Up-converting NaYF4：0.1%Tm^3＋, 20%Yb^3＋ nanoparticles as luminescent labels for deep-tissue optical imaging

Optical imaging plays an important role in biomedical research being extremely useful for early detection, screening and image-guided therapy. Lanthanide-doped up-converting nanoparticles were ideally suited for bioimaging because they could be ex- cited in near infrared （NIR） and emit in NIR or visible （VIS）. Here, we compared lanthanide doped up-converting NaYF4 and organic fluorophores for application in deep-tissue imaging. For that purpose - tissue phantoms mimicking the natural properties of light scat- tering by living tissues were prepared. The studies allowed to quantitatively compare optical resolution of different fluorescent com- pounds, revealing that the NIR photoexcitation was favorable over conventional UV photoexcitation.     

Disinfection By-Product Formation during Long-Term Water Storage in Alaska

In many areas of Northern and Western Alaska, small streams and shallow lakes serve as community raw water supplies. These water supplies freeze completely during winter. In order to supply drinking water during the 6–9 month winter, communities store water that was treated during summer. A chlorine residual is maintained in the stored water. Raw water sources derived from surface water may be heavily laden with dissolved organic matter. At utilities where organic matter escapes treatment, the potential for accumulation of disinfection by-products (DBPs) during storage is a significant health concern. The following study was performed to evaluate this potential threat. Water was collected from five operating utilities, four that normally store water for 6–9 months and one that produces drinking water year-round. Raw, filtered (i.e., unchlorinated) and “finished” (i.e., filtered and chlorinated) water samples were collected during the summer pumping season and stored in the laboratory for 8 months. In order to mimic practice in the field, the chlorine residual was maintained in the finished water for the full storage period. While the concentration of DBPs in the finished water varied over the study period, there was not a statistically significant trend from the third to the eighth month of storage. The observed DBP values were strongly a function of the type of treatment system used. Those systems passing more organic matter had higher DBP values throughout the storage period. The ultraviolet absorbance at 254 nanometers ?start(UV254)end? decreased continuously in the finished water coincident with chlorine consumption. ?startUV254end?, often used as a surrogate for DBPs, remained constant during the entire storage periodin raw and filtered water samples. Filtered water that was stored prior to chlorination accumulated fewer DBPs than finished water that was continuously chlorinated during the storage period. This result suggests that storing filtered water instead of finished water for long periods would limit DBP exposure to consumers. This conclusion was based on a comparison of DBP formation potentials (i.e., raw and filtered water) to DBPs (i.e., finished water). It is important to note that DBP formation potentials are based on a ?start24?hend?chlorine contact time. If long term storage were provided for filtered water, a smaller volume of secondary storage would still be needed to provide contact time for disinfection.     

Study on the relationship between vascular invasion and prognosis in patients with locally confined renal cell carcinoma

This study aimed to develop techniques to allow dynamic imaging of a cavity before, during and after placement of glass-ionomer restorative materials. Cavities were cut in recently extracted third molars and the teeth longitudinally sectioned. Each hemisected tooth surface was placed in green modelling compound at 90 to the optical axis of the microscope. The cavity surface was imaged using a video rate confocal microscope in conjunction with an internally focusable microscope objective. The sample on the stage was pushed up to the objective lens which 'clamped' the cover glass onto it. Water, glycerine or oil was placed below the coverglass, with oil above. Internal tooth structures were imaged by changing the internal focus of the objective. The restorative material was then placed into the cavity. Video images were stored either onto video tape or digitally, using a frame grabber, computer and mass memory storage. Software controls produced time-lapse recordings of the interface over time. Preliminary experiments have examined the placement and early maturation of conventional glass-ionomer cements and a syringeable resin-modified glass-ionomer cement. Initial contact of the cement matrix and glass particles was visible as the plastic material rolled past the enamel and dentine, before making a bond. Evidence for water movement from the dentine into the cement has also been seen. After curing, the early dimensional changes in the cements due to water flux were apparent using the time-lapse facility. This new technique enables examination of developing tooth/restoration interfaces and the tracking of movement in materials.     

Laboratory evaluation of the XR-Bond Dentin/Enamel Bonding System

The shear bond strengths of the XR-Bonding System used in conjunction with Herculite composite, to the dentine of forty extracted human permanent first and second molars were determined after the test specimens were stored in physiological saline at 37 degrees C for 48 hours, one week, two weeks and four weeks, respectively. A shear load was applied to the base of the bonded composite cylinders with a knife-edged rod at a crosshead speed of 0.5 mm/minute. The shear bond strengths were expressed in megapascals (MPa). The quantitative microleakage of Class V preparations in dentine (cementum) in forty-eight extracted human maxillary permanent canines restored with the same dentinal bonding system and after storage in physiological saline at 37 degrees C for the same time intervals as for the shear bond strength tests, was determined. On the final day of each time interval the teeth were thermocycled X 500 in a 2 per cent methylene blue solution between 8 degrees C and 50 degrees C with a dwell time of 15 seconds. Microleakage was determined by a spectrophotometric dye-recovery method and expressed in microgram dye/restoration. There was a significant trend for the shear bond strengths to increase with duration of storage (p = 0.01) but the quantitative microleakage was not significantly different (p = 0.75).     

Impact of various red cell concentrate preparation methods on the efficiency of prestorage white cell filtration and on red cells during storage for 42 days

BACKGROUND: White cell (WBC) reduction prior to storage of red cell (RBC) concentrates may reduce the incidence of HLA alloimmunization and may improve the quality of stored RBCs. STUDY DESIGN AND METHODS: An integrated WBC-reduction filter system was tested after various RBC preparation procedures (from whole blood), and the influence of filtration on RBCs during storage for 42 days was investigated. Four additive system RBC preparation protocols were used. Units prepared from conventional triple blood bags were held for 4 to 6 hours at 22 degrees C, and then the RBCs were separated via a hard spin and filtration, performed immediately (Group 1) or after 18 hours' storage at 4 degrees C (Group 2). Units prepared from a top-and-bottom collection system were held at 22 degrees C for 4 to 6 or 22 to 24 hours; the centrifuged RBCs were filtered immediately after preparation (Groups 3 and 4, respectively, by holding time). WBC reduction and filtration time were analyzed. The impact of WBC filtration on pH, hemolysis rate, hemoglobin content, ATP, potassium glucose, and lactate was investigated weekly during storage for 42 days. RESULTS: Filtration reduced the mean WBC count by 3 to 4 log10, to 0.19 +/- 0.25 x 10(6), regardless of the RBC preparation method. Mean filtration times differed significantly between the groups and were longest for Group 1. Besides hemolysis and pH values, which were greater in all filtered units, no major differences were found in filtered and unfiltered RBCs during the storage interval. CONCLUSION: The efficiency of prestorage WBC filtration of RBCs was unaffected by the preparation procedure. However, the filtration time for RBCs freshly prepared in the conventional triple blood bag system without buffy-coat depletion was unacceptable. No major metabolic differences between filtered and unfiltered RBCs during 42 days of storage were found.     

溶损反应前后焦炭反射率及光学组织的比较

 为了解焦炭中各显微光学组织在溶损反应中的反应行为，对不同条件下溶损反应前后焦炭的反射率及显微光学组织组成进行了分析。试验表明，焦炭的反射率指标及光学组织组成与焦炭的反应性CRI、反应后强度CSR之间存在比较好的相关性。焦炭的平均最大反射率[Rmax]和光学各向异性指数Φ越高，各向同性光学组织越少，其CRI越低，CSR越高。经过1 100 ℃溶损反应后，焦炭的[Rmax]提高，各向同性光学组织含量减少，各向异性光学组织含量增加，说明各向同性的反应性高于各向异性。溶损反应温度提高到1 300 ℃以后，焦炭中各向同性的溶损反应量分别为1 100 ℃时的1.07～3.00倍，而各向异性的溶损反应量分别为1 100 ℃的1.22～8.58倍，且热性能越好的焦炭各向异性反应量增加得越多。     

Preparation and Characteristics of Optical Storage Material CaS:Ce3+, Sm3+

CaS: Ce3+, Sm3 + optical storage material was prepared by wet-method under the reducing atmosphere. Influence of sintering atmosphere on luminescence intensity was studied to get the result that active-carbon reducing atmosphere is better. XRD analysis shows that CaS crystal structure was formed at 700 ℃. The excitation spectrum is in the range of 250 ～ 500 nm with peaks at 260.2, 353.4 and 461.2 nm, the fluorescence spectrum shows a broadband spectrum with peaks at 503, 568 and 604 nm and the emission spectrum of the sample stimulated by 980 nm laser also shows a broadband spectrum with peaks at 508,565 and 600 nm. The result of spectra analysis indicates that this material can absorb and "trap" incoming light energy from ultraviolet and visible light (Information write-in), and release that stored energy in the form of green luminescence (information read-out) upon stimulation from a longer IR wavelength. The optical storage physical mechanism was also discussed.     

Quenching mechanism of Er~(3+) emissions in Er~(3+)-and Er~(3+)/Yb~(3+)-doped SrAl_(12)O_(19) nanophosphors

Nanoscaled SrAl12O19:Er3+ and SrAl12O19:Yb3+,Er3+ phosphors were synthesized by a combustion method.The emission intensities of every sample were compared by a new method with the emission of codoped Gd3+ ions as a reference.Compared with their bulk material prepared by the solid-state reaction method,a higher Er3+ quenching concentration,as high as 20%,was observed in the nanoscaled phosphors for both visible(VIS) and near infrared(NIR) emissions.The higher quenching concentration in both VIS and NIR regio...     

The Investigation on the Microstructure of Metallurgical Molten Slags and the Foundation of the Primary Cluster Theory

This paper presents the characteristics of the properties of metallurgical molten slags based on the bond structure or the existence of certain ion clusters. Some experimental and theoretical approaches were adopted in the investigation. Two sets of high temperature Raman spectroscopy (HTRS) were established at Shanghai University; both can be successfully operated at 2000K or higher. One of them combines the accumulated time resolution together with the spatial resolution, and it is designed for both ultraviolet (UV) and visible (VIS) light. The SiOT model uses 5 kinds of Si‐O tetrahedra (Q_n) as microsturctural units. In this model, each sample contains 250000 or more tetrahedra. The calculation using a GF matrix and electro‐optical parameter (EOP) methods were performed for every tetrahedron one by one to determine the partial Raman spectra of Q_n. Then the spectra were integrated to obtain an envelope of the sample. In addition to the SiOT model, a CEMS model was also developed to link the ion cluster structure and the thermodynamic properties at equilibrium (as mixing free energy).     

Apoptosis after intestinal ischemia-reperfusion injury: a morphological study

BACKGROUND: Apoptosis has been identified after ischemia-reperfusion (IR) injury to the brain, heart, kidney, retina, and the adrenals. Intestinal IR injury causes villous and crypt damage, which has so far been attributed to cellular necrosis. This study was undertaken to investigate the possible role of apoptosis after reperfusion of cold-stored small bowel grafts in syngeneic rats. METHODS: Small intestinal grafts were stored at 4 degrees C for 24 hr in saline (n=6) or in modified University of Wisconsin solution (n=6), followed by reperfusion for 1 hr in syngeneic Lewis rats. Small bowel samples were obtained before storage, after preservation and after 1 hr of reperfusion. They were processed for light and electron microscopy and analyzed for cell death, with particular emphasis on apoptosis. RESULTS: Less than one apoptotic event was seen per 10 crypts in normal and stored bowels. An occasional normal and some denuded villous epithelial cells of stored bowels exhibited apoptosis. After isotransplantation and 1 hr of reperfusion, marked increase in apoptosis was seen in the crypts and denuded villous epithelial cells of both saline- and modified University of Wisconsin-stored bowels. Secondary necrosis was seen in apoptotic cells, as were dark cells. Only a few cells showed signs of primary ischemic necrosis. CONCLUSIONS: Apoptosis occurs after intestinal IR injury. Modulation of its genetic regulatory and biochemical effector machinery might alleviate or even prevent IR injury in small bowel transplanted after similar periods of storage.     

Technical advantages of digital EEG

Digital EEG (DEEG) is the paperless recording of an EEG using computer-based instrumentation. The data are stored on electronic media, such as magnetic drives or optical disks, and displayed on a monitor. DEEG has many advantages compared to analog EEG including automatic event detection, storage, quantification, and networking capabilities. The flexibility of DEEG allows for changes of recording parameters, such as montage, filters, and horizontal and vertical display scales retrospectively during record review. In this review numerous clinical EEG examples are used to demonstrate how these post hoc changes, particularly reformatting the montage, allow for more accurate interpretation of the EEG.     

痕量分析中银溶液的稳定性

评述了痕量分析中,银标准溶液和天然水试样中痕量银贮存的稳定性及影响贮存的重要因素,提出了配制、贮存标准溶液的方法。     

Degradation of histamine solutions used for bronchoprovocation

STUDY OBJECTIVES: To determine optimal storage conditions for histamine diphosphate (HDP) solutions used for bronchoprovocation. DESIGN: HDP was dissolved in buffered saline solution to concentrations of 0.125 to 16 mg/mL and stored in 3-mL unit dose syringes at different temperatures for varying lengths of time, with and without protection from fluorescent light. SETTING: Dark freezer (-20 degrees C), dark refrigerator (4 degrees C), and laboratory counter top (20 degrees C) illuminated by fluorescent light (375 foot-candles). MEASUREMENTS: HDP concentrations were measured after the solutions were prepared and during storage by a high-performance liquid chromatographic assay that differentiates histamine from its break down products. RESULTS: All dilutions were sterile after preparation and contained 97 to 110% of the labeled amount of HDP. Solutions constantly exposed to fluorescent light (375 foot-candles) and room temperature (20 degrees C) contained only 20 to 37% of the initial concentrations after 7 days. The same dilutions stored at room temperature, but protected from light, contained 83 to 94% of the initial concentrations. Dilutions stored in the dark in a refrigerator (4 degrees C) retained 97% of the initial concentrations after 8 weeks, while dilutions stored in the dark freezer (-20 degrees C) were stable for 12 months. CONCLUSIONS: Exposure to fluorescent light at room temperature results in degradation of histamine solutions used for bronchoprovocation. Dilutions stored in unit dose syringes and protected from light are stable for at least 8 weeks in the refrigerator and up to 12 months frozen. Once removed from the refrigerator or freezer, the solutions should be used within 6 h or discarded.     

Storage of fungi using sterile distilled water or lyophilization: comparison after 12 years

The methods used in our laboratory for maintaining culture collections of fungi, i.e. storage in sterile distilled water or lyophilization, were evaluated. Seventy-eight isolates belonging to seven genera were tested. After 12 years of preservation, survival rates associated with distilled water storage and lyophilization were 89.7% and 87.2% respectively. The viability of the dermatophytes after 8 years was confirmed using urease test media, the hair penetration test and dermatophyte test medium (DTM). The results showed that the procedure for maintaining cultures in distilled water is simple, inexpensive and reliable.     

Evaluation of amorphous ursodeoxycholic acid by thermal methods

PURPOSE: The purpose of this study was to characterize the amorphous state of ursodeoxycholic acid (UDCA) samples by using isothermal microcalorimetry, X-ray diffraction, infrared (IR) spectroscopy and solid state carbon 13 nuclear magnetic resonance (13C-NMR) spectroscopy, and to demonstrate the application of the thermal methods (microcalorimetry and differential scanning calorimetry (DSC) for studying the amorphous state and clarifying the dissolution mechanism of UDCA. METHODS: Amorphous UDCA was prepared by grinding and rapid cooling of the melts. The heat of solution of UDCA was measured by an isothermal heat-conduction twin microcalorimeter at 25.0 degrees C. Some physicochemical properties of amorphous UDCA were also studied. RESULTS: The intensities of X-ray diffraction peaks of crystalline UDCA decreased with an increase in grinding time. The heat levels of solution of crystalline UDCA and UDCA ground for 1 min were endothermic, and became exothermic with an increase in grinding time. A good correlation was obtained between the heat of solution and the heat of crystallization determined from the peak area in DSC. Although no significant difference was observed in X-ray diffraction patterns of amorphous UDCA prepared by the two methods, significant differences were recognized in DSC, IR and 13C-NMR, and the heat of solution indicated different values among the two samples. The stability of amorphous UDCA samples stored under 74.5% relative humidity at 40 degrees C was found to depend upon the preparation methods. CONCLUSIONS: Different states of amorphous UDCA were obtained depending on the preparation method. The application of thermal methods to evaluate the amorphous state was demonstrated. The mechanism of dissolution of UDCA was discussed from the results of the heat of solution examination.     

Variability in cytotoxicity and fluoride release of resin-modified glass-ionomer cements

New-generation glass-ionomer cements contain resin to improve their restorative properties. These resin-modified glass-ionomer cements vary considerably in their chemistry, which could result in corresponding variability in their physical and biological properties. This study investigated the cytotoxicity and the fluoride release of two resin-modified glass ionomers, a conventional glass-ionomer cement, and a resin composite. Samples were prepared and extracted in distilled water for 1, 4, and 7 days; eluates were filtered and tested by means of 3T3 mouse fibroblasts. Cytotoxicity (MTT assay) values were low for all materials and extraction times, indicating minimal cytotoxicity of all materials (less than 30% inhibition). Cytotoxicity of one resin-modified glass ionomer was significantly higher than for the other materials (p < 0.001). One resin-modified glass ionomer and the conventional glass-ionomer cement released significantly more fluoride at each time interval (p < 0.001) than the other resin-modified glass-ionomer cement and the resin composite. Fluoride release and cytotoxicity were correlated (r2 = 0.60; p < 0.001), although the fluoride release does not account for the cytotoxicity observed. Cytotoxicity and fluoride release suggest that one hybrid behaved more like a conventional glass ionomer, and the other like a resin composite. These differences may have implications for material selection in specific clinical situations.     

Effects of leukocyte depletion on the storage quality of whole blood

BACKGROUND: According to the German Guidelines for Hemotherapy, preoperative autologous blood donations can be stored and transfused as whole blood. In contrast to the storage of blood components, however, storage of whole blood results in deterioration of the biological quality due to contamination with leukocytes and platelets. In this study we examined the influence of prestorage leukocyte depletion on the quality of filtered whole blood donations during storage. MATERIAL AND METHODS: Whole blood was donated by healthy volunteers (n = 14,500 ml, 70 ml CPDA-1) and was filtered using an integrated whole blood filter system (Leukotrap A1, Fa.Pall, Dreieich, Germany). The leukocyte-depleted whole blood units were then stored for up to 49 days. Several hematological and biochemical parameters indicative of the quality of blood donations were determined during storage. RESULTS: Our data indicate a quality of leukocyte-depleted whole blood donations comparable to buffy-coat-free red blood cell units. CONCLUSIONS: The Leukotrap A1 whole blood filter system is an interesting option for hospitals lacking the technical capacity to separate whole blood into components. The clinical suitability remains to be investigated by means of clinical studies.     

Synthesis and Characterization of Rare Earth Complexes with Phthalanilic Acids and Amino Acids

The phthalanilic acid compounds and the.anuno acid compounds have been follnd to havewide application as drug and plant groWth stimulator. Their transition metal complexes haveexcellent biological activities. Supported byNorthwest Highland Biological Research institute of China Academy of Sciellces, we haveachieved remarkable increasing yield of winterwheat at Xining Farm for three years. Thedrixed ligand complexes of this preparation areprobably new kind of the plant growth regulator.1 Ex…     

Computer-assisted sperm analysis for assessing initial semen quality and changes during storage at 5 degrees C

Computer-assisted sperm analysis equipment was used to evaluate bull sperm initially in a modified Tyrode's solution, in Cornell University extender, and in egg yolk-glycerol-Tris extender (following cooling and storage in the latter two extenders). Two ejaculates of semen were collected from each of eight bulls. Semen was divided into aliquots using a factorial arrangement. The semen, diluted to approximately 20 x 10(6) sperm/ml, was loaded into two 20-micron chambers, and six microscope fields from each chamber were videotaped for each treatment of each ejaculate of semen. Eight sperm characteristics analyzed with the Hamilton Thorne integrated visual optical system (Hamilton Thorne, Beverly, MA) were reported, and some of these characteristics differed significantly among bulls. The initial values of motile sperm in modified Tyrode's solution, Cornell University extender, and egg yolk-glycerol-Tris extender were 87, 79, and 66%; little change followed cooling and storage at 5 degrees C in the latter two extenders. Also, there was a small but significant decline in sperm velocity during 3 d of storage. Hyperactive sperm increased slightly during storage. The procedures used can rapidly and accurately measure many sperm characteristics in fresh semen and in semen stored in egg yolk extenders, and differences among bulls can be detected.     

Gonadal cell apoptosis: hormone-regulated cell demise

We have studied the release of nerve growth factor (NGF), a protein under consideration for treatment of Alzheimer's Disease, from polymer matrices and microspheres to characterize the stability of NGF, the dynamics of NGF release, and the distribution of NGF within the brain interstitium. Poly(ethylene-co-vinyl acetate) (EVAc) disks and poly(L-lactic acid) (PLA) microspheres were formed by codispersing NGF with one of a variety of molecules. The mass of mouse NGF (mNGF) detected following release from EVAc disks into buffered saline varied five-fold over the range of codispersants studied, with carboxymethyldextran providing optimal release, while the mass of recombinant human NGF (rhNGF) released varied four-fold from both EVAc disks and PLA microspheres, with albumin and carboxymethyldextran providing optimal release. Variation of the codispersant species significantly affected NGF release into buffered saline; it also had a noticeable, but small, effect of the amount of NGF found in the brain tissue following implantation of a polymer device. To improve NGF retention in tissue, NGF was conjugated to 70,000 molecular weight dextran and incorporated into a polymeric device. The distribution of NGF was enhanced by conjugation; comparison of NGF concentrations in the brain to a mathematical model of diffusion and elimination suggested that the elimination rate of NGF-dextran conjugate in the tissue was over seven times slower than the elimination rate of NGF. These results indicate that variation of the properties of the controlled release system may be useful in regulating the time course of NGF delivery to tissue, and that modification of the NGF itself can improve penetration and retention in the brain.