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The accurate prediction of the band gaps of halide perovskites within density functional theory is known to be challenging. The recently developed Wannier-localized optimally tuned screened range-separated hybrid functional was shown to be highly accurate for fundamental band gaps of standard semiconductors and insulators. This was achieved by selecting the parameters of the functional to satisfy an ansatz that generalizes the ionization potential theorem to the removal of charge from a state that corresponds to a Wannier function. Here, we present applications of the method to the band gaps of typical halide perovskites. We find a satisfyingly small formal mean absolute error of ∼0.1 eV with respect to experimental band gaps and very good agreement with previous many-body perturbation theory calculations.

Background Corticosteroids are often used in Crohn’s disease (CD) to control inflammation. However, they are associated with adverse events; thus, achieving and maintaining remission without corticosteroids is a major treatment goal. GALAXI 1, a phase 2b, double-blind, placebo (PBO)-controlled study, evaluated efficacy and safety of guselkumab (GUS), a selective interleukin-23p19 subunit antagonist, in patients (pts) with moderately to severely active CD. Primary efficacy and safety data were presented previously. Here, we report corticosteroid-free clinical remission rates through Week (Wk) 48. Methods Pts with moderately to severely active CD were randomised in a treat-through design to GUS 200, 600, 1200mg; ustekinumab (UST) ~6mg/kg; or PBO intravenous (IV) induction followed by maintenance dosing (GUS 200mg IV-->GUS 100mg subcutaneous [SC] every 8 weeks [q8w], GUS 600mg IV-->GUS 200mg SC q4w, GUS 1200mg IV-->GUS 200mg SC q4w, UST ~6mg/kg IV-->UST 90mg SC q8w, PBO nonresponders-->UST ~6mg/kg IV-->UST 90mg SC q8w, PBO responders-->PBO SC q4w). Corticosteroid tapering was mandatory from Wk12 if medically feasible. Efficacy endpoints included corticosteroid-free CD Activity Index (CDAI) clinical remission ( Results At Wk48, 55.7-71.4% of pts in the GUS dose groups achieved corticosteroid-free CDAI clinical remission (Table 1). Similar rates were observed when the corticosteroid-free duration was ≥30 or ≥90 days before Wk48. Among pooled pts in CDAI clinical remission at Wk48 in the GUS groups, 115/120 (95.8%) were corticosteroid free. At Wk48, 49.2-68.3% of pts in the GUS dose groups achieved corticosteroid-free PRO-2 remission (Table 1). Among pooled pts in PRO-2 remission at Wk48 in the GUS groups, 105/110 (95.5%) were corticosteroid free. Outcomes in the reference UST group are shown in Table 1. Among pts in the GUS dose groups, 30.2-39.3% were using corticosteroids at Wk0 (median prednisone equivalent dose 20.0mg/d in each group); at Wk48, 60.0-78.9% of these pts met corticosteroid-free criteria (Table 2). Conclusion High rates of corticosteroid-free CDAI clinical and PRO-2 remission were achieved at Wk48 in the GUS dose groups. Among pts in clinical remission, most were corticosteroid free. Nearly all pts maintained corticosteroid-free CDAI clinical remission for ≥90 days. GUS IV induction followed by SC maintenance therapy also effectively reduced corticosteroid use at Wk48.

Background The orally administered small molecule drug pan-Jak inhibitor tofacitinib (TFB) appears to be effective in the treatment of ulcerative colitis (UC), however, available real world studies are limited by the cohort size. In addition, TFB may also be efficacious in patients with acute severe colitis (ASUC) as a rescue therapy. We aimed to conduct an international cohort study, to investigate the efficacy and safety of TFB in patients with moderate to severe colitis and ASUC. Methods This was a retrospective, international multi-centre, cohort study including 23 tertiary referral centres. UC patients with at least 6 weeks of TFB treatment were included. Physicians categorized the indication as rescue therapy (RT) and chronic activity (CA). Baseline demographic and clinical data, clinical/endoscopic activity indexes, laboratory parameters (including CRP, faecal calprotectin, liver enzymes, lipids, iron homeostasis), adverse events, and hospitalization/colectomy rates were collected at w0, w2-6, w8-14, w22-30 and w48-56 intervals. Steroid-free remission, colectomy rates, primary non-response (PNR) and loss-of response (LOR) rates, and safety was studied. Results A total of 391 UC patients (mean age: 39.2±14.1 years, male/female ratio 208/183; mean follow-up period 33.7±18.1 weeks) were included. 107 patients (27.4%) received TFB as a rescue therapy. Most of the patients received it as a third line treatment (37.4%). Steroid-free remission (SFR) rates were 21.3% (RT: 25.0%, CA: 22.3%) at w14, and 40.1% (RT: 32.5%, CA: 42.2%) at w52. In total, baseline pMayo (OR: 0.856; p=0.007) was negatively associated with w12 SFR, while line of treatment (OR: 0.749; p=0.047) and age (OR: 1.022; p=0.038) influenced the w52 SFR in the CA group. The w12 colectomy rate was 5.1%, and no difference was observed between groups (RT: 8.5%; CA: 3.8%), however, w52 colectomy rate was higher in the RT group (19.2% compared to 5.9%; p Conclusion TFB is effective in both moderate to severe UC, and in patients with ASUC as a rescue therapy. TFB treatment resulted in high rates of SFR and mucosal healing in short- and long term even after anti-TNF and vedolizumab failure. Higher baseline disease activity and number of previous biological therapies negatively influenced efficacy. Serious adverse events were rare.

Interlayer organic cations in quasi-two-dimensional halide perovskites are a versatile tuning vehicle for the optoelectronic properties of these complex systems, but chemical intuition for this design route is yet to be established. Here, we use density functional theory, the GW approximation, and the Bethe-Salpeter equation approach to understand the contribution of the organic cation to the quasiparticle band gap and exciton binding energy of layered perovskites. We show that organic cations in quasi-two-dimensional perovskites contribute significantly to the dielectric screening in these systems, countering quantum confinement effects on the quasiparticle band gap and the exciton binding energy. Using a simple electrostatics model inspired by parallel-plate capacitors, we decouple the organic cation and inorganic layer contributions to the effective dielectric constants and show that dielectric properties of layered perovskites are broadly tunable via the interlayer cation, providing a direct means of tuning photophysical properties for a variety of applications.

Background Individuals with tuberous sclerosis complex are at increased risk of epilepsy. Early seizure control improves developmental outcomes, making identifying at-risk patients critically important. Despite several identified risk factors, it remains difficult to predict. The purpose of the study was to evaluate the combined risk prediction of previously identified risk factors for epilepsy in individuals with tuberous sclerosis complex. Methods The study group (n = 333) consisted of individuals with tuberous sclerosis complex who were enrolled in the Tuberous Sclerosis Complex Autism Center of Excellence Research Network and UT TSC Biobank. The outcome was defined as having an epilepsy diagnosis. Potential risk factors included sex, TSC genotype, and tuber presence. Logistic regression was used to calculate the odds ratio and P value for the association between each variable and epilepsy. A clinical risk prediction model incorporating all risk factors was built. Area under the curve was calculated to characterize the full model's ability to discriminate individuals with tuberous sclerosis complex with and without epilepsy. Results The strongest risk for epilepsy was presence of tubers (95% confidence interval: 2.39 to 10.89). Individuals with pathogenic TSC2 variants were three times more likely (95% confidence interval: 1.55 to 6.36) to develop seizures compared with those with tuberous sclerosis complex from other causes. The combination of risk factors resulted in an area under the curve 0.73. Conclusions Simple characteristics of patients with tuberous sclerosis complex can be combined to successfully predict epilepsy risk. A risk assessment model that incorporates sex, TSC genotype, protective TSC2 missense variant, and tuber presence correctly predicts epilepsy in 73% of patients with tuberous sclerosis complex.

We image charge carrier transport over nanometers–micrometers and picoseconds–microseconds in halide double perovskites Cs2AgBiBr6 and Cs2AgTlBr6 single crystals using stroboscopic scattering micro...

Using ultrafast optical-pump terahertz-probe spectroscopy (OPTP) and ultrafast terahertz emission spectroscopy, we showcase the electron and hole dynamics in Cd 3 As 2 nanowires (NWs), a well-known 3D Dirac semimetal a subgroup of the newly discovered. A temperature-dependent photoconductivity measurement was carried out yielding an incredibly high electron mobility ~ 16,000 cm2/Vs at 5K. Strong THz emission due to helicity-dependent surface photocurrents was also observed for both nanowires and single crystal (SC) which is highly desirable for devices such as THz sources.

The dependence ofab initiomany-body perturbation theory within theGWapproximation on the eigensystem used in calculating quasiparticle corrections limits this method's predictive power. Here, we investigate the accuracy of the recently developed Wannier-localized optimally tuned screened range-separated hybrid (WOT-SRSH) functional as a generalized Kohn-Sham starting point for single-shotGW(G0W0) calculations for a range of semiconductors and insulators. Comparison to calculations based on well-established functionals, namely, PBE, PBE0, and HSE, as well as to self-consistentGWschemes and to experiment, shows that band gaps computed viaG0W0@WOT-SRSH have a level of precision and accuracy that is comparable to that of more advanced methods such as quasiparticle self-consistentGWand eigenvalue self-consistentGW. We also find thatG0W0@WOT-SRSH improves the description of states deeper in the valence band manifold. Finally, we show thatG0W0@WOT-SRSH significantly reduces the sensitivity of computed band gaps to ambiguities in the underlying WOT-SRSH tuning procedure.

The optical interference constitutes a paramount resource in modern physics. At the scale of individual atoms and photons, it is a diverse concept that causes different coherent phenomena. We present the experimental characterization of both coherent and statistical properties of light emitted from ensembles of trapped ions increasing with a number of contributing phase-incoherent independent atomic particles ranging from a single to up to several hundreds. It conclusively demonstrates how super-Poissonian quantum statistics non-trivially arises purely from the finite number of indistinguishable single-photon emitters in the limit of a single detection mode. The achieved new optical emission regime in which these independent atoms contribute coherently to the super-Poissonian statistics provides a new perspective on the emergence of optical coherence at the atomic scale and constitutes a unique toolbox for its generation and control at the most microscopic level.

The precise stacking of different two-dimensional (2D) structures such as graphene and MoS2 has reinvigorated the field of 2D materials, revealing exotic phenomena at their interfaces1,2. These unique interfaces are typically constructed using mechanical or deposition-based methods to build a heterostructure one monolayer at a time2,3. By contrast, self-assembly is a scalable technique, where complex materials can selectively form in solution4–6. Here we show a synthetic strategy for the self-assembly of layered perovskite–non-perovskite heterostructures into large single crystals in aqueous solution. Using bifunctional organic molecules as directing groups, we have isolated six layered heterostructures that form as an interleaving of perovskite slabs with a different inorganic lattice, previously unknown to crystallize with perovskites. In many cases, these intergrown lattices are 2D congeners of canonical inorganic structure types. To our knowledge, these compounds are the first layered perovskite heterostructures formed using organic templates and characterized by single-crystal X-ray diffraction. Notably, this interleaving of inorganic structures can markedly transform the band structure. Optical data and first principles calculations show that substantive coupling between perovskite and intergrowth layers leads to new electronic transitions distributed across both sublattices. Given the technological promise of halide perovskites4, this intuitive synthetic route sets a foundation for the directed synthesis of richly structured complex semiconductors that self-assemble in water. Using organic molecules as directing groups, a wide range of perovskite heterostructures are shown to self-assemble in solution to yield single crystals.

Measuring terahertz (THz) conductivity on an ultrafast time scale is an excellent way to observe charge-carrier dynamics in semiconductors as a function of time after photoexcitation. However, a conductivity measurement alone cannot separate the effects of charge-carrier recombination from effective mass changes as charges cool and experience different regions of the electronic band structure. Here we present a form of time-resolved magneto-THz spectroscopy which allows us to measure cyclotron effective mass on a picosecond time scale. We demonstrate this technique by observing electron cooling in the technologically-significant narrow-bandgap semiconductor indium antimonide (InSb). A significant reduction of electron effective mass from 0.032$m_\mathrm{e}$ to 0.017$m_\mathrm{e}$ is observed in the first 200ps after injecting hot electrons. Measurement of electron effective mass in InSb as a function of photo-injected electron density agrees well with conduction band non-parabolicity predictions from ab initio calculations of the quasiparticle band structure.

TheabinitioBethe-Salpeter equation (BSE) approach, an established method for the study of excitons in materials, is typically solved in a limit where only static screening from electrons is captured. Here, we generalize this framework to include dynamical screening from phonons at lowest order in the electron-phonon interaction. We apply this generalized BSE approach to a series of inorganic lead halide perovskites,CsPbX3, withX = Cl, Br, and I. We find that inclusion of screening from phonons significantly reduces the computed exciton binding energies of these systems. By deriving a simple expression for phonon screening effects, we reveal general trends for their importance in semiconductors and insulators, based on a hydrogenic exciton model. We demonstrate that the magnitude of the phonon screening correction in isotropic materials can be reliably predicted using four material specific parameters: the reduced effective mass, static and optical dielectric constants, and frequency of the most strongly coupled longitudinal-optical phonon mode. This framework helps to elucidate the importance of phonon screening and its relation to excitonic properties in a broad class of semiconductors.

Aims SELECTION (NCT02914522) Maintenance evaluated filgotinib (FIL), a preferential JAK1 inhibitor, as maintenance therapy for patients (pts) with moderately to severely active ulcerative colitis (UC) who achieved clinical remission or Mayo Clinic Score (MCS) response after 10 weeks of FIL 200mg QD, FIL 100mg QD or placebo (PBO) induction. Methods Pts randomized to FIL induction were rerandomized 2:1 to their induction FIL dose or PBO; pts randomized to PBO induction continued PBO maintenance. Steroid tapering was mandatory. The primary endpoint was clinical remission at Week 58. Key secondary endpoints and exploratory endpoints were assessed at Week 58. Results 664 pts were treated in the Maintenance Study (n=93, 270, and 301 from induction with PBO, FIL 100mg and FIL 200mg); efficacy analyses included only FIL induction pts. Baseline demographics and disease characteristics were generally balanced across treatment arms; 40% were biologic experienced. Significantly higher proportion of pts on FIL 200mg or FIL 100mg were in clinical remission vs PBO. Significantly higher proportions of pts achieved key secondary endpoints with FIL 200mg vs PBO. More pts on FIL 200 mg or FIL 100mg achieved an MCS response and endoscopic improvement vs PBO. Incidences of adverse events (AEs), serious AEs and discontinuations due to AEs were similar across arms. Serious infection ( Conclusions FIL 200mg and FIL 100mg were effective as maintenance treatment for pts with moderately to severely active UC who had achieved clinical response to FIL induction treatment. FIL 200 mg met all key secondary endpoints including endoscopic, histologic and 6-month corticosteroid-free remission. FIL was well tolerated in pts with moderate to severely active UC. Funding Agencies None

Halide double perovskites with alternating silver and pnictogen cations are an emerging family of photoabsorber materials with robust stability and band gaps in the visible range. However, the nature of optical excitations in these systems is not yet well understood, limiting their utility. Here, we use ab initio many-body perturbation theory within the $GW$ approximation and the Bethe-Salpeter equation approach to calculate the electronic structure and optical excitations of the double perovskite series Cs$_2$AgBX$_6$, with B=Bi$^{3+}$, Sb$^{3+}$, X = Br$^-$, Cl$^-$. We find that these materials exhibit strongly localized resonant excitons with energies from 170 to 434 meV below the direct band gap. In contrast to lead-based perovskites, the Cs$_2$AgBX$_6$ excitons are computed to be non-hydrogenic, with anisotropic effective masses and sensitive to local field effects, a consequence of their chemical heterogeneity. Our calculations demonstrate the limitations of the Wannier-Mott and Elliott models for this class of double perovskites and contribute to a detailed atomistic understanding of their light-matter interactions.

We present the experimental characterization of coherence of light scattered from ensembles of noninteracting trapped ions. We set up and prove an indistinguishable emission from many ions by observation of photon bunching in a single-mode Hanbury-Brown and Twiss detection scheme.

Quantum control techniques applied at macroscopic scales provide us with opportunities in fundamental physics and practical applications. Among them, measurement-based feedback allows efficient control of optomechanical systems and quantum-enhanced sensing. In this paper, we propose a near-resonant narrow-band force sensor with extremely low optically added noise in an optomechanical system subject to a feedback-controlled in-loop light. The membrane's intrinsic motion consisting of zero-point motion and thermal motion is affected by the added noise of measurement due to the backaction noise and imprecision noise. We show that, in the optimal low-noise regime, the system is analogous to an optomechanical system containing a near quantum-limited optical parametric amplifier coupled to an engineered reservoir interacting with the cavity. Therefore, the feedback loop enhances the mechanical response of the system to the input while keeping the optically added noise of measurement below the standard quantum limit. Moreover, the system based on feedback offers a much larger amplification bandwidth than the same system with no feedback.

Accurate prediction of fundamental band gaps of crystalline solid state systems entirely within density functional theory is a long standing challenge. Here, we present a simple and inexpensive method that achieves this by means of non-empirical optimal tuning of the parameters of a screened range-separated hybrid functional. The tuning involves the enforcement of an ansatz that generalizes the ionization potential theorem to the removal of an electron in an occupied state described by a localized Wannier function in a modestly sized supercell calculation. The method is benchmarked against experiment for a set of systems ranging from narrow band gap semiconductors to large band gap insulators, spanning a range of fundamental band gaps from 0.2 to 14.2 eV and is found to yield quantitative accuracy across the board, with a mean absolute error of $\sim$0.1 eV and a maximal error of $\sim$0.2 eV., Comment: 10 pages, 2 figures

Background The most commonly recognized clinical feature of hypogammaglobulinemia is recurrent infections with high prevalence of gastrointestinal manifestations. In some cases, clinical and endoscopic features are indistinguishable from those of inflammatory bowel disease (IBD). Methods This was a multicenter case series performed as a part of the Collaborative Network of Exceptionally Rare case reports (CONFER) project. Results This report includes 25 patients with primary hypogammaglobinemia and IBD-like features [20 males and 5 females, mean age 50 years (±21.7 SD)]. Crohn’s disease-like features were noted in 22 patients, three patients had ulcerative colitis-like features. The diagnosis of hypogammaglobulinemia preceded IBD-like features diagnosis in 20 patients (mean of 7.7 years prior, range 0.3–35 years), and followed IBD-like features appearance in 5 cases (mean of one year after, 0.4- 9.1 years). Hypogammaglobinemia etiologies were common variable immunodeficiency (72%), Agammaglobulinemia (8%), selective IgA-deficiency (8%), Goods syndrome (8%), IgG subclass deficiency with IgA deficiency (4%). In addition to antibiotics and intravenous immunoglobulin (IVIG) as a treatment for hypogammaglobinemia, fifteen patients received IBD treatment during the follow-up period, of whom two were on 5-aminosalicylic acid, five on corticosteroids, three on immunomodulatory, four on anti-tumor necrosis factor, and one on vedolizumab. By the end of the follow-up [35.5 months (Interquartile range 18–75)], 20 of 25 (80%) patients were in clinical remission. Conclusion This case series illustrates a strong male and CD-like features predilection. The diagnosis of IBD-like features mainly occurs after that of hypogammaglobulinemia, the majority of cases successfully recovered after appropriate treatment.

Perovskite solar cells are gaining increasing popularity due to their unprecedented rise in power conversion efficiency. However, concerns over the potential environmental impact of CH3NH3PbI3 are stimulating experimental and theoretical searches for the replacement of lead by nontoxic elements. In this study we explore all homovalent metal ions which could substitute lead in a perovskite halide configuration by performing a systematic combinatorial search over the entire periodic table. Our screening process selects compounds based on two concurrent criteria: the stability of the compound in a perovskite structure and the band gap. Using these search criteria, we are able to reduce the number of possible compounds from 248 to 25, including 15 compounds which have not yet been proposed as semiconductors for optoelectronics. We identify Mg as a potential candidate for partial replacement of Pb and show that the band gap of hypothetical magnesium iodide perovskites is tunable over a range of 0.8 eV via the ...

Hybrid organic-inorganic halide perovskites have emerged as a disruptive new class of materials, exhibiting optimum properties for a broad range of optoelectronic applications, most notably for photovoltaics. The first report of highly efficient organic-inorganic perovskite solar cells in 2012 marked a new era for photovoltaics research, reporting a power conversion efficiency of over 10%. Only five years after this discovery, perovskite photovoltaic devices have reached a certified efficiency of 22.7%, making them the first solution processable technology to surpass thin film and multi-crystalline silicon solar cells. The remarkable development of perovskite solar cells is due to the ideal optoelectronic properties of organic-inorganic lead-halide perovskites. The prototypical compound, methylammonium lead iodide, CH3NH3PbI3 is a direct band gap semiconductor with a band gap in the visible, high charge carrier mobility, long diffusion length and low excitonic binding energy. Due to these ideal properties, CH3NH3PbI3 is also drawing interest across many other applications beyond photovoltaics, such as light emitting devices, lasers, photocatalysts and transistors. The continued progress of metal-halide perovskite optoelectronics relies not only on a detailed understanding of the electronic and optical properties of materials in this class, but also on the development of practical strategies to tune their properties by controlling parameters such as chemical composition. In this context, ab initio computational modelling can play a key role in providing a physical interpretation of experimental measurements, and guiding the design of novel halide perovskites with tailored properties. In this chapter we will present an account of the contributions to this fast developing field of research from our computational modelling group.

Lead halide perovskites are materials with excellent optoelectronic and photovoltaic properties. However, some hurdles remain prior to commercialization of these materials, such as chemical stability, phase stability, sensitivity to moisture, and potential issues due to the toxicity of lead. Here, we report a new type of lead-free perovskite related compound, Cs2PdBr6. This compound is solution processable, exhibits long-lived photoluminescence, and an optical band gap of 1.6 eV. Density functional theory calculations indicate that this compound has dispersive electronic bands, with electron and hole effective masses of 0.53 and 0.85 me, respectively. In addition, Cs2PdBr6 is resistant to water, in contrast to lead-halide perovskites, indicating excellent prospects for long-term stability. These combined properties demonstrate that Cs2PdBr6 is a promising novel compound for optoelectronic applications.

Lead halide perovskites are materials with excellent optoelectronic and photovoltaic properties. However, some hurdles remain prior to commercialization of these materials, such as chemical stability, phase stability, sensitivity to moisture, and potential issues due to the toxicity of lead. Here, we report a new type of lead-free perovskite related compound, Cs

Background Both anal abscesses and fistulas are potential complications in the course of Crohn’s disease. Chronic immunosuppression, loose stools and poor wound healing in this population pose a challenge to the treatment of perianal diseases. The purpose of our hospital research was to determine the dominant bacterial species found in perianal abscesses and fistula discharge, resulting in anal abscess and/or fistula outflow in patients with Crohn’s disease hospitalised in a tertiary IBD centre in Poland. Methods The results of tests of patients admitted and subsequently conservatively treated or treated for anal fistula or abscess in the period from January 1, 2017 to June 30, 2019 were evaluated. Information obtained from medical records included clinical information, results of laboratory tests and results of swab cultures of perianal lesions for culturing and antibiotic sensitivity of microorganisms isolated. Material was collected from patients in accordance with applicable procedures. Results In the analysed period, a total of 306 swabs from perianal lesions from 44 patients with the diagnosis of Crohn’s Disease were collected, of which microbial growth was observed in 38 patients. Escherichia coli (45.5%, p < 0.001) was the most frequently isolated pathogen, Staphylococcus aureus was the second most common pathogen (15.9%, p < 0.001). In vitro sensitivity tests showed that Escherichia coli (ESBL-extended-spectrum-beta-lactamase producing strain with a broader substrate spectrum) was found in 4 samples, Staphylococcus aureus (MRSA- strain resistant to all beta-lactam antibiotics: penicillins with inhibitors, cephalosporins, monobactams, carbapenems except for ceftaroline). The analysis of the results obtained did not show seasonal variability in the number of positive microbiological tests found on cultures of perianal lesions. Conclusion A retrospective analysis of microbiological results of anal abscesses and fistula outflow was performed in patients with Crohn’s Disease with perianal changesi. Escherichia coli was the predominant pathogen isolated. The second most common organism was Staphylococcus, isolated from 9 patients. Staphylococci were not found in samples from other patients with IBD. The evaluation of the obtained results shows that positive results of cultures of swabs from lesions in the anal area were found more often in samples taken from men (25 samples–65.8%) than from women (13 samples–34.2%).

A

Lead-free pnictogen/noble metal halide double perovskites Cs 2 BiAgCl 6 , Cs 2 BiAgBr 6 , and Cs 2 SbAgCl 6 are some of the most promising environmentally friendly alternatives to lead-halide perovskites. However, due to their relatively large band gaps (1.9-2.2 eV), they are not yet competitive candidates for use in photovoltaic devices. In this work, we perform a systematic study of the thermodynamic stability of the entire family of Cs 2 BB′X 6 compounds (B = Bi and Sb, B′ = Cu, Ag, and Au, and X = Cl, Br, and I), and we explore the possibility of chemical mixing as a route to stabilize pnictogen/noble metal halide perovskites with low band gaps. Our calculations indicate that Cs 2 BiAg 1-x Cu x Cl 6 mixes should be amenable to synthesis and could reduce the band gap down to 1.6-1.9 eV.

The recent discovery of lead-free halide double perovskites with band gaps in the visible represents an important step forward in the design of environmentally friendly perovskite solar cells. Within this new family of semiconductors, Cs2BiAgCl6 and Cs2BiAgBr6 are stable compounds crystallizing in the elpasolite structure. Following the recent computational discovery and experimental synthesis of these compounds, a detailed investigation of their electronic properties is warranted in order to establish their potential as optoelectronic materials. In this work, we perform many-body perturbation theory calculations and obtain high accuracy band gaps for both compounds. In addition, we report on the synthesis of Cs2BiAgBr6 single crystals, which are stable in ambient conditions. From our complementary theoretical and experimental analysis, we are able to assign the indirect character of the band gaps and obtain both experimental and theoretical band gaps of these novel semiconductors that are in close agreement.

Novotna, L., Kuchtik, J., Sustova, K., Zapletal, D. and Filipcik, R. 2009. Effects of lactation stage and parity on milk yield, composition and properties of organic sheep milk. J. Appl. Anim. Res., 36: 71–76. Effects of lactation stage (LS) and parity (PA) on daily milk yield (DMY), composition, properties and rennet curd quality (RCQ) of organic sheep milk were evaluated using 10 crossbred ewes reared on an organic sheep farm. Both LS and PA as well as the interaction of LS × PA had a significant effect on DMY and the contents of total solids, fat, protein, casein and lactose. The DMY for the whole lactation increased with the order of lactation. LS, PA and the interaction of LS × PA also had a significant effect on all milk properties as well as the RCQ. In the course of all lactations, titrable acidity (TA) kept increasing. It was found that the higher the values of titrable acidity, the longer the rennet clotting time became and RCQ became worse.

This study reassessed the clinical effect of Circulator Boot (CB) therapy in patients with cholesterol embolization syndrome (CES) of the lower extremities. The medical records were reviewed of 27 patients consecutively referred to the Bryn Mawr Wound Care and Vascular Center with CES who had not responded to previous therapies. All patients with CES referred from January 1, 1997, to September 19, 2005, were followed up and included in the study. The alternate therapy offered for most patients at the time of referral was limb amputation. The median age of the patients was 65 years (age range, 46-84 years) at the time of diagnosis. Healing of CES was observed after a median interval of 11 months (range, 3-32 months) following the initiation of CB therapy. The total number of legs treated was 41. Of 41 legs, 33 (81%) were totally healed, 6 (15%) improved, and 2 (5%) were amputated. After an initial period of improvement, one patient died a month later of causes unrelated to CES or CB therapy. Another patient improved and discontinued treatment before he was totally healed. Cholesterol embolization syndrome is seen predominantly in patients following cardiac or vascular procedures but may occur spontaneously. The CB seems to be the only effective noninvasive therapy for CES. Early initiation of therapy is essential to minimize tissue loss and patient discomfort.

Lead-based halide perovskites are emerging as the most promising class of materials for next generation optoelectronics. However, despite the enormous success of lead-halide perovskite solar cells, the issues of stability and toxicity are yet to be resolved. Here we report on the computational design and the experimental synthesis of a new family of Pb-free inorganic halide double-perovskites based on bismuth or antimony and noble metals. Using first-principles calculations we show that this hitherto unknown family of perovskites exhibits very promising optoelectronic properties, such as tunable band gaps in the visible range and low carrier effective masses. Furthermore, we successfully synthesize the double perovskite Cs2BiAgCl6, we perform structural refinement using single-crystal X-ray diffraction, and we characterize its optical properties via optical absorption and photoluminescence measurements. This new perovskite belongs to the Fm-3m space group, and consists of BiCl6 and AgCl6 octahedra alternating in a rock-salt face-centered cubic structure. From UV-Vis and PL measurements we obtain an indirect gap of 2.2 eV. The new compound is very stable under ambient conditions., Comment: GV and MRF contributed equally to this work

We use a layered solution crystal growth technique to synthesize high-quality single crystals of phenylalkylammonium lead iodide organic/inorganic hybrid compounds. Single-crystal X-ray diffraction reveals low-dimensional structures consisting of inorganic sheets separated by bilayers of the organic cations. The shortest alkyls yield two-dimensional structures consisting of inorganic sheets of corner-sharing PbI6-octahedra. However, the longer alkyls induce both corner- and face-sharing of the PbI6-octahedra, and form new compounds. Density functional theory calculations including spin-orbit coupling show quantum confinement in two dimensions for the shorter alkyls, and in one dimension for the longer alkyls, respectively. The face-sharing PbI6-octahedra create a confinement leading to effectively one-dimensional behavior. These confinement effects are responsible for the observed peak shifts in photoluminescence for the different phenylalkylammonium lead iodide hybrids. Our results show how the connectivity of the octahedra leads to confinement effects that directly tune the optical band gap.

The relation of total polyphenol content and dynamical astringency was investigated on infusions of yerba mate (YM) (Ilex paraguariensis St. Hilaire), a mild stimulant beverage habitually consumed in South America. YM is a heterogeneous mixture of leaves and small sticks giving place to the types with sticks (YM-S) and without sticks (YM-L) according to the composition. Phytochemical and sensory analysis on three brands of each YM type were performed in order to know if there are differences between types and among brands of the same type. Total polyphenol content, determined by spectrophotometry in six YM infusions at 5% w/v, showed that chlorogenic acid levels were higher for two brands of the YM-L type. Time–intensity (TI) curves revealed that infusions prepared with YM-S lowered their maximal perceived astringency. Neither the type nor the brand of YM assessed affected temporal parameters of astringency TI curves. PRACTICAL APPLICATIONS Dynamic sensory analysis showed its effectiveness to reflect differences in astringent perception of infusions of yerba mate (Ilex paraguariensis St. Hilaire); the presence of sticks in this commodity lowered maximum intensity of astringency. No significant differences were found between these infusions for the remaining time–intensity parameters evaluated.

This study has evaluated the effect of phytohaemagglutinin (PHA) in combination with alpha-ketoglutaric acid (AKG), on GI-tract morphology and N balance in adult rats. Rats, aged approx. 15 months, were assigned to one of four experimental groups, (1) Control group, (2) AKG group, (3) AKG+PHA 100% group and (4) AKG+PHA 1% group. AKG and AKG+PHA were administered via a stomach tube. Rats were treated for a period of 7 days before being killed humanely. Lighter GI-tract weights were found in the AKG and AKG+PHA 1% groups (6.8%, p

In this work, we investigate the vibrational properties of the hybrid organic/inorganic halide perovskite MAPbI3 (MA = CH3NH3) in the range 6-3500 cm-1 by combining first-principles density-functional perturbation theory calculations and low-temperature infrared (IR) absorption measurements on evaporated perovskite films. By using a group factor analysis, we establish the symmetry of the normal modes of vibration and predict their IR and Raman activity. We validate our analysis via explicit calculation of the IR intensities. Our calculated spectrum is in good agreement with our measurements. By comparing theory and experiment, we are able to assign most of the features in the IR spectrum. Our analysis shows that the IR spectrum of MAPbI3 can be partitioned into three distinct regions: the internal vibrations of the MA cations (800-3100 cm-1), the cation librations (140-180 cm-1), and the internal vibrations of the PbI3 network (

Antimony sulphide ${\mathrm{Sb}}_{2}{\mathrm{S}}_{3}$ has emerged as a promising material for a variety of energy applications ranging from solar cells to thermoelectrics and solid-state batteries. The most distinctive feature of ${\mathrm{Sb}}_{2}{\mathrm{S}}_{3}$ is its crystal structure, which consists of parallel 1-nm-wide ribbons held together by weak van der Waals forces. This structure clearly suggests that it should be possible to isolate individual ${\mathrm{Sb}}_{2}{\mathrm{S}}_{3}$ ribbons using micromechanical or liquid-phase exfoliation techniques. However, it is not clear yet how to identify the ribbons postexfoliation using standard optical probes. Using state-of-the-art first-principles calculations based on many-body perturbation theory, here we show that individual ribbons of ${\mathrm{Sb}}_{2}{\mathrm{S}}_{3}$ carry optical signatures clearly distinct from those of bulk ${\mathrm{Sb}}_{2}{\mathrm{S}}_{3}$. In particular, we find a large blueshift of the optical absorption edge (from 1.38 to 2.30 eV) resulting from the interplay between a reduced screening and the formation of bound excitons. In addition, we observe a transition from an indirect band gap to a direct gap, suggesting an enhanced photoluminescence in the green. These unique fingerprints will enable extending the research on van der Waals materials to the case of one-dimensional chalchogenides.

In the last decades, a new interest in active components of phytodrugs as well as in the control of their quality has pointed out new ways to identify and characterize natural plants which, till present, did not fulfill the claimed specifications—Valerians among them. Valerians exhibit numerous and traditional medical uses. In this paper, the use of an electronic nose to discriminate different varieties of Valerians, was investigated. The principal species— valeriana officinalis (VO) and valeriana wallichii (VW)—with different origins and, in some cases, different years of crop, were clearly separated with the electronic nose. The fact that valeric acid is present in VO variety and not in the VW and that there are differences in the valepotriates concentration in both varieties, determined the importance of discriminating both species, since they are active components exhibiting different therapeutic effect. The electronic nose has demonstrated to be a fast and effective tool to separate both species, giving besides other interesting results. Chemical chromatographic analysis was performed enabling the identification of species separated by the electronic nose.

Background: Ilex paraguariensis St. Hilaire (Aquifoliaceae) (“Mate” or “Yerba mate”) is one of the most commercialized plants of South America which grows naturally in NE Argentina, Uruguay, SE Brazil and E Paraguay, where it is also cultivated. It is used to prepare a tea-like beverage (infusions or decoctions) appreciated for its peculiar flavor, stimulation and nutritional properties. Ilex brevicuspis Reisseck grows in the same habitat and is widely used as a substitute or adulterant of Ilex paraguariensis. In a previous work, methylxanthines (caffeine, theobromine and theophylline) were not detected in it by HPLC. Aim of the study: This study was undertaken in order to isolate, identify and quantify the polyphenolic compounds (caffeoyl derivatives and flavonoids) and to investigate some of the pharmacological activities of I. brevicuspis, related with the traditional use of the “Mate” (choleretic, intestinal propulsion and antioxidant activities). Acute toxicity was also investigated. Methods: Decoctions, like extracts, were prepared in order to compare the results with preparations commonly used by the local people. For the phytochemical analysis, the extracts were analyzed by HPLC with a diode array detector. Choleretic and intestinal propulsion activities were assayed in rats. Sodium dehydrocholate (DHC) was used as a choleretic reference standard. Antioxidant activity was tested in liposomes that were oxidized by the free radical generator 2,2'-azobis [amidinopropane] chloride (AAPH). Results: For the first time in I. brevicuspis the following compounds were isolated and quantified: A) caffeoyl derivative compounds (chlorogenic acid; caffeic acid; 3,4-dicaffeoylquinic acid; 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid. B) flavonoids (rutin, quercetin and kaempferol). Biological activity assays demonstrated that I. brevicuspis extracts produced a significant increase of bile flow (BF) in rats in the first 30 min period and in the percentage of BF increase accumulated at 120 min. It also produced an increase in the intestinal propulsion activity. Moreover, this species showed a high antioxidant activity. The acute toxicity test showed that Ilex brevicuspis did not produce any sign of toxicity at the analyzed doses. Conclusions: An Argentinean Ilex specie (I. brevicuspis) has choleretic, intestinal propulsion, antioxidant activities and these results may lead to the potential development of a new “Yerba Mate” and/or phytopharmaceutical products, without central nervous system (CNS) stimulant activity.

International audience; Objectives: Osteoporosis is a skeletal disorder characterized by impaired bone turnover and compromised bone strength, thereby predisposing to increased risk of fracture. Preclinical research has shown that compounds produced by the olive tree ( Olea europaea), may protect from bone loss, by increasing osteoblast activity at the expense of adipocyte formation. The aim of this exploratory study was to obtain a first insight on the effect of intake of an olive extract on bone turnover in postmenopausal women with decreased bone mass ( osteopenia). Design and setting: For that, a double blind, placebo-controlled study was performed in which participants were randomly allocated to either treatment or placebo groups. Participants: 64 osteopenic patients, with a mean bone mineral density ( BMD) T-score between -1.5 and -2.5 in the lumbar spine ( L2-L4) were included in the study. Intervention and measurements: Participants received for 12 months daily either 250 mg/day of olive extract and 1000 mg Ca ( treatment) or 1000 mg Ca alone ( placebo). Primary endpoints consisted of evaluation of bone turnover markers. Secondary endpoints included BMD measurements and blood lipid profiles. Results: After 12 months, the levels of the pro-osteoblastic marker osteocalcin were found to significantly increase in the treatment group as compared to placebo. Simultaneously, BMD decreased in the placebo group, while remaining stable in the treatment group. In addition, improved lipid profiles were observed, with significant decrease in total- and LDL-cholesterol in the treatment group. Conclusion: This exploratory study supports preclinical observations and warrants further research by showing that a specific olive polyphenol extract ( Bonolive(R)) affects serum osteocalcin levels and may stabilize lumbar spine BMD. Moreover, the improved blood lipid profiles suggest additional health benefits associated to the intake of the olive polyphenol extract.