Pre-operative enhanced magnetic resonance imaging combined with clinical features predict early recurrence of hepatocellular carcinoma after radical resection.

BACKGROUND: Indentifying predictive factors for postoperative recurrence of hepatocellular carcinoma (HCC) has great significance for patient prognosis. AIM: To explore the value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) enhanced magnetic resonance imaging (MRI) combined with clinical features in predicting early recurrence of HCC after resection. METHODS: A total of 161 patients with pathologically confirmed HCC were enrolled. The patients were divided into early recurrence and non-early recurrence group based on the follow-up results. The clinical, laboratory, pathological results and Gd-EOB-DTPA enhanced MRI imaging features were analyzed. RESULTS: Of 161 patients, 73 had early recurrence and 88 were had non-early recurrence. Univariate analysis showed that patient age, gender, serum alpha-fetoprotein level, the Barcelona Clinic Liver Cancer stage, China liver cancer (CNLC) stage, microvascular invasion (MVI), pathological satellite focus, tumor size, tumor number, tumor boundary, tumor capsule, intratumoral necrosis, portal vein tumor thrombus, large vessel invasion, nonperipheral washout, peritumoral enhancement, hepatobiliary phase (HBP)/tumor signal intensity (SI)/peritumoral SI, HBP peritumoral low signal and peritumoral delay enhancement were significantly associated with early recurrence of HCC after operation. Multivariate logistic regression analysis showed that patient age, MVI, CNLC stage, tumor boundary and large vessel invasion were independent predictive factors. External data validation indicated that the area under the curve of the combined predictors was 0.861, suggesting that multivariate logistic regression was a reasonable predictive model for early recurrence of HCC. CONCLUSION: Gd-EOB-DTPA enhanced MRI combined with clinical features would help predicting the early recurrence of HCC after operation.

Tunable collective dynamics of ellipsoidal Quincke particles.

Collective behaviors in active systems become dramatically complicated in the presence of chirality. In this study, we show that ellipsoidal Quincke particles driven by an electric field exhibit flexible and tunable chirality because of the tilting of the spinning axis. As the tilting torque decreases with the increase of angular speed, the motion of individual particles transforms from localized circle motion to global rolling. However, because of the anisotropic shape and the resulting anisotropic polar interactions, it is dynamically easier for ellipsoids to bind and form rotating structures rather than to align their velocities. In dense systems, the suppression of velocity aligning produces transient dense clusters which produce dynamic heterogeneity. The formation and dissociation of dense clusters prohibit the emergence of large-scale collective motions and limit the amplitude of density fluctuations. These findings demonstrate that collective dynamics and thus the scale of density fluctuations in active systems with tunable chirality can be well controlled. This has potential applications in exploring disordered hyperuniform states.

Activity waves and freestanding vortices in populations of subcritical Quincke rollers.

Virtually all of the many active matter systems studied so far are made of units (biofilaments, cells, colloidal particles, robots, animals, etc.) that move even when they are alone or isolated. Their collective properties continue to fascinate, and we now understand better how they are unique to the bulk transduction of energy into work. Here we demonstrate that systems in which isolated but potentially active particles do not move can exhibit specific and remarkable collective properties. Combining experiments, theory, and numerical simulations, we show that such subcritical active matter can be realized with Quincke rollers, that is, dielectric colloidal particles immersed in a conducting fluid subjected to a vertical DC electric field. Working below the threshold field value marking the onset of motion for a single colloid, we find fast activity waves, reminiscent of excitable systems, and stable, arbitrarily large self-standing vortices made of thousands of particles moving at the same speed. Our theoretical model accounts for these phenomena and shows how they can arise in the absence of confining boundaries and individual chirality. We argue that our findings imply that a faithful description of the collective properties of Quincke rollers need to consider the fluid surrounding particles.

Synchronized fractionation and phase separation in binary colloids.

Fractionation is necessary for self-assembly in multicomponent mixtures. Here, reversible fractionation and crystallization are realized and studied in two-dimensional binary colloids which are supersaturated by enhancing the attraction between colloidal particles. As a deep and fast supersaturation results in gels with a uniform distribution of binary particles, a gradual quasistatic supersaturation process leads to a two-step crystallization in which small particles and large particles are fractionated as coexisting crystal and liquid phases respectively. Fractionation occurs as well in the quasistatic melting of gels. We show that the synchronized fractionation and phase separation arises from the competition between the size-dependent repulsion and the tunable attraction. The results in this study demonstrate a robust mechanism of fractionation via phase separation, and have important implication in understanding the reversible formation of membraneless organelles in living cells.

Can the pathway of stepwise nucleation be predicted and controlled?

Predicting the critical nucleus size and the nucleation barrier is of central importance in controlling the dynamics of nucleation. However, as the nucleation of a crystal involves intermediate states, the prediction becomes inaccessible with currently available models. Here, we show that based on single-particle level observations, the properties of crystal nuclei in a microscopic stepwise nucleation (MSN) can be well-quantified by incorporating the size and structure order parameter into the formula of free energy without prior knowledge of interfacial tension. The quantified free energy reveals that the intermediate structures arise from thermodynamics rather than kinetics. Precritical and postcritical nuclei are distinct not only in structure but also in the mechanism of crystalline ordering. The relative stability of intermediate structures and the pathway of nucleation can be well-controlled by supercooling. Our studies offer a successful approach to quantify MSN and shed new light on resolving the long-standing discrepancies between simulations and experiments.

Pair aligning improved motility of Quincke rollers.

Density-dependent speed is studied in a two-dimensional active colloid in which the colloidal particles are propelled by an external electric field via a Quincke rotation. Above the critcal electric field, dense dynamic clusters form spotaneously, in which the particles are highly aligned in velocity and move much faster than isolated units. Detailed observations on pair collision reveal that the alignment of velocity is induced by the long-ranged hydrodynamic interactions and the improvement of speed in the clusters arises from pair aligning in which two particles are closely paired and rotate synchronically. In the aligning state, the short-range in-plane dipole-dipole attraction enhances the rotation torque and gives rises to a larger rolling speed. The pair aligning becomes difficult and unstable at high electric field where the normal dipole-dipole repulsion becomes dominant. As a consequence, the dependence of speed on density becomes weak increasingly upon the increase of the electric field. This result offers an interpretation for the discrepancy between our and previous observations on Quincke rollers.

Analysis of Cytokine Levers in Pleural Effusions of Tuberculous Pleurisy and Tuberculous Empyema.

The aim is to examine whether the interleukin-1ß (IL-1ß), IL-2, IL-6, tumor necrosis factor-α (TNF-α), plasminogen activator inhibitor type-1 (PAI-1), and tissue plasminogen activator (t-PA) levels were different in pleural effusions of tuberculous pleurisy and tuberculous empyema. IL-1ß, IL-2, IL-6, TNF-α, PAI-1, and t-PA levels in pleural fluids of 40 patients with tuberculous pleurisy and 38 patients with tuberculous empyema were measured. The levels of IL-1ß, PAI-1, and t-PA in the pleural effusions were different between tuberculous pleurisy and tuberculous empyema; it could be helpful to differentiate the two diseases. The levels of PAI-1, IL-1ß were higher and t-PA, IL-6 were lower in pleural effusions of the patients with tuberculous empyema and who must undergo operation than the patients who could be treated with closed drainage and anti-TB chemotheraphy. These indications may be helpful to evaluate whether the patient needs the operation.

Analysis of Pneumonectomy for Benign Disease: A Single Institution Retrospective Study on 59 Patients.

INTRODUCTION: Pneumonectomy is the only curative treatment for some benign diseases but the operation is a challenging procedure. Herein, we present our experiences of pneumonectomy for 59 patients. METHODS: The medical records of 59 patients who undergone pneumonectomy for benign lung diseases from 2008 to 2013 at the Division of Thoracic Surgery in Beijing Chest Hospital were retrospectively reviewed. RESULTS: There were 23 male and 36 female patients. Three procedures including pneumonectomy, pleuropneumonectomy and completion pneumonectomy were used. The operative time and intraoperative blood loss were statistically different in the patients who undergone different operations. The operative time of the patients with and without tuberculosis had no difference but the intraoperative blood loss was more in the patients with tuberculosis (P = 0.035). The operative type, age and operative blood loss were relevant with the morbidity, the P value were 0.024, 0.042 and 0.027 respectively. CONCLUSIONS: Pneumonectomy for patients with benign disease may be more difficult than for patients with lung cancer, mean while pleuropneumonectomy and completion pneumonectomy may be greater challenges. But with careful patient selection and operative technique, it is a satisfactory treatment method for benign lung disease. The morbidity is acceptable and associated with operative type, age and operative blood loss.

Polydispersity and gelation in concentrated colloids with competing interactions.

In colloids with competing short-range attractions and long-range repulsions, microcrystalline gels are experimentally formed under conditions where computer simulations point to a lamellar phase as the ground state. Here, upon applying a low-frequency alternating electric field, we bring the system from an initial gel state to a columnar-like state. While molecular dynamics simulations on monodisperse colloids reveal that a columnar structure spontaneously evolves towards a lamellar phase, the columnar-like state in experiments relaxes back to the initial disordered gel state once the electric field is switched off. Similarly, a columnar phase in molecular dynamics simulations decomposes into finite-size crystalline clusters as the relative polydispersity of the colloids is around 1.0%. We conclude that the experimentally observed melting of the columnar structure is driven by polydispersity. Moreover, further simulations reveal that the critical polydispersity required to destabilize a long-range ordered structure increases with the attraction range, pointing to the possibility of observing periodic structures in experiments if the attraction range is sufficiently long compared to the polydispersity of the colloids.

Experimental modelling of single-particle dynamic processes in crystallization by controlled colloidal assembly.

In the last few decades, the controlled colloidal assembly was adopted as a new modelling technology for the study of the crystallization mechanism. In colloidal systems, the movement of particles is slow enough to follow and the particle dynamics can be monitored at the single-particle level using normal optical microscopes. So far, the studies of colloidal crystallization have produced a number of insights, which have significantly improved our understanding of crystallization. In this review, we summarize the recent advances in understanding the mechanism of crystallization, which were achieved using colloidal model systems, i.e., the kinetics of nucleation, growth and defect formation. Such model systems allow us to not only visualize some "atomic" details of nucleation and surface processes of crystallization, but also quantify previous models to such an extent that has never been achieved before by other approaches. In the case of nucleation, the quantitative observation of the kinetic process was made at the single-particle level; the results include the ideal case and the deviations from classical theories. The deviations include multi-step crystallization, supersaturation-driven structural mismatch nucleation, defect creation and migration kinetics, surface roughening, etc. It can be foreseen that this approach will become a powerful tool to study the fundamental process of crystallization and other phase transitions.

[Surgical treatment of pulmonary tuberculosis complicated with aspergilloma].

OBJECTIVE: To investigate the surgical indications of pulmonary tuberculosis complicated with aspergilloma , and to reduce postoperative complications. METHODS: From 1993 to 2010, a total of 51 surgically treated patients in pulmonary tuberculosis complicated with aspergilloma were analyzed retrospectively. The common surgical procedure performed was lobectomy(60.8%), followed by segmentectomy(15.7%), pneumonectomy(9.8%), wedge resection(9.8%). RESULTS: Postoperative non-fatal complications occurred in all patients, the complications (13 cases) included postoperative atelectasis(7.8%), bleeding(5.9%), bronchopleural fistula(5.9%), cardiac arrhythmia and heart failure(2.0%), incisional infection(2.0%). CONCLUSIONS: Surgical treatment of pulmonary tuberculosis complicated with aspergilloma is the most effective treatment; pulmonary resection is the treatment of choice when indicated.

Fabrication of large two-dimensional colloidal crystals via self-assembly in an attractive force gradient.

Colloidal particles in a water-lutidine (WL) binary liquid mixture experience temperature-dependent attraction close to the mixture's demixing temperature. This temperature-tunable interaction can be potentially harnessed to assemble colloids and grow colloidal crystals. In this article, for the first time a novel attractive force gradient method is presented to fabricate high-quality, single-domain colloidal crystals. The well-controlled attractive force gradient here arises from a temperature gradient in the WL mixture. The nucleation of colloidal crystals in such a WL mixture preferably occurs in the high-temperature region because of the stronger attraction there. Crystallization propagates from the high-temperature region to the low-temperature region in a well-controlled way. The growth of the colloidal crystal is characterized in detail by Voronoi construction, the pair correlation function, and the orientational order parameter. It is found that the number of crystal-like particles increases with time, and a single-domain 2D colloidal crystal can be produced. The mechanism of the defect-free crystallization process is discussed on the basis of an analogy to cluster beam deposition methods. This study demonstrates an efficient and robust way to prepare colloidal crystals with little to no defects, being suitable for applications such as colloidal lithography and the fabrication of perfect 3D colloidal crystals.

[Bulk heterojunction solar cell based on porphyrin compounds].

Three kinds of porphyrins which can abbreviate as TPP, TPPCu and TMPPFeCl were synthesized by one-step method with mixed solvents. Then these porphyrin materials were used as donors to fabricate organic solar cells with PCBM as accepter by the solution processing of spin-coating method. The structure is ITO/porphyrin : PCBM/Al. The photovoltaic characterizations of these devices were investigated. The device based on TPP : PCBM shows the best performance with an open circuit voltage (V(OC)) of 0.52 V, a short circuit current (J(SC)) of 0.98 mA x cm(-2), and fill factor (FF) of 30.1%. Then the influence of different weight ratio of TPP : PCBM was researched. The best weight ratio of TPP : PCBM is 1 : 1. Increasing or decreasing the quatity of TPP would make J(SC) and V(OC) of the device deterioration and have little effect on the FF.

[Effects of hole-injection layers on the performance of blue organic light-emitting diodes].

The present work investigates the effects of different buffer layers on the performance of blue organic light-emitting diodes (OLEDs), and compares them with the device with no buffer layer. Two kinds of blue OLEDs with 4,4'-bis(2,2'-diphenyl vinyl)-1,1'-biphenyl (DPVBi) as the emitting layer, N, N'-bis-(1-naphthyl)-N, N'-1-diphenyl-1,1 '-biphenyl-4, 4'-diamine (NPB) as the hole transporting layer, and copper phthalocyanine (CuPc) and poly(3,4-ethylenedioxythiophene) : poly (styrenesulphonate) PEDOT : PSS as the hole injection layer respectively were fabricated with the structures of ITO/CuPc/NPB/DPVBi/BCP/Alq3 /Al and ITO/PEDOT : PSS/NPB/DPVBi/BCP/Alq3/Al. Moreover, the effects of different preparation technology of CuPc on the performance of OLEDs were also investigated. It was found that the performance of the devices with a hole injection layer is better than that of the device without any hole-injection layer. Although the luminance and efficiency of the water-soluble CuPc based device are worse than that of the device with thermally evaporated CuPc, but better than that of the device with water-soluble PEDOT : PSS. So the water-soluble CuPc is a good hole injection material because it is easier to fabricate the film than traditional CuPc.

Observation of a microcrystalline gel in colloids with competing interactions.

A stable short-range crystalline structure is observed in colloidal systems with competing short-range attractions and long-range repulsions. We term these structures "microcrystalline gels" as the microcrystals are embedded in a dense disordered network.

Nucleation: what happens at the initial stage?

Crystallizing growth: The initial structure of crystal nuclei is supersaturation-dependent. At low degrees of supersaturation, liquid-like nuclei are formed initially, which undergo a continuous structure transition from liquid-like to crystal-like as the size N increases. This gradual structure evolution substantially lowers the nucleation barrier DeltaG* and facilitates the nucleation relative to the formation of crystal-like clusters from the beginning.

Multistep crystal nucleation: a kinetic study based on colloidal crystallization.

Crystallization via an amorphous precursor, the so-called multistep crystallization (MSC), plays a key role in biomineralization and protein crystallization. MSC has attracted much attention in the past decade, but a quantitative understanding of it has so far not been available. The major challenge is that the kinetics governing the nucleation of crystals occurring in the metastable amorphous precursor remains unclear. In this study, the kinetics of MSC is addressed experimentally. Most importantly, a mathematical method is developed to calculate the local nucleation rate of the crystals in the amorphous precursor, which is not accessible to conventional methods. This local nucleation rate is critical to the understanding of MSC, but it has never been dealt with experimentally because of the difficulties of in situ observation. With the local crystal nucleation rates, the supersaturation for crystallization and the crystal-liquid interfacial free energy in the amorphous precursor are evaluated.

How does a transient amorphous precursor template crystallization.

Crystallization through metastable phases, such as polymorphism, plays an important role in chemical manufacture, biomineralization, and protein crystallization. However, the kinetics creating the final stable crystalline phase from metastable phases has so far remained unclear. In this study, crystallization via an amorphous precursor, the so-called multistep crystallization (MSC), is studied quantitatively in a colloidal model system. In MSC, amorphous dense droplets are first nucleated from the mother phase. Subsequently, a few unstable subcrystalline nuclei can be created simultaneously by fluctuation from the tiny dense droplets, which is different from previous theoretical predictions. It is necessary for these crystalline nuclei to reach a critical size N*(crys) to become stable. However, in contrast to subcrystalline nuclei, a stable mature crystalline nucleus is not created by fluctuation but by coalescence of subcrystalline nuclei, which is unexpected. To accommodate a mature crystalline nucleus larger than the critical size N*(crys), the dense droplets have to first acquire a critical size N*. This implies that only a fraction of amorphous dense droplets can serve as a precursor of crystal nucleation. As an outcome, the overall nucleation rate of the crystalline phase is, to a large extent, determined by the nucleation rate of crystals in the dense droplets, which is much lower than the previous theoretical expectation. Furthermore, it is surprising to see that MSC will promote the production of defect-free crystals. The knowledge acquired in this study will also significantly advance our understandings in polymorphism related processes.