Light-In-Flight Imaging by a Silicon Image Sensor: Toward the Theoretical Highest Frame Rate

Light in flight was captured by a single shot of a newly developed backside-illuminated multi-collection-gate image sensor at a frame interval of 10 ns without high-speed gating devices such as a streak camera or post data processes. This paper reports the achievement and further evolution of the image sensor toward the theoretical temporal resolution limit of 11.1 ps derived by the authors. The theoretical analysis revealed the conditions to minimize the temporal resolution. Simulations show that the image sensor designed following the specified conditions and fabricated by existing technology will achieve a frame interval of 50 ps. The sensor, 200 times faster than our latest sensor will innovate advanced analytical apparatuses using time-of-flight or lifetime measurements, such as imaging TOF-MS, FLIM, pulse neutron tomography, PET, LIDAR, and more, beyond these known applications.

Structural essentials for β-N-acetylhexosaminidase inhibition by amides of prolines, pipecolic and azetidine carboxylic acids

This paper explores the computer modelling aided design and synthesis of β-N-acetylhexosaminidase inhibitors along with their applicability to human disease treatment through biological evaluation in both an enzymatic and cellular setting. We investigated the importance of individual stereocenters, variations in structure-activity relationships along with factors influencing cell penetration. To achieve these goals we modified nitrogen heterocycles in terms of ring size, side chains present and ring nitrogen derivatization. By reducing the inhibitor interactions with the active site down to the essentials we were able to determine that besides the established 2S,3R trans-relationship, the presence and stereochemistry of the CH₂OH side chain is of crucial importance for activity. In terms of cellular penetration, N-butyl side chains favour cellar uptake, while hydroxy- and carboxy-group bearing sidechains on the ring nitrogen retarded cellular penetration. Furthermore we show an early proof of principle study that β-N-acetylhexosaminidase inhibitors can be applicable to use in a potential anti-invasive anti-cancer strategy.

Safety, tolerability, pharmacokinetics and pharmacodynamics of AZP-531, a first-in-class analogue of unacylated ghrelin, in healthy and overweight/obese subjects and subjects with type 2 diabetes

AIM

To explore the safety, pharmacokinetics and pharmacodynamics in humans of the unacylated ghrelin analogue AZP-531, designed to improve glycaemic control and reduce weight.

METHODS

Assessments, including glucose measurements, were performed in a three-part randomized study. In Part A, healthy subjects [n = 44, age 18-50 years, body mass index (BMI) 20-28 kg/m(2) ] received a single subcutaneous dose of 0.3, 3, 15, 30, 60 or 120 µg/kg AZP-531 or placebo. In Part B, overweight/obese subjects (n = 32, age 18-65 years, BMI 28-38 kg/m(2) ) and in Part C, patients with type 2 diabetes [T2D; n = 36, age 18-65 years, BMI 20-40 kg/m(2) , glycated haemoglobin (HbA1c) 7-10%] received AZP-531 or placebo for 14 days (daily doses of 3, 15, 30 or 60 µg/kg and 15, 2 × 30 or 60 µg/kg, respectively).

RESULTS

AZP-531 was well tolerated. Single- and multiple-dose pharmokinetic variables were similar. Maximum AZP-531 concentrations were typically reached at 1 h post-dose. Observed maximum concentration (Cmax ) and area under the curve were dose-proportional. The mean terminal half-life (t1/2 ) was 2-3 h. In Part B, AZP-531 doses of ≥15 µg/kg significantly improved glucose concentrations, without increasing insulin levels, suggesting an insulin-sensitizing effect. AZP-531 decreased mean body weight by 2.6 kg (vs 0.8 kg for placebo). In Part C, glucose variables improved in all groups, including placebo, suggesting a study effect in uncontrolled patients at baseline. Notwithstanding, AZP-531 60 µg/kg reduced HbA1c by 0.4% (vs 0.2% for placebo) and body weight by 2.1 kg (vs 1.3 kg for placebo).

CONCLUSIONS

AZP-531 was well tolerated in this first-in-human study. Its pharmacokinetic profile, suitable for once-daily dosing, and metabolic effects support further clinical development for T2D.

Exact Query Reformulation over Databases with First-order and Description Logics Ontologies

We study a general framework for query rewriting in the presence of an arbitrary first-order logic ontology over a database signature. The framework supports deciding the existence of a safe-range first-order equivalent reformulation of a query in terms of the database signature, and if so, it provides an effective approach to construct the reformulation based on interpolation using standard theorem proving techniques (e.g., tableau). Since the reformulation is a safe-range formula, it is effectively executable as an SQL query. At the end, we present a non-trivial application of the framework with ontologies in the very expressive ALCHOIQ description logic, by providing effective means to compute safe-range first-order exact reformulations of queries.

An expression signature of the angiogenic response in gastrointestinal neuroendocrine tumours: correlation with tumour phenotype and survival outcomes

Background:

Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are heterogeneous with respect to biological behaviour and prognosis. As angiogenesis is a renowned pathogenic hallmark as well as a therapeutic target, we aimed to investigate the prognostic and clinico-pathological role of tissue markers of hypoxia and angiogenesis in GEP-NETs.

Methods:

Tissue microarray (TMA) blocks were constructed with 86 tumours diagnosed from 1988 to 2010. Tissue microarray sections were immunostained for hypoxia inducible factor 1α (Hif-1α), vascular endothelial growth factor-A (VEGF-A), carbonic anhydrase IX (Ca-IX) and somatostatin receptors (SSTR) 1–5, Ki-67 and CD31. Biomarker expression was correlated with clinico-pathological variables and tested for survival prediction using Kaplan–Meier and Cox regression methods.

Results:

Eighty-six consecutive cases were included: 51% male, median age 51 (range 16–82), 68% presenting with a pancreatic primary, 95% well differentiated, 51% metastatic. Higher grading (P=0.03), advanced stage (P<0.001), high Hif-1α and low SSTR-2 expression (P=0.03) predicted for shorter overall survival (OS) on univariate analyses. Stage, SSTR-2 and Hif-1α expression were confirmed as multivariate predictors of OS. Median OS for patients with SSTR-2+/Hif-1α-tumours was not reached after median follow up of 8.8 years, whereas SSTR-2-/Hif-1α+ GEP-NETs had a median survival of only 4.2 years (P=0.006).

Conclusion:

We have identified a coherent expression signature by immunohistochemistry that can be used for patient stratification and to optimise treatment decisions in GEP-NETs independently from stage and grading. Tumours with preserved SSTR-2 and low Hif-1α expression have an indolent phenotype and may be offered less aggressive management and less stringent follow up.

Correlation of cyclin D1 transcript levels, transcript type and protein expression with proliferation and histology among mantle cell lymphoma

BACKGROUND

Cyclin D1 expression is central to mantle cell lymphoma (MCL) biology. The cyclin D1 gene produces two forms of mRNA: long (D1L) and short (D1S) versions.

AIMS

To study the relationship between histology, cyclin D1 mRNA (transcript) levels, cyclin D1 transcript type, cyclin D1 protein expression by immunohistochemistry (IHC), and proliferation (Ki-67%).

METHODS

17 MCLs were initially studied for: levels of expression of cyclin D1 transcripts and for cyclin D1 transcript type by reverse-transcriptase PCR; intensity and percentage cyclin D1 protein expression by IHC; and Ki-67% by IHC. The relationship between cyclin D1 protein expression and proliferation was further validated on an independent set of 23 MCLs.

RESULTS

MCLs expressed variable levels of cyclin D1 at both transcript and protein levels. Furthermore, D1L and D1S were the predominant transcripts in 69% and 31% of cases, respectively. While only 9% of cases with dominance of D1L had blastoid histology, 60% of the cases with dominance of the D1S had blastoid features. Furthermore, the levels of D1L showed direct correlation with cyclin D1 protein expression and Ki-67%. Among these cases, and in the independent set of MCLs (n = 40), the level of cyclin D1 protein expression directly correlated with Ki-67%.

CONCLUSIONS

MCLs express variable levels of cyclin D1 transcripts and protein, and have variable proliferation (Ki-67%). Cases with dominance of D1S transcripts are more likely to be of blastoid morphology. There is correlation between D1L transcripts levels, cyclin D1 protein expression and Ki-67%.

Down Modulation of TNF-α mRNA Placental Expression by AZT Used for the Prevention of HIV-1 Mother-to-Child Transmission

Mechanisms of HIV-1 in utero mother-to-child transmission (MTCT) protection provided by AZT are not completely understood. The placental cytokine network is involved in the control of HIV-1 in utero transmission but the effect of AZT on this network is unknown. To evaluate the effects of AZT on placental cytokine expression, the chorionic villi from HIV-1 uninfected women term placentae were cultured with 0, 100, and 2,000 ng/ml AZT. Tissue fragments were harvested at days 1, 4, and 7 to determine the level of cytokine mRNA by real-time RT-PCR. The viability and morphology of the placental histocultures were monitored by the expression of beta-human chorionic gonadotropin (beta-hCG) gene, lipopolysaccharide (LPS) activation, and microscopic examination. AZT at 2,000 ng/ml significantly down-regulated TNF-alpha mRNA expression at day 1 and day 4, but had no effect on beta-hCG, stromal cell-derived factor 1 (SDF-1), and IL-10 gene expression. AZT did not induce any deleterious impact on placental tissue structure. Furthermore, activation of chorionic villi by LPS for 24 h up-regulated IL-10 and TNF-alpha mRNA expression. Down-regulation of TNF-alpha mRNA could represent a mechanism through which AZT can decrease the risk of HIV-1 MTCT, in addition to its direct effect on HIV-1 replication.

Effects of active fiber length on the tunability of erbium-doped fiber ring lasers

We numerically investigate the effects of the active fiber length on the tunability of erbium-doped fiber ring lasers for the cases of with and without pair-induced quenching (PIQ). The numerical results are confirmed by experiments. We have found that the tuning range shifts from C-band to L-band with an increase in the active fiber length. A maximum tuning range of over 100 nm, covering both the C- and L-band, can be achieved with an optimized active fiber length. It is also found that the PIQ is favorable for Lband lasing though it reduces the output power and degrades the power flatness. Using these findings, a novel method employing active fiber length switching is proposed to extend the tuning range of the laser, which is only limited by the free spectral range (FSR) of the tunable filter. A large tuning range of 102 nm is obtained using a tunable fiber Fabry-Perot filter with an FSR of 75 nm.

A largely tunable CFBG-based dispersion compensator with fixed center wavelength

A largely tunable chirped fiber Bragg grating (CFBG)-based dispersion compensator with fixed center wavelength is demonstrated. Tunable dispersion ranging from 178 to 2126 ps/nm, corresponding to a large range of 3-db bandwidth from 0.42 to 5.04 nm, is realized by using a 10 cm-long CFBG with an original bandwidth of 1.61 nm. The variation in center wavelength is less than 0.2 nm.

Low-cost and efficient coupling technique using reflowed sol-gel microlens

In this paper, we present a novel reflow technique for the fabrication of an elliptical microlens array in sol-gel glass. The fabricated refractive microlens array has a very smooth surface, and structural and dimensional conformity with the designed parameters. It is shown that the microlens array can provide high coupling efficiency of a laser diode to a single mode fiber, and relax the lateral and axial misalignment tolerance. The microlens coupling technique has the advantages of low coupling loss, large misalignment tolerances, and small package volume.

Fast Hankel transform and its application for studying the propagation of cylindrical electromagnetic fields

We present a fast Hankel transform (FHTn) method for direct numerical evaluation of electromagnetic (EM) field propagation through an axially symmetric system. Comparing with the vector-based plane-wave spectrum (VPWS) method, we present an alternative approach to implement the fast Hankel transform which does not require an additional coordinate transformation for Fourier transform. The proposed FHTn method is an efficient approach for numerical evaluation of an arbitrary integer order of the Hankel transform (HT). As an example to demonstrate the effectiveness of the proposed method, we apply the FHTn technique to the analysis of cylindrical EM field propagation through a diffractive microlens.

Single-step fabrication of continuous surface relief micro-optical elements in hybrid sol-gel glass by laser direct writing

A negative tone hybrid sol-gel material was applied to the fabrication of continuous surface relief micro-optical elements by laser direct writing lithography. The hybrid sol-gel glass was synthesized as UV photosensitive material and used for the fabrication of micro-optical elements with continuous surface relief profile. The surface profile was directly controlled by the UV exposure dosage and the exposed areas were crosslinked and converted into sol-gel glass with relief structures. The UV exposure dosage was realized by an acousto-optic modulator (AOM) in the laser direct writing system. Characterization results indicated that the thickness of the sol-gel glass has a linear response to the AOM values ranging from 3.25 to 5.5. The sol-gel thin film was measured to have a refractive index of 1.52 and the maximum thickness of 2 microm. For various designs of diffractive optical elements within the visible wavelength, the sol-gel film enables us to achieve an arbitrary phase change between 0 and 2 pi with the linear AOM exposure range. As an example, a blazed grating with a period of 45 microm and height of 1.17 microm was fabricated in the sol-gel glass using direct laser writing method.

Cost-effective fabrication of microlenses on hybrid sol-gel glass with a high-energy beam-sensitive gray-scale mask

A negative-tone inorganic-organic hybrid SiO(2):TiO(2) glass is investigated for fabrication of refractive microlenses. This sol-gel material enjoys an advantage over materials used in conventional photoresist-based fabrication techniques in that it lends itself to a single-step etching-free process. The application of a high-energy beam-sensitive (HEBS) mask provides a reliable and simple method for fabrication of three-dimensional micro-optical elements with a single UV exposure. The technique of using the sol-gel material with the HEBS gray-scale mask has considerable potential for low-cost mass production of continuous-phase-level diffractive optical elements and micro-optical structures.

Decrease in immune activation in HIV-infected patients treated with highly active antiretroviral therapy correlates with the function of hematopoietic progenitor cells and the number of naive CD4+ cells

This study was conducted to determine the impact of immune activation, cytokine production and apoptosis on the naive CD4+ cell count and the function of hematopoietic progenitor cells during the initial phase of highly active antiretroviral therapy (HAART). Blood samples from 11 HIV-infected patients were collected prior to HAART and after 4 and 12 weeks of therapy. Flow cytometry was used to determine the naive CD4+ count and activated T cells. The cloning efficiency of progenitor cells was determined using a colony-forming cells assay. Finally, apoptosis and cytokine production were determined. During the study period, the naive CD4+ count and the cloning efficiency increased significantly. Immune activation was found in HIV-infected patients and decreased during HAART. The level of immune activation correlated negatively with both the naive CD4+ count and the function of progenitor cells. A negative correlation was found between apoptosis and the naive CD4+ count. Alterations in cytokine production during HAART or correlation between cytokine production and the naive CD4+ count or the cloning efficiency of progenitor cells were not detected. In conclusion, immune activation in HIV-infected patients treated with HAART is inversely correlated with the function of progenitor cells and the naive CD4+ count.

Weak anti-HIV CD8(+) T-cell effector activity in HIV primary infection

HIV-specific CD8(+) T cells play a major role in the control of virus during HIV primary infection (PI) but do not completely prevent viral replication. We used IFN-gamma enzyme-linked immunospot assay and intracellular staining to characterize the ex vivo CD8(+) T-cell responses to a large variety of HIV epitopic peptides in 24 subjects with early HIV PI. We observed HIV-specific responses in 71% of subjects. Gag and Nef peptides were more frequently recognized than Env and Pol peptides. The number of peptides recognized was low (median 2, range 0-6). In contrast, a much broader response was observed in 30 asymptomatic subjects with chronic infection: all were responders with a median of 5 peptides recognized (range 1-13). The frequency of HIV-specific CD8(+) T cells among PBMC for a given peptide was of the same order of magnitude in both groups. The proportion of HIV-specific CD8(+)CD28(-) terminally differentiated T cells was much lower in PI than at the chronic stage of infection. The weakness of the immune response during HIV PI could partially account for the failure to control HIV. These findings have potential importance for defining immunotherapeutic strategies and establishing the goals for effective vaccination.

Adenosquamous carcinoma of the small intestine. Report of a case and review of the literature

Primary adenosquamous carcinomas of the intestine are rare tumors, particularly those occurring in the small bowel. We report the third case of an adenosquamous carcinoma of the ileum in a 55-year-old-man. Histologically, the tumor consisted of malignant glandular and squamous elements. A review of the literature is presented.

Acanthamoeba meningoencephalitis following autologous peripheral stem cell transplantation

Amoebic meningoencephalitis is an unusual complication of bone marrow transplantation. We report a case of Acanthamoeba meningoencephalitis in a patient with non-Hodgkin's lymphoma after autologous stem cell transplantation. Leg weakness, fever and urinary retention developed 69 days following transplantation. The patient then developed fever, generalized tonic clonic seizure, rapid deterioration of mental functions and hypercapneic respiratory failure. Magnetic resonance imaging demonstrated a ring enhancing lesion at the level of the thoracic spines 11 and 12. Examination of the cerebrospinal fluid revealed pleocytosis. Despite empiric therapy with broad-spectrum antimicrobial agents, the patient's condition worsened and she died 11 days following admission. Autopsy findings revealed a subacute meningoencephalitis secondary to Acanthamoeba culbertsoni.

No evidence for proliferation in the blood CD4+ T-cell pool during HIV-1 infection and triple combination therapy

OBJECTIVE

To evaluate the role of cell proliferation in peripheral blood lymphocyte (PBL) dynamics during HIV infection and potent antiretroviral therapy including protease inhibitors.

DESIGN

Transverse study of 150 patients at different stages of infection. Longitudinal study of 50 patients on triple combination antiretroviral therapy with 9-month follow-up.

METHODS

Ex vivo incubation of fresh PBL with the DNA biosynthetic marker bromodeoxyuridine (BrdU). Flow cytometric analysis of cell phenotypes and BrdU incorporation. Parallel determination of plasma virus load and CD4+ cell counts.

RESULTS

Percentages of BrdU+ B and T lymphocytes found in patients with asymptomatic HIV infection were not different from the low values found in HIV-seronegative controls, and were not correlated with the CD4+ cell count. DNA synthesis increased significantly only during acute opportunistic infections occurring in patients with high plasma viral load and fewer than 100 x 10(6) CD4+ cells/l. Triple combination therapy induced a decrease of plasma virus load and a rise of CD4+ cell counts, whereas BrdU incorporation remained low or decreased.

CONCLUSION

Proliferation of peripheral blood T cells observed at late stages of HIV infection corresponds to a response to opportunistic infections. Apart from these particular cases, proliferation in this compartment does not appear as a critical parameter of CD4+ cell kinetics during chronic HIV infection and potent therapy.

Deletions of the Aequorea victoria green fluorescent protein define the minimal domain required for fluorescence

The Green Fluorescent Protein (GFP) from the jellyfish Aequorea victoria is a widely used marker for gene expression and protein localization studies. Dissection of the structure of the protein would be expected to shed light on its potential applications to other fields such as the detection of protease activity. Using deletion analysis, we have defined the minimal domain in GFP required for fluorescence to amino acids 7-229. This domain starts at the middle of the first small alpha helix at the N terminus of GFP and ends immediately following the last beta sheet. Studies of the amino acids at both termini of the minimal domain revealed that positions 6 and 7 at the N terminus are Glu-specific. Change of the Glu residues to other amino acids results in reduction of GFP fluorescence. Position 229 at the C terminus of GFP, however, is nonspecific: the Ile can be replaced with other amino acids with no measurable loss of fluorescence. A total of only 15 terminal amino acids can be deleted from GFP without disrupting fluorescence, consistent with findings of a previous study of GFP crystal structure (Ormo, M., Cubitt, A. B., Kallio, K., Gross, L. A., Tsien, R. Y., Remington, S. J. (1996) Science 273, 1392-1395 and Yang, F., Moss, L. G., and Phillips, G. N., Jr. (1996) Nat. Biotechnol. 14, 1246-1251) that a tightly packed structure exists in the protein. We also generated internal deletions within the loop regions of GFP according to its crystal structure and found that all such deletions eliminated GFP fluorescence.

In vitro assembly of multiprotein complexes containing alpha, beta, and gamma tubulin, heat shock protein HSP70, and elongation factor 1 alpha

We have isolated two sets of multiprotein complexes from supernatants from high-speed centrifugation of nocodazole-arrested CHO cells. One set, assembled in vitro after a 37 degrees C incubation in the presence of ATP or GTP, is composed of equivalent amounts of alpha- and beta-tubulin and a 50-kDa protein, provisionally identified as elongation factor 1 alpha. These complexes, which are heterogeneous in size when analyzed by sucrose gradient ultracentrifugation, also contain the cognate form of heat shock protein HSP70 and gamma-tubulin, a tubulin isoform of low abundance, along with other proteins known to be involved in the regulation of mitosis. Similar but distinct complexes assemble in vitro if the same extracts are incubated at 37 degrees C without added nucleotides; multiprotein complexes generated under these conditions lack HSP70 but contain instead a 43-kDa protein identified as an actin isoform. Both sets of assembled complexes exhibit a globular substructure when analyzed by electron microscopy, and their size distribution suggests that they assemble by the step-wise addition of smaller precursors. The properties of these multiprotein complexes and their presence in cells arrested in a stage between prophase and metaphase suggest that they may be precursors to mitotic centrosomes and are possibly involved in mitotic spindle nucleation.