The hessian blob algorithm : precise particle detection in atomic force microscopy imagery

"Received: 20 October 2017; Accepted: 29 December 2017; Published online: 17 January 2018."Imaging by atomic force microscopy (AFM) offers high-resolution descriptions of many biological systems; however, regardless of resolution, conclusions drawn from AFM images are only as robust as the analysis leading to those conclusions. Vital to the analysis of biomolecules in AFM imagery is the initial detection of individual particles from large-scale images. Threshold and watershed algorithms are conventional for automatic particle detection but demand manual image preprocessing and produce particle boundaries which deform as a function of user-defined parameters, producing imprecise results subject to bias. Here, we introduce the Hessian blob to address these shortcomings. Combining a scalespace framework with measures of local image curvature, the Hessian blob formally defines particle centers and their boundaries, both to subpixel precision. Resulting particle boundaries are independent of user defined parameters, with no image preprocessing required. We demonstrate through direct comparison that the Hessian blob algorithm more accurately detects biomolecules than conventional AFM particle detection techniques. Furthermore, the algorithm proves largely insensitive to common imaging artifacts and noise, delivering a stable framework for particle analysis in AFM

Test of Factorization Hypothesis from Exclusive Non-leptonic B decays

We investigate the possibility of testing factorization hypothesis in non-leptonic exclusive decays of B-meson. In particular, we considered the non factorizable \bar{B^0} -> D^{(*)+} D_s^{(*)-} modes and \bar{B^0} -> D^{(*)+} (\pi^-, \rho^-) known as well-factorizable modes. By taking the ratios BR(\bar{B^0}-> D^{(*)+}D_s^{(*)-})/BR(\bar{B^0}-> D^{(*)+}(\pi^-,\rho^-)), we found that under the present theoretical and experimental uncertainties there's no evidence for the breakdown of factorization description to heavy-heavy decays of the B meson.Comment: 11 pages; submitted to PR

Glass is a viable substrate for precision force microscopy of membrane proteins

Scientific Reports ; 5:12550 ; DOI: 10.1038/srep12550.Chada, N. et al. Glass is a Viable Substrate for Precision Force Microscopy of Membrane Proteins. Sci. Rep. 5, 12550; doi: 10.1038/srep12550 (2015).8 pages.Received: 01 April 2015 ; Accepted: 02 July 2015 ; Published: 31 July 2015.Though ubiquitous in optical microscopy, glass has long been overlooked as a specimen supporting surface for high resolution atomic force microscopy (AFM) investigations due to its roughness. Using bacteriorhodopsin from Halobacterium salinarum and the translocon SecYEG from Escherichia coli, we demonstrate that faithful images of 2D crystalline and non-crystalline membrane proteins in lipid bilayers can be obtained on microscope cover glass following a straight-forward cleaning procedure. Direct comparison between AFM data obtained on glass and on mica substrates show no major differences in image fidelity. Repeated association of the ATPase SecA with the cytoplasmic protrusion of SecYEG demonstrates that the translocon remains competent for binding after tens of minutes of continuous AFM imaging. This opens the door for precision long-timescale investigations of the active translocase in near-native conditions and, more generally, for integration of high resolution biological AFM with many powerful optical techniques that require non-birefringent substrates.Includes bibliographical references

Adherence to cervical and breast cancer programs is crucial to improving screening performance

Publicado onlineINTRODUCTION: Cervical and breast cancer are the most common malignancies among women worldwide. Effective screening can facilitate early detection and dramatically reduce mortality rates. The interface between those screening patients and patients most needing screening is complex, and women in remote areas of rural counties face additional barriers that limit the effectiveness of cancer prevention programs. This study compared various methods to improve compliance with mass screening for breast and cervical cancer among women in a remote, rural region of Brazil. METHODS: In 2003, a mobile unit was used to perform 10,156 mammograms and Papanicolaou smear tests for women living in the Barretos County region of São Paulo state, Brazil (consisting of 19 neighbouring cities). To reach the women, the following community outreach strategies were used: distribution of flyers and pamphlets; media broadcasts (via radio and car loudspeakers); and community healthcare agents (CHCAs) making home visits. RESULTS: The most useful intervention appeared to be the home visits by healthcare agents or CHCAs. These agents of the Family Health Programme of the Brazilian Ministry of Health reached an average of 45.6% of those screened, with radio advertisements reaching a further 11.9%. The great majority of the screened women were illiterate or had elementary level schooling (80.9%) and were of 'poor' or 'very poor' socioeconomic class (67.2%). CONCLUSIONS: Use of a mobile screening unit is a useful strategy in developing countries where local health systems have inadequate facilities for cancer screening in underserved populations. A multimodal approach to community outreach strategies, especially using CHCAs and radio advertisements, can improve the uptake of mass screening in low-income, low-educational background female populations

Stress Urinary Incontinence Correction with Sling: First Results

Purpose: to analyze the surgical results after slings with vaginal wall, performed by the Urogynecology and Vaginal Surgery Sector of UNIFESP/EPM, for the treatment of incontinent women with hypermobility of the bladder neck, who show great risk of surgery failure with other techniques or in those with intrinsic sphincteric deficiency (ISD) and, also, surgery recurrence. Methods: we studied 21 patients submitted to surgery in order to correct urinary incontinence by the vaginal wall sling technique, in the period from December 1997 to February 1999, with postoperative follow-up which varied between 1 and 14 months (average 8.2). The mean age of patients was 56 years (39 to 77 years), 15 (71.4%) were in menopause and 6 (28.6%) in menacme. All patients were evaluated before the surgery through medical interview, physical examination, ultrasound and urodynamic study, the grade of urinary loss being high in 66.7% and moderate in 33.3% of the patients. All patients showed hypermobility of the bladder neck (more than 10 mm) and 12 patients had previous surgery to correct the urinary incontinence. Regarding the urodinamic study, the patients manifested urinary loss with maximum pressure of urethral closure (MPUC) varying from 20 to 124 cmH2O (average 55.2) and Valsalva leak point pressure (VLPP) varying from 18 to 128 cmH2O (average 60.3). The indications of surgery were: ISD (11 patients -- 52.4%), obesity (5 patients -- 23.8%), ISD and obesity (2 patients -- 9.5%), surgery recurrence (2 patients -- 9.5) and ISD and first grade womb prolapse (1 patient -- 4.8%). Results: as complications, 6 patients (28.6%) showed temporary urinary retention after surgery, 1 patient (4.8%) infection in the urinary tract, 1 patient (4.8%) presence of polypropylene suture in the vagina, 1 patient (4.8%) infection of the surgery wound, 4 patients (19%) developed urgency/incontinence, 1 (4.8%) urgency and 1 (4.8%) difficulty in urinating (high postvoiding residue). The grade of the patients' satisfaction was satisfactory, with 15 patients (71.4%) referring cure, 3 patients (14.3%) improvement, in 2 patients (9.5%) the urinary loss remained unchanged and in 1 patient (4.8%) the urinary loss got worse. Conclusions: the vaginal wall sling surgery is efficient for the treatment of specific cases of stress urinary incontinence, emphasizing intrinsic urethral sphincteric incompetence, surgery recurrence and predisposing factors to failure of other techniques.Objetivo: analisar os resultados cirúrgicos após slings com mucosa vaginal, realizados pelo setor de Uroginecologia e Cirurgia Vaginal da UNIFESP/EPM, no tratamento de mulheres incontinentes com hipermobilidade do colo vesical, que apresentam alto risco de falha cirúrgica para outras técnicas ou naquelas com defeito esfincteriano intrínseco e, ainda, recidivas cirúrgicas. Métodos: foram avaliadas 21 pacientes submetidas à cirurgia para correção de incontinência urinária pela técnica de sling vaginal, no período de dezembro de 1997 a fevereiro de 1999, com seguimento pós-operatório que variou de 1 a 14 meses (média de 8,2). A média de idade das pacientes foi de 56 anos (39 a 77 anos), sendo que 15 (71,4%) encontravam-se na menopausa e 6 (28,6%) no menacme. Todas as pacientes foram avaliadas antes da cirurgia por meio de anamnese, exame clínico, estudo ultra-sonográfico e urodinâmico, sendo o grau de perda urinária acentuado em 66,7% e moderado em 33,3% das pacientes. Todas as pacientes apresentavam hipermobilidade da junção uretrovesical (superior a 10 mm) e 12 pacientes apresentavam cirurgia prévia para correção de incontinência urinária. Ao estudo urodinâmico, as pacientes apresentavam perda urinária com pressão máxima de fechamento uretral (PMFU) variando de 20 a 124 cmH2O (média de 55,2) e Valsalva leak point pressure (VLPP) variando de 18 a 128 cmH2O (média de 60,3). As indicações das cirurgias foram: defeito esfincteriano (11 pacientes - 52,4%), obesidade (5 pacientes - 23,8%), defeito esfincteriano e obesidade (2 pacientes - 9,5%), recidiva cirúrgica (2 pacientes - 9,5%) e defeito esfincteriano e prolapso uterino de 1º grau (1 paciente - 4,8%). Resultados: como complicações, 6 pacientes (28,6%) apresentaram retenção urinária temporária no pós-operatório, 1 (4,8%) infecção do trato urinário, 1 (4,8%) presença de fio de polipropileno na vagina, 1 (4,8%) infecção da ferida cirúrgica, 4 pacientes (19%) evoluíram com urgência/incontinência, 1 (4,8%) com urgência miccional e 1 (4,8%) com dificuldade para urinar (elevado resíduo pós-miccional). O grau de satisfação das pacientes foi satisfatório, com 15 pacientes (71,4%) referindo cura, 3 (14,3%) melhora, 2 (9,5%) quadro de perda urinária inalterado e 1 (4,8%) piora da perda urinária. Conclusões: a cirurgia de sling com mucosa vaginal é eficaz para o tratamento de casos específicos de incontinência urinária de esforço, destacando-se defeito esfincteriano, recidivas cirúrgicas e fatores predisponentes para falha de outras técnicas.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Tocogi-necologiaUNIFESP, EPM, Depto. de Tocogi-necologiaSciEL

Glass is a viable substrate for atomic force microscopy of membrane proteins : [abstract]

Abstract only."2314-Pos Board B6.""Page 458a, Tuesday, February 18, 2014."--At top of page.Abstract in program book: Since its invention in the mid-1980s, the atomic force microscope (AFM) has become an invaluable complementary tool for studying membrane proteins in near-native environments. Historically, mica is the most common substrate utilized for biological AFM. Glass being amorphous, transparent, and optically homogeneous has its own set of advantages over mica and has the potential to broaden the use the AFM into fields that require high quality non-birefringent optical access. The use of silanized glass as AFM substrates has been reported as a means to fine tune surface chemistry. However, such coatings usually require hours of additional preparation time and can lead to increased surface roughness. In this work, we present a simple technique for preparing borosilicate glass as a substrate for two membrane systems: non-crystalline translocons (SecYEG) of the general secretary system from E. coli, and bacteriorhodopsin (BR) from H. salinarum. For both these membrane proteins, quantitative comparisons of the measured protein structures on glass versus mica substrates show agreement. An additional advantage of glass is that lipid coverage is rapid (< 10 minutes) and complete (occupying the entire surface). A goal is to study the bacterial export system using recently developed precision measurement techniques such as ultra-stable AFM

Lattice Calculation of Heavy-Light Decay Constants with Two Flavors of Dynamical Quarks

We present results for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios in the presence of two flavors of light sea quarks ($N_f=2$). We use Wilson light valence quarks and Wilson and static heavy valence quarks; the sea quarks are simulated with staggered fermions. Additional quenched simulations with nonperturbatively improved clover fermions allow us to improve our control of the continuum extrapolation. For our central values the masses of the sea quarks are not extrapolated to the physical $u$, $d$ masses; that is, the central values are "partially quenched." A calculation using "fat-link clover" valence fermions is also discussed but is not included in our final results. We find, for example, $f_B = 190 (7) (^{+24}_{-17}) (^{+11}_{-2}) (^{+8}_{-0})$ MeV, $f_{B_s}/f_B = 1.16 (1) (2) (2) (^{+4}_{-0})$, $f_{D_s} = 241 (5) (^{+27}_{-26}) (^{+9}_{-4}) (^{+5}_{-0})$ MeV, and $f_{B}/f_{D_s} = 0.79 (2) (^{+5}_{-4}) (3) (^{+5}_{-0})$, where in each case the first error is statistical and the remaining three are systematic: the error within the partially quenched $N_f=2$ approximation, the error due to the missing strange sea quark and to partial quenching, and an estimate of the effects of chiral logarithms at small quark mass. The last error, though quite significant in decay constant ratios, appears to be smaller than has been recently suggested by Kronfeld and Ryan, and Yamada. We emphasize, however, that as in other lattice computations to date, the lattice $u,d$ quark masses are not very light and chiral log effects may not be fully under control.Comment: Revised version includes an attempt to estimate the effects of chiral logarithms at small quark mass; central values are unchanged but one more systematic error has been added. Sections III E and V D are completely new; some changes for clarity have also been made elsewhere. 82 pages; 32 figure

A study of hormone activity in premenopausal tamoxifen-treated women

Purpose: to evaluate the effects of tamoxifen (TAM) on plasma levels of estradiol, progesterone, prolactin, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and steroid hormone-binding globulin (SHBG) when given to premenopausal women in the doses of 10 and 20 mg/day for 22 days. Patients and Methods: a randomized double-blind study was performed with 43 premenopausal eumenorrheic women. The patients were divided into three groups: A (N = 15, placebo); B (N = 15, TAM 10 mg/day) and C (N = 13, 20 mg/day). They started taking an oral dose of TAM or placebo on the very first day of the menstrual cycle. Two hormone determinations were performed, both on the 22nd day of the menstrual cycle: the first in the cycle that preceded the use of the drug and the second, in the following cycle, after 22 days of using the medication. We used the Levine and Student tests in order to evaluate the homogeneity of the sample and the variation of the hormone determinations respectively. Results:serum levels of estradiol, progesterone and SHBG increased significantly in groups B and C. In group C, we also observed increase in serum level of FSH (p < 0.0045) and a fall in prolactin level (p < 0.0055). Conclusions: TAM promoted a significant increase in serum concentrations of estradiol, progesterone and SHBG either in the doses of 10 or 20 mg/day. However, significant increase in FSH and decrease in prolactin were obtained only with the dose of 20 mg/day.Objetivos: Avaliar o efeito do tamoxifeno nos níveis séricos de progesterona, estradiol, prolactina, hormônio luteinizante (LH), hormônio folículo-estimulante (FSH) e da globulina transportadora dos hormônios sexuais (SHBG), quando administrado a mulheres no menacme, nas doses de 10 e 20 mg/dia por 22 dias. Métodos: Estudo aleatório e duplo-cego. Foram incluídas 43 mulheres pré-menopausadas e eumenorréicas. Foram distribuídas em 3 grupos: A (N = 15; placebo), B (N = 15; 10 mg/dia) e C (N = 13; 20 mg/dia). Foram realizadas duas dosagens hormonais, sendo a primeira no 22º dia do ciclo menstrual que precedeu o uso da droga e a segunda após 22 dias de uso do medicamento. Utilizaram-se os testes de Levene e t-pareado para avaliar a homogeneidade da amostra e a variação das dosagens hormonais, respectivamente. Resultados: As concentrações séricas de estradiol, progesterona e SHBG aumentaram significantemente nos grupos B e C. No grupo C, observou-se ainda elevação no nível sérico de FSH (p < 0,0045) e queda dos valores de prolactina (p < 0,0055). Conclusões: O tamoxifeno promoveu aumento significante nas concentrações séricas de estradiol, progesterona e SHBG, tanto na dose de 10 como de 20 mg/dia. Porém, o aumento significante de FSH e a diminuição da prolactina foram obtidos apenas com a dose de 20 mg/dia.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL

Improved Measurement of the Pseudoscalar Decay Constant fDsf_{D_{s}}

We present a new determination of the Ds decay constant, f_{Ds} using 5 million continuum charm events obtained with the CLEO II detector. Our value is derived from our new measured ratio of widths for Ds -> mu nu/Ds -> phi pi of 0.173+/- 0.021 +/- 0.031. Taking the branching ratio for Ds -> phi pi as (3.6 +/- 0.9)% from the PDG, we extract f_{Ds} = (280 +/- 17 +/- 25 +/- 34){MeV}. We compare this result with various model calculations.Comment: 23 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN