Maternal and neonatal outcomes of COVID-19 in a high-risk pregnant cohort with and without HIV.

BACKGROUND: The impact of SARS-CoV-2 infection in pregnant women living with HIV (PLHIV) has not been described previously. OBJECTIVES: To describe the clinical presentation and outcomes of a cohort of women with high-risk pregnancies with confirmed COVID-19 to determine whether risk factors for disease severity and adverse outcomes of COVID-19 differed in pregnant women without HIV compared with PLHIV. METHODS: We prospectively enrolled pregnant women with COVID-19 attending the high-risk obstetric service at Tygerberg Hospital, Cape Town, South Africa, from 1 May to 31 July 2020, with follow-up until 31 October 2020. Women were considered high risk if they required specialist care for maternal, neonatal and/or anaesthetic conditions. Common maternal or obstetric conditions included hypertensive disorders, morbid obesity (body mass index (BMI) ≥40 kg/m2) and diabetes. Information on demographics, clinical features, and maternal and neonatal outcomes was collected and compared for PLHIV v. pregnant women without HIV. RESULTS: One hundred women (72 without HIV and 28 PLHIV) with high-risk pregnancies had laboratory-confirmed COVID-19. Among the 28 PLHIV, the median (interquartile range) CD4 count was 441 (317 - 603) cells/µL, and 19/26 (73%) were virologically suppressed. COVID-19 was diagnosed predominantly in the third trimester (81%). Obesity (BMI ≥30 in n=61/81; 75%) and hypertensive disorders were frequent comorbidities. Of the 100 women, 40% developed severe or critical COVID-19, 15% required intensive care unit admission and 6% needed invasive ventilation. Eight women died, 1 from advanced HIV disease complicated by bacteraemia and urosepsis. The crude maternal mortality rate was substantially higher in women with COVID-19 compared with all other deliveries at our institution during this period (8/91 (9%) v. 7/4 058 (0.2%); p<0.001). Neonatal outcomes were favourable. No significant differences in COVID-19 risk factors, disease severity, and maternal/neonatal outcome were noted for PLHIV v. those without HIV. CONCLUSIONS: In this cohort of high-risk pregnant women, the impact of COVID-19 was severe, significantly increasing maternal mortality risk compared with baseline rates. Virally suppressed HIV infection was not associated with worse COVID-19 outcomes in pregnancy.

Variation in abdominal wall closure techniques in lower transverse incisions: a nationwide survey across specialties.

PURPOSE: Lower transverse abdominal incisions are typically used by obstetricians/gynecologists and colorectal surgeons. The suture technique and choice of material when closing the abdomen is an essential factor to decrease the risk of incisional hernia. We conducted a nationwide survey among obstetricians/gynecologists and colorectal surgeons investigating the surgical handling of the fascia, rectus muscle, subcutis, peritoneum, and skin, in lower transverse incisions. METHODS: All departments of obstetrics/gynecology and departments of surgery performing colorectal surgery in Denmark were invited to participate. An online questionnaire was sent to consultant obstetricians/gynecologists and colorectal surgeons. The survey consisted of demographic information together with questions on surgical details. The study was reported according to STROBE guidelines. RESULTS: A total of 252 (64.5%) consultants provided a complete response to the survey. We found that 98.0% of the colorectal surgeons and 65.8% of the obstetricians/gynecologists used monofilament suture when closing the fascia. The majority of the colorectal surgeons used continuous suture and small bites technique. This was only the case for half of the obstetricians/gynecologists. Approximately two thirds of the colorectal surgeons and one third of the OB/GYN used the suture length to wound length ratio > 4:1. Furthermore, we found significant differences between the groups in the handling of subcutis, peritoneum, and skin. CONCLUSION: We found significant variation in abdominal wall closure techniques in lower transverse incisions. Disagreement between the current guidelines within the specialties together with insufficient evidence on the closure of lower transverse incisions emphasizes the need for education as well as further studies.

Resource implications of the latent tuberculosis cascade of care: a time and motion study in five countries.

BACKGROUND: The End TB Strategy calls for global scale-up of preventive treatment for latent tuberculosis infection (LTBI), but little information is available about the associated human resource requirements. Our study aimed to quantify the healthcare worker (HCW) time needed to perform the tasks associated with each step along the LTBI cascade of care for household contacts of TB patients. METHODS: We conducted a time and motion (TAM) study between January 2018 and March 2019, in which consenting HCWs were observed throughout a typical workday. The precise time spent was recorded in pre-specified categories of work activities for each step along the cascade. A linear mixed model was fit to estimate the time at each step. RESULTS: A total of 173 HCWs in Benin, Canada, Ghana, Indonesia, and Vietnam participated. The greatest amount of time was spent for the medical evaluation (median: 11 min; IQR: 6-16), while the least time was spent on reading a tuberculin skin test (TST) (median: 4 min; IQR: 2-9). The greatest variability was seen in the time spent for each medical evaluation, while TST placement and reading showed the least variability. The total time required to complete all steps along the LTBI cascade, from identification of household contacts (HHC) through to treatment initiation ranged from 1.8 h per index TB patient in Vietnam to 5.2 h in Ghana. CONCLUSIONS: Our findings suggest that the time requirements are very modest to perform each step in the latent TB cascade of care, but to achieve full identification and management of all household contacts will require additional human resources in many settings.

Nuclear spin assisted quantum tunnelling of magnetic monopoles in spin ice.

Extensive work on single molecule magnets has identified a fundamental mode of relaxation arising from the nuclear-spin assisted quantum tunnelling of nearly independent and quasi-classical magnetic dipoles. Here we show that nuclear-spin assisted quantum tunnelling can also control the dynamics of purely emergent excitations: magnetic monopoles in spin ice. Our low temperature experiments were conducted on canonical spin ice materials with a broad range of nuclear spin values. By measuring the magnetic relaxation, or monopole current, we demonstrate strong evidence that dynamical coupling with the hyperfine fields bring the electronic spins associated with magnetic monopoles to resonance, allowing the monopoles to hop and transport magnetic charge. Our result shows how the coupling of electronic spins with nuclear spins may be used to control the monopole current. It broadens the relevance of the assisted quantum tunnelling mechanism from single molecular spins to emergent excitations in a strongly correlated system.

Pauling Entropy, Metastability, and Equilibrium in Dy_{2}Ti_{2}O_{7} Spin Ice.

Determining the fate of the Pauling entropy in the classical spin ice material Dy_{2}Ti_{2}O_{7} with respect to the third law of thermodynamics has become an important test case for understanding the existence and stability of ice-rule states in general. The standard model of spin ice-the dipolar spin ice model-predicts an ordering transition at T≈0.15 K, but recent experiments by Pomaranski et al. suggest an entropy recovery over long timescales at temperatures as high as 0.5 K, much too high to be compatible with the theory. Using neutron scattering and specific heat measurements at low temperatures and with long timescales (0.35 K/10^{6} s and 0.5 K/10^{5} s, respectively) on several isotopically enriched samples, we find no evidence of a reduction of ice-rule correlations or spin entropy. High-resolution simulations of the neutron structure factor show that the spin correlations remain well described by the dipolar spin ice model at all temperatures. Furthermore, by careful consideration of hyperfine contributions, we conclude that the original entropy measurements of Ramirez et al. are, after all, essentially correct: The short-time relaxation method used in that study gives a reasonably accurate estimate of the equilibrium spin ice entropy due to a cancellation of contributions.

Magnetic and superconducting phase diagram of the half-Heusler topological semimetal HoPdBi.

We report a study of the magnetic and electronic properties of the non-centrosymmetric half-Heusler antiferromagnet HoPdBi (TN = 2.0 K). Magnetotransport measurements show HoPdBi has a semimetallic behavior with a carrier concentration n = 3.7 × 10(18) cm(-3) extracted from the Shubnikov-de Haas effect. The magnetic phase diagram in the field-temperature plane has been determined by transport, magnetization, and thermal expansion measurements: magnetic order is suppressed at BM ~ 3.6 T for T --> 0. Superconductivity with Tc ~ 1.9 K is found in the antiferromagnetic phase. Ac-susceptibility measurements provide solid evidence for bulk superconductivity below Tc = 0.75 K with a screening signal close to a volume fraction of 100%. The upper critical field shows an unusual linear temperature variation with Bc2(T --> 0) = 1.1 T. We also report electronic structure calculations that classify HoPdBi as a new topological semimetal, with a non-trivial band inversion of 0.25 eV.

The relationship between lingual and hypoglossal nerve function and quality of life in head and neck cancer.

Sensorimotor impairment of the tongue has the potential to affect speech and swallowing. The purpose of this study was to critically examine the effects of nerve preservation and reinnervation after reconstruction of the base of tongue on patient-perceived outcomes of quality of life (QoL) related to speech and swallowing through completion of the EORTC QLQ-H&N35 standardised questionnaire. Thirty participants with a diagnosis of base of tongue cancer underwent primary resection and reconstruction with a radial forearm free flap, which may or may not have included nerve repair to the lingual nerve, hypoglossal nerve or both. Eight QoL domains sensitive to changes in motor and sensory nerve function were included in the analysis. Transected lingual and hypoglossal nerves were associated with difficulty in swallowing, social eating, dry mouth and social contact. There were fewer problems reported when these nerves were either repaired or left intact. There were no significant differences between patient nerve status and QoL outcomes for speech, sticky saliva and use of feeding tubes. This study was the first to examine the impact of sensory or motor nerve transection and reconstruction on health-related QoL outcomes.

Magnetization process in Er2Ti2O7 at very low temperature.

We present a model which accounts for the high-field magnetization at very low temperature in the frustrated pyrochlore compound Er2Ti2O7. In Er2Ti2O7, the Er(3+) ion has a planar crystal field anisotropy and the material undergoes a transition to antiferromagnetism at TN = 1.2 K. Our model is a mean-field self-consistent calculation involving the four rare earth sites of a tetrahedron, the building unit of the pyrochlore lattice. It includes the full crystal field Hamiltonian, the infinite range dipolar interaction and anisotropic nearest neighbour exchange described by a 4-component tensor. We discuss the equivalence of our treatment of the exchange tensor, taken to be diagonal in a frame linked to a rare earth-rare earth bond, with the pseudo-spin Hamiltonian recently developed for Kramers doublets in a pyrochlore lattice.

Observation of the Meissner-Ochsenfeld effect and the absence of the Meissner state in UCoGe.

We present low field magnetization and susceptibility measurements made on a single crystal of the ferromagnetic superconductor UCoGe. The interplay between ferromagnetism and superconductivity comes into view in the study of hysteresis along the c axis (easy magnetization axis). The Meissner state (perfect diamagnetism) could not be observed in very low magnetic fields for all three crystallographic directions, implying that the sample is always in the mixed state. Notwithstanding, the Meissner-Ochsenfeld effect (reversible flux expulsion) occurs and is found to be anisotropic. For the c axis in low fields, it is proportional to the bulk magnetization M (and thus to the population of domains) and not to the applied magnetic field H. On a microscopic level, our interpretation of these results implies that flux is expelled independently from each domain proportional to its volume.

Domain-wall spin dynamics in kagome antiferromagnets.

We report magnetization and neutron scattering measurements down to 60 mK on a new family of Fe based kagome antiferromagnets, in which a strong local spin anisotropy combined with a low exchange path network connectivity lead to domain walls intersecting the kagome planes through strings of free spins. These produce unfamiliar slow spin dynamics in the ordered phase, evolving from exchange-released spin flips towards a cooperative behavior on decreasing the temperature, probably due to the onset of long-range dipolar interaction. A domain structure of independent magnetic grains is obtained that could be generic to other frustrated magnets.

Mesoscopic magnetic states in metallic alloys with strong electronic correlations: a percolative scenario for CeNi 1-x Cux.

We present evidence for the existence of magnetic clusters of approximately 20 A in the strongly correlated alloy system CeNi 1-x Cux (0.7

Ordering and excitations in the field-induced magnetic phase of Cs3Cr2Br9.

Field-induced magnetic order has been investigated in detail in the interacting spin 3/2 dimer system Cs3Cr2Br9. Elastic and inelastic neutron scattering measurements were performed up to H=6 T, well above the critical field H(c1) approximately 1.5 T. The ordering displays incommensurabilities and a large hysteresis before a commensurate structure is reached. This structure is fully determined. Surprisingly, the lowest excitation branch never closes. Above H(c1), the gap increases slowly with the field. An analysis in terms of projected pseudospins is given.

Klinefelter syndrome: expanding the phenotype and identifying new research directions.

PURPOSE: The purpose of this study is to summarize new data on etiology and clinical features of Klinefelter syndrome in order to derive research priorities. METHODS: This study was conducted using critical reviews of selective topics, emphasizing less well-recognized clinical findings. RESULTS AND CONCLUSIONS: The phenotype of the prototypic 47,XXY case is well recognized: seminiferous tubule dysgenesis and androgen deficiency. Less well appreciated is the varied expressivity of 47,XXY Klinefelter syndrome, in particular neurological/cognitive perturbations like language and behavioral problems. Effective therapies are available. Reproductive technologies allow 47,XXY men to sire offspring through intracytoplasmic sperm injection (ICSI); however, genetic counseling is complex and success is low. Behavioral and expressive language difficulties are amenable to treatment by androgen therapy and psychological help. Early treatment may be imperative for optimal outcome.

Structure and function of bone marrow hemopoiesis: mechanisms of response to ionizing radiation exposure.

It is the purpose of this presentation to review the unique structure and function of bone marrow anchored hematopoiesis in their significance for its response mechanisms to an exposure to ionizing radiation. The ultimate objective of bone marrow hematopoiesis is to maintain in the peripheral blood a constant level of the different blood cell types (erythrocytes, granulocytes, platelets, lymphocytes, etc.). All of them have their particular turnover kinetics (such as granulocytes 120 x 10(9)/d, erythrocytes 200 x 10(9)/d or thrombocytes 150 x 10(9)/d), are semi-autonomous in their steady state regulatory mechanisms and dependent on a life-long supply of mature cells from a stem cell pool with unlimited replicative and pluripotent differentiative potential. The present knowledge of hematopoietic cellular renewal is the result of years of basic experimental and clinical studies using radionuclides in various metabolic forms including (59)Fe, (32)P (DF (32)P), (51)Cr, (131)I, (60)Co, (3)H ((3)HTdR) and (14)C ((14)CTdR). To understand the physiology but in particular the radiation-pathophysiology, it is essential to recognize in detail the infrastructure of the bone marrow as a distinct unit. Indispensable for a life-long cell production is the capsule of the marrow - the bone cortex -, the arterial supply of blood connected to the sinusoidal microvascular architecture with its sinusoids contorti and recti as well as the central (cell collecting) sinusoids. It is further of importance to recognize the significance of nerval regulation of blood flow, characterized by myelinated and unmyelinated nerve fibers. The type of unique lining cells of the sinusoids is the prerequisite for the cell traffic between the hemopoietic parenchyma and the blood. This in turn cannot be achieved without an alternative opening and closing of the sinusoidal segments which - in turn - requires a rigid long capsule to assure an - in toto - constant volume of each bone marrow unit. If a bone marrow unit is exposed to ionizing radiation, a perturbance of the balance between cellular growth pressure and blood flow dynamics can be observed, resulting in a special type of bone marrow hemorrhage and an "excess cell loss" that may result in an non-thrombopenic exhaustion of the stem cell pool. Of great importance is the question as to the mechanisms that allow the bone marrow hemopoiesis to act as one cell renewal system although the bone marrow units are distributed throughout more than 100 bone marrow areas or units in the skeleton. The observation that "the bone marrow" acts and reacts as "one organ" is due to the regulatory mechanisms: the humeral factors (such as erythropoietins, granulopoietins, thrombopoietins etc.), the nerval factors (central nervous regulation) and cellular factors (continuous migration of stem cells through the blood to assure a sufficient stem cell pool size in each bone marrow "sub-unit"). It should be recalled that the bone marrow functions as a physiological chimera and becomes established by the hematogeneic seeding of stem cells to a mesenchymal matrix during embryogenesis. The repopulation of the bone marrow after partial body irradiation, after strongly inhomogeneous radiation exposure or after total body exposure with stem cell transplantation can well be considered as a repetition of the embryogenesis of bone marrow hemopoiesis with the key element of stem cells migrating via the blood to stromal sites of the marrow prepared to accept stem cells to home and start their replication and differentiation if the micro-environmental quality permits. In summary, the radiation biology of bone marrow hemopoiesis requires a thorough understanding of the physiology and pathophysiology of structure, function and regulation not only of the process of cellular renewal but also of the intricate infrastructure.

Coexistence of superconductivity and ferromagnetism in URhGe.

The discovery of superconductivity at high pressure (albeit over a restricted range) in the ferromagnetic material UGe2 raised the possibility that bulk superconductivity might be found in other ferromagnets. The exact symmetry of the paired state and the dominant mechanism responsible for the pairing, however, remain unidentified. Meanwhile, the conjecture that superconductivity could occur more generally in ferromagnets has been fuelled by the recent observation of a low-temperature transition that suggests an onset of superconductivity in high-quality crystals of the itinerant-ferromagnet ZrZn2 (ref. 2), although the thermodynamic signature of this transition could not be detected. Here we show that the ferromagnet URhGe is superconducting at ambient pressure. In this case, we find the thermodynamic signature of the transition-its form is consistent with a superconducting pairing of a spin-triplet type, although further testing with cleaner samples is needed to confirm this. The combination of superconductivity and ferromagnetism may thus be more common and consequently more important than hitherto realized.

Single-ion versus dipolar origin of the magnetic anisotropy in iron(III)-oxo clusters: a case study.

A multitechnique approach has allowed the first experimental determination of single-ion anisotropies in a large iron(III)-oxo cluster, namely [NaFe6(OCH3)12(pmdbm)6ClO4 (1) in which Hpmdbm = 1,3-bis(4-methoxyphenyl)-1,3-propanedione. High-frequency EPR (HF-EPR). bulk susceptibility measurements, and high-field cantilever torque magnetometry (HF-CTM) have been applied to iron-doped samples of an isomorphous hexagallium(III) cluster [NaGa6(OCH3)12-(pmdbm)6]ClO4, whose synthesis and X-ray structure are also presented. HF-EPR at 240 GHz and susceptibility data have shown that the iron(III) ions have a hard-axis type anisotropy with DFe = 0.43(1) cm(-1) and EFe = 0.066(3) cm(-1) in the zero-field splitting (ZFS) Hamiltonian H = DFe[S2(z) - S(S + 1)/3] + Fe[S2(x) - S2(y)]. HF-CTM at 0.4 K has then been used to establish the orientation of the ZFS tensors with respect to the unique molecular axis of the cluster, Z. The hard magnetic axes of the iron(III) ions are found to be almost perpendicular to Z, so that the anisotropic components projected onto Z are negative, DFe(ZZ)= -0.164(4) cm(-1). Due to the dominant antiferromagnetic coupling, a negative DFe(ZZ) value determines a hard-axis molecular anisotropy in 1, as experimentally observed. By adding point-dipolar interactions between iron(III) spins, the calculated ZFS parameter of the triplet state, D1 = 4.70(9) cm(-1), is in excellent agreement with that determined by inelastic neutron scattering experiments at 2 K, D1 = 4.57(2) cm(-1). Iron-doped samples of a structurally related compound, the dimer [Ga2(OCH3)2(dbm)4] (Hdbm = dibenzoylmethane), have also been investigated by HF-EPR at 525 GHz. The single-ion anisotropy is of the hard-axis type as well, but the DFe parameter is significantly larger [DFe = 0.770(3) cm(-1). EFe = 0.090(3) cm(-1)]. We conclude that, although the ZFS tensors depend very unpredictably on the coordination environment of the metal ions, single-ion terms can contribute significantly to the magnetic anisotropy of iron(III)-oxo clusters, which are currently investigated as single-molecule magnets.

Tuning the magnetic properties of the high-spin molecular cluster Fe8.

The synthesis, crystal structure, and magnetic characterization of a high-spin cluster comprising eight iron ions are presented in this contribution. The cluster has formula [(tacn)6Fe8O2(OH)12Br4.3(ClO4)3.7]·6H2O (Fe8pcl), where tacn is the organic ligand 1,4,7-triazacyclononane. It can be considered a derivative of Fe8 Br8 , a cluster whose low-temperature magnetization dynamics has been extensively investigated, in which four of the bromide ions have been replaced by perchlorate anions. The structure of the central core of the two molecules, [Fe8O(OH)12(tacn)6](8+), is essentially the same, but Fe8pcl has a higher symmetry (the bromide derivative crystallizes in the acentric P1 space group while Fe8pcl crystallizes in the monoclinic P2(1)/c space group). The magnetic properties of Fe8pcl suggest it is very similar to Fe8Br8 having a S=10 ground state as well. The zero-field splitting parameters were accurately determined by high field-high frequency EPR (HF-EPR) measurements. The two clusters have similar axial anisotropy D but Fe8pcl has a larger transverse anisotropy E: The value of E/D is 0.21 for the perchlorate derivative but 0.19 for Fe8Br8. AC susceptibility measurements revealed the cluster behaves like a superparamagnetic particle. However, due to the occurrence of large terms in the transverse anisotropy, the temperature dependence of the relaxation time cannot be reproduced by a simple Arrhenius law model. As observed in the bromide derivative, below 350 mK the relaxation time becomes temperature independent and indicating that a pure tunneling regime is attained. The comparison of the tunneling rate in the two clusters shows that in the perchlorate derivative the relaxation process is 35 times faster. The observed ratio of the tunneling rates is in reasonable agreement with that calculated from the tunneling splitting, namely the energy difference between the two almost-degenerate lowest levels Ms =±10, in the two clusters.