tens of km/s.

Scanning superconducting quantum interference device on a tip for magnetic imaging of nanoscale phenomena.

We describe a new type of scanning probe microscope based on a superconducting quantum interference device (SQUID) that resides on the apex of a sharp tip. The SQUID-on-tip is glued to a quartz tuning fork which allows scanning at a tip-sample separation of a few nm. The magnetic flux sensitivity of the SQUID is 1.8 µΦ(0)/√Hz and the spatial resolution is about 200 nm, which can be further improved. This combination of high sensitivity, spatial resolution, bandwidth, and the very close proximity to the sample provides a powerful tool for study of dynamic magnetic phenomena on the nanoscale. The potential of the SQUID-on-tip microscope is demonstrated by imaging of the vortex lattice and of the local ac magnetic response in superconductors.

Axonal damage to the left musculocutaneous nerve of the left biceps muscle during laparoscopic surgery.

The probable etiology of axonal damage to the left musculocutaneous nerve (motor branch) of the left biceps branchii during a laparoscopic procedure was the position in which the patient was maintained. As a result of unintentional change in the angle of the arm from 90 to approximately 120 degrees while in steep Trendelenburg position, the arm might have suffered hyperextension, resulting in pressure on and stretching of the brachial plexus nerve. This in turn might be the cause of neurologic damage. We recommend taking steps to prevent such occurrences, such as tying the patient's arms parallel to the body.

[Placenta accreta with placenta previa after previous cesarean sections--a growing danger in modern obstetrics].

The increased rate of cesarean sections in recent decades has brought with it an increase in the frequency of placenta accreta. There are direct correlations between previous cesarean deliveries and also maternal age, with the risk of placenta accreta. There is also a direct correlation between placenta accreta and placenta previa. The risk of placenta accreta in women who have had placenta previa is 2% for those younger than 35 years and with no history of uterine surgery. The risk increases to 39% for those over 35 who have had 2 or more cesarean sections. We present 3 cases of placenta accreta admitted in 15 months, all of whom had a history of cesarean sections. The frequency of placenta accreta in our hospital is 1:1,579 deliveries, in line with the 1:1,420 in the literature. We consider hysterectomy the treatment of choice for this serious complication. When performing a cesarean in cases of placenta previa with a history of cesarean sections, the possibility of placenta accreta should be considered.

Pregnancy and laparoscopic surgery.

We reviewed the English literature regarding laparoscopic surgery during pregnancy and found that of 518 reported procedures, the most common was cholecystectomy (45%), followed by adnexal surgery (34%), appendectomy (15%), and other operations (6%). We add six cases to this list; three cholecystectomies, an adnexal procedure, and two for abdominal pain. Thirty-three percent were performed in the first trimester, 56% in the second, and 11% in the third trimester. This review demonstrates a definite trend, indicating that laparoscopy in pregnancy appears to be safe when performed by experienced practitioners. (J Am Assoc Gynecol Laparosc 6(3):347-351, 1999)

[Operative laparoscopy in pregnancy].

The development of laparoscopic surgery in gynecology and general surgery has greatly advanced over the past decade, and recently has been successfully performed in pregnancy. In the English literature we found that of the 518 cases reported (mean age 32 years) the most common was for cholecystectomy (45%), followed by operations on the adnexae (34%), appendectomy (15%) and others (6%). To these we add 3 cases of cholecystectomy and 1 of an adnexal tumor. Of all the reported cases, 33% were performed in the 1st trimester, 56% in the 2nd and 11% in the 3rd. This review demonstrates a definite trend to laparoscopy in pregnancy. It appears to be safe when performed by experienced surgeons, but further studies addressing safety of laparoscopic surgery during pregnancy are needed to reach definitive conclusions.

[Experience with under-water birth].

Underwater birth is now deemed an acceptable type of delivery. Safety is a recurring consideration, the main concern being that of drowning. But in reports of 19,000 underwater births no untoward events were noted. Also, need for pain relief and of intervention during labor were both reduced. The short term indicators of neonatal outcome were good. A recent review explains 5 different physiological factors which inhibit initiation of fetal breathing under warm water. Many studies have shown no increase in risk of infection of either mother or baby. We report our experience with 26 women, 23 of whom actually delivered in the pool with excellent results. We believe that birth under water is safe and beneficial if done properly for low-risk patients.

Lumbar epidural analgesia in hypertensive patients during labour.

Continuous lumbar epidural analgesia (L.E.A.) is considered to be the most effective technique for providing pain relief during labour and delivery. A prospective randomized study of 52 patients with pre-eclamptic toxemia in labour was carried out to investigate various aspects of the use of L.E.A. in view of the considerable disagreement concerning its effect. The results were compared to a control group (n = 52) receiving i.v. infusion of Hydralazine (Apresoline) and MgSO4 according to Zuspan recommendations. The results were evaluated statistically. The incidence of neonatal jaundice was higher in the control group (P less than 0.005). Maternal postpartum complications were similar in both groups. There were fewer forceps deliveries in the control group (P less than 0.05). The decrease in systolic BP after L.E.A. is well documented up to 120 min after the first injection of Marcaine (P less than 0.001-0.025), while after 120 min, by which time the Marcaine effect has finished, the systolic BP rises again (time for topping up). The decrease in the average diastolic BP as compared to the control group is statistically significant (P less than 0.001-0.01) until 180 min after initiation of the L.E.A. After that, the average diastolic BP rises again, unless Marcaine is topped up. Our results favour L.E.A. as the obstetric analgesic method of choice in cases of severe pre-eclampsia.

The incidence of major abdominal surgery after septic abortion--an indicator of complications due to illegal abortion.

That there is a high morbidity associated with illegal abortion is well known, but its exact extent is difficult to assess, since detailed statistics are not available and the nature of the morbidity is diffuse. We have assumed that abortal sepsis is a consequence of illegal interference with pregnancy. The incidence of major abdominal surgery after a septic abortion is used as an indicator of serious complications. This incidence is compared with that following legal abortion.

Rupture of the gravid uterus.

A detailed analysis of 129 cases of rupture of the gravid uterus between 1980 and 1983 is presented and compared with two previous reports from King Edward VIII Hospital, Durban, over the last 2 decades. Statistically significant decrease in the occurrence of this condition (from 2,7 to 1,06/1000 deliveries (P less than 0,001; chi 2 = 20,38)) and in the maternal mortality rate (from 12% to 3%) have taken place since the initial study. The most probable reasons for this improvement are the provision of a community-based obstetric service, the early detection of cephalopelvic disproportion, awareness of the condition, immediate and adequate resuscitation once the diagnosis is established, and the performance of a total abdominal hysterectomy as definitive treatment in most cases.

Peritoneal tuberculosis imitating ovarian carcinoma "special category".

A case report, of a patient with peritoneal tuberculosis in whom the provisional diagnosis of ovarian carcinoma--"special category" was made is presented. As most gynecologists see hardly any cases of peritoneal tuberculosis nowadays, this possible diagnosis--which should always be considered--is reviewed. It illustrates the importance of a definite histopathological diagnosis.

Anti-lipopolysaccharide immunotherapy in management of septic shock of obstetric and gynaecological origin.

Freeze-dried human plasma rich in anti-lipopolysaccharide (anti-LPS) immunoglobulin G was used to treat septic shock (systolic pressure less than or equal to 80 mm Hg, central venous pressure greater than or equal to 6 cm H2O) in obstetric and gynaecological patients. Mortality in conventionally treated patients was 9/19 (47.4%) compared with 1/14 (7.1%) in anti-LPS-treated patients. Anti-LPS caused the mean arterial pressure to rise from 45.1 +/- 7.36 mm Hg to 69.1 +/- 9.07 mm Hg within 75 min of administration. The mean hospital stay of survivors was 28.1 days for controls and 14.2 days for the anti-LPS-treated patients. The development of complications of septic shock was much reduced in the treated group. Anti-LPS thus appears significantly to reduce mortality and morbidity in septicaemia.

The use of antilipopolysaccharide (anti-LPS) antibodies in the management of septic shock. A preliminary report.

Twenty-two patients who were in severe sepsis or in septic shock, some with multiple-system failure, were treated with antilipopolysaccharide (anti-endotoxin) antibodies, given in the form of gammaglobulin or as antibody-rich freeze-dried plasma. Twenty patients responded to the treatment either completely or temporarily. The beneficial effect and the physiological aspects of this treatment as opposed to other suggested treatments in the management of septic shock are discussed.