A 2D ferroelectric vortex pattern in twisted BaTiO3 freestanding layers

The wealth of complex polar topologies1-10 recently found in nanoscale ferroelectrics results from a delicate balance between the intrinsic tendency of the materials to develop a homogeneous polarization and the electric and mechanical boundary conditions imposed on them. Ferroelectric-dielectric interfaces are model systems in which polarization curling originates from open circuit-like electric boundary conditions, to avoid the build-up of polarization charges through the formation of flux-closure11-14 domains that evolve into vortex-like structures at the nanoscale15-17 level. Although ferroelectricity is known to couple strongly with strain (both homogeneous18 and inhomogeneous19,20), the effect of mechanical constraints21 on thin-film nanoscale ferroelectrics has been comparatively less explored because of the relative paucity of strain patterns that can be implemented experimentally. Here we show that the stacking of freestanding ferroelectric perovskite layers with controlled twist angles provides an opportunity to tailor these topological nanostructures in a way determined by the lateral strain modulation associated with the twisting. Furthermore, we find that a peculiar pattern of polarization vortices and antivortices emerges from the flexoelectric coupling of polarization to strain gradients. This finding provides opportunities to create two-dimensional high-density vortex crystals that would enable us to explore previously unknown physical effects and functionalities.

Patient-reported outcomes before treatment for localized prostate cancer: are there differences among countries? Data from the True North Global Registry

INTRODUCTION

Similar Patient-Reported Outcomes (PROs) at diagnosis for localized prostate cancer among countries may indicate that different treatments are recommended to the same profile of patients, regardless the context characteristics (health systems, medical schools, culture, preferences…). The aim of this study was to assess such comparison.

METHODS

We analyzed the EPIC-26 results before the primary treatment of men diagnosed of localized prostate cancer from January 2017 onwards (revised data available up to September 2019), from a multicenter prospective international cohort including seven regions: Australia/New Zealand, Canada, Central Europe (Austria / Czech Republic / Germany), United Kingdom, Italy, Spain, and the United States. The EPIC-26 domain scores and pattern of three selected items were compared across regions (with Central Europe as reference). All comparisons were made stratifying by treatment: radical prostatectomy, external radiotherapy, brachytherapy, and active surveillance.

RESULTS

The sample included a total of 13,483 men with clinically localized or locally advanced prostate cancer. PROs showed different domain patterns before treatment across countries. The sexual domain was the most impaired, and the one with the highest dispersion within countries and with the greatest medians' differences across countries. The urinary incontinence domain, together with the bowel and hormonal domains, presented the highest scores (better outcomes) for all treatment groups, and homogeneity across regions.

CONCLUSIONS

Patients with localized or locally advanced prostate cancer undergoing radical prostatectomy, EBRT, brachytherapy, or active surveillance presented mainly negligible or small differences in the EPIC-26 domains before treatment across countries. The results on urinary incontinence or bowel domains, in which almost all patients presented the best possible score, may downplay the baseline data role for evaluating treatments' effects. However, the heterogeneity within countries and the magnitude of the differences found across countries in other domains, especially sexual, support the need of implementing the PRO measurement from diagnosis.

Challenges and opportunities to prevent tuberculosis in people living with HIV in low-income countries

People living with the human immunodeficiency virus (HIV) (PLHIV) are at high risk for tuberculosis (TB), and TB is a major cause of death in PLHIV. Preventing TB in PLHIV is therefore a key priority. Early initiation of antiretroviral therapy (ART) in asymptomatic PLHIV has a potent TB preventive effect, with even more benefits in those with advanced immunodeficiency. Applying the most recent World Health Organization recommendations that all PLHIV initiate ART regardless of clinical stage or CD4 cell count could provide a considerable TB preventive benefit at the population level in high HIV prevalence settings. Preventive therapy can treat tuberculous infection and prevent new infections during the course of treatment. It is now established that isoniazid preventive therapy (IPT) combined with ART among PLHIV significantly reduces the risk of TB and mortality compared with ART alone, and therefore has huge potential benefits for millions of sufferers. However, despite the evidence, this intervention is not implemented in most low-income countries with high burdens of HIV-associated TB. HIV and TB programme commitment, integration of services, appropriate screening procedures for excluding active TB, reliable drug supplies, patient-centred support to ensure adherence and well-organised follow-up and monitoring that includes drug safety are needed for successful implementation of IPT, and these features would also be needed for future shorter preventive regimens. A holistic approach to TB prevention in PLHIV should also include other important preventive measures, such as the detection and treatment of active TB, particularly among contacts of PLHIV, and control measures for tuberculous infection in health facilities, the homes of index patients and congregate settings.

Latin American Study of Hereditary Breast and Ovarian Cancer LACAM: A Genomic Epidemiology Approach

Purpose: Hereditary Breast and Ovarian Cancer (HBOC) syndrome is responsible for ~5-10% of all diagnosed breast and ovarian cancers. Breast cancer is the most common malignancy and the leading cause of cancer-related mortality among women in Latin America (LA). The main objective of this study was to develop a comprehensive understanding of the genomic epidemiology of HBOC throughout the establishment of The Latin American consortium for HBOC-LACAM, consisting of specialists from 5 countries in LA and the description of the genomic results from the first phase of the study. Methods: We have recruited 403 individuals that fulfilled the criteria for HBOC from 11 health institutions of Argentina, Colombia, Guatemala, Mexico and Peru. A pilot cohort of 222 individuals was analyzed by NGS gene panels. One hundred forty-three genes were selected on the basis of their putative role in susceptibility to different hereditary cancers. Libraries were sequenced in MiSeq (Illumina, Inc.) and PGM (Ion Torrent-Thermo Fisher Scientific) platforms. Results: The overall prevalence of pathogenic variants was 17% (38/222); the distribution spanned 14 genes and varied by country. The highest relative prevalence of pathogenic variants was found in patients from Argentina (25%, 14/57), followed by Mexico (18%, 12/68), Guatemala (16%, 3/19), and Colombia (13%, 10/78). Pathogenic variants were found in BRCA1 (20%) and BRCA2 (29%) genes. Pathogenic variants were found in other 12 genes, including high and moderate risk genes such as MSH2, MSH6, MUTYH, and PALB2. Additional pathogenic variants were found in HBOC unrelated genes such as DCLRE1C, WRN, PDE11A, and PDGFB. Conclusion: In this first phase of the project, we recruited 403 individuals and evaluated the germline genetic alterations in an initial cohort of 222 patients among 4 countries. Our data show for the first time in LA the distribution of pathogenic variants in a broad set of cancer susceptibility genes in HBOC. Even though we used extended gene panels, there was still a high proportion of patients without any detectable pathogenic variant, which emphasizes the larger, unexplored genetic nature of the disease in these populations.

Abstract 4166: Hereditary cancer syndromes in Guatemalan population

BACKGROUND The majority of cancer are sporadic, only around 5 % are considered hereditary. Although it is a low percentage, the study of these cancers are of vital importance, since they require a special clinical monitoring and management. These kind of cancers are caused by the presence of an inherited gene mutation, which increase the risk of developing a tumor. The mutations associated with these tumors are germline mutations, this means that are present in all the patient's cells, including the egg cell an sperm; this is the reason why this type of cancer can transmit to the future generations. There are many syndromes that increase the risk of hereditary cancer development, the most frequent syndromes are: Familial Breast and Ovarian cancer (BRCA1 and BRCA2 gene mutations), Lynch syndrome (MSH2, MLH1, MSH6 and PMS2 mutations), Li-Fraumeni syndrome (TP53 gene mutations) and Familial adenomatous polyposis (APC gene mutations). The aim of this study is to screen the most common hereditary cancer syndromes in Guatemalan population.

METHODS We analyzed 199 blood samples of patients with different types of tumors. We extracted DNA from the samples and then analyzed the gene mutations by next generation sequencing.

RESULTS AND DISCUSSION We have included in the present study, 93 cases with Familial Breast cancer and 106 with another type of tumors. Of all cases, we have found 17 cases with hereditary cancer syndromes (8%). The most frequent is the Breast and Ovarian hereditary syndrome caused by BRCA1 and BRCA2 (12 patients). The other hereditary cancer syndromes are shown in Table 1. The detection of this germline mutations, have a large impact in the familial cases, because these patients and their families could be monitored and evaluated more frequently. This is the first report of these syndromes in our population.

CONCLUSION We reported 6 different syndromes and 17 cases, related to hereditary cancer risk and predisposition in Guatemalan population.

Frequency of hereditary cancer syndromesSYNDROMENUMBER OF PATIENTSCANCER TYPEAGESEXGENE MUTATIONBreast and ovarian hereditary syndrome7Breast cancer29-48FBRCA1Breast and ovarian hereditary syndrome5Breast cancer29-71FBRCA2Lynch syndrome1Breast cancer80FMSH6Li-Fraumeni syndrome1Breast cancer58FTP53Breast hereditary cancer1Breast cancer57FCDH1Peutz-Jeghers syndrome1Pancreatic cancer15FSTK11Familial adenomatous polyposis1Colorectal cancer13MAPC

Citation Format: Claudia L. Carranza, Mariela Guerra, Claudia Osorio, Vanessa Zamora, Vivian Herrera, Jose Gil, Luis Alvarez. Hereditary cancer syndromes in Guatemalan population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4166.

Determination of Anti-Anisakis Simplex Antibodies and Relationship with αβ and γδ Lymphocyte Subpopulations in Patients with Crohn's Disease

BACKGROUND

The etiology of Crohn's disease (CD) is still unknown although new theories are based on defects in innate immunity. We have previously shown a decrease in γδ T cells in CD patients. Previous studies have shown a high prevalence of anti-A. simplex immunoglobulins in CD patients. The diminution of γδ T cells in the peripheral blood and intestinal mucosa of CD patients may create a state of immunosuppression that would facilitate A. simplex infection.

AIMS

To study the antibody responses to Anisakis antigens in Crohn's disease patients and its relationship with αβ and γδ T cell subsets.

METHODS

We recruited 81 CD patients and 81 healthy controls. αβ and γδ T cell subsets and anti-A. simplex antibodies were measured.

RESULTS

Levels of anti-A. simplex IgG and IgM were significantly increased in CD patients. Almost 20% of CD patients were positive for IgG and IgM anti-A. simplex versus only 3.7 and 2.5%, respectively, in normal subjects. However, lower specific IgA levels were observed in the group of CD patients versus healthy subjects. We found an association between CD3 + CD8 + γδ subset and IgM anti-A. simplex levels. In ileal cases and stricturing behavior of CD, we observed the highest levels of specific antibodies with the exception of anti-A. simplex IgA.

CONCLUSIONS

The relationship of specific antibodies with a γδ T cell deficiency makes these cell candidates to play a role in the immune response against Anisakis. In addition, anti-Anisakis antibodies could be considered as markers of risk of progression in CD.

The Use of Ratiometric Fluorescence Measurements of the Voltage Sensitive Dye Di-4-ANEPPS to Examine Action Potential Characteristics and Drug Effects on Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) and higher throughput platforms have emerged as potential tools to advance cardiac drug safety screening. This study evaluated the use of high bandwidth photometry applied to voltage-sensitive fluorescent dyes (VSDs) to assess drug-induced changes in action potential characteristics of spontaneously active hiPSC-CM. Human iPSC-CM from 2 commercial sources (Cor.4U and iCell Cardiomyocytes) were stained with the VSD di-4-ANEPPS and placed in a specialized photometry system that simultaneously monitors 2 wavebands of emitted fluorescence, allowing ratiometric measurement of membrane voltage. Signals were acquired at 10 kHz and analyzed using custom software. Action potential duration (APD) values were normally distributed in cardiomyocytes (CMC) from both sources though the mean and variance differed significantly (APD90: 229 ± 15 ms vs 427 ± 49 ms [mean ± SD, P < 0.01]; average spontaneous cycle length: 0.99 ± 0.02 s vs 1.47 ± 0.35 s [mean ± SD, P < 0.01], Cor.4U vs iCell CMC, respectively). The 10-90% rise time of the AP (Trise) was ∼6 ms and was normally distributed when expressed as 1/[Formula: see text] in both cell preparations. Both cell types showed a rate dependence analogous to that of adult human cardiac cells. Furthermore, nifedipine, ranolazine, and E4031 had similar effects on cardiomyocyte electrophysiology in both cell types. However, ranolazine and E4031 induced early after depolarization-like events and high intrinsic firing rates at lower concentrations in iCell CMC. These data show that VSDs provide a minimally invasive, quantitative, and accurate method to assess hiPSC-CM electrophysiology and detect subtle drug-induced effects for drug safety screening while highlighting a need to standardize experimental protocols across preparations.

Empiric narrowing of the net energy value of reduced-oil corn distillers’ dried grain with solubles for growing-finishing pigs

Smit, M. N., Zamora, V., Young, M. G., Campbell, N., Uttaro, B. and Beltranena, E. 2015. Empiric narrowing of the net energy value of reduced-oil corn distillers’ dried grain with solubles for growing-finishing pigs. Can. J. Anim. Sci. 95: 225–241. This study attempted to empirically narrow down the net energy (NE) value of reduced-oil corn distillers’ dried grains and solubles (RO-cDDGS) by evaluating the response in pig growth performance, live backfat and loin depth, carcass traits, and primal pork cuts tissue composition to feeding diets formulated increasing the assumed NE value of RO-cDDGS, expecting a brisk change in slope of the response at the point at which the NE value of RO-cDDGS would be identified. In total, 1056 cross-bred pigs (31.7 kg) housed in 48 pens by gender were fed dietary regimens including 30% RO-cDDGS (6.7% ether extract) with assumed NE values of 1.7, 1.85, 2.0, 2.15, 2.3, or 2.45 Mcal kg−1over five growth periods (Grower 1: days 0–21, Grower 2: days 22–42, Grower 3: days 43–63, Finisher 1: days 64–76, Finisher 2: day 77 to market weight). Pig body weights were measured and feed disappearance (ADFI) was calculated by pen on days 0, 21, 42, 63, 76 and weekly thereafter until target slaughter weight (120 kg). For the entire trial (days 0–76), increasing the assumed NE value of RO-cDDGS linearly increased (P<0.01) ADFI and total lysine intake, did not affect NE intake and daily weight gain (ADG), quadratically decreased (P<0.05) feed efficiency, linearly decreased (P<0.05) live backfat depth and backfat:loin depth ratio, and did not affect carcass characteristics or pork primal cut tissue composition. Segmented regression only identified a change in slope for carcass ADG and lean ADG at 1.85 Mcal kg−1. These results indicate that the experimental approach taken was not reliable in narrowing down the NE value of RO-cDDGS because the decrease in dietary NE was too small (0.03 Mcal kg−1d), which limited the change in dietary Lys:NE ratio with increasing assumed NE value of RO-cDDGS. The approach resulted in progressive, but small changes in slope rather than a clearly identifiable point where one could conclude that the incremental dietary energy contribution from RO-cDDGS changed the response in a given variable.

Bioactive lipid profiling reveals drug target engagement of a soluble epoxide hydrolase inhibitor in a murine model of tobacco smoke exposure

The inflammatory process underlying chronic obstructive pulmonary disease (COPD) may be caused by tobacco smoke (TS) exposure. Previous studies show that epoxyeicosatrienoic acids (EETs) possess promising anti-inflammatory properties, therefore stabilization of EETs and other fatty acid epoxides through inhibition of soluble epoxide hydrolase (sEH) was investigated in mouse models of acute and sub-chronic inflammation caused by TS exposure. During the entire TS exposure, the potent sEH inhibitor 1-(1-methylsulfonyl-piperidin-4-yl)-3-(4-trifluoromethoxy-phenyl)-urea (TUPS) was given via drinking water. To assess drug target engagement of TUPS, a tandem mass spectrometry method was used for bioactive lipid profiling of a broad range of fatty acid metabolites, including EETs, and their corresponding diols (DHETs) derived from arachidonic acid, as well as epoxides and diols derived from other fatty acids. Several, but not all, plasma epoxide/diol ratios increased in mice treated with sEH inhibitor, compared to non-treated mice suggesting a wider role for sEH involving more fatty acid precursors besides arachidonic acid. This study supports qualitative use of epoxide/diol ratios explored by bioactive lipid profiling to indicate drug target engagement in mouse models of TS exposure relevant to COPD, which may have ramifications for future therapeutic interventions of sEH.

Predicting fat quality from pigs fed reduced-oil corn dried distillers grains with solubles by near infrared reflectance spectroscopy: fatty acid composition and iodine value

This study tested the ability of near infrared reflectance spectroscopy (NIRS) to estimate the fatty acid (FA) composition and iodine value (IV) of backfat from carcasses of pigs fed reduced-oil corn dried distillers grains with solubles. NIRS was suitable for screening purposes for the proportions of total saturated, monounsaturated, polyunsaturated, n-3 and n-6 FAs and some individual FAs such as C16:0, C18:1, C18:2n-6 and C18:3n-3 (R(2)=0.80-0.89; RMSECVs, root mean square errors of cross-validation=0.21-1.37% total FA) in both cold and warm intact backfat samples. This technology also met the requirements for a quick screening for the backfat IV in both cold and warm intact samples (R(2)=0.90 and 0.87; RMSECVs=1.66 and 1.80% total FA, respectively), which would help provide differential feed-back to pig producers and the feed industry and may provide the opportunity for breeding pigs for a desirable fat quality.

Feeding increasing dietary inclusions of extrudedBrassica junceacanola expeller-pressed cake on growth performance, carcass characteristics, and jowl fatty acids of growing-finishing pigs

Zhou, X., Young, M. G., Zamora, V., Zijlstra, R. T. and Beltranena, E. 2014. Feeding increasing dietary inclusions of extruded Brassica juncea canola expeller-pressed cake on growth performance, carcass characteristics, and jowl fatty acids of growing-finishing pigs. Can. J. Anim. Sci. 94: 331–342. The energy value of canola meal is considered low because of its relatively higher fibre and depleted oil content. Brassica juncea is a novel canola species with thinner seed coat and reduced fibre, but twice the glucosinolate content of B. napus. Remaining oil in canola cake provides greater dietary energy compared with solvent-extracted meal. Extrusion prior to expeller pressing may increase fat and protein digestibility and decrease the antinutritive effects of glucosinolates. A total of 880 pigs (38 kg), housed in 40 pens by sex, were fed 0, 5, 10, 15, or 20% extruded B. juncea expeller-pressed cake (EPC) to slaughter weight (120 kg) to evaluate the effects on growth performance, dressing, carcass traits, and jowl fatty acids. Diets provided 9.6 MJ net energy (NE) and 1.0, 0.9, 0.8, 0.7, and 0.7 g standardized ileal digestible Lys:MJ NE over five growth phases (days 0–14, 15–35, 36–56, 57–74, day 75 to slaughter weight). Each 5% EPC inclusion linearly decreased (P<0.05) feed disappearance (ADFI) by 46 g and weight gain (ADG) by 8 g, but did not affect gain:feed. Each 5% EPC inclusion linearly decreased (P<0.01) carcass weight by 440 g, loin depth by 0.6 mm, and increased days on test by 0.43, but did not affect dressing, backfat thickness, lean yield, or carcass index. Each 5% EPC inclusion linearly increased (P<0.001) mono- and polyunsaturated fatty acid content and iodine value by 0.8, 1.0 and 1.4 g 100 g−1of jowl fat, respectively. In conclusion, increasing dietary EPC inclusions decreased ADFI, ADG, carcass weight, and loin depth, and increased jowl fat unsaturation. We attributed much of the decrease in feed intake to greater 3-butenyl (9.7 µmol g−1) content in extruded B. juncea canola expeller-pressed cake, a glucosinolate more bitter than others in conventional canola.

Investigation of cascaded SiN microring resonators at 1.3 µm and 1.5 µm

An optical device operating at wavelengths around 1.3 µm and 1.5 µm is demonstrated experimentally. It is based on cascaded microring resonators (CMRRs) and the Vernier effect (VE). The architecture consists of two microring resonators (MRRs) connected via a common waveguide; two waveguides were added for the interrogation of CMRRs. The free spectral ranges of both MRRs are slightly different in order to activate the VE, which is known to enhance the sensitivity in optical sensors. CMRRs were fabricated on a silicon nitride (SiN) platform. Two types of buffer layers-benzocyclobutene (BCB) polymer and thermal silicon oxide (SiOx)-were tested. A study of CMRRs was carried out with three structures of different structural parameters. The experimental results show good agreement with the theoretical analysis. This approach is promising for the fabrication of highly sensitive optical sensors in wide operating wavelength range.

Probiótico (enterococcus faecium) adicionado a dietas estándar y con baja proteína para cerdos

Se evaluó el comportamiento productivo (ganancia diaria de peso, GDP; consumo de alimento, COA; conversión alimenticia, CA; ganancia de carne magra, GCM), las características de la canal (área del músculo Longissimus, AML; grasa dorsal, GD; porcentaje de carne magra, CM), la concentración de urea en plasma, y la población microbiana en heces de 36 cerdos machos castrados híbridos (Yorkshire×Duroc×Pietrain) en iniciación (11,10 ± 0,51 kg), crecimiento (25,75 ± 1,13 kg), y finalización (51,03 ± 2,20 kg), en respuesta a dos niveles de proteína bruta (PB; iniciación: 20,5 y 16,0 %; crecimiento: 16,0 y 14,5 %; y finalización: 14,0 y 12,5 %) y dos niveles del probiótico (PRO) Enterococcus faecium (0,0 y 1,0 kg t-1 de alimento en cada etapa) en dietas sorgo-pasta de soya, en un diseño completamente al azar con arreglo factorial 2×2, con 9 repeticiones por tratamiento. La energía se mantuvo constante en 3,265 Mcal kg-1. En iniciación, la adición del PRO redujo (p£0,05) el AML, pero no afectó (p>0,05) otras variables en estudio; la urea en plasma disminuyó (p£0,05) en cerdos alimentados con baja proteína. En crecimiento y finalización, al reducir la PB disminuyó (p£0,01) la urea en plasma, pero no afectó (p>0,05) otras variables. Agregar PRO aumentó (p£0,05) la concentración de Enterococcus y el total de bacterias en heces en todas las etapas. Estos resultados indican que agregar PRO aumenta la población microbiana total y de Enterococcus, pero no afecta la respuesta productiva, las características de la canal, ni la concentración de urea en plasma de cerdos alimentados con dietas estándar o con baja proteína.

Effect of amino acids supply in reduced crude protein diets on performance, efficiency of mammary uptake, and transporter gene expression in lactating sows

To test the hypothesis that reduction in dietary CP concentration coupled with crystalline AA inclusion increases the efficiency of AA use for milk production, mammary AA arteriovenous concentration differences (A-V), AA transport efficiency (A-V/A × 100), and transcript abundance of AA transporters and milk protein genes were determined in lactating sows fed 1 of 3 diets containing 9.5% (Deficient), 13.5% (Ideal), or 17.5% (Standard) CP, with a similar profile of indispensable and dispensable AA. On d 7 and 18, arterial and mammary venous blood and mammary tissue were sampled postfeeding. Transcript abundance of AA transporters b(0,+)AT (SLC7A9), y(+)LAT2 (SLC7A6), ATB(0,+) (SLC6A14), CAT-1 (SLC7A1), and CAT-2b (SLC7A2) and milk protein β-casein (CSN2) and LALBA (α-lactalbumin) were determined using reverse transcription quantitative PCR. Piglet ADG increased curvilinearly (linear and quadratic, P < 0.03) with increasing percent CP from Deficient to Standard. On d 7, Lys and Arg A-V and transport efficiency increased quadratically (P < 0.05) with increasing percent CP. On d 18, Lys A-V tended to increase (linear, P = 0.08) with increasing percent CP. Increasing CP increased Ile and Val A-V on d 7 (linear, P = 0.05 and P = 0.08, respectively) and Leu and Val on d 18 (linear, P = 0.07 and P = 0.04, respectively). On d 7, plasma concentrations of branched chain AA (BCAA):Lys decreased quadratically (P < 0.05). Expression of genes SLC7A9, SLC7A6, SLC6A14, SLC7A1, SLC7A2, CSN2, and LALBA was unaffected by diet. In conclusion, decreasing the dietary CP from 17.5% to 13.5% with inclusion of crystalline AA did not affect piglet ADG, AA transporter, or milk protein gene expression but increased mammary transport efficiency and A-V of Lys and Arg on d 7 of lactation. This increase was associated with a decrease in plasma concentration of BCAA:Lys, suggesting a competitive mechanism between cationic and BCAA for transport of AA across mammary cells.

Refractometric sensing with fluorescent-core microcapillaries

Capillaries present a promising structure for microfluidic refractive index sensors. We demonstrate a capillary-type fluorescent core microcavity sensor based on whispering gallery mode (WGM) resonances. The device consists of a microcapillary having a layer of fluorescent silicon quantum dots (QDs) coated on the channel surface. The high effective index of the QD layer confines the electric field near the capillary channel and causes the development of WGM resonances in the fluorescence spectrum. Solutions consisting of sucrose dissolved in water were pumped through the capillary while the fluorescence WGMs were measured with a spectrometer. The device showed a refractometric sensitivity of 9.8 nm/RIU (up to 13.8 nm/RIU for higher solution refractive index) and a maximum detection limit of ~7.2 x 10(-3) RIU. Modeling the field inside the capillary structure, which is analogous to a layered hollow ring resonator, shows that sensitivities as high as 100 nm/RIU and detection limits as low as ~10(-5) RIU may be achievable by optimizing the QD film thickness.

Excitation and interrogation of whispering-gallery modes in optical microresonators using a single fused-tapered fiber tip

We show that whispering-gallery modes (WGMs) in optical microresonators can be excited and detected using a fused-tapered fiber tip (FTFT). The fabrication of FTFTs is simple and inexpensive; they are robust and allow the excitation and interrogation of the resonances with a single fiber. Excitation of high-Q WGMs in silica microcylinders and microspheres is demonstrated.

Immunohistochemical expression of somatostatin receptors in digestive endocrine tumours

INTRODUCTION

Somatostatin receptors are expressed in a large number of human tumours. The somatostatin receptors types 1-5 expression in a series including 100 gastro-entero-pancreatic endocrine tumours were analysed.

METHODS

From a prospectively built database of patients with gastro-entero-pancreatic endocrine tumours referred from three institutions, 100 cases with clinical and pathological data were selected. Somatostatin receptors expression by immunohistochemistry with somatostatin receptor types 1-5 antibodies in tissue paraffin sections were studied and correlated with the histological diagnosis according to the WHO classification, location and functional status.

RESULTS

Of the 100 cases, 67 were gastrointestinal tumours, 25 pancreatic and 8 liver metastasis of unknown origin. Thirty-one of them were functioning tumours: 2 insulinomas, 5 gastrinomas, 1 glucagonoma and 23 carcinoids. Somatostatin receptors expression was observed in 94 tumours. The six negative cases were all non-functioning tumours. Somatostatin receptors 2a and 5 were highly expressed (86 and 62%, respectively), and surprisingly found even in poorly differentiated endocrine carcinomas. Somatostatin receptors expression was less frequent in pancreatic than in gastrointestinal tumours. Well-differentiated neoplasms had a higher density of somatostatin receptors. Only SSTR2a showed membrane staining.

CONCLUSIONS

Immunohistochemistry revealed that somatostatin receptors were highly expressed in both primary and metastatic gastro-entero-pancreatic endocrine tumours with heterogeneous staining distribution. It proved to be a reliable technique even in small tumour samples.

Interrogation of whispering-gallery modes resonances in cylindrical microcavities by backreflection detection

The excitation of whispering-gallery-mode resonances of cylindrical microcavities, using narrow fiber tapers, produces simultaneously the excitation of spiral modes. The power coupled to the spiral modes leads to a significant broadening of the dips observed in the spectrum of light transmitted through the taper. We demonstrate that whispering-gallery modes resonances of cylindrical microcavities can also be interrogated by measuring the reflection spectrum. Unlike the dips observed in transmission, the peaks in the reflection spectrum are symmetric and narrower than the corresponding transmission dips.

Niveles de Lisina y Treonina digestible en dietas Sorgo-pasta de Soya para cerdos en crecimiento

Se evaluó el efecto de diferentes niveles de lisina y treonina en dietas sorgo-pasta de soya para cerdos en crecimiento, sobre el comportamiento productivo, las carácterísticas de la canal y la concentración de nitrógeno de la urea plasmática (NUP). En el experimento 1 se evaluaron cinco niveles de lisina digestible (0,67; 0,75; 0,83; 0,91 y 0,99 %) durante cuatro semanas. Se utilizaron 50 cerdos machos castrados con peso promedio inicial de 22,34 ± 3,45 kg. En el experimento 2 se evaluaron cinco niveles de treonina digestible (0,42; 0,47; 0,52; 0,57 y 0,62%) durante seis semanas. Se utilizaron 50 cerdos (25 machos castrados y 25 hembras) con peso promedio inicial de 24,02 ± 3,73 kg. Los animales fueron distribuidos en un diseño experimental completamente al azar con cinco repeticiones y dos cerdos por unidad experimental. Las variables de respuesta evaluadas en ambos experimentos fueron: consumo diario de alimento (CDA), ganancia diaria de peso (GDP), conversión alimenticia (CA), ganancia de carne magra (GCM), peso final (PF), grasa dorsal (GD), porcentaje de carne magra (%CM), área del músculo longissimus (AML) y NUP. Las variables medidas semanalmente (CDA, GDP y CA), fueron analizadas con PROC MIXED de SAS; las otras variables fueron analizadas con PROC GLM. La comparación de medias se realizó con la prueba de Tukey, y se utilizaron contrastes ortogonales para detectar efectos lineales, cuadráticos y cúbicos. El mejor nivel de lisina digestible para CDA y GDP fue 0,75%; para CA fue 0,91%, y para PF fue de 0,99%. El análisis de contrastes mostró efecto cúbico del nivel de lisina sobre CDA, lineal para CA y cuadrático para AML, %CM y NUP. Los niveles de treonina digestible no afectaron las variables de respuesta productiva, ni las características de la canal; sólo se observó una reducción lineal del NUP al aumentar la treonina digestible. Los machos castrados también redujeron el NUP al aumentar el nivel de treonina digestible en la dieta. Estos resultados indican que el nivel de lisina digestible afecta de manera diferente las variables productivas, las características de la canal, y la concentración de nitrógeno uréico en plasma; y que el nivel de treonina digestible no afecta las variables analizadas aunque se reduce el NUP en cerdos en crecimiento al aumentar la treonina digestible en la dieta.

Refractometric sensor based on whispering-gallery modes of thin capillarie

Whispering-gallery modes resonances of submicron wall thickness capillaries exhibit very large wavelength shifts as a function of the refractive index of the medium that fills the inside. The sensitivity to refractive index changes is larger than in other optical microcavities as microspheres, microdisks and microrings. The outer surface where total internal reflection takes place remains always in air, enabling the measure of refractive index values higher than the refractive index of the capillary material. The fabrication of capillaries with submicron wall thickness has required the development of a specific technique. A refractometer with a response higher than 390 nm per refractive index unit is demonstrated. These sensors are readily compatible with microfluidic systems.