Deterministic Spin-Orbit Torque Switching by a Light-Metal Insertion.

Spin-orbit torque (SOT) switching of magnetization is a promising emerging technology for nonvolatile spintronic memory and logic applications. However, deterministic switching of perpendicular magnetization with SOTs requires an additional symmetry breaking, which is typically provided by an external magnetic field, making it impractical for applications. In this work, we disclose that by the insertion of a slightly asymmetric light-metal layer at the heavy metal-ferromagnet interface of SOT heterostructures, current-induced out-of-plane effective magnetic fields are introduced that enable deterministic switching without an external magnetic field. We obtain uniform perpendicular magnetic anisotropy and switching current density despite the asymmetry of the light-metal layer, and we show the scalability of our approach by studying device sizes that differ by 2 orders of magnitude. Our work provides a practical route for utilization of SOTs for magnetization switching on the wafer scale and paves the way for the practical application of SOT-based technology.

Roadmap of spin-orbit torques.

Spin-orbit torque (SOT) is an emerging technology that enables the efficient manipulation of spintronic devices. The initial processes of interest in SOTs involved electric fields, spin-orbit coupling, conduction electron spins and magnetization. More recently interest has grown to include a variety of other processes that include phonons, magnons, or heat. Over the past decade, many materials have been explored to achieve a larger SOT efficiency. Recently, holistic design to maximize the performance of SOT devices has extended material research from a nonmagnetic layer to a magnetic layer. The rapid development of SOT has spurred a variety of SOT-based applications. In this Roadmap paper, we first review the theories of SOTs by introducing the various mechanisms thought to generate or control SOTs, such as the spin Hall effect, the Rashba-Edelstein effect, the orbital Hall effect, thermal gradients, magnons, and strain effects. Then, we discuss the materials that enable these effects, including metals, metallic alloys, topological insulators, two-dimensional materials, and complex oxides. We also discuss the important roles in SOT devices of different types of magnetic layers, such as magnetic insulators, antiferromagnets, and ferrimagnets. Afterward, we discuss device applications utilizing SOTs. We discuss and compare three-terminal and two-terminal SOT-magnetoresistive random-access memories (MRAMs); we mention various schemes to eliminate the need for an external field. We provide technological application considerations for SOT-MRAM and give perspectives on SOT-based neuromorphic devices and circuits. In addition to SOT-MRAM, we present SOT-based spintronic terahertz generators, nano-oscillators, and domain wall and skyrmion racetrack memories. This paper aims to achieve a comprehensive review of SOT theory, materials, and applications, guiding future SOT development in both the academic and industrial sectors.

COVID-19 in obstetrics 2020: the experience at a New York City medical center.

The global spread of the SARS-CoV-2 virus during the early months of 2020 was rapid and exposed vulnerabilities in health systems throughout the world. Obstetric SARS-CoV-2 disease was discovered to be largely asymptomatic carriage but included a small rate of severe disease with rapid decompensation in otherwise healthy women. Higher rates of hospitalization, Intensive Care Unit (ICU) admission and intubation, along with higher infection rates in minority and disadvantaged populations have been documented across regions. The operational gymnastics that occurred daily during the Covid-19 emergency needed to be translated to the obstetrics realm, both inpatient and ambulatory. Resources for adaptation to the public health crisis included workforce flexibility, frequent communication of operational and protocol changes for evaluation and management, and application of innovative ideas to meet the demand.

Association between Interleukin-21 and Interleukin-21 receptor gene polymorphisms with susceptibility to chronic hepatitis B virus infection and HBV spontaneous clearance in Iranian population.

Hepatitis B virus (HBV) infection is a major public health concern due to the infection often leads to chronic infection, liver cirrhosis and also liver cancer. The host immune response to HBV infection and also genetic background play significant role in outcome of infection. Single nucleotide polymorphisms (SNPs) are the most important kind of variation in genetic sequences that caused by point mutations. As cytokines have major roles in viral infections, it seems that cytokine gene polymorphisms are independently associated with response to viral infections. Interleukin 21 (IL-21) plays an influential role in both innate and adaptive immune responses. Its specific receptor, IL-21R, produced and located on the surface of T, B and natural killer (NK) cells and is critical for the proliferation and differentiation of these immune effector cells. Many studies confirmed that the IL-21 involved in response to viral infections. We aimed to investigate the association of G/T IL-21 (rs2055979) and C/T IL-21R (rs3093390) gene polymorphisms with chronic hepatitis B virus infection and HBV spontaneous clearance in Iranian population. METHODS: In this study, blood samples were gathered from 320 patients with chronic HBV and 310 healthy controls and also 120 HBV spontaneous clearance individuals. Following genomic DNA extraction, genotypes of the selected SNPs determined by PCR and restriction fragment length polymorphism (RFLP) method. The results were analyzed by SPSS software using Chi-square, Logistic Regression, ANOVA and Independent Samples t-Test. RESULTS: According to our results, in IL-21R (rs3093390 C/T) gene polymorphism, allele frequency of T is statistically different in the HBV spontaneous clearance group compared to chronic HBV cases. But there is no significant difference between G/T IL-21 (rs2055979) and C/T IL-21R (rs3093390) genotypes distribution in three groups. Also we found that higher serum aspartate transaminase (AST) level in HBV spontaneous clearance group is significantly associated with TT genotype of IL-21 (rs2055979) compared to GG genotype (P value = 0.006). DISCUSSION: Our results showed that T allele frequency in IL-21R (rs3093390 C/T) gene polymorphism could consider as a host genetic factor for HBV spontaneous clearance. Probably we can serve it as a potential prognostic genetic marker for spontaneous clearance of HBV infection.

Diagnostic accuracy of isolated clubfoot in twin compared to singleton gestations.

Background Our objective was to determine the predictive value of the prenatal diagnosis of isolated clubfoot in twin gestations compared to singleton gestations. Methods A prospectively entered ultrasound database was reviewed for all pregnancies scanned at our institution from 2002 to 2014. Cases of suspected clubfoot were identified. Neonates with associated anomalies or aneuploidy, and patients who delivered at other institutions were excluded. Neonatal charts were reviewed for the confirmation of clubfoot. The chi-squared (χ2) test, Fisher's exact test and the Mann-Whitney U test were used in the analysis, with p < 0.05 considered significant. Results Of those women who had prenatal ultrasound and subsequently delivered at our hospital, 84 pregnancies had isolated clubfoot suspected in the antenatal period. Of these pregnancies, 20 were twin gestations and 64 were singleton gestations. Overall, 51/84 (60.7%) pregnancies had clubfoot confirmed during the neonatal period. Of the twin pregnancies, only 35% (7/20) had a confirmed diagnosis of clubfoot at birth compared to 68.8% (44/64) of the singleton pregnancies (P = 0.008). Gestational age at diagnosis, breech presentation, neonatal gender, unilateral vs. bilateral clubfoot and suspicion of clubfoot in the presenting twin (Twin A) vs. the non-presenting twin (Twin B) did not correlate with an accurate diagnosis of clubfoot in twins. Conclusion False-positive prenatal diagnosis of isolated clubfoot is more common in twin gestations compared to singletons. This may be due to transient malpositioning or a result of diminished space. Obstetric providers should consider the possibility of a false-positive diagnosis and use caution when counseling patients about a prenatal suspicion for clubfoot, especially in twin gestations.

Hyponatremia associated with preeclampsia.

OBJECTIVE: The objective of our study was to evaluate the prevalence and clinical factors associated with hyponatremia in patients with preeclampsia. STUDY DESIGN: This is a descriptive study of all patients who delivered at our institution from 2013 to 2014. Patients with preeclampsia were identified from electronic medical records. Preeclampsia with and without severe features was defined using the criteria outlined in the American Congress of Obstetricians and Gynecologists Hypertension in Pregnancy guidelines. As sodium levels have been shown to be approximately 5 mEq/L lower in pregnancy, hyponatremia was defined as a sodium level <130 mEq/L. RESULTS: We identified 332 pregnancies complicated by preeclampsia, including 277 singletons and 55 twins. Hyponatremia was noted in 32 (9.7%) patients. Preeclampsia with severe features was present in the majority of patients with hyponatremia, and hyponatremia was more common in those with preeclampsia with severe features compared to those without (P<0.001). Hyponatremia also occurred more frequently in twins (P=0.001) and in older women (P=0.017). Only one patient without hyponatremia had an eclamptic seizure. CONCLUSION: Hyponatremia is not uncommon in preeclampsia, and is even more common in those with preeclampsia with severe features and twin gestations. As women with preeclampsia are at risk for hyponatremia, serum sodium should be monitored, especially in women with preeclampsia with severe features or twin gestations.

Low PAPP-A: the impact of ultrasound to evaluate fetal growth.

OBJECTIVE: Our objective was to describe utilization and impact of sonographic growth assessment in pregnancies with low pregnancy-associated plasma protein-A (PAPP-A). METHODS: Singleton pregnancies with PAPP-A ≤5th percentile and no other risk factors for fetal growth restriction from January 2011-June 2013 were included. Antepartum and delivery data were obtained by reviewing medical records. Outcomes of pregnancies referred for sonographic growth assessment were compared with those not referred for ultrasound. Fisher's exact test, chi-square analysis, and Mann-Whitney U were used for statistical comparison. RESULTS: Two hundred ninety-five patients were included. Of 285 pregnancies reaching the third trimester, 77.5% were referred for ultrasound, with the initial scan at a median gestational age of 28 weeks [26-29]. Referral for growth scans was associated with earlier gestational age at delivery and higher rates of delivery for fetal indications. Those who did not undergo growth scans were more likely to deliver a small for gestational age infant at term, 20.7% versus 35.0% (p = 0.04). There was one third-trimester fetal demise, occurring in a patient who had been undergoing growth scans. CONCLUSION: Growth scans in those with low PAPP-A were associated with delivery at earlier gestational age, with higher rates of delivery for fetal indications and lower rates of small for gestational age newborns at term. No significant differences in neonatal outcomes were observed.

Echogenic intracardiac foci: disclosure and the rate of amniocentesis in low-risk patients.

OBJECTIVE: Our objective was to determine the impact of disclosure of echogenic intracardiac focus (EIF) on the rate of amniocentesis in women who have undergone sequential testing. STUDY DESIGN: This was a retrospective study of women who had sequential testing for Down syndrome from 2009 through 2011. The Down syndrome risk was doubled in pregnancies with EIF, consistent with counseling provided to patients. In the control group Down syndrome risk was based on sequential testing. Within risk categories (1 in <250, 251-1000, 1001-5000, >5000) rates of amniocentesis with and without documented EIF were compared using Fisher exact test. RESULTS: In all, 4429 women at a median maternal age were included, including 229 with EIF (5.2%). In those at highest Down syndrome risk (1 in <250), rates of amniocentesis were similar between the 2 groups. In those at lower levels of risk, the rate of amniocentesis was significantly higher following disclosure of EIF compared to pregnancies without EIF at similar levels of risk. CONCLUSION: Except for those at highest risk, rates of invasive testing were significantly higher in pregnancies with isolated EIF vs those at comparable risk.

Reductions in commuting mobility correlate with geographic differences in SARS-CoV-2 prevalence in New York City.

SARS-CoV-2-related mortality and hospitalizations differ substantially between New York City neighborhoods. Mitigation efforts require knowing the extent to which these disparities reflect differences in prevalence and understanding the associated drivers. Here, we report the prevalence of SARS-CoV-2 in New York City boroughs inferred using tests administered to 1,746 pregnant women hospitalized for delivery between March 22nd and May 3rd, 2020. We also assess the relationship between prevalence and commuting-style movements into and out of each borough. Prevalence ranged from 11.3% (95% credible interval [8.9%, 13.9%]) in Manhattan to 26.0% (15.3%, 38.9%) in South Queens, with an estimated city-wide prevalence of 15.6% (13.9%, 17.4%). Prevalence was lowest in boroughs with the greatest reductions in morning movements out of and evening movements into the borough (Pearson R = -0.88 [-0.52, -0.99]). Widespread testing is needed to further specify disparities in prevalence and assess the risk of future outbreaks.

Isolated Fetal Cardiac Abnormalities: Are They Really Isolated?

Objective To determine the rate of unsuspected noncardiac abnormalities in newborns suspected to have isolated cardiac abnormalities in the second trimester. Study Design A review of the ultrasound database from the Weill Cornell Medical Center identified fetuses with a suspected cardiac abnormality from January 2006 to November 2016. Cases with prenatally suspected noncardiac structural abnormalities, abnormal fetal or neonatal karyotype or microarray, and those who delivered at an outside institution or underwent abortion were excluded. Neonatal records were reviewed to confirm prenatal findings and to identify anomalies not suspected in the second trimester. Results Sixty-eight live births met the inclusion criteria. Five newborns (7.4%) had major abnormalities not identified in the second trimester. Three newborns had an imperforate anus. One newborn had left hydronephrosis and absent right lung, and one had hemifacial microsomia and fused ribs. All five newborns with unsuspected anomalies were in the group with suspected conotruncal anomalies, with a 11.9% rate of unsuspected anomalies versus 0% in those with nonconotruncal cardiac anomalies ( p = 0.15). Conclusion Patients with a suspected isolated fetal cardiac anomaly on ultrasound should be aware of the possibility of other major structural abnormalities, especially in cases of conotruncal cardiac anomalies.

Characterization of the "a" determinant region of the hepatitis B virus genome in Iranian patients at different clinical phases of chronic infection.

AIM: To determine the distribution of important mutations of the "a" determinant region in the HBV genome among patients in different clinical phases of HBV infection. BACKGROUND: Variations in Hepatitis B infection not only change the outcome of the disease but also the symptoms from which the chronic HBV patients are suffering. METHODS: We have meticulously selected a total of 40 chronic HBV patients from four different subclasses of chronic HBV clinical phases including immune tolerant (IT), immune active (IA), inactive carrier (IC) and hepatitis B e antigen (HBeAg)-negative (ENEG); 10 samples per each phase. Mutations of the "a" determinant region were identified using PCR-Direct sequencing method. RESULTS: 17 amino-acid substitutions at 12 positions inside the "a" determinant were identified in all forty samples; 3 mutations in the IT group, 6 mutations in the IA phase, 3 mutations in the IC patients and 5 mutations in the ENEG phase. Different substitutions were observed in all four clinical phases. The IA phase was the most variant group with the highest number of amino-acid substitutions. CONCLUSION: These results did not reveal a strong pattern to distinguish different clinical phases of Chronic HBV infection, but there are some obvious differences regarding the number and position of mutations between these four clinical phases.

Interleukin-21 rs2055979 and Interleukin-21 receptor rs3093390 genetic variants and hepatitis C virus chronic infection.

AIM: The aim of this case-control study was to investigate association of G/T IL-21 (rs2055979) and C/T IL-21R (rs3093390) gene polymorphisms with chronic hepatitis C virus in Iranian Patients. BACKGROUND: Interleukin 21 (IL-21) has a significant function in the regulation of cellular immune responses. Its exclusive receptor, IL-21R, expressed on the surface of T, B and NK cells and is important for the proliferation and differentiation of these immune cells. Hence, it was suggested to be involved in response to viral infections. METHODS: This study follows a case-control study design and blood samples were collected from 290 patients with chronic HCV and 290 controls for both genes. Genomic DNA was extracted and then for each position, SNP was genotyped by the dedicated PCR and restriction fragment length polymorphism (RFLP) method. The results were analyzed by SPSS software using logistic regression and Chi-square tests. RESULTS: Genotype frequencies of GG, GT and TT in IL21 gene (rs3093390) were found to be 27.6%, 48.3%, 24.1% and 25.2%, 55,5%, 19,3% respectively in HCV infected patients and control group. For IL21R gene (rs2055979) genotype frequencies of CC, CT and TT were 63.8%, 31.4%, 4.8% and 61.4%, 29.7%, 9.0% respectively in HCV infected patients and control group. P values for genotype and allele frequencies were p=0.188, p=0.769 for IL21 gene, and p=0.144, p=0.179 for IL21R gene respectively. CONCLUSION: As a result, there is no evidence for an association between IL-21 (rs2055979) and IL-21R (rs3093390) gene polymorphisms with chronic hepatitis C virus in Iranian Patients.

Preterm delivery in triplet pregnancies.

PURPOSE: The purpose of this study is to assess the rate of spontaneous preterm birth (SPTB) versus indicated preterm birth (IPTB) in triplet pregnancies and determine factors associated with these outcomes. MATERIALS AND METHODS: This is a review of triplet pregnancies delivering at our institution from 2003 to 2015. Patients delivering prior to 24 weeks gestational age (GA) were excluded. SPTB included cases of preterm labor or preterm premature rupture of membranes <37 weeks. IPTB was defined as deliveries <37 weeks for maternal or fetal complications. RESULTS: Of 80 triplet pregnancies, 18 (22.5%) were not complicated by SPTB or IPTB and reached their scheduled delivery date. In the remaining 62 pregnancies, IPTB occurred in 31 patients and SPTB in 31 patients. Parity was the only significant factor associated with reaching a scheduled delivery, with 56.3% of parous women reaching a scheduled delivery versus 14.1% of nulliparous women (p = 0.001). There were no significant differences in maternal age, parity, chorionicity, or use of ART between the SPTB and ITPB groups. CONCLUSIONS: While the majority of our triplet patients delivered preterm, IPTB occurred as frequently as SPTB in our population. Parous women were significantly less likely to experience SPTB or to require preterm delivery for maternal or fetal indications.

Routine cervical length and fetal fibronectin screening in asymptomatic twin pregnancies: is there clinical benefit?

OBJECTIVE: To determine whether routine cervical length (CL) and fetal fibronectin (fFN) screening is associated with improved clinical outcomes in asymptomatic patients with twin pregnancies. STUDY DESIGN: We compared outcomes between two large cohorts of twin pregnancies who delivered in New York City from 2003 to 2012. One cohort (n = 532) was managed by a single group practice, delivered at one large academic medical center, and underwent routine serial CL and fFN screening. The second cohort (n = 456) delivered at a second large academic center and only underwent CL and fFN testing as clinically indicated. Outcomes measured include cerclage placement, preterm birth (PTB), spontaneous PTB (sPTB), and antenatal corticosteroid (ACS) exposure. RESULTS: Rates of cerclage placement, PTB, and SPTB were similar between the two groups. However, routine CL and fFN screening was associated with improved rates of ACS exposure in patients who delivered <34 weeks (91.3% versus 74.7%, p = 0.005) and 34-36 6/7 weeks (41.3% versus 13.9%, p < 0.001) without increased ACS exposure in women who delivered at term. In patients who delivered <34 weeks, routine CL and fFN screening was significantly associated with improved rates of ACS exposure within 1-14 days of delivery and within 1-7 days of delivery. CONCLUSION: In twin pregnancies, routine CL and fFN screening does not reduce the risk of PTB or SPTB. However, the routine use of these tests is associated with significantly improved ACS exposure and timing for women who deliver preterm without increasing ACS exposure to women who deliver at term.

Prevalence of hepatitis D virus in hepatitis B virus infected patients referred to Taleghani hospital, Tehran, Iran.

AIM: The aim of this study was to determine the prevalence of HDV infection between HBV chronic patients referred to gastroenterology ward of Taleghani hospital Tehran, Iran and also investigating the risk factors in acquiring the HDV infection. BACKGROUND: Hepatitis B virus (HBV) and Hepatitis D virus (HDV) are major public health issues. Worldwide there are approximately 350 million individuals chronically infected with the HBV. A significant part of them, including 15 to 20 million coinfected with HDV. Hepatitis Delta virus is transferred mostly through blood and body fluids. PATIENTS AND METHODS: HBV and HDV infections were evaluated by Enzyme-linked immunosorbent assay (ELISA). Liver functional tests were assessed through auto analyzer. Patients were interviewed and data along the test results were entered into SPSS program. We used chi-square, independent t-test and logistic regression for statistical analysis. RESULTS: 278 (54.6%) patients of the study group were male and 231 (45.4%) were female and the mean age of patients was 40.03 ± 14.93. From 509 patients, 39(7.7%) had anti-HDV antibody. In a uni-variable analysis, age (p=0.001), periodontal procedures (p=0.015), endoscopy (p=0.024) and colonoscopy (p=0.012) were significantly related to HDV seropositivity. After adjustment by logistic regression, age remained the only significant factor in acquiring HDV infection. CONCLUSION: We highly recommend the health care workers to strictly follow the disinfection protocols of medical instruments. Since HDV seroprevalence changes over time, regular epidemiological studies are necessary to monitor the epidemiological trend of infection.

Lack of Association Between Transforming Growth Factor Beta 1 -509C/T and +915G/C Polymorphisms and Chronic Hepatitis B in Iranian Patients.

BACKGROUND: Chronic hepatitis B is one of the world's major health concerns [corrected]. The etiological agent of this infection is hepatitis B virus (HBV), which can evade the immune system response. Transforming growth factor beta 1 (TGF-ß1) can act against HBV by suppressing the viral replication. The TGF-ß1 also plays an important role in preventing liver damage in chronically HBV infected patients. OBJECTIVES: In this study, the association of TGF-ß1 +915G/C and -509C/T gene polymorphisms with chronic hepatitis B was evaluated in Iranian patients. MATERIALS AND METHODS: A population-based case-control study was conducted in Taleghani Hospital, Tehran. A number of 220 patients with chronic hepatitis B and the same number of healthy control subjects were designated the case and the control groups. The PCR-Restriction Fragment Length Polymorphism Method (PCR-RFLP) method was used for genotyping both polymorphisms. Ten percent of the control samples were sequenced to confirm the results. RESULTS: No statically significant differences in genotype distribution and allele frequency were observed for both polymorphisms between healthy controls and patients with chronic hepatitis B. CONCLUSIONS: There was no association between TGF-ß1 -509C/T and +915G/C polymorphisms with chronic hepatitis B and it seems that these changes do not play a significant role in increasing the risk of chronic infection in Iranian patients [corrected].