Development of a plasma-based 3D printing system for enhancing the biocompatibility of 3D scaffold

Fused deposition modeling (FDM) is a three-dimensional (3D) printing technology typically used in tissue engineering. However, 3D-printed row scaffolds manufactured using material extrusion techniques have low cell affinity on the surface and an insufficient biocompatible environment for desirable tissue regeneration. Thus, in this study, plasma treatment was used to render surface modification for enhancing the biocompatibility of 3D-printed scaffolds. We designed a plasma-based 3D printing system with dual heads comprising a plasma device and a regular 3D FDM printer head for a layer-by-layer nitrogen plasma treatment. Accordingly, the wettability, roughness, and protein adsorption capability of the 3D-printed scaffold significantly increased with the plasma treatment time. Hence, the layer-by-layer plasma-treated (LBLT) scaffold exhibited significantly enhanced cell adhesion and proliferation in an in vitro assay. Furthermore, the LBLT scaffold demonstrated a higher tissue infiltration and lower collagen encapsulation than those demonstrated by a non-plasma-treated scaffold in an in vivo assay. Our approach has great potential for various tissue-engineering applications via the adjustment of gas or precursor levels. In particular, this system can fabricate scaffolds capable of holding a biocompatible surface on an entire 3D-printed strut. Thus, our one-step 3D printing approach is a promising platform to overcome the limitations of current biocompatible 3D scaffold engineering.

Providing essential clinical care for non-COVID-19 patients in a Seoul metropolitan acute care hospital amidst ongoing treatment of COVID-19 patients

We assessed infection control efforts by comparing data collected over 20 weeks during a pandemic under a dual-track healthcare system. A decline in non-COVID-19 patients visiting the emergency department by 37.6% (P<0.01) was observed since admitting COVID-19 cases. However, patients with acute myocardial infarction (AMI), stroke, severe trauma and acute appendicitis presenting for emergency care did not decrease. Door-to-balloon time (34.3 (± 11.3) min vs 22.7 (± 8.3) min) for AMI improved significantly (P<0.01) while door-to-needle time (55.7 (± 23.9) min vs 54.0 (± 18.0) min) in stroke management remained steady (P=0.80). Simultaneously, time-sensitive care involving other clinical services, including patients requiring chemotherapy, radiation therapy and haemodialysis did not change.

Erratum: Evolution of π^{0} Suppression in Au+Au Collisions from sqrt[s_{NN}]=39 to 200 GeV [Phys. Rev. Lett. 109, 152301 (2012)]

This corrects the article DOI: 10.1103/PhysRevLett.109.152301.

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

The PHENIX collaboration presents first measurements of low-momentum (0.4<p_{T}<3  GeV/c) direct-photon yields from Au+Au collisions at sqrt[s_{NN}]=39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially enhanced with respect to expectations from prompt processes, similar to the yields observed in Au+Au collisions at sqrt[s_{NN}]=200. Analyzing the photon yield as a function of the experimental observable dN_{ch}/dη reveals that the low-momentum (>1  GeV/c) direct-photon yield dN_{γ}^{dir}/dη is a smooth function of dN_{ch}/dη and can be well described as proportional to (dN_{ch}/dη)^{α} with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high p_{T} (>5  GeV/c), but when results from different collision energies are compared, an additional sqrt[s_{NN}]-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.

Tissue-Engineered Acellularized Valve Xenografts: A Comparative Animal Study between Plain Acellularized Xenografts and Autologous Endothelial Cell Seeded Acellularized Xenografts

Background

Acellularized valve xenografts are considered a promising way of overcoming the inherent limitations of current prosthetic valves. The aim of this study was to compare the biological responses of an autologous endothelial cell seeded acellularized xenograft (AAX) and a plain acellularized xenograft (PAX) implanted in the pulmonary valve leaflet in the same animal.

Methods

Endothelial cells were isolated and cultured from the jugular vein of goats. Porcine valve leaflets were acellularized with Nacl-SDS, and for AAX, leaflets were then seeded with autologous endothelial cells. A PAX and an AAX were implanted as double pulmonary valve leaflet replacement in the same animal in a goat model (n=6). After sacrifice, the implanted valve leaflet tissues were retrieved and analyzed visually and under a light microscope.

Results and Conclusions

Six animals were sacrificed as scheduled during the short-term (6 and 24 hours), mid-term (1 week and 1 month) and long-term (3 and 6 months). Gross and ultrasonographic examinations revealed good valve function with no thrombosis but with slight thickening. Microscopic analysis of the leaflets showed abundant cellular ingrowth into the acellularized leaflets over time. The role of endothelial cell seeding remains controversial. This animal experiment demonstrates the practical feasibility of using acellularized valve xenografts.

Influence of rabbit notochordal cells on symptomatic intervertebral disc degeneration: anti-angiogenic capacity on human endothelial cell proliferation under hypoxia

OBJECTIVES

Symptomatic degenerative disc disease (DDD) is associated with neovascularization and nerve ingrowth into intervertebral discs (IVDs). Notochordal cells (NCs) are key cells that may lead to regeneration of IVDs. However, their activities under conditions of hypoxia, the real environment of IVD, are not well known. We hypothesized that NCs may inhibit neovascularization by interacting with endothelial cells (ECs) under hypoxia.

DESIGN

Human IVDs were isolated and cultured to produce nucleus pulposus (NP) cell conditioned medium (NPCM). Immortalized human microvascular ECs were cultured in NPCM with notochordal cell-rich rabbit nucleus pulposus cells (rNC) under hypoxia. Vascular endothelial growth factor (VEGF), vascular cell adhesion molecule (VCAM), and interleukin-8 (IL-8) were analyzed by ELISA. Focal adhesion kinase (FAK), filamentous actin (F-actin), and platelet-derived growth factor (PDGF) were evaluated to investigate EC activity. Wound-healing migration assays were performed to examine EC migration.

RESULTS

The VEGF level of EC cells cultured in NPCM was significantly higher under hypoxia compared to normoxia. VEGF expression was significantly decreased, and FAK, F-actin, PDGF expression were inhibited when ECs were cocultured with rNCs under hypoxia. ECs cocultured with rNC in NPCM showed significantly decreased migratory activity compared to those without rNC under hypoxia.

CONCLUSIONS

The angiogenic capacity of ECs was significantly inhibited by NCs under hypoxia via a VEGF-related pathway. Our results suggest that NCs may play a key role in the development of IVDs by inhibiting vascular growth within the disc, and this may be a promising novel therapeutic strategy for targeting vascular ingrowth in symptomatic DDD.

Whole-breast US following mammography and breast MRI in newly diagnosed breast cancer patients: can it be more than just a guidance tool for biopsy?

AIM

To evaluate the role of ultrasound (US) following magnetic resonance imaging (MRI) and mammography in patients with newly diagnosed breast cancers by assessing the additional cancer detection rate of US.

MATERIAL AND METHODS

Two hundred and twenty-five women who had undergone 225 MRI examinations followed by US were included. An US-detected additional cancer was defined as a lesion detected using breast US that had not been detected by MRI, and which was shown to be malignant at histopathology. The rate of additional cancer detection, incidence of additional malignancies, positive predictive value (PPV), and false-positive (FP) rate were analysed. Factors associated with an increase in the additional cancer detection rate were analysed.

RESULTS

The additional cancer detection rate was 0% (0/225) for the ipsilateral breast and 0.9% (2/225) for the contralateral breast, and the PPVs were 0% (0/5) and 100% (2/2), respectively. The overall TP:FP ratio was 0.4 (2:5). The additional cancer detection rate was higher for cases with moderate and severe background parenchymal enhancement than cases with minimal and mild background parenchymal enhancement (p=0.003). The additional cancer detection rate for cases with moderate and severe background parenchymal enhancement was 5.7% (2/35) for the contralateral breast (p=0.003).

CONCLUSION

Preoperative breast US following MRI and mammography can help clinicians screen for contralateral cancers with an additional detection rate of 0.9%. Moreover, whole-breast US might be a useful contralateral screening modality in cases with moderate or marked parenchymal enhancement on breast MRI.

Centrality-Dependent Modification of Jet-Production Rates in Deuteron-Gold Collisions at √[s(NN)]=200 GeV

Jet production rates are measured in p+p and d+Au collisions at sqrt[s_{NN}]=200  GeV recorded in 2008 with the PHENIX detector at the Relativistic Heavy Ion Collider. Jets are reconstructed using the R=0.3 anti-k_{t} algorithm from energy deposits in the electromagnetic calorimeter and charged tracks in multiwire proportional chambers, and the jet transverse momentum (p_{T}) spectra are corrected for the detector response. Spectra are reported for jets with 12<p_{T}<50  GeV/c, within a pseudorapidity acceptance of |η|<0.3. The nuclear-modification factor (R_{dAu}) values for 0%-100% d+Au events are found to be consistent with unity, constraining the role of initial state effects on jet production. However, the centrality-selected R_{dAu} values and central-to-peripheral ratios (R_{CP}) show large, p_{T}-dependent deviations from unity, challenging the conventional models that relate hard-process rates and soft-particle production in collisions involving nuclei.

Measurements of Elliptic and Triangular Flow in High-Multiplicity 3He+Au Collisions at √(s(NN))=200 GeV

We present the first measurement of elliptic (v(2)) and triangular (v(3)) flow in high-multiplicity (3)He+Au collisions at √(s(NN))=200  GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in (3)He+Au and in p+p collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the (3)He+Au system. The collective behavior is quantified in terms of elliptic v(2) and triangular v(3) anisotropy coefficients measured with respect to their corresponding event planes. The v(2) values are comparable to those previously measured in d+Au collisions at the same nucleon-nucleon center-of-mass energy. Comparisons with various theoretical predictions are made, including to models where the hot spots created by the impact of the three (3)He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.

Comparison of Cancer Yields and Diagnostic Performance of Screening Mammography vs. Supplemental Screening Ultrasound in 4394 Women with Average Risk for Breast Cancer

PURPOSE

The effectiveness of supplemental screening ultrasound (US) was investigated in women ≥ 40 years at average risk for breast cancer regardless of breast parenchymal density. A total of 4394 women at average risk and having previously undergone screening mammography were classified as the mammography group. 

MATERIALS AND METHODS

Of 4394 women, 2005 underwent screening US after a final assessment of category 1 or 2 on screening mammography, and were categorized as the US group. Category 0, 4, and 5 on mammography and 3, 4, and 5 on US were defined as positive. The cancer yields per 1000 women and diagnostic performance of two groups were compared.

RESULTS

The total cancer and invasive cancer yields for the mammography group were 3.0 (95 % confidence interval 1.6, 5.1) and 2.0 (95 % CI, 0.9, 3.9) per 1000 women, higher than the US values of 2.0 (0.5, 5.1) and 1.0 (0.1, 3.6), not statistically significant. The specificity, accuracy, and positive predictive value (PPV) for mammography were 88.90 % (87.93, 89.81), 88.85 % (87.88, 89.76), and 2.61 % (1.39, 4.41), significantly higher than the US values of 69.07 % (66.99, 71.09), 69.13 % (67.05, 71.15), and 0.64 % (0.18, 1.64). The short-term follow-up rate of mammography was 5.51 % (4.85, 6.22), significantly lower than the rate of 26.58 (24.66, 28.58) for US. 

CONCLUSION

Supplemental screening US in mammographically negative breasts can find additional carcinomas in women at average risk but is not as effective as screening mammography because of the lower cancer yield, invasive cancer yield, specificity, accuracy, PPV and a high short-term follow-up rate.

Measurement of Long-Range Angular Correlation and Quadrupole Anisotropy of Pions and (Anti)Protons in Central d+Au Collisions at sqrt[s_{NN}]=200 GeV

We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d+Au and minimum bias p+p collisions at sqrt[s_{NN}]=200 GeV. The charged hadron is measured at midrapidity |η|<0.35, and the energy is measured at large rapidity (-3.7<η<-3.1, Au-going direction). An enhanced near-side angular correlation across |Δη|>2.75 is observed in d+Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v_{2} for inclusive charged hadrons at midrapidity up to p_{T}=4.5 GeV/c. We also present the measurement of v_{2} for identified π^{±} and (anti)protons in central d+Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p+Pb at sqrt[s_{NN}]=5.02 TeV. The magnitude of the mass ordering in d+Au is found to be smaller than that in p+Pb collisions, which may indicate smaller radial flow in lower energy d+Au collisions.

Additional malignant breast lesions detected on second-look US after breast MRI vs. additional malignant lesions detected on initial US in breast cancer patients: comparison of US characteristics

PURPOSE

The purpose of our study was to review and compare the US findings of synchronous malignant breast lesions other than the index cancer additionally detected on second-look US with those detected on initial US, and therefore to determine differing characteristics that may aid in diagnosis and essentially improve the performance of the initial US examination.

MATERIALS AND METHODS

A retrospective review of 39 mammographically occult synchronous malignant lesions other than the index cancer from 38 patients was performed (21 lesions: detected on second-look US, 18 lesions: detected on initial US). All patients underwent initial mammography, bilateral whole breast US (BWBU) and breast MRI, and all lesions were confirmed pathologically by biopsy or preoperative localization.

RESULTS

Additional malignant breast lesions detected on both initial US and second-look US tended to be subtle and often did not show classic malignant findings. Second-look US lesions (median, 7.0 mm; range, 3 - 22 mm) tended to be smaller than initial US lesions (median, 9.0 mm; range 3 - 45 mm), although the difference was not statistically significant (p = 0.134). Second-look US lesions also showed no posterior acoustic features (p = 0.037) and a significantly higher proportion of lesions with circumscribed or indistinct margins compared to initial US lesions (p = 0.042). Second-look US lesions were significantly subareolar or relatively far (> 5 cm) from the nipple than initial US lesions (p = 0.048).

CONCLUSION

Second-look US lesions showed more subtle findings of posterior acoustic features and margins, and tended to be subareolar or relatively far from the nipple compared to initial US lesions. However, both groups showed subtle US findings and there was no significant difference in other features.

Cold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d + Au collisions at √sNN = 200 GeV

The PHENIX experiment has measured open heavy-flavor production via semileptonic decay over the transverse momentum range 1 < p(T) < 6  GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p + p collisions at √sNN = 200  GeV. In central d+Au collisions, relative to the yield in p + p collisions scaled by the number of binary nucleon-nucleon collisions, a suppression is observed at forward rapidity (in the d-going direction) and an enhancement at backward rapidity (in the Au-going direction). Predictions using nuclear-modified-parton-distribution functions, even with additional nuclear-p(T) broadening, cannot simultaneously reproduce the data at both rapidity ranges, which implies that these models are incomplete and suggests the possible importance of final-state interactions in the asymmetric d + Au collision system. These results can be used to probe cold-nuclear-matter effects, which may significantly affect heavy-quark production, in addition to helping constrain the magnitude of charmonia-breakup effects in nuclear matter.

A risk-adapted approach using US features and FNA results in the management of thyroid incidentalomas identified by 18F-FDG PET

PURPOSE

To assess the risk of malignancy of thyroid incidentalomas found on 18F-FDG PET/CT by US features and cytologic results, and to evaluate the clinical usage of a combination of US features and cytology for post-FNA management of thyroid incidentalomas on 18F-FDG PET/CT.

MATERIALS AND METHODS

From September 2006 to December 2008, 132 patients with 134 thyroid incidentalomas detected on 18F-FDG PET/CT who had undergone US and US-FNA were included in this study. We evaluated the malignancy rate of thyroid incidentalomas in different subgroups subdivided by US features and US-FNA cytology results. Several variables were compared between the benign and malignant group.

RESULTS

The risk of malignancy was 58.2 % (78/132) in thyroid incidentalomas on 18F-FDG PET/CT. Age, gender, and tumor size were not significantly different between the malignant and benign group.  Malignancy rate of thyroid incidentalomas was significantly higher in the suspicious malignant (88.9 %) than in the probably benign group (11.3 %) on US (p < 0.001). Malignancy rates were high in thyroid nodules with "malignancy", "suspicious for malignancy", or "follicular neoplasm" on cytologic results, regardless of US features. However, malignancy rates of thyroid incidentalomas with "unsatisfactory" or "benign" results on cytology were higher in the suspicious malignant (75 %, 12.5 %, respectively) than in the probably benign (0 %) group on US. 

CONCLUSIONS

This study demonstrated that the risk of malignancy was high in thyroid incidentalomas on 18F-FDG PET/CT even without suspicious US features. However, there was no malignancy in nodules with no suspicious US features and benign cytology. Based on these results, we concluded that US may not replace FNA in the diagnosis of PET incidentalomas, and that a follow-up may be considered of thyroid incidentalomas with benign cytology and no suspicious US features.

False negative results in axillary lymph nodes by ultrasonography and ultrasonography-guided fine-needle aspiration in patients with invasive ductal carcinoma

PURPOSE

For preoperative evaluation of ALN status using various methods, axillary US and subsequent US-FNA targeting the LNs suspicious for metastasis are the most widely used methods. The purpose of our study was to assess the rate of false-negative results at preoperative ultrasonography (US) and ultrasonography guided fine needle aspiration (US-FNA) of axillary lymph nodes (ALNs) in breast cancer patients and the number of false-negative lymph nodes, and to evaluate factors related to ALN false negative results in US and/or US-FNA in patients diagnosed with invasive ductal carcinoma.

MATERIALS AND METHODS

Among 317 patients who underwent surgery for invasive ductal carcinoma during 2009 in Severance hospital, 237 patients had no reported ALN metastasis on preoperative US-FNA and US. We retrospectively reviewed the subsequent surgical pathology and clinicopathologic findings and assessed the rate of false-negative results from US and US-FNA of ALN and the number of false-negative lymph node. We performed univariate analysis and multivariate logistic regression analysis to evaluate the relationships between variable clinicopathologic factors (T-stage, position of ALN, hormone receptors, histologic grade, lymphovascular invasion (LVI) and performance of FNA) and cytologic results (false-negative result; FNALN and true negative result; TNALN) from US and/or US-FNA of ALN.

RESULTS

The rate of false-negative results was 42.4 % (59/139) in both US and US-FNA of ALN but among them, 57.6 % (34/59) showed only one metastatic ALN. Breast cancer with FNALN on US and US-FNA was significantly related to positive estrogen receptor (p = 0.003), positive progesterone receptor (p = 0.001), and the presence of LVI (p = 0.004) in univariate analysis. In multivariate analysis, high T stages (≥ T2, odds ratio (OR) 4.007, p = 0.004) and LVI (OR 7.951, p = 0.001) showed significant correlation with FNALN on US and US-FNA.

CONCLUSION

More than half of patients with FNALN showed only one metastatic ALN. LVI and high T-stages were the most important factors attributed to FNALN on US and US-FNA in patients with invasive ductal carcinoma.

Quadrupole anisotropy in dihadron azimuthal correlations in central d+Au collisions at √(s(NN))=200 GeV

The PHENIX collaboration at the Relativistic Heavy Ion Collider (RHIC) reports measurements of azimuthal dihadron correlations near midrapidity in d+Au collisions at √(s(NN))=200 GeV. These measurements complement recent analyses by experiments at the Large Hadron Collider (LHC) involving central p+Pb collisions at √(s(NN))=5.02 TeV, which have indicated strong anisotropic long-range correlations in angular distributions of hadron pairs. The origin of these anisotropies is currently unknown. Various competing explanations include parton saturation and hydrodynamic flow. We observe qualitatively similar, but larger, anisotropies in d+Au collisions at RHIC compared to those seen in p+Pb collisions at the LHC. The larger extracted v2 values in d+Au are consistent with expectations from hydrodynamic calculations owing to the larger expected initial-state eccentricity compared with that from p+Pb collisions. When both are divided by an estimate of the initial-state eccentricity the scaled anisotropies follow a common trend with multiplicity that may extend to heavy ion data at RHIC and the LHC, where the anisotropies are widely thought to arise from hydrodynamic flow.

Nuclear modification of ψ', χc, and J/ψ production in d+Au collisions at sqrt[s(NN)]=200 GeV

We present results for three charmonia states (ψ', χc, and J/ψ) in d+Au collisions at |y|<0.35 and sqrt[s(NN)]=200  GeV. We find that the modification of the ψ' yield relative to that of the J/ψ scales approximately with charged particle multiplicity at midrapidity across p+A, d+Au, and A+A results from the Super Proton Synchrotron and the Relativistic Heavy Ion Collider. In large-impact-parameter collisions we observe a similar suppression for the ψ' and J/ψ, while in small-impact-parameter collisions the more weakly bound ψ' is more strongly suppressed. Owing to the short time spent traversing the Au nucleus, the larger ψ' suppression in central events is not explained by an increase of the nuclear absorption owing to meson formation time effects.

Quantitative analysis on the urban flood mitigation effect by the extensive green roof system

Extensive green-roof systems are expected to have a synergetic effect in mitigating urban runoff, decreasing temperature and supplying water to a building. Mitigation of runoff through rainwater retention requires the effective design of a green-roof catchment. This study identified how to improve building runoff mitigation through quantitative analysis of an extensive green-roof system. Quantitative analysis of green-roof runoff characteristics indicated that the extensive green roof has a high water-retaining capacity response to rainfall of less than 20 mm/h. As the rainfall intensity increased, the water-retaining capacity decreased. The catchment efficiency of an extensive green roof ranged from 0.44 to 0.52, indicating reduced runoff comparing with efficiency of 0.9 for a concrete roof. Therefore, extensive green roofs are an effective storm water best-management practice and the proposed parameters can be applied to an algorithm for rainwater-harvesting tank design.

Evolutionary Dynamics of a Highly Pathogenic Type 2 Porcine Reproductive and Respiratory Syndrome Virus: Analyses of Envelope Protein-Coding Genes

Porcine reproductive and respiratory syndrome virus (PRRSV) has long been an economically devastating swine viral disease. The recent emergence of a highly pathogenic type 2 PRRSV with high mobility and mortality in China, spreading in Vietnam, Laos, and Thailand has placed neighbouring countries at risk. This study applied a codon-based extension of the Bayesian relaxed clock model and the fixed effects maximum-likelihood method to investigate and compare the evolutionary dynamics of type 2 PRRSV for all of known structural envelope protein-coding genes. By comparing the highly pathogenic type 2 PRRSV clade against the typical type 2 PRRSV clade, this study demonstrated that the highly pathogenic clade evolved at high rates in all of the known structural genes but did not display rapid evolutionary dynamics compared with typical type 2 PRRSV. In contrast, the ORF3, ORF5 and ORF6 genes of the highly pathogenic clade evolved in a qualitatively different manner from the genes of the typical clade. At the population level, several codons of the sequence elements that were involved in viral neutralization, as well as codons that were associated with in vitro attenuation/over-attenuation, were predicted to be selected differentially between the typical clade and the highly pathogenic clade. The results of this study suggest that the multigenic factors of the envelope protein-coding genes contribute to diversifying the biological properties (virulence, antigenicity, etc.) of the highly pathogenic clade compared with the typical clade of type 2 PRRSV.

Medium modification of jet fragmentation in Au+Au collisions at √[s(NN)]=200 GeV measured in direct photon-hadron correlations

The jet fragmentation function is measured with direct photon-hadron correlations in p+p and Au+Au collisions at √[s(NN)]=200 GeV. The p(T) of the photon is an excellent approximation to the initial p(T) of the jet and the ratio z(T)=p(T)(h)/p(T)(γ) is used as a proxy for the jet fragmentation function. A statistical subtraction is used to extract the direct photon-hadron yields in Au+Au collisions while a photon isolation cut is applied in p+p. I(AA), the ratio of hadron yield opposite the photon in Au+Au to that in p+p, indicates modification of the jet fragmentation function. Suppression, most likely due to energy loss in the medium, is seen at high z(T). The associated hadron yield at low z(T) is enhanced at large angles. Such a trend is expected from redistribution of the lost energy into increased production of low-momentum particles.

Discordant elastography images of breast lesions: how various factors lead to discordant findings

PURPOSE

To evaluate the rate of the elastography-pathology discordance, and evaluate which various factors have an effect on discordant elastography images (DEI) of breast lesions.

MATERIALS AND METHODS

Elastography images of 284 pathologically confirmed breast lesions of 233 patients were evaluated. Elasticity scores were compared to pathology results, and lesions were divided into 4 groups: benign concordant/discordant, and malignant concordant/discordant. The rate of DEI among benign and malignant lesions was calculated and compared. Patient, lesion factors and image adequacy were compared among the concordant and discordant groups for analysis.

RESULTS

Among the 284 breast lesions, 225 (79.2%) were benign, and 59 (20.8%) were malignant. The rate of DEI among malignant lesions was significantly higher than in benign lesions, i. e., 52.5 vs. 3.1% (p < 0.001). Discordant images were more significantly seen in patients with extremely dense breasts on mammography in benign lesions, 42.9 vs. 11.9% (p = 0.034). Discordant images were more significantly seen in malignant lesions < 10 mm or ≥ 20 mm (p = 0.006), and those with inadequate images (64.5 vs. 35.5%, p < 0.001).

CONCLUSION

The rate of DEI was higher in malignant lesions than in benign lesions. Dense breast parenchyma, lesion size and image adequacy showed significance in discordant images of elastography which need consideration in image acquisition and interpretation.

A Bayesian phylogeographical analysis of type 1 porcine reproductive and respiratory syndrome virus (PRRSV)

Understanding viral transmission is an important factor for the effective prevention one of the most devastating swine diseases, porcine reproductive and respiratory syndrome. Focusing on molecular epidemiology of type 1 PRRSV, this study analysed a large ORF5 dataset collected worldwide from 1991 to 2012 using a coalescent-based Bayesian Markov chain Monte Carlo approach. The results suggested that the virus diversified into unique subpopulations in Russia & Belarus and Italy approximately 100 years ago. Previously unreported consecutive diffusions of the virus were identified, which showed that some countries, such as Spain and Germany, acted as distribution sources to some extent. This study also provided statistical evidence for the existence of an ORF5-based phylogeographical structure of type 1 PRRSV, in which the virus tended to cluster by geographical locations more tightly than expected by chance. In contrast to this tight geographical structure, the evolution of the ORF5 gene, based on mapping of non-synonymous/synonymous substitutions, was best described by a non-homogeneous process that could be implicated as a mechanism for viral immune evasion.

Cold-nuclear-matter effects on heavy-quark production in d+Au collisions at sqrt[S(NN)]=200 GeV

The PHENIX experiment has measured electrons and positrons at midrapidity from the decays of hadrons containing charm and bottom quarks produced in d+Au and p+p collisions at sqrt[S(NN)]=200 GeV in the transverse-momentum range 0.85 ≤ p(T)(e) ≤ 8.5 GeV/c. In central d+Au collisions, the nuclear modification factor R(dA) at 1.5<p(T)<5 GeV/c displays evidence of enhancement of these electrons, relative to those produced in p+p collisions, and shows that the mass-dependent Cronin enhancement observed at the Relativistic Heavy Ion Collider extends to the heavy D meson family. A comparison with the neutral-pion data suggests that the difference in cold-nuclear-matter effects on light- and heavy-flavor mesons could contribute to the observed differences between the π(0) and heavy-flavor-electron nuclear modification factors R(AA).

Interobserver variability and diagnostic performance in US assessment of thyroid nodule according to size

PURPOSE

To evaluate the interobserver variability for US assessments of thyroid nodules and analyze the diagnostic performances of US assessments in thyroid nodules according to nodule size.

MATERIALS AND METHODS

This was an IRB-approved retrospective study with waiver of informed consent. A total of 400 surgically-confirmed thyroid nodules were included. Nodules were divided into 4 groups by size; group 1 (nodule size < 5 mm), group 2 (5 mm ≤ nodule size < 10 mm), group 3 (10 mm ≤ nodule size < 20 mm), and group 4 (nodule size ≥ 20 mm). Three experienced (7 - 10 years) radiologists retrospectively reviewed the US images. Agreement of each US descriptor and final US assessment, and diagnostic performances were calculated in each group and compared.

RESULTS

Composition represented substantial or good agreement (k = 0.719 - 0.89). Margin showed the lowest agreement (k = 0.322 - 0.365). Individual kappa values for final assessment according to nodule size were as follows: group 1 (k = 0.674), group 2 (k = 0.596), group 3 (k = 0.674), and group 4 (k = 0.673). Specificity, PPV, and accuracy were significantly different among the groups with different size (p value < 0.05) and lowest in group 1. NPV, specificity, PPV and accuracy except PPV of observer 3 increased with nodule size (p < 0.05).

CONCLUSION

Interobserver agreements were relatively good (k = 0.637) in final US assessment regardless of nodule size in experienced radiologists. High false-positive rate was observed in US assessment in nodules less than 5 mm in maximum diameter.

Is US-guided core needle biopsy (CNB) enough in probably benign nodules with interval growth?

PURPOSE

To investigate whether ultrasound-guided 14-gauge core needle biopsy (US-CNB) is efficient in the diagnosis of probably benign lesions showing interval growth on follow-up US. 

MATERIALS AND METHODS

From March 2008 to August 2009, 116 breast lesions in 113 women (mean age: 41.2 years, range: 19 - 63 years) which were initially assessed as category 3 showing interval growth on follow-up US underwent US-CNB, and subsequent US-guided vacuum-assisted excision, surgical excision or follow-up US for at least 12 months. Diagnostic performances of US-CNB were evaluated with histopathologic results and follow-up US as standard reference. Clinical features of the patient and lesions characteristics including follow-up interval (I), the most increased diameter (D), D per I, increased volume (%V) and %V per I were calculated and compared.

RESULTS

Of the 116 lesions, 4 lesions were diagnosed as malignancy and 112 as benign on final pathology. Malignancy rate of probably benign lesions showing interval growth was 3.4 % (4/116). Incorrect biopsy rate was 0.9 % (1/116). Palpability or newly developed suspicious US features were more associated with malignancy, 75.0 to 13.4 % and 50.0 to 25.9 %, respectively, but without significance (p = 0.063 and 0.290). Significant differences were seen in average rank when comparing between benign and malignancy in D, %V, D per follow-up interval (I), and %V/I (p = 0.037, 0.017, 0.043 and 0.009, respectively).

CONCLUSION

US-CNB is an efficient diagnostic method for probably benign lesions showing interval growth, with discordant biopsy rate of 0.9 %.

Evolution of π(0) suppression in Au+Au collisions from √(s(NN))=39 to 200 GeV

Neutral-pion π(0) spectra were measured at midrapidity (|y|<0.35) in Au+Au collisions at √(s(NN))=39 and 62.4 GeV and compared with earlier measurements at 200 GeV in a transverse-momentum range of 1<p(T)<10 GeV/c. The high-p(T) tail is well described by a power law in all cases, and the powers decrease significantly with decreasing center-of-mass energy. The change of powers is very similar to that observed in the corresponding spectra for p+p collisions. The nuclear modification factors (R(AA)) show significant suppression, with a distinct energy, centrality, and p(T) dependence. Above p(T)=7 GeV/c, R(AA) is similar for √(s(NN))=62.4 and 200 GeV at all centralities. Perturbative-quantum-chromodynamics calculations that describe R(AA) well at 200 GeV fail to describe the 39 GeV data, raising the possibility that, for the same p(T) region, the relative importance of initial-state effects and soft processes increases at lower energies. The p(T) range where π(0) spectra in central Au+Au collisions have the same power as in p+p collisions is ≈5 and 7 GeV/c for √(s(NN))=200 and 62.4 GeV, respectively. For the √(s(NN))=39 GeV data, it is not clear whether such a region is reached, and the x(T) dependence of the x(T)-scaling power-law exponent is very different from that observed in the √(s(NN))=62 and 200 GeV data, providing further evidence that initial-state effects and soft processes mask the in-medium suppression of hard-scattered partons to higher p(T) as the collision energy decreases.

Comparison of the underestimation rate in cases with ductal carcinoma in situ at ultrasound-guided core biopsy: 14-gauge automated core-needle biopsy vs 8- or 11-gauge vacuum-assisted biopsy

OBJECTIVE

The objective of this study was to compare the underestimation rate of invasive carcinoma in cases with ductal carcinoma in situ (DCIS) at percutaneous ultrasound-guided core biopsies of breast lesions between 14-gauge automated core-needle biopsy (ACNB) and 8- or 11-gauge vacuum-assisted biopsy (VAB), and to determine the relationship between the lesion type (mass or microcalcification on radiological findings) and the DCIS underestimation rate.

METHODS

We retrospectively reviewed imaging-guided biopsies of breast lesions performed from February 2003 to August 2008. 194 lesions were diagnosed as DCIS at ultrasound-guided core biopsy: 138 lesions in 132 patients by 14-gauge ACNB, and 56 lesions in 56 patients by 8- or 11-gauge VAB. The histological results of the core biopsy samples were correlated with surgical specimens. The clinical and radiological findings were also reviewed. The histological DCIS underestimation rates were compared between the two groups and were analysed for differences according to the clinical and radiological characteristics of the lesions.

RESULTS

The DCIS underestimation rate was 47.8% (66/138) for 14-gauge ACNB and 16.1% (9/56) for VAB (p<0.001). According to the lesion type on sonography, DCIS underestimation was 43.4% (63/145) in masses (47.6% using ACNB and 15.8% using VAB; p=0.012) and 24.5% (12/49) in microcalcifications (50.0% using ACNB and 16.2% using VAB; p=0.047).

CONCLUSION

The underestimation rate of invasive carcinoma in cases with DCIS at ultrasound-guided core biopsies was significantly higher for ACNB than for VAB. Furthermore, this difference does not change according to the lesion type on ultrasound. Therefore, ultrasound-guided VAB can be a useful method for the diagnosis of DCIS lesions presented as either mass or microcalcification.

Simvastatin inhibits osteoclast differentiation by scavenging reactive oxygen species

Osteoclasts, together with osteoblasts, control the amount of bone tissue and regulate bone remodeling. Osteoclast differentiation is an important factor related to the pathogenesis of bone-loss related diseases. Reactive oxygen species (ROS) acts as a signal mediator in osteoclast differentiation. Simvastatin, which inhibits 3-hydroxy-3-methylglutaryl coenzyme A, is a hypolipidemic drug which is known to affect bone metabolism and suppresses osteoclastogenesis induced by receptor activator of nuclear factor-κB ligand (RANKL). In this study, we analyzed whether simvastatin can inhibit RANKL-induced osteoclastogenesis through suppression of the subsequently formed ROS and investigated whether simvastatin can inhibit H2O2-induced signaling pathways in osteoclast differentiation. We found that simvastatin decreased expression of tartrate-resistant acid phosphatase (TRAP), a genetic marker of osteoclast differentiation, and inhibited intracellular ROS generation in RAW 264.7 cell lines. ROS generation activated NF-κB, protein kinases B (AKT), mitogen-activated protein kinases signaling pathways such as c-JUN N-terminal kinases, p38 MAP kinases as well as extracellular signal- regulated kinase. Simvastatin was found to suppress these H2O2-induced signaling pathways in osteoclastogenesis. Together, these results indicate that simvastatin acts as an osteoclastogenesis inhibitor through suppression of ROS-mediated signaling pathways. This indicates that simvastatin has potential usefulness for osteoporosis and pathological bone resorption.

Suppression of back-to-back hadron pairs at forward rapidity in d+Au collisions at √s(NN)=200 GeV

Back-to-back hadron pair yields in d+Au and p+p collisions at √s(NN)=200 GeV were measured with the PHENIX detector at the Relativistic Heavy Ion Collider. Rapidity separated hadron pairs were detected with the trigger hadron at pseudorapidity |η|<0.35 and the associated hadron at forward rapidity (deuteron direction, 3.0<η<3.8). Pairs were also detected with both hadrons measured at forward rapidity; in this case, the yield of back-to-back hadron pairs in d+Au collisions with small impact parameters is observed to be suppressed by a factor of 10 relative to p+p collisions. The kinematics of these pairs is expected to probe partons in the Au nucleus with a low fraction x of the nucleon momenta, where the gluon densities rise sharply. The observed suppression as a function of nuclear thickness, p(T), and η points to cold nuclear matter effects arising at high parton densities.

Cold nuclear matter effects on J/ψ yields as a function of rapidity and nuclear geometry in d+A collisions at sqrt[s(NN)]=200 GeV

We present measurements of J/ψ yields in d+Au collisions at sqrt[s(NN)]=200  GeV recorded by the PHENIX experiment and compare them with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/ψ rapidity (-2.2<y<2.4) with high statistical precision and are compared with two theoretical models: one with nuclear shadowing combined with final state breakup and one with coherent gluon saturation effects. In order to remove model dependent systematic uncertainties we also compare the data to a simple geometric model. The forward rapidity data are inconsistent with nuclear modifications that are linear or exponential in the density weighted longitudinal thickness, such as those from the final state breakup of the bound state.

Cross section and parity-violating spin asymmetries of W± boson production in polarized p + p collisions at sqrt[s] = 500 GeV

Large parity-violating longitudinal single-spin asymmetries A(L)(e+) = -0.86(-0.14) (+0.30) and A(L)(e-) = 0.88(-0.71) (+0.12) are observed for inclusive high transverse momentum electrons and positrons in polarized p+p collisions at a center-of-mass energy of sqrt[s] = 500 GeV with the PHENIX detector at RHIC. These e± come mainly from the decay of W± and Z0 bosons, and their asymmetries directly demonstrate parity violation in the couplings of the W± to the light quarks. The observed electron and positron yields were used to estimate W± boson production cross sections for the e± channels of σ(pp → W+ X) × BR(W+ → e+ ν(e)) = 144.1 ± 21.2(stat)(-10.3) (+3.4) (syst) ± 21.6(norm)  pb, and σ(pp → W- X) × BR(W- → e- ν[over ¯](e)) = 31.7 ± 12.1(stat)(-8.2) (+10.1) (syst) ± 4.8(norm)  pb.

Value of specimen radiographs in diagnosing multifocality of thyroid cancer

BACKGROUND

Specimen radiography has been used widely to evaluate the complete excision of calcified breast lesions but has not been evaluated for thyroid cancer.

METHODS

Specimen radiographs were evaluated retrospectively to identify additional cancers that were demonstrated only as calcifications. Receiver operating characteristic curve analysis was performed to compare the combination of specimen radiography and ultrasonography versus ultrasonography alone for detecting multifocality.

RESULTS

Some 122 thyroid cancer specimens were obtained from 122 patients between January and April 2008. Specimen radiography detected 27 cancers (18.5 per cent) not detected by ultrasonography. Diagnoses were changed after evaluation of specimen radiographs in three of these patients. The area under the curve of the combination of specimen radiography and ultrasonography was significantly higher than that of ultrasonography alone (P = 0.005).

CONCLUSION

Specimen radiography is a potentially useful tool for diagnosing cancer type and predicting the extent of thyroid cancer.

Active reassortment of H9 influenza viruses between wild birds and live-poultry markets in Korea

Surveillance of H9 avian influenza viruses in Korean live-poultry markets from September 2004 through October 2007 was carried out to investigate active reassortment between wild migratory birds and domestic poultry in Korea. Antigenic and phylogenetic analyses showed that most of the isolates belong to the previous Korean H9N2-like lineage and differ from the southeastern Chinese strains. Interestingly, the Ck/Korea/LPM77/06 group (genotype B) and Dk/Korea/LPM248/07 group (genotype C) showed unique properties distinct from those of other Korean H9N2 strains. Although the HA genes of these two groups belong to Korean H9N2-like lineage, the PA genes closely resemble those of the Chinese Y280-like lineage. In addition, the PB2 genes of the Dk/Korea/LPM248/07 group were closely related to those isolated from migratory birds. Several other isolates also clustered within the H9N2 B genotype, an indication that there are at least two predominant H9N2 influenza genotypes in Korea. Another isolate, Dk/Korea/LPM71/06, was identified as an H9N1 subtype, the first ever discovered in Korean live-poultry markets. These findings reveal that reassortment of Korean H9 influenza viruses has occurred frequently in live-poultry markets and may have been mediated by introduction of genetic material from viruses circulating among migratory wild birds to domestic birds. Consequently, the new dominant H9N2 genotypes have become established in Korean live-poultry markets through continued reassortment.

Ecology of H3 avian influenza viruses in Korea and assessment of their pathogenic potentials

To determine the genetic origins of novel H3 avian influenza viruses of chickens and ducks in Korea, genetic characterization of H3 avian influenza viruses isolated from live poultry markets and migratory aquatic birds in South Korea during 2004–2006 was conducted. Phylogenetic analysis revealed that at least four novel genotypes of H3N2 and two genotypes of H3N6 avian influenza viruses were co-circulating in backyard poultry of Korea. The viruses were reassortants between H9N2 viruses of Korean chickens and unknown influenza viruses of migratory birds. Genetic comparison of H3 viruses from live bird markets with those from wild bird isolates revealed that certain gene segments of wild bird isolates are related closely to those of Korean group H9N2 viruses isolated from live poultry markets in 2003. Furthermore, animal-challenge studies demonstrated that the pathogenicity of certain avian H3 influenza viruses was altered due to reassortment, leading to H3 avian influenza viruses in Korea that can potentially expand their host range to include mammals. These studies emphasize the continuing need to monitor backyard poultry at live poultry markets to better understand interspecies transmission and the emergence of novel influenza viruses that have the potential to infect humans.

Identification of DNA copy-number aberrations by array-comparative genomic hybridization in patients with schizophrenia

Chromosomal abnormalities are implicated as important markers for the pathogenesis in patients with schizophrenia. In this study, with using bacterial artificial chromosome (BAC) array-based comparative genomic hybridization (CGH), we analyzed DNA copy-number changes among 30 patients with schizophrenia. The most frequent changes were partial gain of Xq23 (52%) and loss of 3q13.12 (32%). Other frequent gains were found in: 1p, 6q, 10p, 11p, 11q, 14p, and 15q regions, and frequent losses were found in: 2p, 9q, 10q, 14q, 20q, and 22q regions. The set of abnormal regions was confirmed by real-time PCR (9q12, 9q34.2, 11p15.4, 14q32.33, 15q15.1, 22q11.21, and Xq23). All real-time PCR results were consistent with the array-CGH results. Therefore, it is suggested that array-CGH and real-time PCR analysis could be used as powerful tools in screening for schizophrenia-related genes. Our results might be useful for further exploration of candidate genomic regions in the pathogenesis of schizophrenia.

Merlin facilitates ubiquitination and degradation of transactivation-responsive RNA-binding protein

The Nf2 tumor suppressor codes for merlin, a protein whose function is largely unknown. We have previously demonstrated a novel interaction between merlin and TRBP, which inhibits the oncogenic activity of TRBP. In spite of the significance of their functional interaction, its molecular mechanism still remains to be elucidated. In this report, we investigated how merlin inhibits the oncogenic activity of TRBP in association with cell growth conditions. In the human embryonic kidney 293 cell line, the level of endogenous merlin increased, whereas that of endogenous TRBP significantly decreased along with the increase in cell confluence. We demonstrated that the carboxyl-terminal region of TRBP was responsible for this phenomenon using stable cell lines expressing deletion mutants of TRBP. The overexpression of merlin decreased the protein level of TRBP, and the ubiquitin-like subdomain of merlin's FERM domain was important for this activity. We also demonstrated that TRBP is ubiquitinylated and the ubiquitinylated forms of TRBP are accumulated by ectopically expressed merlin or cell confluence in the presence of MG132, a proteasome inhibitor. Furthermore, we showed that the regulation of TRBP in response to cell confluence was abolished upon knockdown of merlin expression by specific small interfering RNA. Finally, we showed that ectopically expressed merlin restored cell-cell contact inhibition in cells stably expressing TRBP but not in TRBPDeltac. These results suggest that merlin is involved in the regulation of TRBP protein level by facilitating its ubiquitination in response to such cues as cell-cell contacts.

Comparative analysis on the 5'-untranslated region of bovine viral diarrhea virus isolated in Korea

Samples of 249 bovine abortuses, one intestine, and four diarrheal stools from 254 cows were collected, and bovine viral diarrhea virus (BVDV) was detected by reverse transcription-polymerase chain reaction (RT-PCR). Subsequently, virus isolation was preformed with PCR-positive samples, and then PCR product of 5^′-untranslated region (UTR) of BVDV isolate was sequenced and analyzed. Among the samples collected, 20 (from 17 bovine abortuses, one intestine, and two diarrheal stools) were positive for BVDV RT-PCR; four BVDVs (from two bovine abortuses, one intestine, and one diarrheal stool) were isolated. When the four isolates were biotyped in cell culture, one BVDV isolate from a bovine abortus was cytopathic and the others were non-cytopathic. In addition, three isolates were genotyped as BVDV-1 and one isolate from a diarrheal stool as BVDV-2. In phylogenetic analysis, it suggested that the BVDV-2 isolate in Korea is closer to the North American strains than Asian strains. This is the first report on the identification and isolation of BVDV-2 in Korea.

Color stability of glass-ionomers and polyacid-modified resin-based composites in various environmental solutions

PURPOSE

To evaluate the degree of color stability of glass-ionomers (GIs) and polyacid modified resin-based composites (PMRBCs) in various environmental solutions.

MATERIALS AND METHODS

Seven polyacid-based esthetic restorative materials were used: three chemical-cured GIs, one resin-modified GI and three polyacid-modified RBCs. A light-cured resin-based composite (RBC) (Z 100) was used as a control. Disk type specimens were prepared and were aged in four different solutions (deionized water, 0.1 mole acetic acid solution, 75% ethanol, and 10% hydrogen peroxide solution) for 1, 7, 14, 21, 28, and 56 days. The specimens were kept at 37 degrees C throughout the study. Color coefficients (CIE L*a*b*) were measured by a reflection spectrophotometer with SCE mode, and the surface of specimens was examined by a stereo zoom microscope.

RESULTS

In deionized water, all specimens showed an acceptable color stability. All of the GIs and PMRBCs showed significant color change in 0.1 mole acetic acid solution. The light-cured resin-modified GI showed a significant color change in 75% ethanol solutions. 10% hydrogen peroxide solution resulted in degradation and a high degree of color change for chemical-cured GIs. The light-cured resin-modified GI and PMRBCs showed high color change in 10% hydrogen peroxide solution. The light-cured RBC (Control), showed excellent color stability in all experimental solutions.

Surgical anatomy of the anterior ethmoidal canal in ethmoid roof

OBJECTIVES/HYPOTHESIS

This study was undertaken to examine three main relationships. First, the distance and angle from the anterior ethmoidal canal to the limen nasi and the sill were measured. Second, the location of the anterior ethmoidal canal was examined in relation to the lamellas and the skull base. Third, the existence of bony defects in the canal and the course of the canal through the anterior cranial fossa were studied.

STUDY DESIGN

This study employed both sagittal computed tomography and cadaver dissection.

METHODS

Seventy sagittally divided heads from randomly chosen Korean adult cadavers were used. Sagittal computed tomography was performed on all specimens. Then they were meticulously dissected under a surgical microscope.

RESULTS

The mean distance and angle between the limen nasi and the anterior ethmoidal canal were 49.0 mm and 54.5 degrees, respectively. The anterior ethmoidal canal was located between the second and third lamella in 61 of 70 cases. In 60 of 70 cases it was attached to the base of the skull, and in the remaining 10 cases it ran 2 to 3 mm below the skull base. When viewed from the superior side, the course of the anterior ethmoidal canal formed a diagonal line from the lateral to the medial side. Partial bony defects of the anterior ethmoidal canal were observed in eight cases, and complete bony defects in none.

CONCLUSION

This study provides surgeons with a better understanding of the anatomy of the anterior ethmoidal canal.

Structural basis of non-specific lipid binding in maize lipid-transfer protein complexes revealed by high-resolution X-ray crystallography

Non-specific lipid-transfer proteins (nsLTPs) are involved in the movement of phospholipids, glycolipids, fatty acids, and steroids between membranes. Several structures of plant nsLTPs have been determined both by X-ray crystallography and nuclear magnetic resonance. However, the detailed structural basis of the non-specific binding of hydrophobic ligands by nsLTPs is still poorly understood. In order to gain a better understanding of the structural basis of the non-specific binding of hydrophobic ligands by nsLTPs and to investigate the plasticity of the fatty acid binding cavity in nsLTPs, seven high-resolution (between 1.3 A and 1.9 A) crystal structures have been determined. These depict the nsLTP from maize seedlings in complex with an array of fatty acids.A detailed comparison of the structures of maize nsLTP in complex with various ligands reveals a new binding mode in an nsLTP-oleate complex which has not been seen before. Furthermore, in the caprate complex, the ligand binds to the protein cavity in two orientations with equal occupancy. The volume of the hydrophobic cavity in the nsLTP from maize shows some variation depending on the size of the bound ligands. The structural plasticity of the ligand binding cavity and the predominant involvement of non-specific van der Waals interactions with the hydrophobic tail of the ligands provide a structural explanation for the non-specificity of maize nsLTP. The hydrophobic cavity accommodates various ligands from C10 to C18. The C18:1 ricinoleate with its hydroxyl group hydrogen bonding to Ala68 possibly mimics cutin monomer binding which is of biological importance. Some of the myristate binding sites in human serum albumin resemble the maize nsLTP, implying the importance of a helical bundle in accommodating the non-specific binding of fatty acids.

Comparative analysis of alpha-stat and pH-stat strategies with a membrane oxygenator during deep hypothermic circulatory arrest in young pigs

Using young pigs, this study compared the strategies of alpha-stat and pH-stat during deep hypothermic circulatory arrest (DHCA) for the cooling time of brains during the induction of hypothermia and rewarming time with cardiopulmonary bypass (CPB); the cerebral perfusion rate and metabolism rate, and the ratio of these 2 rates; and the extent of the cerebral edema development after circulatory arrest. Fourteen young pigs were assigned to 1 of 2 strategies of gas management. Cerebral blood flow was measured with a cerebral venous outflow technique. With CPB, core cooling was initiated and continued until the nasopharyngeal temperature fell below 20 degrees C. The flow rate was set at 2,500 ml/min. Once the temperature reached below 20 degrees C, the animals were subjected to DHCA for 40 min. During the cooling period, the acid-base balance was maintained using either alpha-stat or pH-stat strategy. After DHCA, the body was rewarmed to the normal body temperature. The animals then were sacrificed, and we measured the brain water content. The cerebral perfusion and metabolism rates were measured before the onset of CPB, before cooling, before DHCA, 15 min after rewarming, and upon the completion of rewarming. The cooling time was significantly shorter with alpha-stat than with pH-stat strategy while no significant differences were observed in the rewarming time between groups. Also, no significant differences were found in cerebral blood flow volume, metabolic rate, or flow/metabolic rate ratio between groups. In each group, the cerebral blood flow volume, metabolic rate, and flow/metabolic rate ratio showed significant differences in body temperature. Brain water content showed no significant differences between the 2 groups. In summary, this study found no significant differences between alpha-stat and pH-stat strategies, except in the cooling time. The cooling time was rather shorter with the alpha-stat than with the pH-stat strategy.

Cylindrical microcavity laser based on the evanescent-wave-coupled gain

A microcavity laser based on the gain only in the evanescent field region of whispering gallery modes has been demonstrated. A cylindrical microcavity of 125 microm diam was surrounded by rhodamine 6G dye molecules in an ethanol solution of lower refractive index such that whispering gallery modes of the microcavity underwent laser oscillation when the dye molecules in the evanescent field region outside the cavity were excited by a second harmonic of a Nd:YAG laser. For particular pumping spots, single-mode laser oscillation of a transverse magnetic mode was observed at about 600 nm with associated cavity Q of 3x10(7).

Efficient diffusive reflector-type diode side-pumped Nd:YAG rod laser with an optical slope efficiency of 55%

We fabricated a compact diode side-pumped Nd:YAG laser with a diffusive reflector, in which the diode laser power is transferred directly into the threefold symmetric diffusive cavity through long narrow slits. With a 7.5% output coupler in a linear resonator, we obtained 62.4-W multimode output power with an optical slope efficiency of 53.4% at a diode power of 182 W, which corresponds to an optical-to-optical efficiency of 34.3%. The optical slope efficiency increased to 55.5% when we used an 11% output coupler. From the leakage power analysis method, the pumping efficiency was measured to be approximately 82%. We discuss the thermal lens and the slope efficiency with respect to absorbed power that is derived from the measured pumping efficiency.

Rabbit model of cardiopulmonary bypass

Mainly because of technical problems, the use of rabbits as a cardiopulmonary bypass (CPB) animal model with direct cannulation of the ascending aorta is known to be extremely difficult. The objectives of this study were the establishment of a CPB model in rabbits with direct cannulation of the ascending aorta, and the evaluation of the protective effect of steroid on the development of brain edema during circulatory arrest (CA) in an established rabbit CPB model. Fifteen New Zealand white rabbits were divided into three groups; control CA group, CA with Trendelenberg position, and CA with Trendelenberg position and steroid administration. After anesthetic induction and tracheostomy, median sternotomy was performed. An aortic cannula (3.3 mm) and a venous cannula (14 Fr) were inserted into the ascending aorta and the right atrium, respectively. The CPB circuit consisted of a roller pump and a bubble oxygenator. With 120-150 ml of blood, the priming volume of the circuit was approximately 450 ml, and CPB at a flow rate of 80-85 ml/kg/min was initiated. Blood in the priming solution was obtained from donor rabbits through cardiac puncture. Ten minutes later, CA with cessation of CPB was established for 40 min at 20 degrees C (rectal temperature). After CA, CPB was restarted with a 20 min period of rewarming. Ten minutes after weaning, the animal was sacrificed. Between 1 and 2 g of the brain was removed and the water content was determined and compared between groups. CPB with CA was successfully performed in all cases, with a flow rate of 60-100 ml/kg/min maintained throughout the CPB procedure. At that time, blood gases were reasonably maintained and aortic pressure ranged from 35 to 55 mmHg. After weaning from CPB, all hearts resumed beating spontaneously. Among the three groups, there were no statistically significant differences in the water content of the brain. These results indicate that: (1) if the proper technique is used, CPB in rabbits with direct cannulation of the ascending aorta is a reliable procedure, and (2) the effect of steroid on the prevention of brain edema related to the Trendelenburg position during CA is not established within the scope of this study.

Observation of Q-spoiling ef fects on the resonance modes from a noncircularly deformed liquid jet

Spectral changes in fluorescence and lasing spectra were observed from a noncircularly deformed ink-doped ethanol jet, which was induced by a lateral gas flow. The distortion parameter was determined from the analysis of diffraction patterns to be as much as ~10%. Q -spoiling effects were clearly observed in the appearance of high- Q (~10(7)) modes in fluorescence and their disappearance in lasing. From the behavior of resonance modes, we concluded that the effective Q does not decrease so rapidly as predicted by the relation obtained from the ray-optics model. We also found that the signals leak out, with a wide angular spreading, mainly from near the boundary of the major axis, even for a large distortion parameter.

Optical vortices produced with a nonspiral phase plate

We present simple methods to produce optical vortices on the axis of beam propagation with nonspiral phase plates. We show that a phase plate that provides linear phase retardation on one half of a laser beam produces optical vortices, which is demonstrated experimentally by use of a thickness-varying glass platelet. We also demonstrate and explain that mixed dislocations of a bent edge dislocation transform into a pair of vortices with opposing topological charges.

Single-particle scattering effects on the resonance modes of microdroplets

Scattering patterns captured at two different directions from ink-doped ethanol droplets containing submicrometer-sized particles, which had been pumped by nanosecond pulses, were obtained simultaneously. By use of ray optics we interpreted the various scattering patterns of the lasing in droplets. The scattering image of one side and the spectral image of the opposite side were also detected simultaneously. We observed that particles scatter with similar output couplings among modes of the same order. We also found that a single particle could react to modes of different orders with different output couplings.

Homogenized stress analysis in a dental implant system

In this study, the stress state occurring at each trabecular due to three different types of dental implant is investigated by a homogenization technique, in which the trabecular structure is assumed to be composed of repeating hexagonal units. This technique helps make a proper material model of bone and to analyse such a non-homogeneous structure at the level of an individual microstructural unit. Stress analyses with the homogenization technique show a much higher stress level in the sponge bone, compared to those with conventional FEM. It also shows that even a minor lateral force results in crucial stresses in the dental implant system. The stress states of the mandible with a hemisphere-rooted implant and a wedge type implant show similar levels, while those with a rectangular-rooted implant result in higher stresses. It is suggested that the distance between the implant tip and cortical bone be kept far enough apart to prevent stress concentrations in the mandible.