Topologically protected magnetoelectric switching in a multiferroic.

Electric control of magnetism and magnetic control of ferroelectricity can improve the energy efficiency of magnetic memory and data-processing devices1. However, the necessary magnetoelectric switching is hard to achieve, and requires more than just a coupling between the spin and the charge degrees of freedom2-5. Here we show that an application and subsequent removal of a magnetic field reverses the electric polarization of the multiferroic GdMn2O5, thus requiring two cycles to bring the system back to the original configuration. During this unusual hysteresis loop, four states with different magnetic configurations are visited by the system, with one half of all spins undergoing unidirectional full-circle rotation in increments of about 90 degrees. Therefore, GdMn2O5 acts as a magnetic crankshaft that converts the back-and-forth variations of the magnetic field into a circular spin motion. This peculiar four-state magnetoelectric switching emerges as a topologically protected boundary between different two-state switching regimes. Our findings establish a paradigm of topologically protected switching phenomena in ferroic materials.

Structural phase purification of bulk HfO2:Y through pressure cycling.

We combine synchrotron-based infrared absorption and Raman scattering spectroscopies with diamond anvil cell techniques and first-principles calculations to explore the properties of hafnia under compression. We find that pressure drives HfO[Formula: see text]:7%Y from the mixed monoclinic ([Formula: see text]) [Formula: see text] antipolar orthorhombic ([Formula: see text]) phase to pure antipolar orthorhombic ([Formula: see text]) phase at approximately 6.3 GPa. This transformation is irreversible, meaning that upon release, the material is kinetically trapped in the [Formula: see text] metastable state at 300 K. Compression also drives polar orthorhombic ([Formula: see text]) hafnia into the tetragonal ([Formula: see text]) phase, although the latter is not metastable upon release. These results are unified by an analysis of the energy landscape. The fact that pressure allows us to stabilize targeted metastable structures with less Y stabilizer is important to preserving the flat phonon band physics of pure HfO[Formula: see text].

Acute leukemia and lymphoma in pregnancy, a retrospective study from a tertiary center in Malaysia.

INTRODUCTION: Most evidence about the management of cancer and hematological malignancy in pregnancy are derived from retrospective observational studies with a small sample size. Availability of sufficiently large data has enabled evidence-based decision-making in this clinical dilemma. MATERIALS AND METHODS: Retrospective study looking into patients diagnosed with acute leukemia or lymphoma in pregnancy from 1st January 2014 to 1st January 2020 in Ampang General Hospital including newly or previously diagnosed and relapsed disease RESULTS: 37 cases of acute leukemia or lymphoma in pregnancy occurred in 34 patients. Majority of acute leukemia or lymphoma in pregnancy diagnosed in 1st trimester or in the setting of previously established or relapsed disease was therapeutically terminated. Thirteen pregnancies treated with antenatal chemotherapy resulted in livebirths except one stillbirth. More adverse obstetric outcomes are observed in pregnancies that did not receive antenatal chemotherapy, but association did not reach statistical significance. There was no significant difference in fetal outcome between cohort with and without antenatal chemotherapy. No treatment related mortality was observed in pregnancies with antenatal chemotherapy. Overall survival for newly diagnosed acute leukemia in pregnancy is significantly better with antenatal chemotherapy versus no antenatal chemotherapy. CONCLUSION: Treatment with chemotherapy in 2nd trimester of pregnancy onwards appears to have tolerable risks with favorable obstetric and fetal outcome. Deferment of treatment for acute leukemia in pregnancy to after delivery may cause increased risk of maternal and fetal adverse outcome.

MJP going green.

No abstract available.

ENPP4 and HOXA3 as potential leukaemia stem cell markers in acute myeloid leukaemia.

INTRODUCTION: Acute myeloid leukaemia (AML) is a heterogeneous malignant disease with a high degree of treatment failure using chemotherapy. Leukaemia stem cells (LSCs) are CD34+CD38- early progenitors associated with poor prognosis in AML. A unique LSC phenotype that excludes rare normal haematopoietic stem cells (HSC) is still elusive. This study aimed to determine expression of selected potential LSC markers in normal and leukaemic myeloid cells and correlate prognosis in AML patients. MATERIALS AND METHODS: Flow cytometry and RT-qPCR measured expressions of ALDH, IL3RA/CD123, CLEC12A/CLL-1/CD371, HOXA3 and ENPP4. Normal cord blood (n=3) and blood monocytes (n=5) represented HSC and mature cells, respectively. Myeloid leukaemia cell lines (THP-1, KG-1a, K562 and HL-60) represented progenitor cells at various stages of maturation. AML samples included chemo-resistant (n=8), early relapse (n=2) and late relapse (n=18). RESULTS: Combining protein/gene expressions, CD34+CD38- was a feature of immature cells seen in cord blood, KG-1a, and K562 but not more mature cells (blood monocytes and HL-60). Normal cells expressed CD371 while mature cells (blood monocytes and HL-60) lacked CD123. ENPP4 was not expressed on normal cells while HOXA3 was expressed only on cord blood and THP-1. In AML, CD123, HOXA3, ENPP4 (but not CD371) were significantly increased in the CD34+CD38- fraction of chemo-resistant patients while ALDH was associated with chemo-resistance. CONCLUSION: CD34+CD38- presented an immature phenotype and with ALDH were associated with poor prognosis. CD123, HOXA3 and ENPP4 further enriched the LSC population. ENPP4 has not been reported and has the advantage of not being expressed on HSC and normal monocytes.

Observation of chiral surface excitons in a topological insulator Bi2Se3.

The protected electron states at the boundaries or on the surfaces of topological insulators (TIs) have been the subject of intense theoretical and experimental investigations. Such states are enforced by very strong spin-orbit interaction in solids composed of heavy elements. Here, we study the composite particles-chiral excitons-formed by the Coulomb attraction between electrons and holes residing on the surface of an archetypical 3D TI, [Formula: see text] Photoluminescence (PL) emission arising due to recombination of excitons in conventional semiconductors is usually unpolarized because of scattering by phonons and other degrees of freedom during exciton thermalization. On the contrary, we observe almost perfectly polarization-preserving PL emission from chiral excitons. We demonstrate that the chiral excitons can be optically oriented with circularly polarized light in a broad range of excitation energies, even when the latter deviate from the (apparent) optical band gap by hundreds of millielectronvolts, and that the orientation remains preserved even at room temperature. Based on the dependences of the PL spectra on the energy and polarization of incident photons, we propose that chiral excitons are made from massive holes and massless (Dirac) electrons, both with chiral spin textures enforced by strong spin-orbit coupling. A theoretical model based on this proposal describes quantitatively the experimental observations. The optical orientation of composite particles, the chiral excitons, emerges as a general result of strong spin-orbit coupling in a 2D electron system. Our findings can potentially expand applications of TIs in photonics and optoelectronics.

Therapeutic potential of mesenchymal stem cells and their derivatives in sarcopenia.

Sarcopenia is a common condition in the geriatric population. It refers to age-related and progressive decline in muscle mass and function, which has a great impact on one's mobility and quality of life. Patients with sarcopenia are mainly treated with nutritional therapy, exercise therapy, or a combination of both. Since the identification of mesenchymal stem cells (MSCs) several decades ago, many studies have explored the application of MSCs in the field of regenerative medicine. MSCs are popular candidates for cell-based therapy owing to their multipotent nature and immunomodulatory properties. Even though MSCs do not naturally differentiate into myogenic cells, they are important players in skeletal muscle health, as MSCs support myogenic differentiation of other cells and promote recovery of injured skeletal muscle. Recent studies have found that MSCs may be of benefits in the treatment of sarcopenia. This article gives an overview of sarcopenia and the role of MSCs in skeletal muscle homeostasis. It also discusses the therapeutic potential of MSCs and their derivatives, as well as the underlying mechanisms of the therapeutic effects of MSCs and MSC-based products in sarcopenia.

Medical record archives in the era of digitalisation.

No abstract available.

Guidelines on retention of pathology records and materials (Version 2/2022).

No abstract available.

Total Angular Momentum Dichroism of the Terahertz Vortex Beams at the Antiferromagnetic Resonances.

Terahertz vortex beams with different superposition of the orbital angular momentum l=±1, ±2, ±3, and ±4 and spin angular momentum σ=±1 were used to study antiferromagnetic (AFM) resonances in TbFe_{3}(BO_{3})_{4} and Ni_{3}TeO_{6} single crystals. In both materials we observed a strong vortex beam dichroism for the AFM resonances that are split in external magnetic field. The magnitude of the vortex dichroism is comparable to that for conventional circular dichroism due to σ. The selection rules at the AFM resonances are governed by the total angular momentum of the vortex beam: j=σ+l. In particular, for l=±2, ±3, and ±4 the sign of l is shown to dominate over that for conventional circular polarization σ.

From One- to Two-Magnon Excitations in the S=3/2 Magnet ß-CaCr_{2}O_{4}.

We apply neutron spectroscopy to measure the magnetic dynamics in the S=3/2 magnet ß-CaCr_{2}O_{4} (T_{N}=21 K). The low-energy fluctuations, in the ordered state, resemble large-S linear spin waves from the incommensurate ground state. However, at higher energy transfers, these semiclassical and harmonic dynamics are replaced by an energy and momentum broadened continuum of excitations. Applying kinematic constraints required for energy and momentum conservation, sum rules of neutron scattering, and comparison against exact diagonalization calculations, we show that the dynamics at high-energy transfers resemble low-S one-dimensional quantum fluctuations. ß-CaCr_{2}O_{4} represents an example of a magnet at the border between classical Néel and quantum phases, displaying dual characteristics.

Mask-induced dermatoses during the COVID-19 pandemic: a questionnaire-based study in 12 Korean hospitals.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, various adverse skin reactions to long-term mask wearing have been reported. AIM: To assess the clinical features of mask-induced dermatoses and to recommend prevention and treatment options. METHODS: From April to August 2020, questionnaires including topics such as demographic information, pre-existing skin disorders, reported mask-related symptoms, daily mask-wearing duration and frequency, types of masks used and whether the participant was a healthcare worker, were distributed to patients in 12 hospitals. Dermatologists assessed skin lesions, confirmed diagnosis and recorded treatments. RESULTS: Itchiness was the most frequent symptom, mostly affecting the cheeks. The most common skin disease was new-onset contact dermatitis (33.94%), followed by new-onset acne (16.97%) and worsening of pre-existing acne (16.97%). Daily wearing of masks was significantly (P = 0.02) associated with new-onset contact dermatitis. More than half of patients with pre-existing skin problems experienced disease worsening while wearing masks. Longer duration of wearing (> 6 h/day, P = 0.04) and use of cotton masks (P < 0.001) significantly increased acne flare-up. Healthcare workers had a higher incidence of skin disease. Skin lesions were generally mild and well tolerated with topical treatment. The study had some limitations: the effect of seasonal characteristics and other risk factors were not assessed, and the patients were visiting dermatological clinics and had interest in their skin status, thus, there may have been selection bias. CONCLUSION: Mask-induced/-triggered dermatoses contribute to increase the dermatological burden during the pandemic.

Role of circular RNAs in determining the fate of mesenchymal stem cells.

Ribonucleic acid (RNA) has been well-understood for its linear form for many years. With advances in high-throughput sequencing, there is an increasing focus on circular RNAs (circRNAs) recently. Although they were previously regarded as splicing error by-products, research has shown that they play a pivotal role in many cellular processes, one of which is the control of stem cell differentiation and fate. On the other hand, decades of research have demonstrated the promising therapeutic potential of mesenchymal stem cells (MSCs). To this end, there is a growing body of research on the role of circRNAs in the determination of the fate of MSCs. This review critically examines the current evidence and consolidates key findings from studies that explore the involvement of circRNAs in the regulation of MSC differentiation.

Therapeutic potentials of neural stem cells in Alzheimer's disease.

The commonest cause of dementia among the elderly population is Alzheimer's disease (AD). It is a health concern globally as the number of people affected by dementia worldwide is rapidly increasing. Several genes have been linked to AD and the pathogenesis of the disease has been extensively and vigorously examined. Thus far, only a few drugs have been approved by the Food and Drug Administration (FDA) for the pharmacological treatment of AD and a growing body of research has turned to alternative options such as stem cell therapy. This review will give an overview of the pathological and clinical aspects of AD. Although researchers have explored the suitability and feasibility of using various types of stems cells to treat AD, this review will focus mainly on neural stem cells (NSCs)/ neural progenitor cells (NPCs). The behaviour and properties of NSCs will be described, accompanied by a comprehensive discussion of the therapeutic strategies involving the use of NSCs/NPCs in the treatment of the disease.

Challenges of Covid-19 testing.

No abstract available.

Terahertz Vortex Beam as a Spectroscopic Probe of Magnetic Excitations.

Circularly polarized light with spin angular momentum is one of the most valuable probes of magnetism. We demonstrate that light beams with orbital angular momentum (OAM), or vortex beams, can also couple to magnetism exhibiting dichroisms in a magnetized medium. Resonant optical absorption in a ferrimagnetic crystal depends strongly on both the handedness of the vortex and the direction of the beam propagation with respect to the sample magnetization. This effect exceeds the conventional dichroism for circularly polarized light. Our results demonstrate the high potential of the vortex beams with OAM as a new spectroscopic probe of magnetism in matter.

CT of blunt splenic injuries: what the trauma team wants to know from the radiologist.

Splenic injury is commonly encountered in severe blunt abdominal trauma. Technological improvements and the increasing availability of both diagnostic computed tomography (CT) and therapeutic splenic artery embolisation (SAE) are key factors in defining the high success rate of modern-day non-operative management (NOM) for blunt splenic injuries (BSIs). The Association for Surgery for Trauma (AAST) Organ Injury Scale (OIS) is commonly used by both radiologists and clinicians to stratify injury severity, traditionally based on the degree of parenchymal disruption seen on CT, and guide management. Its recent 2018 update takes splenic vascular injuries (i.e., active bleed, pseudoaneurysm, and traumatic arteriovenous fistulae) into consideration, the presence of which will indicate at least a grade IV (i.e., high-grade) injury. This is a reflection of the paradigm shift towards spleen conservation with regular use of SAE as the current standard of treatment. Prompted by the latest AAST OIS revision, which represents a more complete and current grading system, we present the spectrum of pertinent CT findings that the diagnostic radiologist should accurately identify and convey to the multidisciplinary trauma team (including the interventional radiologist). This review divides imaging findings based on the AAST OIS definitions and categorises them into (1) parenchymal and (2) vascular injuries. Features that may help in the detection of subtle BSIs are also described. Lastly, it touches on the key changes made to the new AAST OIS, substantiated by case illustrations.

Technical note: Development and evaluation of a standardized technique to assess blood perfusion in teats of dairy cows using power Doppler ultrasonography.

Ample research has described the assessment of dimensional changes for different teat traits, whereas diagnostic techniques to reliably assess blood circulation in teats of dairy cows are limited. Here, we describe the development and evaluation of a scanning technique to quantify blood flow in teats of dairy cows using power Doppler ultrasonography. In 2 consecutive trials, 384 teat scans [trial 1, n = 256 (sagittal plane, n = 128; transverse plane, n = 128); trial 2, n = 128 (transverse plane)] from 16 cows were obtained by the same 2 operators. Perfusion intensity from single images (trial 1) and video images (trial 2) were assessed using a commercially available software program. Intraclass correlation coefficients (ICC) and concordance correlation coefficients (CCC) were used to assess interoperator reproducibility (agreement between measurements performed by different operators) and intraoperator repeatability (agreement between measurements performed by the same operator). In trial 1, interoperator ICC and CCC indicated poor agreement (ICC ≤0.26, CCC ≤0.26). Intraoperator ICC and CCC demonstrated poor agreement between duplicate measurements within operators (ICC ≤0.19, CCC ≤0.19). Modifications after trial 1 included (1) a different ultrasound device, (2) analysis of video clips rather than single images, (3) restriction to 1 sectional plane (i.e., transverse), and (4) a scanning sequence such that repeated scans within operators were measured one after another. Through these modifications, intraoperator repeatability in trial 2 yielded fair to good agreement, with intraoperator ICC and CCC over both operators ranging from 0.44 to 0.70 and from 0.57 to 0.69, respectively, whereas interoperator ICC and CCC showed poor agreement (ICC = 0.35, CCC = 0.34). We conclude that repeatable measurements of blood perfusion intensity of teats in dairy cows can be attained with power Doppler ultrasonography. Power Doppler ultrasonography is a suitable tool to quantify slow flow in small vessels and may be an acceptable diagnostic technique to assess changes in blood circulation that result from machine milking in teats of dairy cows, although further research is necessary to validate this hypothesis.

Pyometra and unilateral uterine horn torsion in a sheep.

A 13-year-old Romanov sheep presented for evaluation of vaginal discharge, depression and anorexia. Blood work demonstrated mature neutrophilia and marked hyperlactatemia. Transrectal and transabdominal ultrasound revealed echogenic fluid (pus) within the uterus. Purulent uterine fluid culture yield Escherichia coli. A diagnosis of pyometra was made. After medical treatment without clinical improvement, an exploratory laparotomy was performed, and a 360-degree uterine left horn torsion was identified with the pyometra and multiple corpora lutea on both ovaries. Ovariohysterectomy was performed and the ewe recovered uneventfully.

Reprogramming human dermal fibroblast into induced pluripotent stem cells using nonintegrative Sendai virus for transduction.

INTRODUCTION: Induced pluripotent stem cells (iPSC) that exhibit embryonic stem cell-like properties with unlimited self-renewal and multilineage differentiation properties, are a potential cell source in regenerative medicine and cell-based therapy. Although retroviral and lentiviral transduction methods to generate iPSC are well established, the risk of mutagenesis limits the use of these products for therapeutic applications. MATERIALS AND METHODS: In this study, reprogramming of human dermal fibroblasts (NHDF) into iPSC was carried out using non-integrative Sendai virus for transduction. The iPSC clones were characterised based on the morphological changes, gene expression of pluripotency markers, and spontaneous and directed differentiation abilities into cells of different germ layers. RESULTS: On day 18-25 post-transduction, colonies with embryonic stem cell-like morphology were obtained. The iPSC generated were free of Sendai genome and transgene after passage 10, as confirmed by RT-PCR. NHDF-derived iPSC expressed multiple pluripotency markers in qRT-PCR and immunofluorescence staining. When cultured in suspension for 8 days, iPSC successfully formed embryoid body-like spheres. NHDF-derived iPSC also demonstrated the ability to undergo directed differentiation into ectoderm and endoderm. CONCLUSION: NHDF were successfully reprogrammed into iPSC using non-integrating Sendai virus for transduction.