Mass Measurement of Upper fp-Shell N=Z-2 and N=Z-1 Nuclei and the Importance of Three-Nucleon Force along the N=Z Line

Using a novel method of isochronous mass spectrometry, the masses of ^{62}Ge, ^{64}As, ^{66}Se, and ^{70}Kr are measured for the first time, and the masses of ^{58}Zn, ^{61}Ga, ^{63}Ge, ^{65}As, ^{67}Se, ^{71}Kr, and ^{75}Sr are redetermined with improved accuracy. The new masses allow us to derive residual proton-neutron interactions (δV_{pn}) in the N=Z nuclei, which are found to decrease (increase) with increasing mass A for even-even (odd-odd) nuclei beyond Z=28. This bifurcation of δV_{pn} cannot be reproduced by the available mass models, nor is it consistent with expectations of a pseudo-SU(4) symmetry restoration in the fp shell. We performed ab initio calculations with a chiral three-nucleon force (3NF) included, which indicate the enhancement of the T=1 pn pairing over the T=0 pn pairing in this mass region, leading to the opposite evolving trends of δV_{pn} in even-even and odd-odd nuclei.

Strategies of strengthening mechanical properties in the osteoinductive calcium phosphate bioceramics

Calcium phosphate (CaP) bioceramics are widely applied in the bone repairing field attributing to their excellent biological properties, especially osteoinductivity. However, their applications in load-bearing or segmental bone defects are severely restricted by the poor mechanical properties. It is generally considered that it is challenging to improve mechanical and biological properties of CaP bioceramics simultaneously. Up to now, various strategies have been developed to enhance mechanical strengths of CaP ceramics, the achievements in recent researches need to be urgently summarized. In this review, the effective and current means of enhancing mechanical properties of CaP ceramics were comprehensively summarized from the perspectives of fine-grain strengthening, second phase strengthening, and sintering process optimization. What's more, the further improvement of mechanical properties for CaP ceramics was prospectively proposed including heat treatment and biomimetic. Therefore, this review put forward the direction about how to compatibly improve mechanical properties of CaP ceramics, which can provide data and ideas for expanding the range of their clinical applications.

ROR1-AS1 promotes tumorigenesis of colorectal cancer via targeting Wnt/β-catenin

OBJECTIVE

Recent studies have discovered that long noncoding RNAs (lncRNAs) play an important role in malignant tumors. In this research, lncRNA ROR1-AS1 was selected to identify how it affected the development of colorectal cancer (CRC).

PATIENTS AND METHODS

ROR1-AS1 expression was detected by Real-time quantitative polymerase chain reaction (RT-qPCR) in CRC tissue samples. ROR1-AS1 expression level and patients' overall survival time were analyzed. Functional experiments were conducted to identify the changes of biological behaviors in CRC cells after knockdown of ROR1-AS1. Moreover, we also explored the underlying mechanism.

RESULTS

Detection of ROR1-AS1 expression level in patients' tissues showed that ROR1-AS1 was higher in CRC tissues than that in adjacent ones. ROR1-AS1 expression was negatively associated with patients' overall survival time. Cell growth ability was inhibited due to knockdown of ROR1-AS1 in vitro. Moreover, cell migration and invasion abilities were repressed after ROR1-AS1 was knockdown. Furthermore, due to the knockdown of ROR1-AS1, the targeted proteins in Wnt/β-catenin signaling pathway were suppressed.

CONCLUSIONS

These results suggested that ROR1-AS1 could enhance cell metastasis and proliferation via inducing Wnt/β-catenin signaling pathway, which might offer a potential therapeutic target in CRC.

ROR1-AS1 promotes tumorigenesis of colorectal cancer via targeting Wnt/β-catenin

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "ROR1-AS1 promotes tumorigenesis of colorectal cancer via targeting Wnt/β-catenin, by T. Liao, S.-L.-M. Maierdan, C. Lv, published in Eur Rev Med Pharmacol Sci 2019; 23 (3 Suppl): 217-223-DOI: 10.26355/eurrev_201908_18650-PMID: 31389604" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/18650.

Ephedrine causes liver toxicity in SD rats via oxidative stress and inflammatory responses

Ephedrine abuse has spread in many parts of the world and severely threatens human health. The mechanism of ephedrine-induced toxicity still remains unclear. This study was performed to investigate the effects of ephedrine treatment on the liver and explore the underlying mechanisms. Sprague Dawley rats were divided into saline and ephedrine groups. Rats were treated with ephedrine at 20 mg/kg or 40 mg/kg ( n = 10) by oral gavage daily for 7 days. Pathological changes were examined by hematoxylin and eosin staining and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling assay. Enzyme-linked immunosorbent assays were used to measure the liver functional markers, oxidative stress markers, and inflammatory cytokines. Real-time polymerase chain reaction and Western blot were used to measure gene and protein expression, respectively. Our data showed that ephedrine treatment increased hepatocellular cell apoptosis and impaired liver function. Moreover, ephedrine treatment increased oxidative stress and inflammatory responses, which may be due to the increase of transforming growth factor β (TGF-β)/Smad3 expression. Our study demonstrated that short-term treatment of ephedrine caused liver toxicity in rats through regulating TGF-β/Smad pathway.

[Massive hemorrhage caused by fungal infections after donation-after-cardiac-death kidney transplantation: clinical features, prevention and treatment experience]

OBJECTIVE

To study the characteristics and prevention and treatment strategies of massive hemorrhage caused by fungal infections after donation-after-cardiac-death (DCD) kidney transplantation.

METHODS

A total of 91 cases of DCD kidney transplantation between August 25, 2013 and June 30, 2015 in Third Affiliated Hospital of Sun Yat-sen Univservity were retrospectively analyzed. The characteristics of and prevention and treatments strategies for postoperative massive hemorrhage caused by fungal infections were summarized.

RESULTS

Ninety-one cases of DCD kidney transplantation were divided into 2 groups based on regimens for preventing postoperative fungal infections: fluconazole prophylaxis group: a total of 26 cases of renal transplant before June 11, 2014 received fluconazole regimen, from postoperative day 0 to 2 weeks; micafungin prophylaxis group: a total of 65 cases of renal transplant after June 11, 2014 received micafungin regimen, also for 2 weeks from postoperative day 0. Two cases in fluconazole group developed postoperative massive hemorrhage. In case 1, the hemorrhage occurred at 2 weeks after transplantation. Graft nephrectomy was performed during surgical exploration for hemostasis, yet the massive hemorrhage relapsed 2 weeks later. Endoluminal exclusion of external iliac artery using endovascular covered stent-graft at the anastomosis site was performed and the massive bleeding was successfully stopped. The patient was restored to hemodialysis and waited for second kidney transplantation. Candia albicans was detected in the culture of blood and drainage liquid from incision. The other case of hemorrhage occurred at 3 weeks after transplantation. Graft nephrectomy plus endovascular exclusion using covered stent-graft were also performed to stop the massive bleeding. Massive fungal hyphae and spores were observed at the stump of renal graft artery under microscope. The patient received second kidney transplantation after 6 months successfully. No massive hemorrhage caused by fungal infections occurred in micafungin prophylaxis group.

CONCLUSIONS

Massive hemorrhage cased by fungal infections after DCD kidney transplantation is usually characterized by delayed and recurrent course, and may result in graft nephrectomy or even death of patients. Endovascular exclusion using covered stent can successfully stop bleeding and rescue life of patients. Two-week preemptive prophylaxis of fungal infections using micafungin can effectively prevent delayed fungal massive hemorrhage in DCD kidney transplantation.

Genetic diversity in fragmented populations of Populus talassica inferred from microsatellites: implications for conservation

Populus talassica Kom. is an ecologically important species endemic to central Asia. In China, its main distribution is restricted to the Ili region in the Xinjiang Autonomous Region. An understanding of genetic diversity and population structure is crucial for the development of a feasible conservation strategy. Twenty-six high-level simple sequence repeat (SSR) markers were screened and used to genotype 220 individuals from three native populations. A high level of genetic diversity and low population differentiation were revealed. We identified 163 alleles, with a mean of 6.269 alleles per locus. The observed and expected heterozygosities ranged from 0.472 to 0.485 (with a mean of 0.477), and from 0.548 to 0.591 (mean 0.569), respectively. Analysis of molecular variance revealed 93% variation within populations and 7% among populations. A model-based population structure analysis divided P. talassica into two groups (optimal K = 2). These genetic data provide crucial insight for conservation management.

A novel regulatory function for miR-29a in keloid fibrogenesis

BACKGROUND

A growing body of evidence has shown that microRNA-29 (miR-29) plays a central role in the progression of fibrosis. However, the mechanisms underlying the role of miR-29 in keloid fibrogenesis remain unknown.

AIM

To investigate the roles of miR-29 in dermal fibroblasts in the pathogenesis of keloids.

METHODS

Primary fibroblasts from 9 patients with keloid and 6 healthy controls (HCs) were cultured and pretreated with transforming growth factor (TGF)-β1. Next, fibroblasts were transfected with precursor miRNA and anti-miR-29a miRNA. TGF-β1-associated miR-29 alterations were investigated by quantitative real-time PCR. Collagen I and collagen III protein levels were analysed by western blotting.

RESULTS

miR-29a, miR-29b and miR-29c levels were significantly lower in keloid compared with healthy fibroblasts (P < 0.05), and in particular, miR-29a was especially markedly reduced (P < 0.001). Type I and type III collagen mRNA and protein levels were decreased in keloid fibroblasts transfected with pre-miR-29a (P < 0.05), whereas knockdown with anti-miR-29a increased type I and type III collagen mRNA and protein expression (P < 0.05) in the fibroblasts. Interestingly, pretreatment of fibroblasts with TGF-β1 significantly decreased miR-29a (P < 0.05), whereas miR-29b and miR-29c were reduced to a lesser extent, which was not significant.

CONCLUSIONS

These findings show that miR-29a exerts as a novel regulator in the fibrogenesis of keloid, suggesting that miR-29a might be a novel marker for keloid.

Altered circulating endothelial progenitor cells in patients with keloid

Evidence has suggested that vascular endothelial growth factor (VEGF), a crucial growth factor in regulating endothelial progenitor cells (EPCs), plays a central role in keloid formation. However, the levels of circulating EPCs in patients with keloid have not yet been explored. The aim of this study was to determine the number of circulating EPCs in patients with keloid. Circulating EPCs (defined as CD45- CD34+CD133+VEGFR2+cells) and VEGF levels from 39 patients with keloid and 22 healthy controls (HCs) were assessed by flow cytometry and ELISA, respectively. EPCs were detectable in the peripheral blood of patients with keloid. The number of circulating EPCs and the levels of plasma VEGF were significantly higher in patients with keloid than in HCs. However, no correlation was found between the number of circulating EPCs and the serum VEGF levels. This study provides the first evidence that EPCs are increased in the peripheral blood of patients with keloid. Understanding the roles of EPCs in keloid fromation may lead to the development of novel therapeutic strategies for keloid.

Vitamin D: a novel therapeutic approach for keloid, an in vitro analysis

BACKGROUND

Vitamin D and its metabolites play an important role in calcium homeostasis, bone remodelling, hormone secretion, cell proliferation and differentiation. Recent studies also suggest a beneficial role of vitamin D in slowing the progression of tissue fibrosis. However, their effects on dermal fibrosis and keloids are unknown. Objectives  To investigate the effect of 1,25-dihydroxyvitamin D3 (1,25D) in the pathogenesis of tissue fibrosis by keloid fibroblasts (KFs).

METHODS

KFs were cultured and exposed to different concentrations of 1,25D in the presence or absence of transforming growth factor (TGF)-β1. KF phenotypes and protein production were analysed by real-time reverse transcriptase-polymerase chain reaction, Western blot, immunofluorescence and multiplex enzyme-linked immunosorbent assay techniques. Collagen synthesis was evaluated by measuring (3) H-proline incorporation. The effect of 1,25D on cell proliferation and viability was evaluated by Formazan assay, proliferating cell nuclear antigen expression and the colorimetric conversion of 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide.

RESULTS

We confirmed the presence of vitamin D receptors (VDRs) in cultured keloid fibroblasts. Fibroblasts transfected with a vitamin D response element reporter construct and exposed to the active vitamin D metabolite 1,25D showed increased promoter activity indicating VDR functionality in these cells. Incubation of KFs with 1,25D suppressed TGF-β1-induced collagen type I, fibronectin and α-smooth muscle actin expression. 1,25D also modulated plasminogen activator inhibitor-1 and matrix metalloproteinase-9 expression induced by TGF-β1. Interestingly, 1,25D induced hepatocyte growth factor mRNA expression and protein secretion in keloid fibroblasts.

CONCLUSIONS

This study highlights key mechanistic pathways through which vitamin D decreases fibrosis, and provides a rationale for studies to test vitamin D supplementation as a preventive and/or early treatment strategy for keloid and related fibrotic disorders.

Role of caveolin-1 in the pathogenesis of tissue fibrosis by keloid-derived fibroblasts in vitro

BACKGROUND

Recent studies have suggested that caveolin-1 (cav-1) plays an important role in the regulation of transforming growth factor (TGF)-β1 signalling and participates in the pathogenesis of tissue fibrosis. However, its effects on dermal fibrosis keloids are unknown.

OBJECTIVES

To investigate the effect of cav-1 in the pathogenesis of tissue fibrosis by keloid fibroblasts.

METHODS

Keloid fibroblasts were cultured and exposed to different concentrations of cav-1 cell-permeable peptides (cav-1p) in the presence of TGF-β1. Keloid fibroblast phenotypes and protein production were analysed by real-time reverse transcriptase-polymerase chain reaction, Western blot, and multiplex enzyme-linked immunosorbent assay techniques. The effect of cav-1p on cell viability was evaluated by MTT assay.

RESULTS

Cav-1 was markedly decreased in the keloid-derived fibroblasts. Moreover, cav-1p significantly reduced TGF-β receptor type I levels and Smad2/3 phosphorylation in response to added TGF-β1. Additionally, TGF-β1 decreased cav-1 expression in human skin fibroblasts. Cav-1 was able to suppress TGF-β1-induced extracellular matrix production in cultured keloid fibroblasts through regulation of the mitogen-activated protein kinase pathway.

CONCLUSIONS

Cav-1 appears to participate in the pathogenesis of tissue fibrosis in keloid. Restoration of cav-1 function by treatment with a cell-permeable peptide corresponding to the cav-1 scaffolding domain may be a novel therapeutic approach in keloid.

Comparative responses in rare minnow exposed to 17beta-estradiol during different life stages

Present in the excrement of humans and animals, 17beta-estradiol (E(2)) has been detected in the aquatic environment in a range from several nanograms to several hundred nanograms per liter. In this study, the sensitivities of rare minnows during different life stages to E(2) at environmentally relevant (5, 25, and 100 ng l(-1)) and high (1000 ng l(-1)) concentrations were compared using vitellogenin (VTG) and gonad development as biomarkers under semistatic conditions. After 21 days of exposure, VTG concentrations in whole-body homogenates were analyzed; the results indicated that the lowest observed effective concentration for VTG induction was 25 ng l(-1) E(2) in the adult stage, but 100 ng l(-1) E(2) in the larval and juvenile stages. After exposure in the early life stage, the larval and juvenile fish were transferred to clean water until gonad maturation. No significant difference in VTG induction was found between the exposure and control groups in the adults. However, a markedly increased proportion of females and appearance of hermaphrodism were observed in the juvenile-stage group exposed to 25 ng l(-1) E(2). These results showed that VTG induction in the adult stage is more sensitive than in larval and juvenile stages following exposure to E(2). The juvenile stage may be the critical period of gonad development. Sex ratio could be a sensitive biomarker indicating exposure to xenoestrogens in early-life-stage subchronic exposure tests. The results of this study provide useful information for selecting sensitive biomarkers properly in aquatic toxicology testing.

Effects of leptin deficiency and short-term repletion on hepatic gene expression in genetically obese mice

By supplying most organs of the body with metabolic substrates, the liver plays a central role in maintaining energy balance. Hepatic metabolism of glucose, fatty acids, and lipoproteins is disrupted in the leptin-deficient obese (Lep(ob)/Lep(ob)) mouse, leading to hyperglycemia, steatosis, and hypercholesterolemia. Microarray expression profiles were used to identify transcriptional perturbations that underlie the altered hepatic physiology of Lep(ob)/Lep(ob) mice. A wide variety of genes involved in fatty acid metabolism are altered in expression, which suggests that both fatty acid synthesis and oxidation programs are activated in obese mice. The expression of a small subset of genes is upregulated by leptin deficiency, not modulated by caloric restriction, and markedly suppressed by short-term leptin treatment. Among these leptin-regulated genes, apolipoprotein A-IV is a strong candidate for mediating the atherogenic-resistant phenotype of Lep(ob)/Lep(ob) mice.

Chronic donepezil treatment is associated with slowed cognitive decline in Alzheimer's disease

OBJECTIVE

To compare rates of cognitive decline between probable Alzheimer's disease (AD) patients treated with long-duration cholinesterase inhibitors (ChE-Is) and those who remained untreated.

BACKGROUND

ChE-Is, including donepezil and tracrine, have shown beneficial effects on cognition and global functioning in patients with AD. The duration of these benefits is unknown because the longest double-blind placebo-controlled studies reported were only approximately 6 months long. Ethical concerns regarding randomization of patients to placebo for long periods make it difficult to undertake trials of longer duration.

METHODS

We identified patients in 4 AD centers who were or were not consistently treated with ChE-Is and who had demographic, psychometric and follow-up data. We compared 205 ChE-I-treated and 218 untreated AD patients on baseline variables hypothesized to differ between these groups, on baseline Mini Mental Status Examination (MMSE) scores and on rates of MMSE change at 1 year. The analysis was performed initially with all ChE-I-treated patients as a single group versus untreated subjects, and then with donepezil versus untreated subjects and tacrine versus untreated subjects.

RESULTS

As expected, treated and untreated patients differed with respect to age, education, ethnicity, percentage of community dwelling and exact days of follow-up (ANOVA and chi2) in several comparisons, but did not differ on baseline MMSE score. These baseline variables were highly intercorrelated. MMSE scores declined significantly more slowly after 1 year of ChE-I treatment compared to untreated patients (p = 0.05) after controlling for baseline differences in age, education, ethnicity and percentage of community dwelling. Slowing of decline was significant in the donepezil-treated patients (p = 0.007) but not in the tacrine-treated group (p = 0.33).

CONCLUSIONS

This study, utilizing concurrent, nonrandomized controls, suggests that donepezil continues to have efficacy over at least the first year of therapy. Other studies are needed to determine whether the benefits are maintained beyond 1 year.

Quantification of L-ascorbic acid and total ascorbic acid in fruits and spinach by capillary zone electrophoresis

A standard curve for the quantification of L-ascorbic acid (L-AA) by capillary zone electrophoresis (CZE) was established, and the quantification of ascorbic acid and total ascorbic acid in fruits (lemon, Sunkist, and pineapple) and spinach were performed using D-isoascorbic acid (D-IAA) as an internal standard. The minimum detection limits (MDLs) for L-AA and D-IAA were determined to be 1 and 2 microg/mL, respectively, at 265 nm. Dehydroascorbic acid (DHAA) in fruits and spinach was quantified in the presence of DL-homocysteine. The recoveries for L-AA in these juices were between 95 and 105%.

Does APO epsilon4 correlate with MRI changes in Alzheimer's disease?

OBJECTIVE

To assess the relation between APO E genotype and MRI white matter changes in Alzheimer's disease. The APO epsilon4 allele is correlated with amyloid angiopathy and other neuropathologies in Alzheimer's disease and could be associated with white matter changes. If so, there should be a dose effect.

METHODS

104 patients with probable Alzheimer's disease (NINCDS-ADRDA criteria) in this Alzheimer's Disease Research Centre were studied. Patients received MRI and APO E genotyping by standardised protocols. Axial MRI was scored (modified Schelten's scale) for the presence and degree of white matter changes and atrophy in several regions by a neuroradiologist blinded to genotype. Total white matter and total atrophy scores were also generated. Data analysis included Pearson's correlation for regional and total imaging scores and analysis of variance (ANOVA) (or Kruskal-Wallis) and chi(2) for demographic and disease related variables.

RESULTS

30 patients had no epsilon4, 53 patients were heterozygous, and 21 patients were homozygous. The three groups did not differ in sex distribution, age of onset, age at MRI, MMSE, clinical dementia rating, or modified Hachinski ischaemia scores. There were no significant correlations between total or regional white matter scores and APO E genotype (Pearson correlation).

CONCLUSIONS

No correlation between total or regional white matter scores and APO E genotype was found. The pathogenesis of white matter changes in Alzheimer's disease may be independent of APO E genotype.

Epimeric separation of L-ascorbic acid and D-isoascorbic acid by capillary zone electrophoresis

Capillary zone electrophoresis (CZE) was used for separation of L-ascorbic acid (L-AA) and D-isoascorbic acid (D-IAA) in a model system. The effects of borate buffer concentration (0.05-0.25 M) and pH (pH 7.5-9.0) on migration time, resolution (Rs), and theoretical plates (N) were investigated. The migration times of L-AA and D-IAA increased with the increasing pH of carrier electrolyte (0.2 borate buffer), and the resolutions (Rs) of L-AA and D-IAA were calculated to be 12.98 at pH 9.0. Concentrations of borate buffer (pH 9.0) increased the Rs values of L-AA and D-IAA, and buffer concentrations >0.1 M were found to be effective for separation of L-AA and D-IAA. Methanol in the carrier electrolyte was also influential in improving the separation of L-AA and D-IAA, which increased with the increasing concentrations (0-10%) of methanol. The optimal separation conditions for L-AA and D-IAA were as follows: carrier electrolyte, 0.2 M borate buffer (pH 9.0); applied voltage, 25 kV, with an uncoated fused silica capillary, 75 microm (i.d.) x 57 cm.

[A study on pearl fat transplantation--concentration of basic fibroblast growth factor (bFGF) and carrier of sustained delivery selected by orthogonal design]

OBJECTIVE

The experiment was designed to solve the problem that free fat transplantation survived at low percentage.

METHODS

Based on physiochemical and biological characteristics of bFGF, fibrinogen was used as its carrier of sustained delivery. We applied bFGF and fibrinogen in pearl adipose transplantation. Different concentrations of bFGF and fibrinogen were used. The relation between the concentration of bFGF and fibrinogen and their effects on fat graft maintenance were observed.

RESULTS

At three months after transplantation, the weight of the fat graft varied from 98% to 225%. The latter was approximately consistent with synchronous increase of the body weight of the animal. Weight increase of the graft was closely related to the concentration of bFGF and the sustained delivery carrier. When bFGF in the concentration of 4000 U/10 microliters and fibrinogen of 1000 mg% were applied, the fat graft obtained the greatest weight increase. Histologically, the structure of the transplanted fat was normal with fibrotic envelope and mature adipocytes.

CONCLUSION

bFGF with fibrinogen as its carrier of sustained delivery favors the survival of fat graft and weight increase. The effects of bFGF and fibrinogen depend on their concentration.

Integrated-optic array illuminator: a new design for guided-wave optical interconnections

An integrated array illuminator can be used not only as an opticalpower distributor for an array of guided-wave optic devices but also asa key element for guided-wave optical interconnections. We presenta new design for an integrated-optic array illuminator with focusingwaveguide diffractive doublet arrays. This integrated arrayilluminator allows independent optimizations of efficient and uniformoptical power distribution and focusing performance. Furthermore, the device can be fabricated with all-optical lithographic technologyand hence has the advantages of mass production with lowcost.

Radiation characteristics of waveguide diffractive doublets

The radiation characteristics of waveguide diffractive doublets consisting of double gratings located on two surfaces of waveguide cladding film are modeled based on a singular perturbation method. We determine the conditions under which the presence of the upper grating does not affect the radiation characteristics of the waveguide diffractive doublet as a whole. This allows independent performance of the upper grating, which may be replaced by a general diffractive optical element, and of the lower grating as a waveguide grating coupler. The results obtained provide an alternative method for determining the thickness of cladding film in the waveguide diffractive doublets for guided-wave manipulation.

Integrated waveguide diffractive doublet for guided-wave manipulation

An integrated waveguide diffractive doublet consisting of a uniform grating coupler and a diffractive optical element is proposed. Design of this waveguide diffractive doublet for guided-wave manipulation is described in detail. Experimental results for a fabricated waveguide diffractive doublet are also presented to demonstrate the device principles. It was found that this waveguide diffractive doublet can enhance device functionality while remaining simple and compact and having a planar structure. Furthermore, this device can be fabricated by use of all-optical lithography.

Focusing waveguide grating coupler using a diffractive doublet

A novel focusing waveguide grating coupler comprising an integrated uniform grating coupler and binary-phase-only diffractive lens is proposed, designed, and fabricated. Experimental results are also presented to demonstrate the device performance. This device is in direct competition with single-element focusing grating couplers defined by direct-write electron-beam lithography and its structure is attractive because the fabrication procedure is better suited for mass production.

Reversible inactivation of pancreatic deoxyribonuclease A by sodium dodecyl sulfate. Removal of COOH-terminal residues from the denatured protein by carboxypeptidase A

In the course of experiments on the role of the COOH-terminal residues in pancreatic deoxyribonuclease, we undertook to ascertain whether the presence of sodium dodecyl sulfate would render the normally unavailable terminus susceptible to hydrolysis by carboxypeptidase A. When DNase A is dissolved in 0.005% sodium dodecyl sulfate the protein becomes enzymically inactive when assayed against DNA in the same sodium dodecyl sulfate concentration. The loss of activity caused by treatment with sodium dodecyl sulfate for 1 hour at 45 degrees can be fully restored if the detergent-containing solution is diluted 10-fold into 6 M guanidinium chloride and then 10-fold into a pH 7.0 buffer, 10 mM in CaCl2, prior to a 100-fold dilution for assay. The presence of Ca2+ is essential for the refolding process. If the same degree of dilution is made into sodium dodecyl sulfate-free buffer without the guanidinium chloride step, there is very little reversal of the inactivation. An almost complete loss of regenerable activity is caused by 1 hour of digestion by carboxypeptidase at 45 degrees in the presence of 0.03% sodium dodecyl sulfate. Although up to 6 amino acid residues can be removed from the COOH terminus, the loss of activity can be correlated with the removal of either 1 or 2 amino acid residues (-Leu-Thr) from the COOH-terminal sequence. Thus, DNase A is one of the several enzymes in which residues at the COOH terminus are essential to the active conformation. If the enzyme minus 2 to 6 terminal residues was mixed with a 15-residue COOH-terminal peptide (obtained by cyanogen bromide cleavage), only about 2% activity could be regenerated.

Deoxythymidine 3', 5'-di-p-nitrophenyl phosphate as a synthetic substrate for bovine pancreatic deoxyribonuclease

Bovine pancreatic deoxyribonuclease liberates p-nitrophenol from the 3'-group of deoxythymidine 3', 5'-di-p-nitrophenyl phosphate. A similar hydrolysis occurs with deoxythymidine 3'-p-nitrophenyl phosphate 5'-phsophate, but the rate is less than 2% of that with the di-p-nitrophenyl ester. The rate of formation of the p-nitrophenol, measured spectrophotometrically at 400 nm, varies linearly with DNase concentration. The binding of the substrate is not strong (K-m(app) in the 10 mM range), but the hydrolysis is rapid; 1 mug of DNase (free from other phosphodiesterases) can be assayed in 3 min after addition to a 10 mM substrate solution at pH 7.2, 10mM in MnCl2, and 1mM in CaCl2. All four bovine pancreatic DNases (A,B,C, and D) show the same relative activities toward DNA and toward the di-p-nitrophenyl ester; both activities are lost when DNase is inactivated by iodoacetate or by trypsin. The specificity of DNase toward the di-p-nitrophenyl substrate is different from that which has been established for the enzyme's predominant action on DNA or synthetic oligonucleotides, where a monoesterified phosphate group is formed at the 5'-position.