Observation of fractional edge excitations in nanographene spin chains.

Fractionalization is a phenomenon in which strong interactions in a quantum system drive the emergence of excitations with quantum numbers that are absent in the building blocks. Outstanding examples are excitations with charge e/3 in the fractional quantum Hall effect1,2, solitons in one-dimensional conducting polymers3,4 and Majorana states in topological superconductors5. Fractionalization is also predicted to manifest itself in low-dimensional quantum magnets, such as one-dimensional antiferromagnetic S = 1 chains. The fundamental features of this system are gapped excitations in the bulk6 and, remarkably, S = 1/2 edge states at the chain termini7-9, leading to a four-fold degenerate ground state that reflects the underlying symmetry-protected topological order10,11. Here, we use on-surface synthesis12 to fabricate one-dimensional spin chains that contain the S = 1 polycyclic aromatic hydrocarbon triangulene as the building block. Using scanning tunnelling microscopy and spectroscopy at 4.5 K, we probe length-dependent magnetic excitations at the atomic scale in both open-ended and cyclic spin chains, and directly observe gapped spin excitations and fractional edge states therein. Exact diagonalization calculations provide conclusive evidence that the spin chains are described by the S = 1 bilinear-biquadratic Hamiltonian in the Haldane symmetry-protected topological phase. Our results open a bottom-up approach to study strongly correlated phases in purely organic materials, with the potential for the realization of measurement-based quantum computation13.

Integrated photon pair source based on a silicon nitride micro-ring resonator for quantum memories.

We report the design of an integrated photon pair source based on spontaneous four-wave mixing (SFWM), implemented in an integrated micro-ring resonator in the silicon nitride platform (Si3N4). The signal photon is generated with emission at 606 nm and bandwidth of 3.98 MHz, matching the spectral properties of praseodymium ions (Pr), while the idler photon is generated at 1430.5 nm matching the wavelength of a CWDM channel in the E-band. This novel, to the best of our knowledge, device is designed to interact with a quantum memory based on a Y2SiO5 crystal doped with Pr3+ ions, in which we used cavity-enhanced SFWM along with dispersion engineering to reach the required wavelength and the few megahertz signal photon spectral bandwidth.

Soluble B-cell maturation antigen in multiple myeloma.

B-cell maturation antigen (BCMA) has emerged as a promising immunotherapeutic target in multiple myeloma (MM) management, with the successive approval of antibody-drug conjugates, bispecific antibodies, and chimeric antigen receptor T-cell therapies directed to this membrane receptor. Soluble BCMA (sBCMA), a truncated version produced through gamma-secretase cleavage, can be quantified in serum/plasma samples from patients with MM via electrochemiluminescence, fluorescence, or enzyme-linked immunosorbent assays, as well as through mass spectrometry-based proteomics. Besides its short serum half-life and independence from kidney function, sBCMA represents a reliable and convenient tool for MM monitoring in patients with nonsecretory or oligosecretory disease. Numerous studies have suggested a potential utility of this bioanalyte in the risk stratification of premalignant plasma cell disorders, diagnosis and prognostication of MM, and response evaluation following anti-myeloma therapies. In short, sBCMA might be the "Swiss army knife" of MM laboratory testing, but is it ready for prime time?

Characterization and Quantification of the Major Bioactive Compounds in Mexican Purple Tomatoes.

The present work carries out a quantitative analysis of the major bioactive compounds found in the native Mexican purple tomatoes. Total phenolic content ranged from 7.54 to 57.79 mg TPC/g DM, total flavonoid content ranged from 1.89 to 16.93 mg TFC/g DM, total anthocyanin content ranged from 0.29 to 2.56 mg TAC/g DM, and total carotenoid content ranged from 0.11 to 0.75 mg TCC/ g DM. In addition, 14 phenolic acids were identified, among which caffeoylquinic acid derivatives were the most abundant compounds with chlorogenic acid concentration up to 9.680 mg/g DM, together with flavonoids, such as rutin and quercetin-hexoxide. The qualitative analysis also showed the presence of 9 acylated anthocyanins and 2 carotenoids with significant functional features. As for anthocyanins, their chemical structures disclosed special structural features: glycosylated anthocyanins exhibited cis-trans hydroxycinnamic moieties and petunidin-3-(trans-p-coumaroyl)-rutinoside-5-glucoside was reported to be the main anthocyanin, whitin the range of concentrations between 0.160 and 1.143 mg/g DM.

Studies of the transition between amplified spontaneous emission and optical lasing in ultrahigh-Q polymeric micro-pedestals.

In this work, we demonstrate the properties of Rhodamine B-doped polymeric cylindrical microlasers to perform either as gain amplification devices through amplified spontaneous emission (ASE) or as optical lasing gain devices. A study based on different %wt concentrations of microcavity families with distinct geometrical features demonstrates the characteristic dependence on either gain amplification phenomena. Principal component analysis (PCA) discriminates the relationship between the main ASE and lasing properties and the geometrical aspects of the cavity families. ASE and optical lasing thresholds were found, respectively, as low as 0.2 µJcm-2 and 0.1 µJcm-2 passing the best-reported microlaser performances in literature for cylindrical cavities, even in comparison with those based on 2D patterns. Moreover, our microlasers showed ultrahigh Q-factor of ∼3 × 106, and for the first time, to the best of our knowledge, a visible emission comb constituted by above a hundred peaks at 40 µJcm-2 with a registered free spectral range (FSR) of 0.25 nm corroborated through the whispery gallery mode (WGM) theory.

Continuous organelle separation in an insulator-based dielectrophoretic device.

Heterogeneity in organelle size has been associated with devastating human maladies such as neurodegenerative diseases or cancer. Therefore, assessing the size-based subpopulation of organelles is imperative to understand the biomolecular foundations of these diseases. Here, we demonstrated a ratchet migration mechanism using insulator-based dielectrophoresis in conjunction with a continuous flow component that allows the size-based separation of submicrometer particles. The ratchet mechanism was realized in a microfluidic device exhibiting an array of insulating posts, tailoring electrokinetic and dielectrophoretic transport. A numerical model was developed to elucidate the particle migration and the size-based separation in various conditions. Experimentally, the size-based separation of a mixture of polystyrene beads (0.28 and 0.87 µ$\umu $ m) was accomplished demonstrating good agreement with the numerical model. Furthermore, the size-based separation of mitochondria was investigated using a mitochondria mixture isolated from HepG2 cells and HepG2 cells carrying the gene Mfn-1 knocked out, indicating distinct size-related migration behavior. With the presented continuous flow separation device, larger amounts of fractionated organelles can be collected in the future allowing access to the biomolecular signature of mitochondria subpopulations differing in size.

"Inner clocks" of glass-forming liquids.

Providing a physically sound explanation of aging phenomena in non-equilibrium amorphous materials is a challenging problem in modern statistical thermodynamics. The slow evolution of physical properties after quenches of control parameters is empirically well interpreted via the concept of material time (or internal clock) based on the Tool-Narayanaswamy-Moynihan model. Yet, the fundamental reasons of its striking success remain unclear. We propose a microscopic rationale behind the material time on the basis of the linear laws of irreversible thermodynamics and its extension that treats the corresponding kinetic coefficients as state functions of a slowly evolving material state. Our interpretation is based on the recognition that the same mathematical structure governs both the Tool model and the recently developed non-equilibrium extension of the self-consistent generalized Langevin equation theory, guided by the universal principles of Onsager's theory of irreversible processes. This identification opens the way for a generalization of the material-time concept to aging systems where several relaxation modes with very different equilibration processes must be considered, and partially frozen glasses manifest the appearance of partial ergodicity breaking and, hence, materials with multiple very distinct inner clocks.

Extraction of Lipophilic Antioxidants from Native Tomato Using Green Technologies.

Research background: Tomato (Solanum lycopersicum L.) fruit is highly consumed worldwide and contains high amounts of carotenoids and tocopherols, two powerful antioxidants. Native tomato genotypes are rarely used in large-scale market but serve as a reservoir to diversify the species gene pool and can be employed to obtain functional compounds. Extraction methods are currently changing towards cleaner procedures that are more efficient and environmentally friendly, including avoiding toxic or polluting solvents. Experimental approach: In this study, factorial and fractional factorial designs were used to evaluate the efficiency of digestive enzymes, sonication and green solvents to obtain lipophilic antioxidant extracts from native tomato. To monitor the efficiency of the extraction process, spectrophotometric quantification of total carotenoids and antioxidant activity was carried out, and then individual quantification of carotenoids and tocopherols in the extracts was done by HPLC. Results and conclusions: Digestive enzymes and sonication increased the carotenoid content and the antioxidant activity of the obtained extracts when applied individually. However, when these treatments were applied together and in combination with isopropyl acetate, a green solvent, the obtained extracts had the highest carotenoid and tocopherol contents as well as the maximal antioxidant activity. A correlation analysis suggested that antioxidant activity resulted from synergistic effects rather than individual compounds. Tomato extracts were obtained through a rapid and environmentally friendly extraction method and their antioxidant activity was enhanced. Novelty and scientific contribution: Tomato fruits have been the subject of numerous studies; however, functional compound extraction through environmentally friendly methods remains an attractive use of native tomato fruit, enhancing its limited production and harnessing a large amount of tomato product industry. There are few reports where environmentally friendly extraction methods are combined; even rarer are those where green solvents are also used. In this work, the combination of different environmentally friendly extraction methods improved the extraction of carotenoids and tocopherols and allowed to establish a more efficient process. These results could stimulate the use of clean technologies and make the native tomato more attractive for industrial or compound extraction processes.

Multi-institutional retrospective analysis of adverse events following rigid tracheobronchoscopy.

BACKGROUND AND OBJECTIVE: Rigid tracheobronchoscopy (RTB) has seen an increasing interest over the last decades with the development of the field of IPM but no benchmark exists for complication rates in RTB. We aimed to establish benchmarks for complication rates in RTB. METHODS: A multicentric retrospective analysis of RTB performed between 2009 and 2015 in eight participating centres was performed. RESULTS: A total of 1546 RTB were performed over the study period. One hundred and thirty-one non-lethal complications occurred in 103 procedures (6.7%, 95% CI: 5.5-8.0%). The periprocedural mortality rate was 1.2% (95% CI: 0.6-1.8%). The 30-day mortality rate was 5.6% (95% CI: 4.5-6.8%). Complication rate increases further when procedures were performed in an emergency setting. Procedures in patients with MAO are associated with a higher 30-day mortality (8.1% vs 2.7%, P < 0.01) and a different complication profile when compared to procedures performed for BAS. CONCLUSION: RTB is associated with a 6.7% non-lethal complication rate, a 1.2% periprocedural mortality rate and a 5.6% 30-day mortality in a large multicentre cohort of patients with benign and malignant airway disease.

Low-cost fabrication of microlasers based on polymeric micropedestals.

Our current work exploits direct laser writing (DLW) and low one-photon absorption (LOPA) in a low-cost three-dimensional optical fabrication system designed to print micrometric polymeric structures. Micropedestals were obtained by focusing a laser beam on a photoresist layer deposited on a silica glass substrate. Subsequent coating with rhodamine 6G dye allows these pedestals to function as microlasers upon optical excitation at 532 nm. Our microlasers, with a diameter of ∼53µm and a height of ∼40µm, exhibit a broad fluorescence peak in the spectral range 540-600 nm, in addition to narrow lasing peaks, exhibiting quality factors Q exceeding 2000 and a lasing threshold of ∼5µJcm-2. The observed free spectral range associated with the lasing peaks of ∼1.3nm is consistent with simulations, which we include in this paper. In addition, we present simulations for the longitudinal shift of the patterning laser spot, which occurs particularly for relatively thick photoresist layers, coupled with a large index contrast at the photoresist top surface. Such a shift could introduce errors in the resulting microfabricated structures if left unaccounted for. We hope that our work will contribute to the development of microlasers for various photonic applications, particularly if dimensions can be reduced, for on-chip optical communications and data processing.

The Impact of Social Media on Plastic Surgery Residency Applicants.

BACKGROUND: Plastic surgeons have been early adopters of social media, and the efficacy and ethics of this practice have been studied. In addition, plastic and reconstructive surgery (PRS) training programs have begun using social media to connect with the public, including prospective PRS applicants. The ability of social media to attract prospective residency applicants is unknown. This study aims to examine the influence of social media on prospective residency applicants and their perception of a plastic surgery program. METHODS: In the academic years 2018 and 2019, we conducted an anonymous, voluntary survey among applicants applying to both the integrated and independent Harvard PRS residency programs. The survey collected data regarding demographics, social media usage, online information gathering, and PRS programs' social media influence on applicants' perception/rank position of programs. RESULTS: One hundred nine surveys were completed (23%). Ninety-seven percent of respondents reported searching online for information about residency programs. Twenty percent of respondents noted that a residency program's social media platform "influenced their perception of a program or intended rank position of a program" and 72% of those respondents indicated a positive effect on their perception of a program and its rank list position. At least 15% of respondents were concerned that engaging with a program's social media account would attract attention to their own social media accounts. CONCLUSIONS: Applicants routinely rely on online resources to gather information regarding prospective residency programs. Fear of attracting attention to their own personal social media pages may limit applicants' engagement with PRS programs on social media. However, residency programs can still utilize social media to deliver important messages, especially as social media usage continues to grow.

C-reactive protein, interleukin-6 and pre-eclampsia: large-scale evidence from the GenPE case-control study.

Multiple small studies have suggested that women with pre-eclampsia present elevated levels of C-reactive protein (CRP) and interleukin-6 (IL-6). However, little is known regarding the source of this CRP and IL-6 increase. Therefore, the aim of this study was to evaluate the relationship between CRP and IL-6 levels with pre-eclampsia considering different confounding factors. Using data from a large Colombian case-control study (3,590 cases of pre-eclampsia and 4,564 normotensive controls), CRP and IL-6 levels were measured in 914 cases and 1297 controls. The association between maternal serum levels of CRP and IL-6 with pre-eclampsia risk was evaluated using adjusted logistic regression models. Pre-eclampsia was defined as presence of blood pressure ≥140/90 mmHg and proteinuria ≥300mg/24 h (or ≥1 + dipstick). There was no evidence of association between high levels of CRP and IL-6 with pre-eclampsia after adjusting for the following factors: maternal and gestational age, ethnicity, place and year of recruitment, multiple-pregnancy, socio-economic position, smoking, and presence of infections during pregnancy. The adjusted OR for 1SD increase in log-CRP and log-IL-6 was 0.96 (95%CI 0.85, 1.08) and 1.09 (95%CI 0.97, 1.22), respectively. Although previous reports have suggested an association between high CRP and IL-6 levels with pre-eclampsia, sample size may lack the sufficient power to draw robust conclusions, and this association is likely to be explained by unaccounted biases. Our results, the largest case-control study reported up to date, demonstrate that there is not a causal association between elevated levels of CRP and IL-6 and the presence of pre-eclampsia.

Exchange Rules for Diradical π-Conjugated Hydrocarbons.

A variety of planar π-conjugated hydrocarbons such as heptauthrene, Clar's goblet and, recently synthesized, triangulene have two electrons occupying two degenerate molecular orbitals. The resulting spin of the interacting ground state is often correctly anticipated as S = 1, extending the application of Hund's rules to these systems, but this is not correct in some instances. Here we provide a set of rules to correctly predict the existence of zero mode states as well as the spin multiplicity of both the ground state and the low-lying excited states, together with their open- or closed-shell nature. This is accomplished using a combination of analytical arguments and configuration interaction calculations with a Hubbard model, both backed by quantum chemistry methods with a larger Gaussian basis set. Our results go beyond the well established Lieb's theorem and Ovchinnikov's rule, as we address the multiplicity and the open-/closed-shell nature of both ground and excited states.

Collective All-Carbon Magnetism in Triangulene Dimers.

Triangular zigzag nanographenes, such as triangulene and its π-extended homologues, have received widespread attention as organic nanomagnets for molecular spintronics, and may serve as building blocks for high-spin networks with long-range magnetic order, which are of immense fundamental and technological relevance. As a first step towards these lines, we present the on-surface synthesis and a proof-of-principle experimental study of magnetism in covalently bonded triangulene dimers. On-surface reactions of rationally designed precursor molecules on Au(111) lead to the selective formation of triangulene dimers in which the triangulene units are either directly connected through their minority sublattice atoms, or are separated via a 1,4-phenylene spacer. The chemical structures of the dimers have been characterized by bond-resolved scanning tunneling microscopy. Scanning tunneling spectroscopy and inelastic electron tunneling spectroscopy measurements reveal collective singlet-triplet spin excitations in the dimers, demonstrating efficient intertriangulene magnetic coupling.

Longitudinal Microsurgery Laboratory Training during Hand Surgery Fellowship.

BACKGROUND: Laboratory training courses have traditionally offered an attractive method to learn microsurgery in a low-risk environment. However, courses are often limited by cost, accessibility, and their one-time, nonlongitudinal nature. Our aims were to (1) describe our institution's microsurgical training course for hand surgery fellows, which is longitudinal and integrated within our fellowship curriculum and (2) investigate how this course affects the microsurgical confidence and competence of trainees throughout their fellowship year. METHODS: All hand fellows who trained in our 1-year combined hand surgery fellowship from 2016 through 2018 participated in this study. Baseline data on the type and duration of residency training, previous microsurgery experience and self-reported confidence, knowledge, and interest in microsurgery were recorded. Self-reported scores were documented using a continuous scale ranging from 0 to 10. An initial 3-day laboratory course combining the use of didactic teaching, a nonliving synthetic model, and a live rat model was conducted. Repeat laboratory training occurred thereafter at 6 and 12 months. At the end of each session, fellows repeated the baseline questionnaire and faculty assessed their microsurgical competence using a standardized global rating scale (GRS). RESULTS: A total of six fellows (2 years) were enrolled. At the end of the initial course, there was a statistically significant increase in mean self-reported confidence in microsurgery from 4.3 to 6.2 and knowledge from 4.7 to 6.5. Mean scores in interest were unchanged, from 9.2 to 9.3. There was also an increase in mean GRS score from day 3 to months 6 and 12. CONCLUSION: A longitudinal microsurgical training course integrated within a hand surgery fellowship is associated with increased confidence and microsurgical skill. This study describes our approach and its feasibility.

Genetic ancestry and prostate cancer susceptibility SNPs in Puerto Rican and African American men.

BACKGROUND: The Puerto Rican (PR) population is a racially admixed population that has a high prostate cancer (PCa) mortality rate. We hypothesized in this pilot study that West African Ancestry (WAA) was associated with PCa in this heterogeneous (PR) population. METHODS: A case/case and case/control study was performed. Controls, 207 African American (AA) and 133 PR were defined as men with no PCa, a serum PSA < 2.5 ng/mL and a negative rectal examination. Cases were patients with pathological specimens from radical prostatectomies (RP) (291 PR and 200 AA). DNA was extracted from whole blood of controls and from paraffin embedded normal seminal vesicle from the RPs. We assessed the association of PCa and aggressiveness with genetic ancestry using an ancestry informative marker panel (AIMs) and Wilcoxon rank-sum test and the association of PCa and aggressiveness with 15 previously PCa associated SNPs using Chi square test. Gleason Score (GS) and tumor stage (TS) were used to define low risk (GS ≤ 7[3 + 4]), TS ≤ pT2) and high risk (GS≥ 7[4 + 3], TS > pT2) PCa. Statistical analyses were done using SAS. RESULTS: No difference in overall percent WAA was found between PR cases and controls. Among PR or AA cases WAA was not associated with disease severity based upon risk group, Gleason score or stage. Among AA controls WAA was significantly higher than in cases. The SNP rs7824364 (chromosome 8q24) PCa risk allele was significantly increased among cases versus controls for both AA (P < 0.0001) and PR (P = 0.0001) men. PR men with ≥1 risk allele exhibited a higher percent of WAA (39% vs 29%, P = 0.034). CONCLUSION: The SNP rs7824364, a local marker of WAA in the 8q24 region was associated with PCa among both AA and PR men and with increased WAA among PR men. This novel relationship of PCA risk loci, WAA with PCa and its phenotype among PR men deserves further study.

Outcomes of Minimally Invasive Inguinal Hernia Repair at the Time of Robotic Radical Prostatectomy.

Abdominal straining associated with voiding dysfunction or constipation has traditionally been associated with the development of abdominal wall hernias. Thus, classic general surgery dictum recommends that any coexistent bladder outlet obstruction should be addressed by the urologist before patients undergo surgical repair of a hernia. While organ-confined prostate cancer is usually not associated with the development of lower urinary tract symptoms, a modest proportion of patients treated with radical prostatectomy may have coexisting benign prostatic hyperplasia with elevated symptom scores and hernias may be incidentally detected at the time of surgery. Furthermore, dissection of the space of Retzius during retropubic or minimally invasive prostatectomy may result exposure of abdominal wall defects which may have been present, but asymptomatic if plugged with preperitoneal fat. Herein we examine the literature regarding the incidence of postoperative inguinal hernias after prostatectomy, review potential risk factors which could aid in preoperative patient identification, and discuss the published experience regarding concurrent hernia repair at the time of open or minimally invasive radical prostatectomy.

Preoperative International Prostate Symptom Score Predictive of Inguinal Hernia in Patients Undergoing Robotic Prostatectomy.

PURPOSE: Studies have shown that encountering an inguinal hernia during robotic radical prostatectomy is not uncommon. We reviewed our experience with simultaneous robotic prostatectomy and mesh hernia repair to identify variables predictive of a hernia. MATERIALS AND METHODS: Our cohort consisted of 693 consecutive men who underwent robotic radical prostatectomy as performed by 1 surgeon. Hernias were repaired with mesh composed of equal parts of absorbable polyglecaprone-25 and nonabsorbable polypropylene monofilament. Preoperative variables potentially predictive of an inguinal hernia were evaluated. RESULTS: Inguinal hernias were encountered in 55 of 639 patients (8.6%), of which 22.3% were bilateral for a total of 68 hernia sides. Only 26 of 55 hernias (47.2%) were evident preoperatively. Men with a preoperative I-PSS (International Prostate Symptom Score) of 15 or greater had a 22.4% chance (30 of 134) of requiring a hernia repair compared with 5% in those without such a score (OR 5.54, 95% CI 3.13-9.81, p <0.0001). There were no differences between the hernia and nonhernia groups in prostate size, body mass index, age, blood loss, transfusions, operative time, length of stay or any Clavien grade II-V complication. In 47 patients there was 1 recurrence at a median followup of 27.9 months. There were no cases of mesh associated pain or erosion. CONCLUSIONS: Independent of prostate size, men with preoperative lower urinary tract dysfunction were at 5 times the risk of a hernia at robotic radical prostatectomy (22.4% vs 5%). Given that half of the hernias were subclinical, patients with an I-PSS of 15 or greater should be counseled about the potential need for hernia repair at robotic radical prostatectomy.