[Clinical features and surgical treatment of right cardiac system tumors].

A total of 25 patients with right cardiac system tumors in the Department of Cardiac Surgery, Beijing Anzhen Hospital from January 2012 to October 2022 were retrospectively included in the study. The preoperative data, and information of surgical treatment and perioperative management on these patients were analyzed and summarized. One patient developed pulmonary embolism and died before surgery, and the other 24 patients (16 males and 8 females) received surgical treatment, with an average age of (44.7±10.2) years (24-74 years). Nine patients were diagnosed with malignant tumors. Among the 24 patients who received surgical treatment, two patients died during the perioperative period, in-situ tumor recurrence was seen in three patients within about 1 year after surgery (two patients died without surgery, and one patient died 3 months after surgery), two patients had distant metastasis, and 17 patients had a good prognosis. Right cardiac system tumors are rare, with a high malignant rate, and the clinical manifestations vary greatly. Active surgical intervention is found to be effective, and the prognosis is closely related to the pathological type and extent of tumor invasion.

Vulnerable newborn types: analysis of subnational, population-based birth cohorts for 541 285 live births in 23 countries, 2000-2021.

OBJECTIVE: To examine prevalence of novel newborn types among 541 285 live births in 23 countries from 2000 to 2021. DESIGN: Descriptive multi-country secondary data analysis. SETTING: Subnational, population-based birth cohort studies (n = 45) in 23 low- and middle-income countries (LMICs) spanning 2000-2021. POPULATION: Liveborn infants. METHODS: Subnational, population-based studies with high-quality birth outcome data from LMICs were invited to join the Vulnerable Newborn Measurement Collaboration. We defined distinct newborn types using gestational age (preterm [PT], term [T]), birthweight for gestational age using INTERGROWTH-21st standards (small for gestational age [SGA], appropriate for gestational age [AGA] or large for gestational age [LGA]), and birthweight (low birthweight, LBW [<2500 g], nonLBW) as ten types (using all three outcomes), six types (by excluding the birthweight categorisation), and four types (by collapsing the AGA and LGA categories). We defined small types as those with at least one classification of LBW, PT or SGA. We presented study characteristics, participant characteristics, data missingness, and prevalence of newborn types by region and study. RESULTS: Among 541 285 live births, 476 939 (88.1%) had non-missing and plausible values for gestational age, birthweight and sex required to construct the newborn types. The median prevalences of ten types across studies were T+AGA+nonLBW (58.0%), T+LGA+nonLBW (3.3%), T+AGA+LBW (0.5%), T+SGA+nonLBW (14.2%), T+SGA+LBW (7.1%), PT+LGA+nonLBW (1.6%), PT+LGA+LBW (0.2%), PT+AGA+nonLBW (3.7%), PT+AGA+LBW (3.6%) and PT+SGA+LBW (1.0%). The median prevalence of small types (six types, 37.6%) varied across studies and within regions and was higher in Southern Asia (52.4%) than in Sub-Saharan Africa (34.9%). CONCLUSIONS: Further investigation is needed to describe the mortality risks associated with newborn types and understand the implications of this framework for local targeting of interventions to prevent adverse pregnancy outcomes in LMICs.

[Comparative study of laparoscopic Keyhole and Sugarbaker technique in the treatment of terminal paracolostomy hernia].

Objective: To compare laparoscopic Keyhole repair with Sugarbaker repair in consecutive patients with parastomal hernia. Methods: From January 2015 to December 2021, 117 patients with parastomal hernia were treated with Keyhole or Sugarbaker laparoscopy repairs in the Department of Hernia and Bariatrci Surgery, the First Affiliated Hospital of University of Science and Technology of China, and the clinical data were retrospectively analyzed. There were 45 males and 72 females, aged (68.6±8.6) years (range: 44 to 84 years). Laparoscopic Sugarbaker repair was performed in 89 cases, and Keyhole repair was performed in 28 cases. The t-test, Mann-Whitney U test, χ2 test and Fisher exact test were used to compare the observation indicators between the two groups, such as operation time, incidence of operation-related complications, and postoperative recurrence rate. Results: The follow-up period was (M(IQR)) 33 (36) months (range: 12 to 84 months). Compared to the Sugarbaker group, the hernia ring area of the Keyhole group was bigger (35 (26) cm2 vs. 25 (16) cm2, Z=1.974, P=0.048), length of stay was longer ((22.0±8.0) d vs. (14.1±6.2) d, t=5.485, P<0.01), and the postoperative rate of recurrence was higher (28.6% (8/28) vs. 6.7% (6/89), χ2=7.675, P=0.006). There was no difference in operation time and postoperative complications between the two groups. Conclusions: Laparoscopic Sugarbaker repair is superior to Keyhole repair in the recurrence rate of parastomal hernia treated with compsite mesh (not funnel-shaped mesh). There are no differences in operation time and postoperative complications between the two groups.

Local quantum phase transition in YFe2Al10.

A phase transition occurs when correlated regions of a new phase grow to span the system and the fluctuations within the correlated regions become long lived. Here, we present neutron scattering measurements showing that this conventional picture must be replaced in YFe2Al10, a compound that forms naturally very close to a [Formula: see text] quantum phase transition. Fully quantum mechanical fluctuations of localized moments are found to diverge at low energies and temperatures; however, the fluctuating moments are entirely without spatial correlations. Zero temperature order in YFe2Al10 is achieved by an entirely local type of quantum phase transition that may originate with the creation of the moments themselves.

[Impact of left ventricle remodeling on perioperative risk and short-term prognosis in patients with heart failure and reduced ejection fraction undergoing coronary artery bypass grafting].

Objective: To explore the impact of left ventricle remodeling on perioperative risk and short-term survival in patients with heart failure and reduced ejection fraction (HFrEF) undergoing coronary artery bypass grafting (CABG). Methods: A total of 78 coronary artery disease (CAD) patients (54 males, 24 females) with symptoms and signs of heart failure and a left ventricular ejection fraction (LVEF)<40% were consecutively enrolled from January 2014 to December 2018 in Beijing Anzhen Hospital. The average age was (59±8) years old. Transthoracic echocardiography was performed to measure LVEF and left ventricle end-systolic volume index (LVESVI) during hospitalization, and the average LVESVI was (92±18) ml/m(2). According to the mean value of LVESVI, the patients were divided into 2 groups: mild left ventricle remodeling group (group M, n=46, LVESVI<92 ml/m(2)) and severe left ventricle remodeling group (group S, n=32, LVESVI≥92 ml/m(2)). The follow-up period was (30±12) months. Operative mortality, perioperative complications and long-term survival were compared between the two groups. Results: Perioperative mortality was 5.1% (4/78), which was significantly higher in group S than that of group M (9.4% vs 2.2%, P=0.03). The proportion of patients with intra-aortic balloon pump (IABP) was higher in group S than that of group M during the perioperative period (62.5% vs 36.9%, P<0.01). Compared with patients in group M, those with severe left ventricle remodeling were more susceptible to atrial fibrillation after surgery (25.0% vs 6.5%, P=0.02). The mean follow-up time was (30±12) months. There was no difference in major adverse cardiac event (MACE)-free survival in 12 month, 24 month and 36 month between the two groups (100% vs 100%, 87.9% vs 92.1%, 80.3% vs 78.3%, P=0.68). Conclusion: Left ventricular remodeling increases the perioperative mortality and complications of patients with ischemic HFrEF undergoing CABG, but it has no impact on short-term survival.

[Short-term outcomes of sequential radial artery grafting in patients with coronary artery disease].

Objective: To explore the short-term outcomes of patients with coronary artery disease (CAD) who underwent coronary artery bypass graft (CABG) with sequential radial artery graft. Methods: Clinical data of patients with CAD who underwent CABG with sequential radial artery graft from August to December 2018 in Beijing Anzhen Hospital was retrospectively analyzed. Computer tomography angiography was employed to evaluate the patency of grafts and the incidence of adverse cardiovascular events was followed up 3 months after surgery. Results: A total of thirty patients were included, with an average age of (60.2±7.3) years old, among whom 83.3% were male, and 93.3% had three-vessel disease detected by coronary angiography. All patients had left internal mammary artery (LIMA) anastomosed to the left anterior descending (LAD) and sequential radial artery graft. Among sequential radial artery grafts, the most frequent anastomosis of sequential radial artery graft was aortic artery (AO)-first diagonal branch (D1)-first obtuse marginal branch (OM1) (13 patients, 43.3%), followed by AO-OM1-second obtuse marginal branch (OM2) (9 patients, 30.0%), and 18 patients also underwent saphenous vein graft. None of 30 patients experienced adverse cardiovascular events during postoperative period in hospital. Three-months follow-up outcomes showed that LIMA-LAD in 1 patient (3.3%) occluded, 3 patients had occluded anastomosis of sequential radial artery graft, 1 patient (3.3%) had heart failure, and 1 patient (3.3%) had recurrent angina. Conclusion: The radial artery could be used as the second arterial graft for CAD patients undergoing CABG with a sequential anastomosis technique, and these patients need regular anti-arterial spasm drug treatment after CABG.

Quantum critical fluctuations in layered YFe2Al10.

The absence of thermal fluctuations at T = 0 makes it possible to observe the inherently quantum mechanical nature of systems where the competition among correlations leads to different types of collective ground states. Our high precision measurements of the magnetic susceptibility, specific heat, and electrical resistivity in the layered compound YFe2Al10 demonstrate robust field-temperature scaling, evidence that this system is naturally poised without tuning on the verge of ferromagnetic order that occurs exactly at T = 0, where magnetic fields drive the system away from this quantum critical point and restore normal metallic behavior.

Anisotropic Exchange within Decoupled Tetrahedra in the Quantum Breathing Pyrochlore Ba_{3}Yb_{2}Zn_{5}O_{11}.

The low energy spin excitation spectrum of the breathing pyrochlore Ba_{3}Yb_{2}Zn_{5}O_{11} has been investigated with inelastic neutron scattering. Several nearly resolution limited modes with no observable dispersion are observed at 250 mK while, at elevated temperatures, transitions between excited levels become visible. To gain deeper insight, a theoretical model of isolated Yb^{3+} tetrahedra parametrized by four anisotropic exchange constants is constructed. The model reproduces the inelastic neutron scattering data, specific heat, and magnetic susceptibility with high fidelity. The fitted exchange parameters reveal a Heisenberg antiferromagnet with a very large Dzyaloshinskii-Moriya interaction. Using this model, we predict the appearance of an unusual octupolar paramagnet at low temperatures and speculate on the development of intertetrahedron correlations.

Roles of oxidative DNA damage of bone marrow hematopoietic cells in steroid-induced avascular necrosis of femoral head.

An animal model of steroid-induced avascular necrosis of femoral head (SANFH) was established to investigate the role of oxidative DNA damage of bone marrow hematopoietic cells in SANFH. Forty-five-month-old Japanese white rabbits (male or female, 2.5 ± 0.5 kg) were randomly divided into groups A (methylprednisolone + Escherichia coli endotoxin), B (methylprednisolone alone), C (E. coli endotoxin alone), and D (blank control). The animals were sacrificed two and four weeks after administration of the last dose (N = 5 each group and each time). Left and right femoral heads were fixed and decalcified. Empty lacunae were counted by hematoxylin and eosin staining and oxidative DNA damage of bone marrow hematopoietic cells was detected by immunohistochemistry. At week 2, the rate of oxidative DNA damage in bone marrow hematopoietic cells was significantly higher in group A than in groups B, C, and D (P < 0.01), while there was no significant difference between groups B, C, and D. At week 4, the rate of oxidative DNA damage in bone marrow hematopoietic cells was significantly higher in group A than in groups B, C, and D (P < 0.01), while there was no significant difference among groups B, C, and D. Thus, oxidative DNA damage of bone marrow hematopoietic cells appears to play an important role in SANFH.

Roles of osteocyte apoptosis in steroid-induced avascular necrosis of the femoral head.

An animal model of steroid-induced avascular necrosis of the femoral head (SANFH) was established to investigate the roles of osteocyte apoptosis in this process. Forty five-month-old male and female Japanese white rabbits were randomly divided into groups A (hormone + endotoxin), B (hormone alone), C (endotoxin alone), and D (blank control). Animals were sacrificed two and four weeks following the final treatment (N = 5 for each group at each time point). Bilateral femoral heads were fixed and decalcified, and empty lacunae were counted by hematoxylin staining. At weeks 2 and 4, the empty lacunae percentage was significantly higher in group A than that in groups B, C, or D (P < 0.01), while no significant difference was observed between these latter three. At week 2, all osteocyte apoptosis indexes were within normal ranges in all the groups, which therefore did not significantly differ in this respect (P > 0.05). However, at week 4, the apoptotic index was significantly higher in group A than that in groups B, C, or D (P < 0.01), comparisons between which revealed no such differences. Moreover, a positive correlation was observed between the percentage of empty lacunae and the apoptotic index at week 4 in group A (r = 0.893). We conclude that osteocyte apoptosis plays an important role in SANFH.

[Expression and clinical significance of CCL17, CCL22, and CCR4 in newly diagnosed multiple myeloma].

Objective: To study the expressions of C-C class chemokine 17 (CCL17), C-C class chemokine 22 (CCL22), and C-C chemokine receptor 4 (CCR4) in newly diagnosed multiple myeloma (NDMM) for analyzing their correlations with clinical features and to preliminarily explore their roles in the development of NDMM. Methods: The study included 40 patients with NDMM and 20 healthy volunteers from the Department of Hematology of the Affiliated Hospital of Zunyi Medical University from July 2020 to December 2022. Peripheral blood, bone marrow, and bone marrow biopsy tissue samples were collected from the two groups. The expression levels of CCL17, CCL22, and CCR4 in patients with NDMM were analyzed using real-time quantitative reverse transcriptase polymerase chain reaction (RQ-PCR), enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry. The mRNA expression levels of CCL17, CCL22, and CCR4 in the bone marrow mononuclear cell (BMMNC) of patients with NDMM were analyzed to assess their correlations with clinical indicators. Results: The mRNA expression levels of CCL17, CCL22, and CCR4 in BMMNC were higher in patients with NDMM than in controls (all P<0.05). The protein expression levels of CCL17 and CCL22 in peripheral blood supernatants and bone marrow supernatants were higher in patients with NDMM than in controls (all P<0.05). The expression levels of CCL17, CCL22, and CCR4 in bone marrow biopsy tissues were higher in patients with NDMM than in controls (all P<0.05). The mRNA expression level of CCL17 was increased in NDMM patients with combined anemia, bone damage, renal damage, and M protein level ≥30 g/L (all P<0.05). The mRNA expression level of CCL22 was increased in NDMM patients with combined anemia, bone damage, and renal damage (all P<0.05). The mRNA expression level of CCR4 was increased in NDMM patients with combined anemia and renal damage (all P<0.05) . Conclusion: CCL17, CCL22, and CCR4 were highly expressed in clinical samples from patients with NDMM compared to those from controls, and they may be involved in the occurrence and development of NDMM.

Integrated microfluidic multiple electrode aggregometry for point-of-care platelet function analysis.

Point-of-care (POC) platelet function analysis can enable timely and precise management of bleeding and clotting in emergency rooms, operation rooms and intensive care units. However, POC platelet testing is currently not commonly performed, due to the complexity of sample preparation and limitations of existing technologies. Here, we report the development of an integrated microfluidic multiple electrode aggregometry (µMEA) sensor which uses multi-frequency impedance measurement of an embedded microelectrode array to perform platelet aggregometry directly from whole blood, sensing and measuring platelet activation in a label-free manner and without requiring any additional sample preparation. Additionally, the sensor incorporates blood flow during the assay to account for physiological flow and shear conditions. We show that the impedance signal from the sensor can be used to accurately detect and quantify platelet aggregation in a label-free manner, which was further validated by simultaneous fluorometric measurement and visualization of platelet aggregation. Further, we optimized the sensitivity and repeatability of the sensor using its frequency response and demonstrated that the sensor could be used to characterize drug dose-response in antiplatelet therapy with a frequency-tunable dynamic range. We also demonstrate that the sensor provides high sensitivity to perform platelet aggregometry under thrombocytopenic or low platelet count conditions. The µMEA sensor could thus enable POC platelet function analysis across several clinical applications.

Preliminary exploration of the clinical features of Chinese patients with skin malignancies and premalignancies: a retrospective study of 1420 cases from Peking University First Hospital.

BACKGROUND: The epidemiological and clinical characterization data of skin malignancies and premalignancies in Chinese population is scarce and inadequate. OBJECTIVE: To systematically investigate the clinical features and the trend of skin malignancies and premalignancies in 1420 Chinese cases. METHODS: A total of 1398 patients (presenting 1420 skin tumours) were included. Clinical and demographic information for every individual was collected, including age, age of onset, sex, lesion location, disease duration and tumour histology, which was analyzed for each type of skin tumours. RESULTS: The number of skin malignancies and premalignancies increased over time, with Basal cell carcinoma (BCC) as the most common type (30.5%). The majority of the patients were above 60 years of age both at onset and at diagnosis (52.8% and 62.9%, respectively), yet around one-third of patients were between 35-59 years (35.3% and 31.2%, respectively). Skin malignancies and premalignancies were mainly located in the head and neck (58.6%), followed by the trunk (18.3%) and the extremities (15.0%). Of all BCCs, nodular BCC was the most common histologic subtype (62.8%), while 15.8% were classified as aggressive subtypes. Malignant melanoma (MM) comprised the lowest proportion of 3.7%, with 75% located on extremities. The diagnostic accordance rates varied from 49.5% to 90.4%, with BCC being 67.9%. CONCLUSIONS: The clinical features of skin malignancies and premalignancies in this study showed some similarities with those observed in Caucasian and other Asian populations, with several distinguished features in Chinese patients also being recognized. Closer attention to suspicious lesions in young and middle-aged people is needed.

Multiple fermion scattering in the weakly coupled spin-chain compound YbAlO3.

The Heisenberg antiferromagnetic spin-1/2 chain, originally introduced almost a century ago, is one of the best studied models in quantum mechanics due to its exact solution, but nevertheless it continues to present new discoveries. Its low-energy physics is described by the Tomonaga-Luttinger liquid of spinless fermions, similar to the conduction electrons in one-dimensional metals. In this work we investigate the Heisenberg spin-chain compound YbAlO3 and show that the weak interchain coupling causes Umklapp scattering between the left- and right-moving fermions and stabilizes an incommensurate spin-density wave order at q = 2kF under finite magnetic fields. These Umklapp processes open a route to multiple coherent scattering of fermions, which results in the formation of satellites at integer multiples of the incommensurate fundamental wavevector Q = nq. Our work provides surprising and profound insight into bandstructure control for emergent fermions in quantum materials, and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic systems.

Inhibitory effects of epidermal growth factor on progesterone production of ovarian granulosa cells in Tsaiya duck (Anas platyrhynchos var. domestica).

1. The purpose of this study was to investigate the effects of epidermal growth factor (EGF) on progesterone (P(4)) secretion from ovarian granulosa cells in Tsaiya ducks (Anas platyrhynchos var. domestica). 2. We obtained the largest (F1) follicle from Tsaiya duck, the granulosa layer was separated and the cells were isolated according to their proximity to the germinal disc. 3. The granulosa cells were cultured in vitro, the culture media and the cells were used to determine P(4) and steroidogenic enzyme concentrations, respectively. 4. P(4) concentrations were decreased in cultured granulosa cells taken proximal to the germinal disc (GD) compared to those distal to the germinal disc (NGD). 5. EGF inhibited both basal and ovine luteinising hormone (oLH)-induced P(4) concentrations. It also inhibited the P(4) secretion via protein kinase A (PKA) pathway when cultured with GD and NGD granulose cells (mixed together) in vitro. 6. Western blot results showed decreased concentrations of cytochrome P450 side-chain cleavage (P450scc) enzyme, 3ß-hydroxysteroid dehydrogenase (3ß-HSD) enzyme and steroid acute regulatory (StAR) protein expression, when the cells were co-treated with EGF and oLH. 7. The inhibitory effect of oLH-induced P(4) production was attenuated by EGF by the addition of MAP-erk kinase (MEK) inhibitor (PD98059) suggests EGF may inhibit P(4) production by affecting via the mitogen-activated protein kinase (MAPK) pathway.

The polymorphisms of interleukin 17A (IL17A) gene and its association with pediatric asthma in Taiwanese population.

BACKGROUND: The interleukin 17A (IL17A) gene, located on chromosome 6p and linked to asthma phenotype, is a highly potential candidate gene conferring asthma susceptibility. The purpose of this study was to investigate the genetic association between single nucleotide polymorphisms (SNPs) of IL17A and asthma in Taiwanese children. METHODS: We selected and performed genotyping on nine SNPs that encompass the genomic region of IL17A in Taiwanese children with or without asthma. A total of 1939 subjects containing 1027 subjects in testing group and 931 subjects in validation group were recruited in this study. RESULTS: After Bonferroni correction, SNP rs8193036 was found to have a weak association (P = 0.0074 x 9 = 0.066) in genotype frequency test. This association was confirmed by validation group. Logistic regression adjusted allergy comorbidity and gender showed a slightly weaker association. CONCLUSIONS: The results indicated an independent role of IL17A promoter polymorphism rs8193036 in the association with pediatric asthma in Taiwanese population.

Abundantly expressed hepatic genes and their differential expression in liver of prelaying and laying geese.

Geese have a short egg-laying period and a low egg production rate. To induce and maintain egg laying, genes related to generating hepatic lipid for yolk deposition should be adequately expressed. Liver mRNA from 6 laying geese was extracted and used for construction of a full-length enriched cDNA library. About 2,400 clones containing gene sequences were determined and National Center for Biotechnology Information Gallus gallus Gene Index databases were used to compare and analyze these sequences. Ten highly expressed genes were selected to determine the differential expression between laying and prelay goose liver. Tissue distribution data showed that very low density apolipoprotein II, liver type fatty acid binding protein, vitellogenin I, and vitellogenin II transcripts were specifically expressed in the liver of laying geese. Ovoinhibitor, preproalbumin, alpha-2-hs-glycoprotein, and vitamin D binding protein mRNA were highly expressed in the liver and to a lesser extent in other tissues. Ovotransferrin mRNA was expressed in liver, ovary, oviduct, shell gland, brain, and adipose tissues. The concentration of transthyretin mRNA was high in the liver and brain. The mRNA concentrations of liver type fatty acid binding protein, alpha-2-hs-glycoprotein, and transthyretin in the livers of laying and prelay geese were not different. The concentrations of hepatic ovotransferrin, ovoinhibitor, preproalbumin, very low density apolipoprotein II, vitellogenin I, vitellogenin II, and vitamin D binding protein mRNA were higher in the liver of laying geese than in prelay geese, suggesting that these genes may be involved in laying function or lipid metabolism related to egg formation.

Effects of porcine epidemic diarrhea virus infection on tight junction protein gene expression and morphology of the intestinal mucosa in pigs.

Tight junction proteins are important for the maintenance and repair of the intestinal mucosal barrier. The present study investigated relationships among tight junction protein gene expression, porcine epidemic diarrhea virus (PEDV) infection, and intestinal mucosal morphology in piglets. We compared the expression of six tight junction proteins (ZO-1, ZO-2, Occludin, Claudin-1, Claudin-4, and Claudin-5) between seven-day-old piglets infected with PEDV and normal piglets, as well as in PEDV-infected porcine intestinal epithelial cells (IPEC-J2). We also evaluated differences in mucosal morphology between PEDV-infected and normal piglets. The expression of six tight junction protein genes was lower in PEDV-infected piglets than in the normal animals. The expression of ZO-1, ZO-2, Occludin, and Claudin-4 in the intestine tissue was significantly lower (p⟨0.05) in PEDV-infected than in normal piglets. The expression of Claudin-5 in the jejunum was significantly lower in PEDV-infected piglets than in the normal animals (p⟨0.01). The expression of Claudin-1 and Claudin-5 genes in the ileum was significantly higher in PEDV-infected piglets than in normal piglets (p⟨0.01). Morphologically, the intestinal mucosa in PEDV-infected piglets exhibited clear pathological changes, including breakage and shedding of intestinal villi. In PEDV-infected IPEC-J2 cells, the mRNA expression of the six tight junction proteins showed a downward trend; in particular, the expression of the Occludin and Claudin-4 genes was significantly lower (p⟨0.01). These data suggest that the expression of these six tight junction proteins, especially Occludin and Claudin-4, plays an important role in maintaining the integrity of the intestinal mucosal barrier and resistance to PEDV infection in piglets.

Spinon confinement and a sharp longitudinal mode in Yb2Pt2Pb in magnetic fields.

The fundamental excitations in an antiferromagnetic chain of spins-1/2 are spinons, de-confined fractional quasiparticles that when combined in pairs, form a triplet excitation continuum. In an Ising-like spin chain the continuum is gapped and the ground state is Néel ordered. Here, we report high resolution neutron scattering experiments, which reveal how a magnetic field closes this gap and drives the spin chains in Yb2Pt2Pb to a critical, disordered Luttinger-liquid state. In Yb2Pt2Pb the effective spins-1/2 describe the dynamics of large, Ising-like Yb magnetic moments, ensuring that the measured excitations are exclusively longitudinal, which we find to be well described by time-dependent density matrix renormalization group calculations. The inter-chain coupling leads to the confinement of spinons, a condensed matter analog of quark confinement in quantum chromodynamics. Insensitive to transverse fluctuations, our measurements show how a gapless, dispersive longitudinal mode arises from confinement and evolves with magnetic order.

Tomonaga-Luttinger liquid behavior and spinon confinement in YbAlO3.

Low dimensional quantum magnets are interesting because of the emerging collective behavior arising from strong quantum fluctuations. The one-dimensional (1D) S = 1/2 Heisenberg antiferromagnet is a paradigmatic example, whose low-energy excitations, known as spinons, carry fractional spin S = 1/2. These fractional modes can be reconfined by the application of a staggered magnetic field. Even though considerable progress has been made in the theoretical understanding of such magnets, experimental realizations of this low-dimensional physics are relatively rare. This is particularly true for rare-earth-based magnets because of the large effective spin anisotropy induced by the combination of strong spin-orbit coupling and crystal field splitting. Here, we demonstrate that the rare-earth perovskite YbAlO3 provides a realization of a quantum spin S = 1/2 chain material exhibiting both quantum critical Tomonaga-Luttinger liquid behavior and spinon confinement-deconfinement transitions in different regions of magnetic field-temperature phase diagram.