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Photodynamic therapy (PDT) is a non-invasive therapy with many advantages over other therapeutic methods, but it is restricted to treat superficial cancers due to the shallow tissue penetration of visible light. The biological window in the near infrared region (NIR) offers hope to extend the penetration depth, but there is no natural NIR excited photosensitizer. Here, we report a novel photosensitizer: NaYbF4 nanoparticles (NPs). By using a 1,3-diphenylisobenzofuran (DPBF) sensor, we show that the Yb3+ ions can absorb the NIR light and transfer energy directly to oxygen to generate reactive oxygen species (ROS). The efficiency of transferring energy to oxygen by NaYbF4 NPs is comparable to that of traditional photosensitizers. We have carried out PDT both in vitro and in vivo based on NaYbF4 NPs; the results demonstrate that NaYbF4 NPs are indeed an effective NIR photosensitizer, which can help extend the application of PDT to solid tumors owing to the much deeper penetration depth of NIR light.

Lost circulations of drilling fluids during drilling and completion can be an expensive and time-consuming problem. Commonly used lost circulation materials (LCMs) like nutshells or cross-linked polymer gels can’t be easily removed after plugging with a risk of formation damage. Magnesium oxysulfate cement (MOS cement) provides a reliable solution for solving the severe loss that occurs in production and non-production zones. In this paper, the effects of harsh downhole conditions including density, bentonite content, salt content, and temperature on the setting time and compressive strength of the MOS settable system are studied using the orthogonal experimental analysis method. At the same time, laboratory plugging experiments and field application are used to evaluate the ability of the MOS settable system to seal the severe loss. The results show that the downhole conditions have a significant effect on the setting time and compressive strength of the system. By adding calcium carbonate particles, the permeability of the MOS settable system can be reduced and the pressure-bearing capacity of the MOS solidified plug can be improved. Field application shows that this settable system can solve severe loss that conventional LCMs cannot solve and has a good application prospect.

Photodynamic therapy (PDT) is a non-invasive therapy with many advantages over other therapeutic methods, but it is restricted to treat superficial cancers due to the shallow tissue penetration of visible light. The biological window in the near infrared region (NIR) offers hope to extend the penetration depth, but there is no natural NIR excited photosensitizer. Here, we report a novel photosensitizer: NaYbF

Oil resources are abundant in the offshore area that is an important channel for the human to obtain oil and gas. With oil exploration and development, the marine ecological environment has been influenced increasingly. Through a large number of laboratory tests, the evaluation indexes of the environmental offshore drilling fluid system were established, which are consisted of heavy metal, petroleum, acute biological toxicity, biodegradability, and so on. Four types of agents for environmental offshore drilling fluid and a novel environmental offshore drilling fluid system were developed on the basis of establishing the evaluation indexes. The basic formulation of the novel drilling fluid system is: 400 mL Seawater + 0.3% Na2CO3 + 0.2% NaOH + 4% Bentonite +0.5% HXB-1 + 2% MMF + 1.5% SDR-30 + 1%HXJ + 1% SDE-1 + 2%NFA-25, and the system has been applied successfully to Bohai Bay in Shengli oil field. The results showed that the environmental offshore drilling fluid system had favorable drilling performances...

Gas-well production will be increased greatly after altering the wettability of porous media from preferential liquid-wetting to preferential gas-wetting in gas-condensate reservoirs. Moreover, the degree of gas wetness strongly affects the production. Thus, the study of gas-wet quantitative measurement methods is of great significance. The wetting ability parameter of gas versus liquid ζG-L is calculated from the proposed formula in the sessile drop method, and the gas contact angle θ G in the captive bubble method was separately used to measure gas wettability and propose the wettability criteria. Also, the concept of gas wettability was defined. After treated by fluorocarbon polymer (Zonyl8740), glass slides, and glass capillary tubes got tested on gas wetness. The results show that with the increase of the concentration of Zonyl8740 solution, the surface free energy of glass slides decreases and gas-wetness of them is enhanced. And capillary tube rise tests showed the same conclusion, demonstrating th...

The rock wettability near wellbore plays a key role to the productivity of the condensate gas reservoir. In order to research the wettability reversal extent, a novel gas-wetting reversal FC-1 and its effect have been studied. After the core is treated by FC-1, both water/gas and oil/gas spontaneous imbibition proved that FC-1 has superior gas-wetting reversing performance (wettability converted from amphiphilic to intermediate gas-wetting). Wettability reversal effect is enhanced after 100°C aging treatment, which proved that better hydrophobicity and oleophobicity of low FC-1 concentration could be obtained under that condition. Contact angles have no obvious change after 15 days, suggesting that FC-1 has a good durability and could realize the durable conversion on the condensate gas reservoir core.

In the separation process of oil dehydration and wastewater deoiling, a very stable and viscous colloid layer is formed on the oil-water interface, which is high in viscosity and water content, and also contains more oil ingredient, which is difficult to deal with and achieve dehydration. As a result the work of equipment is greatly affected. In the meantime, a direct landfill or open pile will affect the surrounding environment, soil environment, and underground water condition. This will make it difficult to retrieve crude oil from the flocculate, which causes a waste of crude oil. The authors studied the formation process, stable factors, and formation mechanism of flocculate in crude oil gathering and transferring. On this basis, drying treatment for burning was developed according to the characteristics of oilfield flocculate. By using the drying treatment technology, flocculate can be used as the additive agent in burning coal, which improves the calorific value of coal because the drying flocculate...

Aiming at the cutting bed settling problems in horizontal section during drilling process, a novel additive FGC for cuttings transport is applied. The experimental results show that the wettability was converted to amphiphobic and the cuttings preferentially attached to gas bubbles after FGC adsorption on the cuttings’ surface. The surface area of the cuttings is increased and the density of it is reduced, making cuttings more easily to be driven by liquid and settlement decrease. Tested by the horizontal simulation device, the cuttings transport effect is good and most of cuttings can be circulated to the outlet position by drilling fluid.

This paper will take the complex layer of the Qunkuqiake region of Tarim Basin as a research object in order to find the reasons of the borehole instability. The layered drilling fluid design technique is put forward firstly and a new drilling fluid technology to solve the problems of wall instability of the Qunkuqiake regions in Tarim Basin is developed.

Excellent drilling fluid techniques are one of the significant guarantee measures to insure the safety, quality, efficiency, and speediness of drilling operations. However, these drilling fluids are generally discarded and become wastes, which have the largest number and the largest influence on the environment after the completion of drilling operations. These drilling materials and additives together with drilling cuttings, oil, and water entered formations constitute waste drilling fluids, which ultimately went into soil, surface water, groundwater, and air. Among all kinds of drilling fluid systems that have been developed and applied at present, acrylic acid and its derivatives drilling fluid system and polysulfonate drilling fluid system are widely used. Environment pollutions are serious in complex wells or high-temperature deep wells, and even in oil-based drilling fluid systems. This article is based on lots of laboratory experiments on the chemical toxicity, biological toxicity, and bio...

The solidification rate of molten steel was accurately controlled by the use of directional solidification technology and superfine dispersion titanium oxides were acquired in this study. The size, amount and composition of oxides have been observed by scanning electron microscope and the volume fraction of oxides during solidification has been examined. The results showed that the oxides are mainly composed of Ti2O3. The average diameters of the oxides are 2·0, 1·2 and 1·0 μm, the numbers per unit volume are 2·5 × 104, 2·8 × 105 and 3·2 × 105 mm−3 when the solidification rates are 6, 60 and 96 μm s−1 respectively. The volume fraction changes little with the change of solidification rate. It has been proved that superfine inclusions precipitated during solidification is feasible.

To estimate the probability of N2 lymph node metastasis and to assist physicians in making diagnosis and treatment decisions.We reviewed the medical records of 739 patients with computed tomography-defined stage I non-small cell lung cancer (NSCLC) that had an exact tumor-node-metastasis stage after surgery. A random subset of three fourths of the patients (n=554) were selected to develop the prediction model. Logistic regression analysis of the clinical characteristics was used to estimate the independent predictors of N2 lymph node metastasis. A prediction model was then built and externally validated by the remaining one fourth (n=185) patients which made up the validation data set. The model was also compared with 2 previously described models.We identified 4 independent predictors of N2 disease: a younger age, larger tumor size, central tumor location, and adenocarcinoma or adenosquamous carcinoma pathology. The model showed good calibration (Hosmer-Lemeshow test: P=0.923) with an area under the receiver operating characteristic curve (AUC) of 0.748 (95% confidence interval, 0.710-0.784). When validated with all the patients of group B, the AUC of our model was 0.781 (95% CI: 0.715-0.839) and the VA model was 0.677 (95% CI: 0.604-0.744) (P =0.04). When validated with T1 patients of group B, the AUC of our model was 0.837 (95% CI: 0.760-0.897) and Fudan model was 0.766 (95% CI: 0.681-0.837) (P0.01).Our prediction model estimated the pretest probability of N2 disease in computed tomography-defined stage I NSCLC and was more accurate than the existing models. Use of our model can be of assistance when making clinical decisions about invasive or expensive mediastinal staging procedures.

Tryptophan hydroxylase (TPH) is the initial and rate-limiting enzyme in the biosynthesis of serotonin. The inherent instability of TPH has prevented a crystallographic structure from being resolved. For this reason, multiple sequence alignment-based molecular modeling was utilized to generate a full-length model of human TPH. Previously determined crystal coordinates of two highly homologous proteins, phenylalanine hydroxylase and tyrosine hydroxylase, were used as templates. Analysis of the model aided rational mutagenesis studies to further dissect the regulation and catalysis of TPH. Using rational site-directed mutagenesis, it was determined that Tyr235 (Y235), within the active site of TPH, appears to be involved as a tryptophan substrate orienting residue. The mutants Y235A and Y235L displayed reduced specific activity compared to wild-type TPH ( approximately 5 % residual activity). The K(m) of tryptophan for the Y235A (564 microM) and Y235L (96 microM) mutant was significantly increased compared to wild-type TPH (42 microM). In addition, kinetic analyses were performed on wild-type TPH and a deletion construct that lacks the amino terminal autoregulatory sequence (TPH NDelta15). This sequence in phenylalanine hydroxylase (residues 19 to 33) has previously been proposed to act as a steric regulator of substrate accessibility to the active site. Changes in the steady-state kinetics for tetrahydrobiopterin (BH(4)) and tryptophan for TPH NDelta15 were not observed. Finally, it was demonstrated that both Ser58 and Ser260 are substrates for Ca(2+)/calmodulin-dependent protein kinase II. Additional analysis of this model will aid in deciphering the regulation and substrate specificity of TPH, as well as providing a basis to understand as yet to be identified polymorphisms.

We have performed Photoreflectance (PR), Raman Scattering (RS), and Photoluminescence (PL) experiments to characterize the In 0.52 Al 0.48 As surface exposed to plasma by a gas mixture of CH 4 /H 2 /Ar, PR spectra indicate that RIE (plasma) causes defects such as nonradiative recombination centers, scattering centers, and defects leading to the decrease of signal intensity, broaden line width and red shift of the transitions by increasing the rf power. In the Raman scattering study, RIE causes defects against InAs-like and AlAs-like LO modes vibration. As the rf power increased, the maximum of two LO modes shifts towards lower frequency and the line shape becomes increasingly asymmetric. Also, the intensity degrades gradually by disorder and point defects with increasing rf power. The PL transition energies show a red-shift with increasing the rf power. In addition, the spectral feature broadens, and the intensity decreases with rf power higher than 200 W. The consistence of the PL, PR, and RS results indicate that these three methods can be used as sensitive probes to evaluate the near surface damage of the epilayer.

Praseodymium-doped GaAs and Al 0.3 Ga 0.7 As epilayers grown on Semi-Insulating (SI) GaAs substrates by Liquid Phase Epitaxy (LPE) were first studied in this present work. Measurement techniques, such ns microscopic observation, X-ray diffraction, Secondary Ion Mass Spectroscopy (SIMS), and Hall measurement were employed. Layers doped with Pr resulted in a mirror-like surface, except several high Pr-doped layers having droplet surfaces. Hall measurements reveal that the grown layers contained p-type layers, carrier concentrations from 6.3 × 10 15 to 1.2 × 10 16 cm -3 , and from 6.3 × 10 15 to 3.5 × 10 16 cm −3 for Pr-doped GaAs and Al 0.3 Ga 0.7 As epilayers, respectively. Although p-type conduction exists, in the light of electrical features, doping of Pr into the GaAs and Al 0.3 Ga 0.7 As growth melts is still considered to exhibit gettering properties rather than to become a new acceptor itself. Additional photoluminescence examinations were taken. Their results also indicate that Pr-doped layers produce no new emission lines and support the electrical observations

Photoluminescence and Raman measurements are used to characterize the In x Al 1−x As (0.48 < x < 0.573) epilayers grown on InP substrate by molecular beam epitaxy. It is found that as In composition, x, deviates too much from 0.52, misfit dislocations may be introduced. These dislocations will dramatically reduce the radiative efficiency of the InA/As epilayers. Raman spectra become broader and more asymmetry due to alloy potential fluctuations as the mismatch becomes large

Photoluminescence and Raman spectroscopies are employed to study undoped InGaP layers grown on GaAs (100) substrates at 750 °C by liquid phase epitaxy. There are four peaks in the photoluminescence spectrum in the energy range between 1.55 and 2.25 eV. Besides a bound exciton recombination, three longitudinal optical phonon replicas with one superimposed donor‐acceptor emission are identified based upon their dependences of emission energies on temperature and excitation intensity.

Tryptophan hydroxylase (TPH), the rate-limiting enzyme in the biosynthesis of the neurotransmitter serotonin (5-HT) belongs to the aromatic amino acid hydroxylase superfamily, which includes phenylalanine hydroxylase (PAH) and tyrosine hydroxylase (TH). The crystal structures for both PAH and TH have been reported, but a crystallographic model of TPH remains elusive. For this reason, we have utilized the information presented in the TH crystal structure in combination with primary sequence alignments to design point mutations in potential structural domains of the TPH protein. Mutation of a TH salt bridge (K170E) was sufficient to alter enzyme macromolecular assembly. We found that the disruption of the cognate intersubunit dimerization salt bridge (K111-E223) in TPH, however, did not affect the macromolecular assembly of TPH. Enzyme peaks representing only tetramers were observed with size exclusion chromatography. By contrast, a single-point mutation within the tetramerization domain of TPH (L435A) was sufficient to disrupt the normal homotetrameric assembly of TPH. These studies indicate that, although the proposed salt bridge dimerization interface of TH is conserved in TPH, this hypothetical TPH intersubunit binding domain, K111-E223, is not required for the proper macromolecular assembly of the protein. However, leucine 435 within the tetramerization domain is necessary for the proper macromolecular assembly of TPH.