Sounding out the dynamics: a concise review of high-speed photoacoustic microscopy

Significance

Photoacoustic microscopy (PAM) offers advantages in high-resolution and high-contrast imaging of biomedical chromophores. The speed of imaging is critical for leveraging these benefits in both preclinical and clinical settings. Ongoing technological innovations have substantially boosted PAM's imaging speed, enabling real-time monitoring of dynamic biological processes.

Aim

This concise review synthesizes historical context and current advancements in high-speed PAM, with an emphasis on developments enabled by ultrafast lasers, scanning mechanisms, and advanced imaging processing methods.

Approach

We examine cutting-edge innovations across multiple facets of PAM, including light sources, scanning and detection systems, and computational techniques and explore their representative applications in biomedical research.

Results

This work delineates the challenges that persist in achieving optimal high-speed PAM performance and forecasts its prospective impact on biomedical imaging.

Conclusions

Recognizing the current limitations, breaking through the drawbacks, and adopting the optimal combination of each technology will lead to the realization of ultimate high-speed PAM for both fundamental research and clinical translation.

Efficient label-free in vivo photoacoustic imaging of melanoma cells using a condensed NIR-I spectral window

In this paper, we propose an efficient label-free in vivo photoacoustic (PA) imaging of melanoma using a condensed near infrared-I (NIR-I) supercontinuum light source. Although NIR-II spectral window is advantageous such as longer penetration depth compared to the NIR-I region, supercontinuum light sources emitting both NIR-I and NIR-II region could lower the efficiency to target melanoma because of low optical power density in the melanoma's absorption spectra. To exploit efficient in vivo PA imaging of melanoma, we demonstrated the light source emitting from visible (532-600 nm) to NIR-I (600-1000 nm) by optimizing stimulated Raman scattering induced supercontinuum generation. The melanoma's structure is successfully differentiated from blood vessels at a high pulse energy of 2.5 µJ and a flexible pulse repetition rate (PRR) of 5-50 kHz. The proposed light source with the microjoules energies and tens of kHz of PRR can potentially accelerate clinical trials such as early diagnosis of melanoma.

High-speed photoacoustic microscopy: A review dedicated on light sources

In recent years, many methods have been investigated to improve imaging speed in photoacoustic microscopy (PAM). These methods mainly focused upon three critical factors contributing to fast PAM: laser pulse repetition rate, scanning speed, and computing power of the microprocessors. A high laser repetition rate is fundamentally the most crucial factor to increase the PAM speed. In this paper, we review methods adopted for fast PAM systems in detail, specifically with respect to light sources. To the best of our knowledge, ours is the first review article analyzing the fundamental requirements for developing high-speed PAM and their limitations from the perspective of light sources.

Ultra-widefield photoacoustic microscopy with a dual-channel slider-crank laser-scanning apparatus for in vivo biomedical study

Photoacoustic microscopy (PAM) is an important imaging tool that can noninvasively visualize the anatomical structure of living animals. However, the limited scanning area restricts traditional PAM systems for scanning a large animal. Here, we firstly report a dual-channel PAM system based on a custom-made slider-crank scanner. This novel scanner allows us to stably capture an ultra-widefield scanning area of 24 mm at a high B-scan speed of 32 Hz while maintaining a high signal-to-noise ratio. Our system's spatial resolution is measured at ∼3.4 μm and ∼37 μm for lateral and axial resolution, respectively. Without any contrast agent, a dragonfly wing, a nude mouse ear, an entire rat ear, and a portion of mouse sagittal are successfully imaged. Furthermore, for hemodynamic monitoring, the mimicking circulating tumor cells using magnetic contrast agent is rapidly captured in vitro. The experimental results demonstrated that our device is a promising tool for biological applications.

Odderon Exchange from Elastic Scattering Differences between pp and pp[over ¯] Data at 1.96 TeV and from pp Forward Scattering Measurements

We describe an analysis comparing the pp[over ¯] elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96 TeV to that in pp collisions as measured by the TOTEM Collaboration at 2.76, 7, 8, and 13 TeV using a model-independent approach. The TOTEM cross sections, extrapolated to a center-of-mass energy of sqrt[s]=1.96  TeV, are compared with the D0 measurement in the region of the diffractive minimum and the second maximum of the pp cross section. The two data sets disagree at the 3.4σ level and thus provide evidence for the t-channel exchange of a colorless, C-odd gluonic compound, also known as the odderon. We combine these results with a TOTEM analysis of the same C-odd exchange based on the total cross section and the ratio of the real to imaginary parts of the forward elastic strong interaction scattering amplitude in pp scattering for which the significance is between 3.4σ and 4.6σ. The combined significance is larger than 5σ and is interpreted as the first observation of the exchange of a colorless, C-odd gluonic compound.

Quickly Alternating Green and Red Laser Source for Real-time Multispectral Photoacoustic Microscopy

Multispectral photoacoustic microscopy uses a wavelength-dependent absorption difference as a contrast mechanism to image the target molecule. In this paper, we present a novel multispectral pulsed fiber laser source, which selectively alternates the excitation wavelengths between green and red colors based on the stimulated Raman scattering (SRS) effect for imaging. This laser has a high pulse repetition rate (PRR) of 300 kHz and high pulse energy of more than 200 nJ meeting the real-time requirements of optical-resolution photoacoustic microscopy imaging. By switching the polarization state of the pump light and optical paths of the pump light, the operating wavelengths of the light source can be selectively alternated at the same fast PRR for any two SRS peak wavelengths between 545 and 655 nm. At 545 nm excitation wavelength, molecular photoacoustic signals from both blood vessels and gold nanorods were obtained simultaneously. However, at 655 nm, the photoacoustic signals of gold nanorods were dominant because the absorption of light by the blood vessels decreased drastically in the spectral region over 600 nm. Thus the multispectral photoacoustic system designed using the novel laser source implemented here could simultaneously monitor the time-dependent fast movement of two molecules independently, having different wavelength-dependent absorption properties at a high repetition rate of 0.49 frames per second (fps).

Measurement of the Effective Weak Mixing Angle in pp[over ¯]→Z/γ^{*}→ℓ^{+}ℓ^{-} Events

We present a measurement of the effective weak mixing angle parameter sin^{2}θ_{eff}^{ℓ} in pp[over ¯]→Z/γ^{*}→μ^{+}μ^{-} events at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider and corresponding to 8.6  fb^{-1} of integrated luminosity. The measured value of sin^{2}θ_{eff}^{ℓ}[μμ]=0.23016±0.00064 is further combined with the result from the D0 measurement in pp[over ¯]→Z/γ^{*}→e^{+}e^{-} events, resulting in sin^{2}θ_{eff}^{ℓ}[comb]=0.23095±0.00040. This combined result is the most precise measurement from a single experiment at a hadron collider and is the most precise determination using the coupling of the Z/γ^{*} to light quarks.

Photoacoustic Imaging-Guided Photothermal Therapy with Tumor-Targeting HA-FeOOH@PPy Nanorods

Cancer theragnosis agents with both cancer diagnosis and therapy abilities would be the next generation of cancer treatment. Recently, nanomaterials with strong absorption in near-infrared (NIR) region have been explored as promising cancer theragnosis agents for bio-imaging and photothermal therapy (PTT). Herein, we reported the synthesis and application of a novel multifunctional theranostic nanoagent based on hyaluronan (HA)-coated FeOOH@polypyrrole (FeOOH@PPy) nanorods (HA-FeOOH@PPy NRs) for photoacoustic imaging (PAI)-guided PTT. The nanoparticles were intentionally designed with rod-like shape and conjugated with tumor-targeting ligands to enhance the accumulation and achieve the entire tumor distribution of nanoparticles. The prepared HA-FeOOH@PPy NRs showed excellent biocompatible and physiological stabilities in different media. Importantly, HA-FeOOH@PPy NRs exhibited strong NIR absorbance, remarkable photothermal conversion capability, and conversion stability. Furthermore, HA-FeOOH@PPy NRs could act as strong contrast agents to enhance PAI, conducting accurate locating of cancerous tissue, as well as precise guidance for PTT. The in vitro and in vivo photothermal anticancer activity results of the designed nanoparticles evidenced their promising potential in cancer treatment. The tumor-bearing mice completely recovered after 17 days of PTT treatment without obvious side effects. Thus, our work highlights the great potential of using HA-FeOOH@PPy NRs as a theranostic nanoplatform for cancer imaging-guided therapy.

Real-time functional optical-resolution photoacoustic microscopy using high-speed alternating illumination at 532 and 1064 nm

Optical-resolution photoacoustic microscopy (OR-PAM), which has been widely used and studied as a noninvasive and in vivo imaging technique, can yield high-resolution and absorption contrast images. Recently, metallic nanoparticles and dyes, such as gold nanoparticles, methylene blue, and indocyanine green, have been used as contrast agents of OR-PAM. This study demonstrates real-time functional OR-PAM images with high-speed alternating illumination at 2 wavelengths. To generate 2 wavelengths, second harmonic generation at 532 nm with an LBO crystal and a pump wavelength of 1064 nm is applied at a pulse repetition rate of 300 kHz. For alternating illumination, an electro-optical modulator is used as an optical switch. Therefore, the A-line rate for the functional image is 150 kHz, which is half of the laser repetition rate. To enable fast signal processing and real-time displays, parallel signal processing using a graphics processing unit (GPU) is performed. OR-PAM images of the distribution of blood vessels and gold nanorods in a BALB/c-nude mouse's ear can be simultaneously obtained with 500 × 500 pixels and real-time display at 0.49 fps.

Upstream Enhancer Elements of Shh Regulate Oral and Dental Patterning

Sonic hedgehog ( Shh) is important in pattern formation during development. Shh transcription is modulated by a long-range regulatory mechanism containing a number of enhancers, which are spread over nearly 850 kb in the mouse genome. Shh enhancers in the nervous system have been found between intron and 430 kb upstream of Shh. Enhancers in the oral cavity, pharynx, lung, gut, and limbs have been discovered between 610 kb and 850 kb upstream of Shh. However, the intergenic region ranging from 430 to 610 kb upstream of Shh remains to be elucidated. In the present study, we found a novel long-range enhancer located 558 kb upstream of Shh. The enhancer showed in vivo activity in oral cavity and whiskers. A targeted deletion from the novel enhancer to mammal reptile conserved sequence 1 (MRCS1), which is a known enhancer of Shh in oral cavity, resulted in supernumerary molar formation, confirming the essential role of this intergenic region for Shh transcription in teeth. Furthermore, we clarified the binding of Lef1/Tcfs to the new enhancer and MRCS1, suggesting that Wnt/β-catenin signaling regulates Shh signaling in the oral cavity via these enhancers.

In vivo photoacoustic monitoring using 700-nm region Raman source for targeting Prussian blue nanoparticles in mouse tumor model

Photoacoustic imaging (PAI) is a noninvasive imaging tool to visualize optical absorbing contrast agents. Due to high ultrasonic resolution and superior optical sensitivity, PAI can be used to monitor nanoparticle-mediated cancer therapy. The current study synthesized Food and Drug Administration-approved Prussian blue (PB) in the form of nanoparticles (NPs) with the peak absorption at 712 nm for photoacoustically imaging tumor-bearing mouse models. To monitor PB NPs from the background tissue in vivo, we also developed a new 700-nm-region stimulated Raman scattering (SRS) source (pulse energy up to 200 nJ and repetition rate up to 50 kHz) and implemented optical-resolution photoacoustic microscopy (OR-PAM). The SRS-assisted OR-PAM system was able to monitor PB NPs in the tumor model with micrometer resolution. Due to strong light absorption at 712 nm, the developed SRS light yielded a two-fold higher contrast from PB NPs, in comparison with a 532-nm pumping source. The proposed laser source involved cost-effective and simple system implementation along with high compatibility with the fiber-based OR-PAM system. The study highlights the OR-PAM system in conjunction with the tunable-color SRS light source as a feasible tool to assist NP-mediated cancer therapy.

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is A_{FB}^{tt[over ¯]}=0.128±0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions.

Evidence for a B_{s}^{0}π^{±} State

We report evidence for a narrow structure, X(5568), in the decay sequence X(5568)→B_{s}^{0}π^{±}, B_{s}^{0}→J/ψϕ, J/ψ→μ^{+}μ^{-}, ϕ→K^{+}K^{-}. This is evidence for the first instance of a hadronic state with valence quarks of four different flavors. The mass and natural width of this state are measured to be m=5567.8±2.9(stat)_{-1.9}^{+0.9}(syst)  MeV/c^{2} and Γ=21.9±6.4(stat)_{-2.5}^{+5.0}(syst)  MeV/c^{2}. If the decay is X(5568)→B_{s}^{*}π^{±}→B_{s}^{0}γπ^{±} with an unseen γ, m(X(5568)) will be shifted up by m(B_{s}^{*})-m(B_{s}^{0})∼49  MeV/c^{2}. This measurement is based on 10.4  fb^{-1} of pp[over ¯] collision data at sqrt[s]=1.96  TeV collected by the D0 experiment at the Fermilab Tevatron collider.

Evidence for Simultaneous Production of J/ψ and ϒ Mesons

We report evidence for the simultaneous production of J/ψ and ϒ mesons in 8.1  fb^{-1} of data collected at sqrt[s]=1.96  TeV by the D0 experiment at the Fermilab pp[over ¯] Tevatron Collider. Events with these characteristics are expected to be produced predominantly by gluon-gluon interactions. In this analysis, we extract the effective cross section characterizing the initial parton spatial distribution, σ_{eff}=2.2±0.7(stat)±0.9(syst)  mb.

Inclusive Production of the X(4140) State in pp[over ¯] Collisions at D0

We present a study of the inclusive production of the X(4140) state with the decay to the J/ψϕ final state in hadronic collisions. Based on 10.4  fb^{-1} of pp[over ¯] collision data collected by the D0 experiment at the Fermilab Tevatron collider, we report the first evidence for the prompt production of an X(4140) state and find the fraction of X(4140) events originating from b hadrons to be f_{b}=0.39±0.07(stat)±0.10(syst). The ratio of the nonprompt X(4140) production rate to the B_{s}^{0} yield in the same channel is R=0.19±0.05(stat)±0.07(syst). The values of the mass M=4152.5±1.7(stat)_{-5.4}^{+6.2}(syst)  MeV and width Γ=16.3±5.6(stat)±11.4(syst)  MeV are consistent with previous measurements.

Search for Violation of CPT and Lorentz Invariance in Bs(0) Meson Oscillations

We present the first search for CPT-violating effects in the mixing of Bs(0) mesons using the full Run II data set with an integrated luminosity of 10.4  fb(-1) of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the CPT-violating asymmetry in the decay Bs(0)→μ(±)Ds(±) as a function of celestial direction and sidereal phase. We find no evidence for CPT-violating effects and place limits on the direction and magnitude of flavor-dependent CPT- and Lorentz-invariance violating coupling coefficients. We find 95% confidence intervals of Δa⊥<1.2×10(-12)  GeV and (-0.8<ΔaT-0.396ΔaZ<3.9)×10(-13)  GeV.

Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element V_{tb}

We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb^{-1} per experiment. The t-channel cross section is measured to be σ_{t}=2.25_{-0.31}^{+0.29} pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in σ_{s+t}=3.30_{-0.40}^{+0.52} pb, without assuming the standard model value for the ratio σ_{s}/σ_{t}. The resulting value of the magnitude of the top-to-bottom quark coupling is |V_{tb}|=1.02_{-0.05}^{+0.06}, corresponding to |V_{tb}|>0.92 at the 95% C.L.

Measurement of the Effective Weak Mixing Angle in pp[over ¯]→Z/γ^{*}→e^{+}e^{-} Events

We present a measurement of the fundamental parameter of the standard model, the weak mixing angle sin^{2}θ_{eff}^{ℓ} which determines the relative strength of weak and electromagnetic interactions, in pp[over ¯]→Z/γ^{*}→e^{+}e^{-} events at a center of mass energy of 1.96 TeV, using data corresponding to 9.7 fb^{-1} of integrated luminosity collected by the D0 detector at the Fermilab Tevatron. The effective weak mixing angle is extracted from the forward-backward charge asymmetry as a function of the invariant mass around the Z boson pole. The measured value of sin^{2}θ_{eff}^{ℓ}=0.23147±0.00047 is the most precise measurement from light quark interactions to date, with a precision close to the best LEP and SLD results.

Tevatron constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quark pairs

Combined constraints from the CDF and D0 Collaborations on models of the Higgs boson with exotic spin J and parity P are presented and compared with results obtained assuming the standard model value JP=0+. Both collaborations analyzed approximately 10  fb(-) of proton-antiproton collisions with a center-of-mass energy of 1.96 TeV collected at the Fermilab Tevatron. Two models predicting exotic Higgs bosons with JP=0- and JP=2+ are tested. The kinematic properties of exotic Higgs boson production in association with a vector boson differ from those predicted for the standard model Higgs boson. Upper limits at the 95% credibility level on the production rates of the exotic Higgs bosons, expressed as fractions of the standard model Higgs boson production rate, are set at 0.36 for both the JP=0- hypothesis and the JP=2+ hypothesis. If the production rate times the branching ratio to a bottom-antibottom pair is the same as that predicted for the standard model Higgs boson, then the exotic bosons are excluded with significances of 5.0 standard deviations and 4.9 standard deviations for the JP=0- and JP=2+ hypotheses, respectively.

Measurement of the B(s)(0) lifetime in the flavor-specific decay channel B(s)(0)→D(s)(-)μ(+)νX

We present an updated measurement of the B(s)(0) lifetime using the semileptonic decays B(s)(0)→D(s)(-)μ(+)νX, with D(s)(-)→ϕπ(-) and ϕ→K(+)K(-) (and the charge conjugate process). This measurement uses the full Tevatron Run II sample of proton-antiproton collisions at √[s]=1.96  TeV, comprising an integrated luminosity of 10.4  fb(-1). We find a flavor-specific lifetime τ(fs)(B(s)(0))=1.479±0.010(stat)±0.021(syst)  ps. This technique is also used to determine the B(0) lifetime using the analogous B(0)→D(-)μ(+)νX decay with D(-)→ϕπ(-) and ϕ→K(+)K(-), yielding τ(B(0))=1.534±0.019(stat)±0.021(syst)  ps. Both measurements are consistent with the current world averages, and the B(s)(0) lifetime measurement is one of the most precise to date. Taking advantage of the cancellation of systematic uncertainties, we determine the lifetime ratio τ(fs)(B(s)(0))/τ(B(0))=0.964±0.013(stat)±0.007(syst).

Measurement of the forward-backward asymmetry in the production of B(±) mesons in pp̄ collisions at √s=1.96 TeV

We present a measurement of the forward-backward asymmetry in the production of B(±) mesons, A(FB)(B(±)), using B(±)→J/ψK(±) decays in 10.4  fb(-1) of pp̄ collisions at sqrt[s]=1.96  TeV collected by the D0 experiment during Run II of the Tevatron collider. A nonzero asymmetry would indicate a preference for a particular flavor, i.e., b quark or ̄b antiquark, to be produced in the direction of the proton beam. We extract A(FB)(B(±)) from a maximum likelihood fit to the difference between the numbers of forward- and backward-produced B(±) mesons. We measure an asymmetry consistent with zero: A(FB)(B(±))=[-0.24±0.41  (stat)±0.19  (syst)]%.

Association of a microRNA-323b polymorphism with the persistence of hepatitis B virus infection by the enhancement of viral replication

Recent studies have shown that some mammalian microRNAs (miRNAs) play a role in antiviral defence. However, little is known about the role of miRNA-323b in hepatitis B virus (HBV)-host interaction. We explored whether single nucleotide polymorphism (SNP) of miRNA-323b affects HBV replication in a Korean HBV cohort. Genotyping was performed in a total of 1439 subjects composed of 404 spontaneously recovered (SR) subjects as normal controls and 1035 chronic carriers (CC) of HBV who were further classified into 313 patients with chronic hepatitis, 305 patients with liver cirrhosis and 417 patients with hepatocellular carcinoma. To confirm the effect of SNP of miRNA-323b on HBV replication in vitro, HepAD38 cells were transfected with miRNA-323b wild type or miRNA-323b SNP plasmid vectors, and HBV replication was induced for 5 days. HBV DNA was isolated and quantified using real-time PCR. The polymorphism rs56103835C>T in the pre-miRNA region of miRNA-323b revealed significant minor allele frequency (0.273). rs56103835C>T SNP showed significantly affect persistence of HBV in CC group compared with SR group (OR = 1.29, P = 0.009 in a codominant model; OR = 1.29, P = 0.03 in a dominant model; and OR = 1.78, P = 0.03 in a recessive model). In vitro, the total intracellular HBV DNA content was significantly reduced by miRNA-323b wild-type plasmid vector transfection (P = 0.014). The polymorphism of miRNA-323b was significantly associated with persistence of HBV by the enhancement of HBV replication (P = 0.021). Our findings provide a novel perspective on the role SNP of miRNAs in host-virus interactions in HBV infection.

Constraints on models for the Higgs boson with exotic spin and parity in VH → Vbb final states

We present constraints on models containing non-standard-model values for the spin J and parity P of the Higgs boson H in up to 9.7 fb(-1) of pp collisions at sqrt[s] = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. These are the first studies of Higgs boson J(P) with fermions in the final state. In the ZH → ℓℓbb, WH → ℓνbb, and ZH → ννbb final states, we compare the standard model (SM) Higgs boson prediction, J(P) = 0(+), with two alternative hypotheses, J(P) = 0(-) and J(P) = 2(+). We use a likelihood ratio to quantify the degree to which our data are incompatible with non-SM J(P) predictions for a range of possible production rates. Assuming that the production rate in the signal models considered is equal to the SM prediction, we reject the J(P) = 0(-) and J(P) = 2(+) hypotheses at the 97.6% CL and at the 99.0% CL, respectively. The expected exclusion sensitivity for a J(P) = 0(-) (J(P) = 2(+)) state is at the 99.86% (99.94%) CL. Under the hypothesis that our data are the result of a combination of the SM-like Higgs boson and either a J(P) = 0(-) or a J(P) = 2(+) signal, we exclude a J(P) = 0(-) fraction above 0.80 and a J(P) = 2(+) fraction above 0.67 at the 95% CL. The expected exclusion covers J(P) = 0(-) (J(P) = 2(+)) fractions above 0.54 (0.47).

Precision measurement of the top quark mass in lepton + jets final States

We measure the mass of the top quark in lepton+jets final states using the full sample of pp collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at sqrt[s] = 1.96 TeV, corresponding to 9.7 fb(-1) of integrated luminosity. We use a matrix element technique that calculates the probabilities for each event to result from tt production or background. The overall jet energy scale is constrained in situ by the mass of the W boson. We measure m(t) = 174.98 ± 0.76 GeV. This constitutes the most precise single measurement of the top-quark mass.

Embolization of percutaneous transhepatic portal venous access tract with N-butyl cyanoacrylate

OBJECTIVE

To evaluate the safety and feasibility of N-butyl cyanoacrylate (N-BCA) embolization of percutaneous transhepatic portal venous access tract and to establish an appropriate technique.

METHODS

40 consecutive patients underwent percutaneous transhepatic portal venous intervention for various reasons. Embolization of percutaneous transhepatic portal venous access tract was performed after the procedure in all of the patients using N-BCA and Lipiodol® (Lipiodol Ultra Fluide; Laboratoire Guerbet, Aulnay-sous-Bois, France) mixture. Immediate ultrasonography and fluoroscopy were performed to evaluate perihepatic haematoma formation and unintended embolization of more than one segmental portal vein. Follow-up CT was performed, and haemoglobin and haematocrit levels were checked to evaluate the presence of bleeding.

RESULTS

Immediate haemostasis was achieved in all of the patients, without development of perihepatic haematoma or unintended embolization of more than one segmental portal vein. Complete embolization of percutaneous access tract was confirmed in 39 out of 40 patients by CT. Seven patients showed decreased haemoglobin and haematocrit levels. Other complications included mild pain at the site of embolization and mild fever, which resolved after conservative management. 16 patients died during the follow-up period owing to progression of the underlying disease.

CONCLUSION

Embolization of percutaneous transhepatic portal vein access tract with N-BCA is feasible and technically safe. With the appropriate technique, N-BCA can be safely used as an alternate embolic material since it is easy to use and inexpensive compared with other embolic materials.

ADVANCES IN KNOWLEDGE

This is the first study to investigate the efficacy of N-BCA for percutaneous transhepatic portal venous access tract embolization.

Observation of s-channel production of single top quarks at the Tevatron

We report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb(-1) per experiment. The measured cross section is σ(s) = 1.29(-0.24)(+0.26) pb. The probability of observing a statistical fluctuation of the background to a cross section of the observed size or larger is 1.8 × 10(-10), corresponding to a significance of 6.3 standard deviations for the presence of an s-channel contribution to the production of single-top quarks.

Measurement of the W boson production charge asymmetry in pp̄→W+X→eν+X events at √s=1.96 TeV

We present a measurement of the W boson production charge asymmetry in pp̄→W+X→eν+X events at a center of mass energy of 1.96 TeV, using 9.7  fb-1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The neutrino longitudinal momentum is determined by using a neutrino weighting method, and the asymmetry is measured as a function of the W boson rapidity. The measurement extends over wider electron pseudorapidity region than previous results and is the most precise to date, allowing for precise determination of proton parton distribution functions in global fits.

Measurement of the direct CP-violating charge asymmetry in Ds ± → ϕ π ± decays

We present a measurement of the direct CP-violating charge asymmetry in Ds+ → ϕ π(±) decays where the ϕ meson decays to K(+)K(-), using the full Run II data set with an integrated luminosity of 10.4  fb-1 of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. The normalized difference A(CP) in the yield of D(s)(+) and D(s)(-) mesons in these decays is measured by fitting the difference between their reconstructed invariant mass distributions. This results in an asymmetry of A(CP) = [-0.38 ± 0.27]%, which is the most precise measurement of this quantity to date. The result is consistent with the standard model prediction of zero CP asymmetry in this decay.

Measurement of associated production of z bosons with charm quark jets in pp collisions at √s=1.96 TeV

We present the first measurements of the ratios of cross sections σ(pp → Z+c jet)/σ(pp → Z+jet) and σ(pp → Z+c jet)/σ(pp → Z+b jet) for the associated production of a Z boson with at least one charm or bottom quark jet. Jets have transverse momentum ​pT(jet)​>20  GeV and pseudorapidity |​η(jet)​|<2.5. These cross section ratios are measured differentially as a function of jet and Z boson transverse momenta, based on 9.7  fb(-1) of pp collisions collected with the D0 detector at the Fermilab Tevatron Collider at √s=1.96  TeV. The measurements show significant deviations from perturbative QCD calculations and predictions from various event generators.

Determination of the individual atomic site contribution to the electronic structure of 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA)

We have studied the element and orbital-specific electronic structure of thin films of 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) using a combination of synchrotron radiation-exited resonant x-ray emission spectroscopy, x-ray absorption spectroscopy, x-ray photoelectron spectroscopy, as well as density functional theory calculations. Resonant and non-resonant x-ray emission spectroscopies were used to measure the C and O 2p partial densities of state in PTCDA. Furthermore, resonant x-ray emission at the C and O K-edges is shown to be able to measure the partial densities of states associated with individual atomic sites. The flat molecular orientation of PTCDA on various substrates is explained in terms of the carbonyl O atom acting as a hydrogen-bond acceptor leading to multiple in-plane intermolecular C=O···H-C hydrogen bonding between carbonyl groups and the perylene core of the neighboring PTCDA molecules. We support this conclusion by comparison of our calculations to measurements of the electronic structure using element-, site-, and orbital-selective C and O K-edge resonant x-ray emission spectroscopy, and photoemission spectroscopy.

Measurement of direct CP violation parameters in B± → J/ψK± and B± → J/ψπ± decays with 10.4 fb-1 of Tevatron data

We present a measurement of the direct CP-violating charge asymmetry in B(±) mesons decaying to J/ψK(±) and J/ψπ(±) where J/ψ decays to μ(+) μ(-), using the full run II data set of 10.4 fb(-1) of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. A difference in the yield of B(-) and B(+) mesons in these decays is found by fitting to the difference between their reconstructed invariant mass distributions resulting in asymmetries of A(J/ψK) = [0.59 ± 0.37]%, which is the most precise measurement to date, and A(J/ψπ) = [-4.2 ± 4.5]%. Both measurements are consistent with standard model predictions.

The band structure of WO3 and non-rigid-band behaviour in Na0.67WO3 derived from soft x-ray spectroscopy and density functional theory

The electronic structure of single-crystal WO3 and Na0.67WO3 (a sodium-tungsten bronze) has been measured using soft x-ray absorption and resonant soft x-ray emission oxygen K-edge spectroscopies. The spectral features show clear differences in energy and intensity between WO3 and Na0.67WO3. The x-ray emission spectrum of metallic Na0.67WO3 terminates in a distinct Fermi edge. The rigid-band model fails to explain the electronic structure of Na0.67WO3 in terms of a simple addition of electrons to the conduction band of WO3. Instead, Na bonding and Na 3s-O 2p hybridization need to be considered for the sodium-tungsten bronze, along with occupation of the bottom of the conduction band. Furthermore, the anisotropy in the band structure of monoclinic γ-WO3 revealed by the experimental spectra with orbital-resolved geometry is explained via density functional theory calculations. For γ-WO3 itself, good agreement is found between the experimental O K-edge spectra and the theoretical partial density of states of O 2p orbitals. Indirect and direct bandgaps of insulating WO3 are determined from extrapolating separations between spectral leading edges and accounting for the core-hole energy shift in the absorption process. The O 2p non-bonding states show upward band dispersion as a function of incident photon energy for both compounds, which is explained using the calculated band structure and experimental geometry.

Measurement of the semileptonic charge asymmetry using B(s)(0) → D(s)μX decays

We present a measurement of the time-integrated flavor-specific semileptonic charge asymmetry in the decays of B(s)(0) mesons that have undergone flavor mixing, a(sl)(s), using B(s)(0)(B(s)(0)) → D(s)(-/+) μ(±) X decays, with D(s)(-/+) → [symbol: see text]π(-/+) and [symbol: see text]→ K(+) K(-), using 10.4 fb(-1) of proton-antiproton collisions collected by the D0 detector during Run II at the Fermilab Tevatron Collider. A fit to the difference between the time-integrated D(s)(-) and D(s)(+) mass distributions of the B(s)(0) and B(s)(0) candidates yields the flavor-specific asymmetry a(sl)(s) = [-1.12 ± 0.74(stat) ± 0.17(syst)]%, which is the most precise measurement and in agreement with the standard model prediction.

Search for the standard model Higgs boson in associated WH production in 9.7 fb(-1) of pp collisions with the D0 detector

We present a search for the standard model Higgs boson in final states with a charged lepton (electron or muon), missing transverse energy, and two or three jets, at least one of which is identified as a b-quark jet. The search is primarily sensitive to WH→ℓνbb production and uses data corresponding to 9.7 fb(-1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron pp Collider at √s = 1.96 TeV. We observe agreement between the data and the expected background. For a Higgs boson mass of 125 GeV, we set a 95% C.L. upper limit on the production of a standard model Higgs boson of 5.2 × σ(SM), where σ(SM) is the standard model Higgs boson production cross section, while the expected limit is 4.7 × σ(SM).

Combined search for the standard model Higgs boson decaying to bb using the D0 run II data set

We present the results of the combination of searches for the standard model Higgs boson produced in association with a W or Z boson and decaying into bb using the data sample collected with the D0 detector in pp collisions at √s = 1.96 TeV at the Fermilab Tevatron Collider. We derive 95% C.L. upper limits on the Higgs boson cross section relative to the standard model prediction in the mass range 100 GeV ≤ M(H) ≤ 150 GeV, and we exclude Higgs bosons with masses smaller than 102 GeV at the 95% C.L. In the mass range 120 GeV ≤ M(H) ≤145 GeV, the data exhibit an excess above the background prediction with a global significance of 1.5 standard deviations, consistent with the expectation in the presence of a standard model Higgs boson.

Search for the standard model Higgs boson in ZH→ℓ(+)ℓ(-)bb production with the D0 detector in 9.7 fb(-1) of pp collisions at √s = 1.96 TeV

We present a search for the standard model (SM) Higgs boson produced in association with a Z boson in 9.7 fb(-1) of pp collisions collected with the D0 detector at the Fermilab Tevatron Collider at √s = 1.96 TeV. Selected events contain one reconstructed Z→e(+)e(-) or Z→μ(+)μ(-) candidate and at least two jets, including at least one jet identified as likely to contain a b quark. To validate the search procedure, we also measure the cross section for ZZ production in the same final state. It is found to be consistent with its SM prediction. We set upper limits on the ZH production cross section times branching ratio for H→bb at the 95% C.L. for Higgs boson masses 90 ≤ M(H) ≤ 150 GeV. The observed (expected) limit for M(H) = 125 GeV is 7.1 (5.1) times the SM cross section.

Evidence for a particle produced in association with weak bosons and decaying to a bottom-antibottom quark pair in higgs boson searches at the tevatron

We combine searches by the CDF and D0 Collaborations for the associated production of a Higgs boson with a W or Z boson and subsequent decay of the Higgs boson to a bottom-antibottom quark pair. The data, originating from Fermilab Tevatron pp collisions at √s = 1.96 TeV, correspond to integrated luminosities of up to 9.7 fb(-1). The searches are conducted for a Higgs boson with mass in the range 100-150 GeV/c(2). We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 120 and 135 GeV/c(2). The largest local significance is 3.3 standard deviations, corresponding to a global significance of 3.1 standard deviations. We interpret this as evidence for the presence of a new particle consistent with the standard model Higgs boson, which is produced in association with a weak vector boson and decays to a bottom-antibottom quark pair.

Search for violation of Lorentz invariance in top quark pair production and decay

Using data collected with the D0 detector at the Fermilab Tevatron Collider, corresponding to 5.3 fb(-1) of integrated luminosity, we search for violation of Lorentz invariance by examining the tt[over ¯] production cross section in lepton+jets final states. We quantify this violation using the standard-model extension framework, which predicts a dependence of the tt[over ¯] production cross section on sidereal time as the orientation of the detector changes with the rotation of the Earth. Within this framework, we measure components of the matrices (c(Q))(μν33) and (c(U))(μν33) containing coefficients used to parametrize violation of Lorentz invariance in the top quark sector. Within uncertainties, these coefficients are found to be consistent with zero.

Measurements of WW and WZ production in W + jets final states in pp collisions

We study WW and WZ production with ℓνqq (ℓ=e,μ) final states using data collected by the D0 detector at the Fermilab Tevatron Collider corresponding to 4.3  fb(-1) of integrated luminosity from pp collisions at sqrt[s]=1.96  TeV. Assuming the ratio between the production cross sections σ(WW) and σ(WZ) as predicted by the standard model, we measure the total WV (V=W,Z) cross section to be σ(WV)=19.6(-3.0)(+3.2)  pb and reject the background-only hypothesis at a level of 7.9 standard deviations. We also use b-jet discrimination to separate the WZ component from the dominant WW component. Simultaneously fitting WW and WZ contributions, we measure σ(WW)=15.9(-3.2)(+3.7)  pb and σ(WZ)=3.3(-3.3)(+4.1)  pb, which is consistent with the standard model predictions.

Measurement of the W boson mass with the D0 detector

We present a measurement of the W boson mass using data corresponding to 4.3  fb(-1) of integrated luminosity collected with the D0 detector during Run II at the Fermilab Tevatron pp collider. With a sample of 1,677,394 W → eν candidate events, we measure M(W) = 80.367 ± 0.026  GeV. This result is combined with an earlier D0 result determined using an independent Run II data sample, corresponding to 1  fb(-1) of integrated luminosity, to yield M(W) = 80.375 ± 0.023  GeV.

Search for universal extra dimensions in pp collisions

We present a search for Kaluza-Klein (KK) particles predicted by models with universal extra dimensions (UED) using a data set corresponding to an integrated luminosity of 7.3 fb(-1), collected by the D0 detector at a pp center-of-mass energy of 1.96 TeV. The decay chain of KK particles can lead to a final state with two muons of the same charge. This signature is used to set a lower limit on the compactification scale of R(-1)>260 GeV in a minimal UED model.

Search for charged massive long-lived particles

We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2  fb(-1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron pp collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss (dE/dx) inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gauginolike charginos below 267 GeV and Higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.

Evidence for spin correlation in t ̅t production

We present a measurement of the ratio of events with correlated t and t ̅t spins to the total number of t ̅t events. This ratio f is evaluated using a matrix-element-based approach in 729 t ̅t candidate events with a single lepton ℓ (electron or muon) and at least four jets. The analyzed p ̅p collisions data correspond to an integrated luminosity of 5.3 fb(-1) and were collected with the D0 detector at the Fermilab Tevatron collider operating at a center-of-mass energy √s=1.96 TeV. Combining this result with a recent measurement of f in dileptonic final states, we find f in agreement with the standard model. In addition, the combination provides evidence for the presence of spin correlation in t ̅t events with a significance of more than 3 standard deviations.

Search for doubly charged Higgs boson pair production in pp¯ collisions at √s=1.96 TeV

We present a search for pair production of doubly charged Higgs bosons in the processes qq¯→H(++)H(--) decaying through H(±±)→τ(±)τ(±),μ(±)τ(±),μ(±)μ(±). The search is performed in pp¯ collisions at a center-of-mass energy of √s = 1.96 TeV using an integrated luminosity of up to 7.0 fb(-1) collected by the D0 experiment at the Fermilab Tevatron Collider. The results are used to set 95% C.L. limits on the pair production cross section of doubly charged Higgs bosons and on their mass for different H(±±) branching fractions. Models predicting different H(±±) decays are investigated. Assuming B(H(±±)→τ(±)τ(±))=1 yields an observed (expected) lower limit on the mass of a left-handed H(L)(±±) boson of 128 (116) GeV and assuming B(H(±±)→μ(±)τ(±))=1 the corresponding limits are 144 (149) GeV. In a model with B(H(±±)→τ(±)τ(±))=B(H(±±)→μ(±)τ(±))=B(H(±±)→μ(±)μ(±))=1/3, we obtain M(H(L)(±±))>130 (138) GeV.

Intravitreal bevacizumab and ranibizumab injections for patients with polypoidal choroidal vasculopathy

PURPOSE

To compare the effectiveness of intravitreal injection of bevacizumab and ranibizumab in patients with treatment-naïve polypoidal choroidal vasculopathy (PCV).

METHODS

A total of 66 and 60 eyes of 121 consecutive patients who received intravitreal bevacizumab (1.25 mg) or ranibizumab (0.5 mg) injection for treatment of PCV were retrospectively reviewed. After initial three loading injections by month, injection was performed as needed. Main outcome measures included best corrected visual acuity (BCVA), foveal center thickness (FCT) as assessed by spectral domain optical coherence tomography (SD-OCT), and change in polypoidal lesion on indocyanine green angiography (ICGA).

RESULTS

At 12 months, average number of injections was 4.72±1.84 in the bevacizumab group and 5.52±1.54 in the ranibizumab group. Mean logarithm of the minimum angle of resolution of BCVA from baseline at 12 months after injection improved by 0.11 in the bevacizumab group (P=0.02) and by 0.14 in the ranibizumab group (P=0.01). Average FCT decreased from 368±62.48 to 298±40.77 μm in the bevacizumab group (P=0.01) and from 371±50.79 to 286±36.93 μm in the ranibizumab group (P=0.01). Polyp regression rate was 24.2% (16 eyes out of 66 eyes) in the bevacizumab group and 23.3% (14 eyes out of 60 eyes) in the ranibizumab group. There was no statistically significant difference in BCVA improvement achieved, FCT improvement achieved, and polyp regression rate between groups.

CONCLUSION

Intravitreal injections of bevacizumab and ranibizumab have similar effects in stabilization of visual acuity, macular edema, and regression of polypoidal complex with PCV eyes.

Wγ production and limits on anomalous WWγ couplings in pp collisions at sqrt[s] = 1.96 TeV

We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(→lν) + γ production in eγ and μγ final states. Using data corresponding to an integrated luminosity of 4.2  fb(-1) collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process pp → Wγ + X → lνγ + X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WWγ couplings for data from hadron colliders: -0.4<Δκ(γ)<0.4 and -0.08<λ(γ)<0.07 at the 95% C.L.

Search for a fermiophobic and standard model Higgs boson in diphoton final states

We present a search for the standard model Higgs boson and a fermiophobic Higgs boson in the diphoton final states based on 8.2  fb(-1) of pp collisions at sqrt[s]=1.96  TeV collected with the D0 detector at the Fermilab Tevatron Collider. No excess of data above background predictions is observed and upper limits at the 95% C.L. on the cross section multiplied by the branching fraction are set which are the most restrictive to date. A fermiophobic Higgs boson with a mass below 112.9 GeV is excluded at the 95% C.L.

Search for neutral minimal supersymmetric standard model Higgs bosons decaying to tau pairs produced in association with b quarks in pp collisions at √s = 1.96 TeV

We report results from a search for neutral Higgs bosons produced in association with b quarks using data recorded by the D0 experiment at the Fermilab Tevatron Collider and corresponding to an integrated luminosity of 7.3 fb(-1). This production mode can be enhanced in several extensions of the standard model (SM) such as in its minimal supersymmetric extension (MSSM) at high tanβ. We search for Higgs bosons decaying to tau pairs with one tau decaying to a muon and neutrinos and the other to hadrons. The data are found to be consistent with SM expectations, and we set upper limits on the cross section times branching ratio in the Higgs boson mass range from 90 to 320 GeV/c(2). We interpret our result in the MSSM parameter space, excluding tanβ values down to 25 for Higgs boson masses below 170 GeV/c(2).

Precision measurement of the ratio B(t→Wb)/B(t→Wq) and extraction of V(tb)

We present a measurement of the ratio of top quark branching fractions R=B(t→Wb)/B(t→Wq), where q can be a d, s, or b quark, in the lepton+jets and dilepton tt final states. The measurement uses data from 5.4 fb(-1) of pp collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure R=0.90±0.04, and we extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |V(tb)| as |V(tb)|=0.95±0.02, assuming unitarity of the 3×3 CKM matrix.

Search for a fourth generation t' Quark in p ̄p collisions at √s = 1.96 TeV

We present a search for pair production of a fourth generation t' quark and its antiparticle, followed by their decays to a W boson and a jet, based on an integrated luminosity of 5.3 fb(-1) of proton-antiproton collisions at √s = 1.96  TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the t' ̄t' production cross section that exclude at the 95% C.L. a t' quark that decays exclusively to W+jet with a mass below 285 GeV. We observe a small excess in the μ+jets channel which reduces the mass range excluded compared to the expected limit of 320 GeV in the absence of a signal.