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All‐inorganic perovskites have recently drawn considerable attention due to their excellent optoelectronic properties. With the help of gap‐plasmon nanostructures, the optical properties of perovskites can be tuned through the coupled near‐field. Here, the optical coupling between CsPbBr3 quantum dots (QDs) and gap‐plasmon through placing QDs in a 2‐nm tetrahedral amorphous carbon gap region of collapsible Ag nanofingers is demonstrated. Compared to the CsPbBr3 QDs on SiO2, the photoluminescence (PL) of CsPbBr3 QDs on collapsed nanofinger is enhanced by 4 times and the lifetime decreases from 11.04 to 3.8 ns. A Purcell‐enhanced emission can be achieved by combining QDs and plasmonic nanofingers. In addition, the intensity of PL can be manipulated by the polarization of incident light because of the different polarization responses of dimer nanofingers. More importantly, PL intensity shows a quadric dependence on the incident power and lasing‐like PL spectra can be observed at room temperature by continuous‐wave laser excitation. Such observations can be ascribed to the strong coupling between CsPbBr3 QDs and surrounding Ag nanofingers. This finding indicates that it is possible to achieve lasing‐like PL through coupling CsPbBr3 QDs to the near‐field of plasmonic nanostructures, which can enrich the applications of CsPbBr3 QDs in nanolasing devices. [ABSTRACT FROM AUTHOR]

Pancreatic exocrine insufficiency (PEI) results in maldigestion of fat, leading to steatorrhea, malabsorption and weight loss. Sjögren's syndrome (SS) is a chronic autoimmune rheumatic disease with unknown etiology. The exocrine pancreas and the salivary glands are functionally and histologically comparable, and pancreatic dysfunction in SS has been hypothesized. Patients were recruited from the Department for Rheumatology at the Karolinska University Hospital in Stockholm, Sweden, between June and December 2019. PEI was assessed by fecal elastase-1 (FE-1) and 13C-mixed triglyceride breath test (13C-MTG-BT). The presence and severity of gastrointestinal symptoms were assessed by a well-established and validated survey based on a seven-point Likert scale. Fifty-seven patients with primary SS were included in the study, comprising 92% females with a median age of 63 years. In total, 87% of SS patients were tested for FE-1 and all had normal results. All patients who underwent a 13C-MTG-BT had a normal cumulative 13C-exhalation. Compared to the control group, significantly more patients suffered from gastrointestinal (GI) symptoms (p <.01). The same number of patients noted moderate to severe loose bowel movements or constipation (38%). Eleven GI symptom parameters were compared to controls and the highest odd ratios were noted for the following moderate to severe symptoms: bloating, feeling of incompletely emptied bowel after defecation and abdominal pain relieved by bowel action. In our study, most SS patients suffered from irritable bowel syndrome (IBS)-like GI symptoms that could not be attributed to PEI. [ABSTRACT FROM AUTHOR]

The low-temperature states of bosonic fluids exhibit fundamental quantum effects at the macroscopic scale: the best-known examples are Bose-Einstein condensation and superfluidity, which have been tested experimentally in a variety of different systems. When bosons interact, disorder can destroy condensation, leading to a 'Bose glass'. This phase has been very elusive in experiments owing to the absence of any broken symmetry and to the simultaneous absence of a finite energy gap in the spectrum. Here we report the observation of a Bose glass of field-induced magnetic quasiparticles in a doped quantum magnet (bromine-doped dichloro-tetrakis-thiourea-nickel, DTN). The physics of DTN in a magnetic field is equivalent to that of a lattice gas of bosons in the grand canonical ensemble; bromine doping introduces disorder into the hopping and interaction strength of the bosons, leading to their localization into a Bose glass down to zero field, where it becomes an incompressible Mott glass. The transition from the Bose glass (corresponding to a gapless spin liquid) to the Bose-Einstein condensate (corresponding to a magnetically ordered phase) is marked by a universal exponent that governs the scaling of the critical temperature with the applied field, in excellent agreement with theoretical predictions. Our study represents a quantitative experimental account of the universal features of disordered bosons in the grand canonical ensemble., Disorder can have a very strong effect on quantum fluids. Owing to their wave-like nature, quantum particles are subject to interference when scattering against disordered potentials. This leads to their [...]

Epithelial tissues constitute an exotic type of active matter with non-linear properties reminiscent of amorphous materials. In the context of a proliferating epithelium, modeled by the quasistatic vertex model, we identify novel discrete tissue scale rearrangements, i.e. cellular rearrangement avalanches, which are a form of collective cell movement. During the avalanches, the vast majority of cells retain their neighbors, and the resulting cellular trajectories are radial in the periphery, a vortex in the core. After the onset of these avalanches, the epithelial area grows discontinuously. The avalanches are found to be stochastic, and their strength is correlated with the density of cells in the tissue. Overall, avalanches redistribute accumulated local spatial pressure along the tissue. Furthermore, the distribution of avalanche magnitudes is found to obey a power law, with an exponent consistent with sheer induced avalanches in amorphous materials. To understand the role of avalanches in organ development, we simulate epithelial growth of the Drosophila eye disc during the third instar using a computational model, which includes both chemical and mechanistic signaling. During the third instar, the morphogenetic furrow (MF), a ~10 cell wide wave of apical area constriction propagates through the epithelium. These simulations are used to understand the details of the growth process, the effect of the MF on the growth dynamics on the tissue scale, and to make predictions for experimental observations. The avalanches are found to depend on the strength of the apical constriction of cells in the MF, with a stronger apical constriction leading to less frequent and more pronounced avalanches. The results herein highlight the dependence of simulated tissue growth dynamics on relaxation timescales, and serve as a guide for in vitro experiments. Author summary: Epithelial tissues have interesting properties. They are often described as viscoelastic materials, behaving like an elastic solid on short time scales and as a liquid on long time scales. When tissues proliferate, cell division requires the cells to rearrange and displace each other. To relieve proliferative stress, cells are equipped with machinery that allows them to respond to mechanical cues and rearrange. Herein, we perform computational simulations, based on the vertex model, to investigate epithelial growth. In our simulations, when the tissue size reaches thousands of cells, we observe the prevalence of stochastic step-like growth discontinuities. These newly identified events, which we term avalanches, involve the collective rearrangement of all cells in the tissue, and they are accompanied with localized cellular pressure redistribution and a collective net radial displacement of cells. We study their properties in the simple setting of a spatially uniform and time independent growth model and in the context of an experimentally calibrated Drosophila eye disc growth model. Utilizing the eye disc growth model, we also investigate the relationship between localized cellular mechanical deformations and global growth dynamics. We conclude that avalanches constitute a macroscopic pathway for epithelial tissues to release accumulated proliferative stress when local processes are insufficient. [ABSTRACT FROM AUTHOR]

Chemotactic bacteria form emergent spatial patterns of variable cell density within cultures that are initially spatially uniform. These patterns are the result of chemical gradients that are created from the directed movement and metabolic activity of billions of cells. A recent study on pattern formation in wild bacterial isolates has revealed unique collective behaviors of the bacteria Enterobacter cloacae. As in other bacterial species, Enterobacter cloacae form macroscopic aggregates. Once formed, these bacterial clusters can migrate several millimeters, sometimes resulting in the merging of two or more clusters. To better understand these phenomena, we examine the formation and dynamics of thousands of bacterial clusters that form within a 22 cm square culture dish filled with soft agar over two days. At the macroscale, the aggregates display spatial order at short length scales, and the migration of cell clusters is superdiffusive, with a merging acceleration that is correlated with aggregate size. At the microscale, aggregates are composed of immotile cells surrounded by low density regions of motile cells. The collective movement of the aggregates is the result of an asymmetric flux of bacteria at the boundary. An agent-based model is developed to examine how these phenomena are the result of both chemotactic movement and a change in motility at high cell density. These results identify and characterize a new mechanism for collective bacterial motility driven by a transient, density-dependent change in motility. Author summary: Bacteria growing and swimming in soft agar often aggregate to form elaborate spatial patterns. Here we examine the patterns formed by the bacteria Enterobacter cloacae. An unusual behavior of these bacteria is the collective movement of cells after the initial aggregation into a tiny spot. Despite the majority of the cells within an aggregate being immotile at any point in the time, the flux of cells entering and leaving the aggregate, as motility is lost and regained in individual cells, led to a net, collective movement of the aggregate. These spots sometimes run into each other and combine. By looking at the cells within these spots under a microscope, we find that cells within each spot stop swimming. The process of switching back and forth between swimming and not swimming causes the movement and fusion of the spots. A numerical simulation shows that the migration and merging of these spots can be expected if the cells swim towards regions of space with high concentrations of attractant molecules and stop swimming in locations crowded with many cells. This work identifies a novel process through which populations of bacteria cooperate and control the movement of large groups of cells. [ABSTRACT FROM AUTHOR]

Background and Study Aims In patients with obesity and type-2 diabetes, short-time very low-calorie diet may ameliorate hyperglycemia and hepatic steatosis. Whether this also implies the glucose-regulating hormone glucagon remains to be elucidated. This study investigated the effects of a very low-calorie diet on plasma levels of glucagon and liver fat in obese patients with type-2 diabetes. Patients and Methods Ten obese patients with type-2 diabetes, 6 men and 4 women, were included. At baseline, fasting plasma glucagon, insulin and glucose were determined, and liver fat and stiffness evaluated by transient elastography. The subjects were then prescribed a very low-calorie diet of maximum 800 kcal/day for 7 weeks and reexamined after 7 weeks and 12 months. Results At baseline, BMI was 42±4 kg/m2 and fasting glucose 10.6±3.4 mmol/l. All patients had hepatic steatosis. Plasma glucagon was strongly related to liver fat (r2 =0.52, p=0.018). After 7 weeks of very low-calorie diet, plasma glucagon was significantly decreased by nearly 30% (p=0.004) along with reductions of BMI (p<0.0001), glucose (p=0.02), insulin (p=0.03), liver fat (p=0.007) and liver stiffness (p=0.05). At 12 months follow-up, both glucagon and liver fat increased and were not different to basal levels, despite persistent reductions of BMI (p<0.002) and glucose (p=0.008). Conclusion In obese type-2 diabetic subjects, plasma glucagon and liver fat are correlated and similarly affected by a very low-calorie diet, supporting a role of hepatic steatosis in glucagon metabolism. [ABSTRACT FROM AUTHOR]

Background and Aim: Pain is the primary symptom of chronic pancreatitis (CP) and associates with a number of patient and disease characteristics. However, the complex interrelations of these parameters are incompletely understood, and pain treatment remains unsatisfactory in a large proportion of patients. The aim of this study is to investigate multiple pain risk factors in a large population of CP patients, with a special emphasis on patients' patterns of smoking and alcohol use. Methods: This was a multicenter, cross‐sectional study including 1384 patients with CP. Patient demographics and disease characteristics, as well as current patterns of smoking and alcohol use, were compared for patients with pain (n = 801) versus without pain (n = 583). Multivariate logistic regression models were performed to assess the variables associated with the presence and type of pain (constant vs intermittent pain). Results: The mean age of participants was 52.1 ± 14.6 years, and 914 (66%) were men. Active smoking (odds ratio 1.6 [95% confidence interval 1.1–2.2], P = 0.005) and alcohol consumption (odds ratio 1.8 [95% confidence interval 1.1–3.0], P = 0.03) were independently associated with the presence of pain. In addition, patients' age at diagnosis, pancreatic duct pathology, and the presence of pseudocysts, duodenal stenosis, and exocrine pancreatic insufficiency were confirmed as pain risk factors (all P ≤ 0.01). Constant pain, as opposed to intermittent pain, was more frequently reported by smokers (P = 0.03), while alcohol consumption was associated with intermittent pain (P = 0.006). Conclusion: Multiple patient and disease characteristics, including patterns of smoking and alcohol consumption, associate with the presence and type of pain in patients with CP. [ABSTRACT FROM AUTHOR]

Synthesis of semiconductor device design requires access to realistic physical models and adaptive algorithms. To demonstrate that such synthesis is feasible we design elements of a quantum-confined Stark-effect modulator. Optimization with respect to a target function is achieved using a genetic algorithm. It is then shown how automated searches of configuration space may be performed without the need to input a specific target function. [ABSTRACT FROM AUTHOR]

The photon scattering properties of aperiodic nanoscale dielectric structures can be tailored to closely match a desired response by using adaptive algorithms for device design. We show that broken symmetry of aperiodic designs provides access to device functions not available to conventional periodic photonic crystal structures. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Using adaptive algorithms, the design of nanoscale dielectric structures for photonic applications is explored. Widths of dielectric layers in a linear array are adjusted to match target responses of optical transmission as a function of energy. Two complementary approaches are discussed. The first approach uses adaptive local random updates and progressively adjusts individual dielectric layer widths. The second approach is based on global updating functions in which large subgroups of layers are adjusted simultaneously. Both schemes are applied to obtain specific target responses of the transmission function within selected energy windows, such as discontinuous cutoff or power-law decay filters close to a photonic band edge. These adaptive algorithms are found to be effective tools in the custom design of nanoscale photonic dielectric structures. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Diagonalizing clusters from 26 sites of a two-dimensional spin-1/2 Heisenberg antiferromagnet help determine its Raman spectrum. The theoretical determination of Raman spectra is identical to the experimentally observed spectra. A difference is observed in the two-magnon peak near 0.4 electron volts.

Background and aims: Detection of early cholangiocarcinoma (CCA) in primary sclerosing cholangitis (PSC) is challenging. The aim of this study was to evaluate the diagnostic accuracy of a stepwise approach to biliary brush cytology with sequential use of fluorescence in‐situ hybridization (FISH) for the detection of biliary malignancy in PSC. Method: We retrospectively studied consecutive patients with PSC who underwent biliary brushings at Karolinska University Hospital between 2009 and 2015 (n = 208). Brush samples were categorized as benign, equivocal (atypical or suspicious) and malignant. Equivocal cases were further analysed with FISH. Samples with a malignant cytology or positive FISH were considered positive. The diagnosis was determined after 12 months of follow‐up. Results: The diagnosis CCA was confirmed in 15 patients (7%), high‐grade dysplasia in three patients, and low‐grade dysplasia in five patients at follow‐up. Using the diagnostic algorithm, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) for a diagnosis of CCA were 80% (95%CI 52%‐96%), 96% (95%CI 92%‐98%), 60% (95%CI 36%‐81%) and 98% (95% CI 95%‐100%). In patients with equivocal cytology (n = 61), the sensitivity for CCA diagnosis increased to 100% (95%CI 72%‐100%) with a lower PPV of 58% (95%CI 34%‐78%). The diagnostic accuracy for detection of CCA in all patients was 95% (95%CI 91%‐97%). Conclusion: Biliary brush cytology with sequential use of FISH in equivocal cases seems to be a highly predictive diagnostic test for CCA in PSC. These results support the use of FISH when cytology is equivocal for detection of biliary malignancy in PSC. [ABSTRACT FROM AUTHOR]

During development of biological organisms, multiple complex structures are formed. In many instances, these structures need to exhibit a high degree of order to be functional, although many of their constituents are intrinsically stochastic. Hence, it has been suggested that biological robustness ultimately must rely on complex gene regulatory networks and clean-up mechanisms. Here we explore developmental processes that have evolved inherent robustness against stochasticity. In the context of the Drosophila eye disc, multiple optical units, ommatidia, develop into crystal-like patterns. During the larva-to-pupa stage of metamorphosis, the centers of the ommatidia are specified initially through the diffusion of morphogens, followed by the specification of R8 cells. Establishing the R8 cell is crucial in setting up the geometric, and functional, relationships of cells within an ommatidium and among neighboring ommatidia. Here we study an PDE mathematical model of these spatio-temporal processes in the presence of parametric stochasticity, defining and applying measures that quantify order within the resulting spatial patterns. We observe a universal sigmoidal response to increasing transcriptional noise. Ordered patterns persist up to a threshold noise level in the model parameters. In accordance with prior qualitative observations, as the noise is further increased past a threshold point of no return, these ordered patterns rapidly become disordered. Such robustness in development allows for the accumulation of genetic variation without any observable changes in phenotype. We argue that the observed sigmoidal dependence introduces robustness allowing for sizable amounts of genetic variation and transcriptional noise to be tolerated in natural populations without resulting in phenotype variation. [ABSTRACT FROM AUTHOR]

Morbid obesity is a lifelong disease, and all patients require complementary follow-up including nutritional surveillance by a multidisciplinary team after bariatric procedures. Pancreatic exocrine insufficiency (PEI) refers to an insufficient secretion of pancreatic enzymes and/or sodium bicarbonate. PEI is a known multifactorial complication after upper gastrointestinal surgery, and might constitute an important clinical problem due to the large number of bariatric surgical procedures in the world. Symptoms of PEI often overlap with sequelae of gastric bypass, making the diagnosis difficult. Steatorrhea, weight loss, maldigestion and malabsorption are pathognomonic for both clinical conditions. Altered anatomy after bypass surgery can make the diagnostic process even more difficult. Fecal elastase-1 (FE1) is a useful diagnostic test. PEI should be considered in all patients after bariatric surgery with prolonged gastrointestinal complaints that are suggestive of maldigestion and/or malabsorption. Appropriate pancreatic enzyme replacement therapy should be part of the treatment algorithm in patients with confirmed PEI or symptoms suggestive of this complication. [ABSTRACT FROM AUTHOR]

Objectives:Chronic pancreatitis (CP) is a multifaceted disease associated with several risk factors and a complex clinical presentation. We established the Scandinavian Baltic Pancreatic Club (SBPC) Database to characterise and study the natural history of CP in a Northern European cohort. Here, we describe the design of the database and characteristics of the study cohort. Methods:Nine centres from six different countries in the Scandinavian-Baltic region joined the database. Patients with definitive or probable CP (M-ANNHEIM diagnostic criteria) were included. Standardised case report forms were used to collect several assessment variables including disease aetiology, duration of CP, preceding acute pancreatitis, as well as symptoms, complications, and treatments. The clinical stage of CP was characterised according to M-ANNNHEIM. Yearly follow-up is planned for all patients. Results:The study cohort comprised of 910 patients (608 men: 302 women; median age 58 (IQR: 48–67) years with definite 848 (93%) or probable CP 62 (7%). Nicotine (70%) and alcohol (59%) were the most frequent aetiologies and seen in combination in 44% of patients. A history of recurrent acute pancreatitis was seen in 49% prior to the development of CP. Pain (69%) and exocrine pancreatic insufficiency (68%) were the most common complications followed by diabetes (43%). Most patients (30%) were classified as clinical stage II (symptomatic CP with exocrine or endocrine insufficiency). Less than 10% of the patients had undergone pancreatic surgery. Conclusion:The SBPC database provides a mean for future prospective, observational studies of CP in the Northern European continent. [ABSTRACT FROM AUTHOR]

Presents a study which addressed the interactions between the longitudinal terms that enhance the ordered staggered magnetic moment and the transverse terms representing the quantum fluctuations that suppress the sub lattice magnetization. Discussion on the anisotropic Heisenberg antiferromagnet of spin S on a square lattice; Plot for the sublattice magnetization and the transversal correlation for the pure spin-S anisotropic antiferromagnet and for the antifferromagnet.