Mechanism of Pressure Difference Variations on Heavy Oil Start-Up and Percolation Effects.

To investigate the influence of pressure difference changes on the micro start-up and percolation of heavy oil, a micro visualization displacement device was used to characterize the start-up time and oil-water percolation state of heavy oil. The mechanism of different pressure differences, as well as the frequency and amplitude of pressure difference changes, on the start-up and percolation balance of heavy oil was clarified. The results indicate that high-pressure difference and pressure difference changes can reduce the start-up time of heavy oil. A reasonable frequency of pressure difference changes effectively promotes the balance between positive and negative pressure shear and fluid-solid response. Large pressure difference changes can effectively break the viscous and adsorption resistance during heavy oil start-up; reasonable pressure difference can exert the synergistic effect of pressure difference and infiltration, achieving a balance between the water wave and the initial water film thickening process as well as the continuous percolation process of wire drawing, oil droplets, and oil columns during the medium-to-high water content period; a reasonable frequency of pressure difference variation during the high water content period can promote the superposition of inertia effects at the oil-water interface and break the balance of the oil-water interface. A large amplitude of pressure difference variation is beneficial for the strong deformation of the oil-water interface and the shear dislocation peeling of the oil-solid interface. Therefore, a relatively high amplitude of pressure difference variation and a reasonable frequency of pressure difference variation, as well as the synergistic effect of pressure difference and infiltration, are the keys to effectively start heavy oil and improving oil recovery during the ultrahigh water-cut period.

Implementation of Innovative Teaching Approaches for Standardized Training of New Nurses in the Operating Room.

Objective: This study aims to investigate the impact of a novel and diversified teaching approach on training new nurses in the operating room. Methods: A comparative observational study with a quasi-experimental design was conducted. We selected 32 new nurses undergoing standardized training in the operating room at Panzhihua Central Hospital between March 2017 and March 2020, along with 29 nurses trained from January 2014 to December 2016, as research participants. These nurses were divided into a study group and a control group. The control group underwent traditional training, while the study group experienced an innovative and diversified training mode over a 3-year period. We conducted a comprehensive comparison of theoretical knowledge, professional competence, operation duration, and medical satisfaction between the two groups. Results: The study group, exposed to the innovative teaching approach, demonstrated significantly higher scores in both theoretical and practical examinations compared to the control group (P < .05). Moreover, the study group exhibited a notable reduction in the connection time between operating tables, fostering improved coordination. This group also reported enhanced tacit understanding between doctors and nurses. Notably, the study group expressed higher levels of satisfaction. These findings collectively suggest that the implementation of the new diversified teaching mode positively influences the theoretical knowledge, practical skills, and collaborative dynamics among nurses and medical professionals in the operating room. Conclusions: The implementation of the new diversified teaching mode significantly enhances the standardized training of new nurses in the operating room. This approach contributes to their improved clinical performance, offering valuable insights for future training methodologies.

Abnormal Systemic and Ocular Responses to the Valsalva Manoeuvre in Primary Open-Angle Glaucoma: A Case for Autonomic Failure?

OBJECTIVE: This study aimed to examine the association of primary open-angle glaucoma (POAG) with autonomic dysfunction by assessing the differences in systemic and ocular responses to an autonomic provocation test, the Valsalva manoeuvre (VM), between POAG patients and normal subjects. METHODS: Forty POAG and forty control subjects were subjected to the VM. Systemic and ocular parameters were measured at baseline, phase 2, and phase 4 of the VM (VM2 and VM4), where VM2 and VM4 are sympathetic and parasympathetic nervous activation states, respectively. Heart rate variability was used to assess the autonomic nervous activity, among which the high-frequency component (HF) and the low-frequency (LF)/HF ratio were used as indices of parasympathetic and sympathetic activation, respectively. RESULTS: POAG patients demonstrated higher sympathetic activation (LF/HF ratio median: 2.17 vs. 1.53, P=0.000) than controls at baseline and exhibited attenuated sympathetic and parasympathetic responses (a smaller change in LF/HF and HF values) during the VM than controls. During VM, the intraocular pressure (IOP), mean blood pressure (MAP), mean ocular perfusion pressure (MOPP), and the Schlemm's canal area (SCAR) increased from baseline to VM2 and then decreased from VM2 to VM4 in both the POAG and control groups (all P<0.05). However, when we compared the changes above, the fluctuations in IOP, MAP, and MOPP were more pronounced in POAG than in controls (all P<0.05), while the changes in amplitudes of SCAR were smaller in POAG (P<0.05). Furthermore, from VM2 to VM4, the choroid thickness (ChT) in the POAG group was significantly decreased, while it was unchanged in normal subjects (P=0.258). A regression analysis showed a significant correlation of the baseline LF/HF with IOP change values (ΔIOP) from baseline to VM2 in POAG (R2=0.147, P=0.014). CONCLUSION: Patients with POAG showed more pronounced fluctuations in IOP, MAP, MOPP and ChT during the VM than controls. These reactions could be associated with autonomic dysfunction in POAG.

Artificial intelligence method based on multi-feature fusion for automatic macular edema (ME) classification on spectral-domain optical coherence tomography (SD-OCT) images.

Purpose: A common ocular manifestation, macular edema (ME) is the primary cause of visual deterioration. In this study, an artificial intelligence method based on multi-feature fusion was introduced to enable automatic ME classification on spectral-domain optical coherence tomography (SD-OCT) images, to provide a convenient method of clinical diagnosis. Methods: First, 1,213 two-dimensional (2D) cross-sectional OCT images of ME were collected from the Jiangxi Provincial People's Hospital between 2016 and 2021. According to OCT reports of senior ophthalmologists, there were 300 images with diabetic (DME), 303 images with age-related macular degeneration (AMD), 304 images with retinal-vein occlusion (RVO), and 306 images with central serous chorioretinopathy (CSC). Then, traditional omics features of the images were extracted based on the first-order statistics, shape, size, and texture. After extraction by the alexnet, inception_v3, resnet34, and vgg13 models and selected by dimensionality reduction using principal components analysis (PCA), the deep-learning features were fused. Next, the gradient-weighted class-activation map (Grad-CAM) was used to visualize the-deep-learning process. Finally, the fusion features set, which was fused from the traditional omics features and the deep-fusion features, was used to establish the final classification models. The performance of the final models was evaluated by accuracy, confusion matrix, and the receiver operating characteristic (ROC) curve. Results: Compared with other classification models, the performance of the support vector machine (SVM) model was best, with an accuracy of 93.8%. The area under curves AUC of micro- and macro-averages were 99%, and the AUC of the AMD, DME, RVO, and CSC groups were 100, 99, 98, and 100%, respectively. Conclusion: The artificial intelligence model in this study could be used to classify DME, AME, RVO, and CSC accurately from SD-OCT images.

Sympathetic activation leads to Schlemm's canal expansion via increasing vasoactive intestinal polypeptide secretion from trabecular meshwork.

We previously demonstrated vasoactive intestinal polypeptide (VIP) eyedrops reduce intraocular pressure (IOP) and stabilize cytoskeleton of the Schlemm's canal (SC) endothelium in a chronic ocular hypertension rat model. Here we determine if the trabecular meshwork (TM) releases endogenous VIP and affect SC in paracrine manner, and whether this cellular interaction via VIP is strengthened under stimulated sympathetic activity. A rat model of moderate-intensity exercise was established to stimulate sympathetic activation. IOP post exercise was measured by a rebound tonometer. Sympathetic nerve activity at the TM was immunofluorescence-stained with DßH and PGP9.5. Morphological changes of TM and SC were quantitatively measured by hematoxylin-eosin (HE) staining. Further, epinephrine was applied to mimic sympathetic excitation on primary rat TM cells, and ELISA to measure VIP levels in the medium. The cytoskeleton protective effect of VIP in the epinephrine-stimulated conditioned medium (Epi-CM) was evaluated in oxidative stressed human umbilical vein endothelial cells (HUVECs). Elevated sympathetic nerve activity was found at TM post exercise. Changes accompanying the sympathetic excitation included thinned TM, expanded SC and decreased IOP, which were consistent with epinephrine treatment. Epinephrine decreased TM cell size, enhanced VIP expression and release in the medium in vitro. Epi-CM restored linear F-actin and cell junction integrity in H2O2 treated HUVECs. Blockage of VIP receptor by PG99-465 attenuated the protective capability of Epi-CM. VIP expression was upregulated at TM and the inner wall of SC post exercise in vivo. PG99-465 significantly attenuated exercise-induced SC expansion and IOP reduction. Thus, the sympathetic activation promoted VIP release from TM cells and subsequently expanded SC via stabilizing cytoskeleton, which resulted in IOP reduction.

Biomechanically and biochemically functional scaffold for recruitment of endogenous stem cells to promote tendon regeneration.

Tendon regeneration highly relies on biomechanical and biochemical cues in the repair microenvironment. Herein, we combined the decellularized bovine tendon sheet (DBTS) with extracellular matrix (ECM) from tendon-derived stem cells (TDSCs) to fabricate a biomechanically and biochemically functional scaffold (tECM-DBTS), to provide a functional and stem cell ECM-based microenvironment for tendon regeneration. Our prior study showed that DBTS was biomechanically suitable to tendon repair. In this study, the biological function of tECM-DBTS was examined in vitro, and the efficiency of the scaffold for Achilles tendon repair was evaluated using immunofluorescence staining, histological staining, stem cell tracking, biomechanical and functional analyses. It was found that tECM-DBTS increased the content of bioactive factors and had a better performance for the proliferation, migration and tenogenic differentiation of bone marrow-derived stem cells (BMSCs) than DBTS. Furthermore, our results demonstrated that tECM-DBTS promoted tendon regeneration and improved the biomechanical properties of regenerated Achilles tendons in rats by recruiting endogenous stem cells and participating in the functionalization of these stem cells. As a whole, the results of this study demonstrated that the tECM-DBTS can provide a bionic microenvironment for recruiting endogenous stem cells and facilitating in situ regeneration of tendons.

Study of the Surfactant Transport Law Based on an Improved Adsorption Model with an Artificial Seismic Wave.

To explore the law and mechanism of enhanced surfactant flooding with a low-frequency artificial seismic wave, for single-phase fluids in porous media, a heterogeneous two-stage adsorption model for a surfactant with a low-frequency artificial seismic wave is introduced into the surfactant transport equation of a single-phase fluid. With this model, the surfactant fluid transport model in porous media with an artificial seismic wave is obtained. The model is solved using the C-N difference and chasing method. The migration law of the surfactant is simulated and quantitatively analyzed for different vibration accelerations, injection slug sizes, displacement speeds, and reservoir parameters with the action of low-frequency artificial seismic waves. The results show that artificial seismic waves can increase the effective range of the surfactants and reduce the number of chemical agents through reduced adsorption. Low-frequency vibration with the same surfactant injection rate can increase the effective range by a factor greater than one. For the same effective action distance, the dose of chemical agents can be reduced by more than 60%, and the optimal acceleration and the injection slug size are 0.3 m/s2 and 0.4 PV, respectively. With the increase of the injection rate, the effect of low-frequency vibration on the diffusion and transport of the surfactant decreases. A low-frequency wave combined surfactant has a better effect on the low permeability reservoirs. The research results provide important support for further understanding of the low-frequency artificial seismic wave composite surfactant flooding law and the optimization of the field parameters.

Ocular Autonomic Nervous System: An Update from Anatomy to Physiological Functions.

The autonomic nervous system (ANS) confers neural control of the entire body, mainly through the sympathetic and parasympathetic nerves. Several studies have observed that the physiological functions of the eye (pupil size, lens accommodation, ocular circulation, and intraocular pressure regulation) are precisely regulated by the ANS. Almost all parts of the eye have autonomic innervation for the regulation of local homeostasis through synergy and antagonism. With the advent of new research methods, novel anatomical characteristics and numerous physiological processes have been elucidated. Herein, we summarize the anatomical and physiological functions of the ANS in the eye within the context of its intrinsic connections. This review provides novel insights into ocular studies.

Mechanism of Ultrasonic Physical-Chemical Viscosity Reduction for Different Heavy Oils.

In this study, the mechanism of physical-chemical viscosity reduction of different heavy oils under ultrasonic wave is explored. Experiments of viscosity reduction and viscosity recovery of different heavy oils under ultrasonic excitation were carried out, and the optimal ultrasonic parameters, ultrasonic physical disturbance, and cavitation viscosity reduction extent of different oil samples were determined. Based on the element analysis methods, four-component analysis, gas chromatography analysis, and formation water pH value test, the micro-mechanism of the oil chemical structure change and water samples under ultrasonic wave was analyzed. The results show that the water content, temperature, and initial viscosity of heavy oil are the key to reduce the viscosity of heavy oil. The higher viscosity of the initial oil sample, the higher water content, and the temperature were needed. Compared with the lower viscosity oil sample, the higher viscosity oil sample has higher extent of cavitation viscosity reduction and lower extent of physical disturbance viscosity reduction under ultrasonic wave. After ultrasonic treatment, the contents of heteroatoms, resins, and asphaltenes in heavy oil samples with high viscosity decreased significantly, and the conversion extent of high carbon chain to low carbon chain was greater. In addition, the pH of water in heavy oils decreased after ultrasonic treatment, and the pH of water in high viscosity heavy oil decreased more significantly after ultrasonic treatment.

Preparation and evaluation of an injectable curcumin loaded chitosan/hydroxyapatite cement.

Curcumin (Cur) is an active ingredient of Curcuma longa. Cur has many pharmacological effects, such as anti-inflammation, anti-oxidation, anticoagulation, hypolipidemic, anti-angiogenesis and anti-cancer. An injectable curcumin loaded chitosan/hydroxyapatite bone cement (Cur-CS/HA) was prepared as a bone scaffold and drug delivery. Tween 20, a nonionic surfactant, was incorporated into the cement to improve the solubility of curcumin. Four types of Cur-CS/HA (Group0, Group1, Group5 and Group10) were prepared with different Tween 20 ratios (0, 1, 5 and 10%, respectively). The samples were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Compression tests were carried out to evaluate the strength of the scaffolds. In addition, the inhibition assay was carried out on MG63 cells with the extracts of drug loaded materials. The results showed that Cur had an effect on the setting time (p < 0.05). Cur reduced the compressive strength of the CS/HA cement (p < 0.05). The release studies showed that Tween 20 could effectively improve the solubility of curcumin. When the Tween 20 content in cement increased from 0 to 10%, the cumulative release (30 d) of Cur increased from 5.5 to 10.6%. Moreover, the cement had good injectability, good anti-collapsibility and good biocompatibility to meet the clinical requirements. The result of inhibition assay showed that Cur-CS/HA could inhibit the proliferation of MG63 cells. Tween 20 incorporated Cur-CS/HA had great potential to use as a drug-loaded artificial bone material.

Gemini Surfactant with Unsaturated Long Tails for Viscoelastic Surfactant (VES) Fracturing Fluid Used in Tight Reservoirs.

The high dosage of surfactant terribly restrains the extensive application of viscoelastic surfactant (VES) fracturing fluid. In this study, a novel gemini surfactant (GLO) with long hydrophobic tails and double bonds was prepared and a VES fracturing fluid with a low concentration of GLO was developed. Because of the long tails bending near the double bonds, there is a significant improvement of the surfactant aggregate architecture, which realized the favorable viscosity of the VES fluid at a more economical concentration than the conventional VES fracturing fluids. Fourier transform infrared spectrometry (FT-IR), nuclear magnetic resonance spectrometry (1H NMR, 13C NMR), and high-resolution mass spectrometry (HRMS) were employed to study the formation of the product and the structure of GLO. The designed GLO was produced according to the results of the structure characterizations. The formula of the VES fracturing fluid was optimized to be 2.0 wt % GLO + 0.4 wt % sodium salicylate (NaSal) + 1.0 wt % KCl based on the measurements of the viscosity. The viscosity of the VES fluid decreased from 405.5 to 98.7 mPa·s as the temperature increased from 18 to 80 °C and reached equilibrium at about 70.2 mPa·s. The VES fluid showed a typical elastic pseudoplastic fluid with a yield stress of 0.5 Pa in the rheological tests. It realized a proppant setting velocity as low as 0.08 g/min in the dynamic proppant transport test carried by GLO-based VES fracturing fluid. Compared to the formation water, the filtrate of the VES fracturing fluid decreased the water contact angle (CA) from 56.2 to 45.4° and decreased the water/oil interfacial tension (IFT) from 19.5 to 1.6 mN/m. Finally, the VES fracturing fluid induced a low permeability loss rate of 10.4% and a low conductivity loss rate of 5.4% for the oil phase in the experiments of formation damage evaluation.

Traumatic Obturator Dislocation of the Hip Joint Associated with Greater Trochanter Fracture: A Case Report.

BACKGROUND: Traumatic obturator dislocation of the hip joint associated with greater trochanter fracture is a rare injury. We used the lateral approach through the rectus abdominis to remove the femoral head dislocated into the obturator, and the posterolateral approach was used for reduction and internal fixation of the femoral greater trochanteric fracture and total hip replacement (THR). Good follow-up results were achieved. To the best of our knowledge, this is the first report on this particular type of injury and on this approach to treating this type of injury. CASE REPORT: The patient was hospitalized due to a traffic accident that resulted in the patient experiencing swelling and deformity accompanied by limited mobility of the left hip and left knee. X-ray examination and CT confirmed that the patient suffered from left hip obturator dislocation, greater trochanter fracture, pelvic fracture (Tile B), left acetabular fracture, right open tibiofibular comminuted fracture (Gustilo III), and posterior urethral injury. The femoral head was removed from the pelvic cavity through a pararectus approach under general anesthesia. A posterolateral approach was used for open reduction, and cable internal fixation for the left intertrochanteric fracture and uncemented THR were performed. RESULTS: The ability to work was restored 6 months after the operation. The Harris hip score, reflecting joint function, was 86 points after 2 years of follow-up observation. CONCLUSION: A lateral approach of rectus abdominis to remove the dislocated femoral head in the pelvis from the obturator should be selected, along with the posterolateral approach for reduction and internal fixation of the intertrochanteric fracture and THR. This case also provides a new reference for the treatment of this type of hip fracture dislocation.

Mechanical strength improvement of chitosan/hydroxyapatite scaffolds by coating and cross-linking.

Coating and cross-linking have been widely used to improve the properties of materials in tissue engineering. A chitosan/hydroxyapatite (CS/HA) comby scaffold with high porosity was prepared via a 3D printed pore-forming mold. The scaffold was then treated with gelatin (Gel) coating and was cross-linked by glutaraldehyde (GA) in order to improve the mechanical strength. The materials were characterized by infrared spectroscopy (IR) and X-ray diffraction (XRD). The structure of the scaffolds was observed by Scanning Electron Microscopy (SEM). Compression tests were carried out to evaluate the strength of the scaffolds. The behaviors and responses of preosteoblast cells on the scaffolds were studied as well. The results showed that gelatin coating and cross-linking significantly enhanced the mechanical strength of the porous scaffolds. Cell culture experiment indicated that the scaffold had good cytocompatibility. The combined application of 3DP structure construction and biopolymer coating/cross-linking would offer some new ideas in fabrication of porous scaffolds with enhanced strength and good biocompatibility for tissue engineering.

Molecular data provide new insights into the phylogeny of Cladonotinae (Orthoptera: Tetrigoidea) from China with the description of a new genus and species.

Considerable effort has been devoted to elucidating the phylogenetic relationships of tetrigides. However, there is still no commonly accepted phylogenetic hypothesis. Therefore, the phylogenetic relationships among some subfamilies remain unclear; e.g., Cladonotinae is a controversial group, in which the phylogenetic relationships between genera and the boundaries of some of the included genera are unclear, causing some of the taxa to be difficult to identify. Therefore, an in-depth phylogenetic analysis of Cladonotinae is urgently needed. In this study, a robust phylogenetic framework for the tetrigides was reconstructed based on the combined mitochondrial cytochrome oxidase subunit I (COI), 16S ribosomal RNA (16S rRNA), and nuclear 18S ribosomal RNA (18S rRNA) gene sequences of 25 species belonging to 16 genera of Tetrigoidea from China, which included 13 species from 8 genera of Cladonotinae. Phylogenetic inferences were performed using the combined dataset and Bayesian inference (BI) and Maximum Parsimony (MP) methods, and the phylogenetic tree of Cladonotinae was reconstructed. All inferences based on the results of the present study supported the Cladonotinae subfamily as a polyphyletic group; within the Cladonotinae subfamily, Tetradinodula, and Tuberfemurus were closely related to Tetriginae, while Austrohancockia and Gibbotettix showed a close relationship to the Scelimenidae subfamily. Additionally, a new genus and new species of the Cladonotinae subfamily are described and illustrated: Hainantettix Deng, gen. nov. and Hainantettix strictivertex Deng, sp. nov.

An annotated catalogue of the pygmy grasshoppers of the genus Criotettix Bolívar, 1887 (Orthoptera: Tetrigidae) with two new Criotettix species from China.

The tetrigid genus Criotettix Bolívar, 1887 from China is taxonomically reviewed. The genus now includes 39 species from China, in which two new species are described and illustrated, namely: Criotettix longispinus Deng, sp. nov. and Criotettix undatifemurus Deng, sp. nov..Their distribution and an annotated identification key to Chinese species are provided.

A review of the genus Systolederus Bolivar (Orthoptera: Metrodorinae) from China.

The tetrigid genus Systolederus Bolivar, 1887 from China is taxonomically reviewed. The genus now includes 16 species from China, in which one new species is described and illustrated, namely: Systolederus aspinus Deng, sp. nov.. Their distribution and an annotated identification key to Chinese species are provided.

Water-soluble benzylidene cyclopentanone based photosensitizers for in vitro and in vivo antimicrobial photodynamic therapy.

Antimicrobial photodynamic therapy (aPDT) has been proposed to cope with the increasing antibiotic resistance among pathogens. As versatile pharmacophores, benzylidene cyclopentanone based photosensitizers (PSs) have been used in various bioactive materials. However, their reports as aPDT agents are very limited, and relationships between their chemical structures and antibacterial abilities have not been systematically discussed. Here, nine water-soluble benzylidene cyclopentanone PSs modified by polyethylene glycol (PEG), carboxylate anionic or pyridyl cationic agents are studied for aPDT. It is found that the binding/uptake abilities and aPDT effects of these PSs toward bacterial cells vary significantly when adjusting the number and position of their terminal charged groups. Though the comparable (also best) binding/uptake amounts are achieved by both cationic PS P3 and anionic PS Y1, only Y1 exhibits much more excellent aPDT activities than other PSs. Antibacterial mechanisms reveal that, relative to the favorable cell wall-binding of cationic PS P3, the anionic PS Y1 can accumulate more in the spheroplast/protoplast of methicillin-resistant Staphylococcus aureus (MRSA), which ensures its high efficient aPDT abilities both in vitro and in vivo. This study suggests the great clinical application potential of Y1 in inactivation of MRSA.

Effective Two-Photon Excited Photodynamic Therapy of Xenograft Tumors Sensitized by Water-Soluble Bis(arylidene)cycloalkanone Photosensitizers.

A series of bis(arylidene)cycloalkanone photosensitizers modified by polyethylene glycol (PEG) have been studied for two-photon excited photodynamic therapy (2PE-PDT). As compared with their prototype compounds, these PEGylated photosensitizers show enhanced water solubilities while their photophysical and photochemical properties, including linear absorption, two-photon absorption, fluorescence, and singlet oxygen quantum yield, remain unaltered. In vitro behaviors (cellular uptake, subcellular localization, photocytotoxicity in both PDT and 2PE-PDT) of these photosensitizers reveal that an optimized lipid-water partition coefficient can be obtained by adjusting the length and position of the PEG chains. Among them, the photosensitizer modified asymmetrically by two tetraethylene glycol chains presents the best performance as a 2PE-PDT candidate. Selective blood-vessel closure and obvious therapeutic effect in inhibiting the growth of tumors are confirmed by in vivo 2PE-PDT after intravenous injection of this photosensitiezer. The survival periods of treated tumor-bearing mice are significantly prolonged. This study demonstrates the feasibility of using a simple molecule to construct a potential candidate for 2PE-PDT.

Synthesis and in vitro photocytotoxicity of coumarin derivatives for one- and two-photon excited photodynamic therapy.

Triethylene glycol functionalized coumarin derivatives 1-5 were synthesized and investigated as photosensitizers for one- and two-photon excited photodynamic therapy (PDT). Their absorption, fluorescence, triplet-state quantum yields, and singlet oxygen quantum yields were found to be significantly related to the substituent at the 7-position of the coumarin ring. In vitro photocytotoxicity of these derivatives toward HepG2 cells was examined and compared with a clinical drug. In vitro generation of reactive oxygen species (ROS), cellular uptake, and intracellular distribution of these derivatives were also characterized to fully reveal their structure-property relationships. The results showed that derivative 5, with a two-photon absorption cross section value of 1556 GM, could be a powerful PDT agent for both superficial diseases and solid tumors.

Thermosensitive PNIPAM semi-hollow spheres for controlled drug release.

Thermosensitive poly(N-isopropylacrylamide) (PNIPAM) semi-hollow spheres consisting of low density cores, dense shells and separated cavities between cores and shells were prepared via two-step precipitation polymerization. The self-cross-linked poly(N-isopropylacrylamide-co-methacrylic acid) (PNIPAM-co-PMAA) gels with low solid density were prepared in the first precipitation polymerization and served as the templates on which dense PNIPAM shells cross-linked by N,N'-methylenebis(acrylamide) (BMA) were formed in the second precipitation polymerization. The shell thickness of the semi-hollow spheres could be controlled via adjusting the feeding core/shell mass ratios. The carboxylic groups on the core were conjugated with doxorubicin (DOX) via disulfide bonds which could be degraded by the reduction of glutathione (GSH). The release of DOX from the cores could be controlled by temperature and shell thickness with the disulfide bonds degraded by GSH. The cell viability assay indicated that the semi-hollow particles conjugated with DOX by disulfide bonds showed remarkable toxicity to Hela cells, and the toxicity was related to the shell thickness of the particles.