Methods for extending working distance using modified photonic crystal for near-field lithography

Near-field lithography has evident advantages in fabricating super-resolution nano-patterns. However, the working distance (WD) is limited due to the exponential decay characteristic of the evanescent waves. Here, we proposed a novel photolithography method based on a modified photonic crystal (PC), where a defect layer is embedded into the all-dielectric multilayer structure. It is shown that this design can amend the photonic band gap and enhance the desired high-kwaves dramatically, then the WD in air conditions could be extended greatly, which would drastically relax the engineering challenges for introducing the near-field lithography into real-world manufacturing applications. Typically, deep subwavelength patterns with a half-pitch of 32 nm (i.e.,λ/6) could be formed in photoresist layer at an air WD of 100 nm. Moreover, it is revealed that diversified two-dimensional patterns could be produced with a single exposure using linear polarized light. The analyses indicate that this improved dielectric PC is applicable for near-field lithography to produce super-resolution periodic patterns with large WD, strong field intensity, and great uniformity.

First mtgenome sequences from three genera and phylogenetic relationships of the family Apidae based on mtgenome sequences (Hymenoptera: Apoidea)

In this study, we report the complete mitochondrial genomes (mtgenome) of Thyreus decorus, Ceratina okinawana and Amegilla calceifera, which are the first time of mtgenome report also for the genera Thyreus, Ceratina and Amegilla in the family Apidae. They contain 15,237, 15,207, and 17,728 bp, with AT content of 84.97%, 79.30%, and 84.63%, respectively. Each mtgenome includes 13 protein-coding genes (PCGs), 22 transfer RNA (tRNAs), two ribosomal RNA (16S and 12S rRNA) and an AT-rich control region (CR). The phylogenetic relationships of 45 species in the family were constructed using Bayesian Inference based on concatenated nucleotide sequences of 13 PCGs. Our study suggests that the subfamily Apinae is a paraphyletic group, with the genus Eucera claded into the subfamily Xylocopinae and the genera Amegilla and Thyreus into the subfamily Nomadinae. In Apinae, the genera Melipona and Bombus are significantly sister group, and the genus Apis is the sister group with Melipona + Bombus.

Superoscillation: from physics to optical applications

The resolution of conventional optical elements and systems has long been perceived to satisfy the classic Rayleigh criterion. Paramount efforts have been made to develop different types of superresolution techniques to achieve optical resolution down to several nanometres, such as by using evanescent waves, fluorescence labelling, and postprocessing. Superresolution imaging techniques, which are noncontact, far field and label free, are highly desirable but challenging to implement. The concept of superoscillation offers an alternative route to optical superresolution and enables the engineering of focal spots and point-spread functions of arbitrarily small size without theoretical limitations. This paper reviews recent developments in optical superoscillation technologies, design approaches, methods of characterizing superoscillatory optical fields, and applications in noncontact, far-field and label-free superresolution microscopy. This work may promote the wider adoption and application of optical superresolution across different wave types and application domains.

Creation of Sub-diffraction Longitudinally Polarized Spot by Focusing Radially Polarized Light with Binary Phase Lens

The generation of a sub-diffraction longitudinally polarized spot is of great interest in various applications, such as optical tweezers, super-resolution microscopy, high-resolution Raman spectroscopy, and high-density optical data storage. Many theoretical investigations have been conducted into the tight focusing of a longitudinally polarized spot with high-numerical-aperture aplanatic lenses in combination with optical filters. Optical super-oscillation provides a new approach to focusing light beyond the diffraction limit. Here, we propose a planar binary phase lens and experimentally demonstrate the generation of a longitudinally polarized sub-diffraction focal spot by focusing radially polarized light. The lens has a numerical aperture of 0.93 and a long focal length of 200λ for wavelength λ = 632.8 nm, and the generated focal spot has a full-width-at-half-maximum of about 0.456λ, which is smaller than the diffraction limit, 0.54λ. A 5λ-long longitudinally polarized optical needle with sub-diffraction size is also observed near the designed focal point.

[Research progress in water quality monitoring technology based on ultraviolet spectrum analysis]

The water quality monitoring technology based on ultraviolet spectrum analysis has the characteristics of small volume, low cost, and no secondary pollution, and it doesn't need any reagent and sample pretreatment. On account of these characteristics, the direct ultra-violet technology has remarkable superiority over traditional technologies when applied in online monitoring of drinking water, surface water and industrial wastewater, and it has become an important development tendency of modern water monitoring technologies. The principle, characteristics, present situation and development trend of modern water quality monitoring technology based on ultra-violet spectrum analysis were introduced, and the key technical problems were further discussed in this paper.

[Infrared spectroscopy based on quantum cascade lasers]

Quantum cascade lasers (QCLs) are promising infrared coherent sources. Thanks to the quantum theory and band-gap engineering, QCL can access the wavelength in the range from 3 to 100 microm. Since the fingerprint spectrum of most gases are located in the mid-infrared range, mid-infrared quantum cascade laser based gas sensing technique has become the research focus world wide because of its high power, narrow linewidth and fast scanning. Recent progress in the QCL technology leads to a great improvement in laser output power and efficiency, which stimulates a fast development in the infrared laser spectroscopy. The present paper gives a broad review on the QCL based spectroscopy techniques according to their working principles. A discussion on their applications in gas sensing and explosive detecting is also given at the end of the paper.

[Application of relevance vector machines in nitrate detection of wastewater]

On account of the high dimension and band overlapping features of the ultraviolet spectrum of complex wastewater, the relevance vector machine (RVM) algorithm combined with contiguous ultraviolet spectrum technology was applied in nitrate modeling to realize the rapid and accurate prediction of nitrate-nitrogen. At first the algorithm principle of RVM was introduced, and then based on the ultraviolet spectra of collected pharmacy effluent samples, ultraviolet absorption data between 230 and 245 nm were selected for modeling. Multivariate linear regression, partial least squares, classical support vector machines (SVM) and RVM methods were applied in nitrate modeling respectively and model performances were compared. Experimental result indicates that RVM method has advantages of higher prediction accuracy, sparser model than other compared methods and faster operation speed than SVM method. The relative full-range error is less than 4.5% F. S. Finally, it can be concluded that the LS-SVM method is effective in rapid and accurate detection of nitrate in practical wastewater with complicated composition.

[Design of concave grating for ultraviolet-spectrum]

Ultraviolet-spectrum technology is a kind of low signal and multianalysis technology. For taking full advantage of spectral information and reducing the volume of spectrometer, we used high efficiency spectroscopy structure based on concave grating. Based on concave grating theory and optic design software ZEMAX, a flat field concave grating for ultraviolet spectrophotometer was designed from primary structure, which relied on global optimization of the software. The contradiction between wide spectrum bound and limited spectrum extension was resolved, aberrations were reduced successfully, spectrum information was utilized fully, and the optic structure of spectrometer was highly efficient. For better preference of this spectrophotometer, after get the structure parameter, combine grating fabrication condition with practice working condition, grating diffractive theory, holographic optics theory and software PCG rate was used for diffraction efficiency design and improve. A paradigm of flat field concave grating is given, it works between 190 nm to 410 nm, the diameter of the concave grating is 20 mm, and F/# is 0.21. The design result was analyzed and evaluated. It was showed that if the slit source, whose width is 50 microm, is used to reconstruction, the theoretic resolution capacity is better than 3 nm.

[Near infrared spectroscopy system structure with MOEMS scanning mirror array]

A method which uses MOEMS mirror array optical structure to reduce the high cost of infrared spectrometer is given in the present paper. This method resolved the problem that MOEMS mirror array can not be used in simple infrared spectrometer because the problem of imaging irregularity in infrared spectroscopy and a new structure for spectral imaging was designed. According to the requirements of imaging spot, this method used optical design software ZEMAX and standard-specific aberrations of the optimization algorithm, designed and optimized the optical structure. It works from 900 to 1 400 nm. The results of design analysis showed that with the light source slit width of 50 microm, the spectrophotometric system is superior to the theoretical resolution of 6 nm, and the size of the available spot is 0.042 mm x 0.08 mm. Verification examples show that the design meets the requirements of the imaging regularity, and can be used for MOEMS mirror reflectance scan. And it was also verified that the use of a new MOEMS mirror array spectrometer model is feasible. Finally, analyze the relationship between the location of the detector and the maximum deflection angle of micro-mirror was analyzed.

Pregnancy outcome and prognosis in fetuses with increased first-trimester nuchal translucency

OBJECTIVE

One of the concerns of prenatal diagnosis is to find sensitive markers to screen for chromosome abnormalities, such as serum assays or nuchal translucency (NT). This study reports our experience with NT measurement during the first trimester of pregnancy.

MATERIALS

The study was performed prospectively on 252 fetuses with either NT > or =3 mm or cystic hygroma.

RESULTS

We observed 50 abnormal karyotypes, i.e. 19.8%. The incidence of chromosome abnormalities increased with increasing maternal age and increasing NT thickness. For the 202 fetuses with normal karyotypes, outcome was unfavourable in 32 cases: 23 elective terminations of pregnancy, 8 spontaneous abortions and 1 neonatal death. Outcome was favourable in 141 cases. Twenty-nine pregnancies were lost to follow-up.

CONCLUSION

Measurement of NT at 12 weeks' gestation seems to be a good marker for chromosome abnormalities. When the karyotype is normal, the pregnancy outcome remains correlated with the degree of NT thickness. The finding of NT >3 mm between 10 and 14 weeks' gestation dictates rigorous ultrasound monitoring and caution when predicting pregnancy outcome.

Structure and organization of bacteriophage Pf3 probed by Raman and ultraviolet resonance Raman spectroscopy

The Pseudomonas bacteriophage Pf3 is a long and narrow filament consisting of a covalently closed DNA single strand of 5833 bases sheathed by approximately 2500 copies of a 44-residue subunit. Ultraviolet resonance Raman spectra excited at 257, 244, 238, and 229 nm and off-resonance Raman spectra excited at 514.5 nm are reported for Pf3 in both H2O and D2O solutions. The key Raman bands are assigned to specific protein and DNA groups of the native virion assembly. The results are compared with proposed assembly models and Raman spectra recently reported for the isomorphous (class II) Pseudomonas phage Pf1 and the morphologically distinct (class I) coliphage fd [Wen, Z. Q., Overman, S. A., and Thomas, G. J. , Jr. (1997) Biochemistry 36, 7810-7820; Wen, Z. Q., Armstrong, A., and Thomas, G. J., Jr. (1999) Biochemistry 38, 3148-3156]. Surprisingly, deoxynucleosides of the packaged DNA genome of Pf3 adopt the same conformation (C3'-endo/anti) found for DNA packaged in the class I fd virion rather than that (C2'-endo/anti) associated with DNA in the isomorphous Pf1 virion. However, DNA base stacking in Pf3, as judged by Raman hypochromic effects, differs significantly from that occurring in either Pf1 or fd. Thus, the single-stranded DNA genomes of Pf3, Pf1, and fd are all organized differently within their respective capsids, implying that local subunit-DNA interactions may be important in determining the structure specific to each native assembly. The present study confirms a completely alpha-helical secondary structure for the Pf3 subunit and an unusual indolyl ring environment for the subunit tryptophan residue (Trp-38).

Ultraviolet-resonance raman spectroscopy of the filamentous virus Pf3: interactions of Trp 38 specific to the assembled virion subunit

The class II filamentous virus Pf3 packages a circular single-stranded DNA genome of approximately 5833 [corrected] nucleotides within a cylindrical capsid constructed from approximately 2500 [corrected] copies of a 44 residue alpha-helical subunit. The single tryptophan residue (Trp 38) of the capsid subunit is located within a basic C-terminal sequence (.R(+)WIK(+)AQFF). The local environment of Trp 38 in the native Pf3 assembly has been investigated using 229 nm excited ultraviolet-resonance Raman (UVRR) spectroscopy and fluorescence spectroscopy. Trp 38 exhibits an anomalous UVRR signature in Pf3, including structure-diagnostic Raman bands (763, 1228, 1370, and 1773 cm(-)(1)) that are greatly displaced from corresponding Raman markers observed in either detergent-disassembled Pf3, class I filamentous viruses, most globular proteins, or aqueous L-TRP. An unusual and highly quenched fluorescence spectrum is also observed for Trp 38. These distinctive UVRR and fluorescence signatures together reflect interactions of the Trp 38 side chain that are specific to the native PF3 assembly. The experimental results on PF3 and supporting spectroscopic data from other proteins of known three-dimensional structure favor a model in which pi electrons of the Trp 38 indolyl ring interact specifically with a basic side chain of the subunit C-terminal sequence. Residues Arg 37 AND Lys 40 are plausible candidates for the proposed cation-pi interaction of Trp 38. The present study suggests that raman spectroscopy may be a generally useful probe of interactions between the indolyl pi-electron system of tryptophan and electropositive groups in proteins and their assemblies.

Demonstration by ultraviolet resonance Raman spectroscopy of differences in DNA organization and interactions in filamentous viruses Pf1 and fd

Pf1, a class II filamentous virus, has been investigated by ultraviolet resonance Raman (UVRR) spectroscopy with excitation wavelengths of 257, 244, 238, and 229 nm. The 257-nm UVRR spectrum is rich in Raman bands of the packaged single-stranded DNA (ssDNA) genome, despite the low DNA mass (6%) of the virion. Conversely, the 229-nm UVRR spectrum is dominated by tyrosines (Tyr 25 and Tyr 40) of the 46-residue alpha-helical coat subunit. UVRR spectra excited at 244 and 238 nm exhibit Raman bands diagnostic of both viral DNA and coat protein tyrosines. Raman markers of packaged Pf1 DNA contrast sharply with those of the DNA packaged in the class I filamentous virus fd [Wen, Z. Q., Overman, S. A., and Thomas, G. J., Jr. (1997) Biochemistry 36, 7810-7820]. Interestingly, deoxynucleotides of Pf1 DNA exhibit sugars in the C2'-endo/anti conformation and bases that are largely unstacked, compared with C3'-endo/anti conformers and very strong base stacking in fd DNA; hydrogen-bonding interactions of thymine carbonyls are also different in Pf1 and fd. On the other hand, coat protein tyrosines of Pf1 exhibit Raman markers of ring environment identical to those of fd, including an anomalous singlet at 853 cm-1 in lieu of the canonical Fermi doublet (850/830 cm-1) found in globular proteins. The results indicate markedly different modes of organization of ssDNA in Pf1 and fd virions, despite similar environments for coat protein tyrosines, and suggest strong hydrogen-bonding interactions between DNA bases and coat subunits of Pf1 but not between those of fd. We propose that structural relationships between the protein coat and encapsidated ssDNA genome are also fundamentally different in the two assemblies.

Submicroscopic deletion of chromosome 16p13.3 in patients with Rubinstein-Taybi syndrome

The Rubinstein-Taybi syndrome (RTS) is a well-defined entity characterized by growth and mental retardation, broad thumbs and halluces, and typical face. The RTS locus was assigned to 16p13.3, and interstitial submicroscopic deletions of this region (RT1 cosmid, D16S237) were initially identified in 25% of RTS patients. The gene for the human CREB binding protein, the transcriptional coactivator CBP, is included in the RT1 cosmid, and mutations in CBP have recently been identified in nondeleted RTS patients. We investigated 30 French patients with RTS. Among these patients, 3 had the RT1 microdeletion (frequency 10%). There is no obvious phenotypic difference between the patients with and without the RT1 deletion. The RT1 probe appears useful for confirmation of the diagnosis but is of little interest as a screening tool. By pooling data including the previous series and our current series, the cumulative frequency of the 16p13.3 microdeletion is 11.9% (19 in 159). This frequency of approximately 12% deleted patients appears more accurate than the 25% previously reported. Molecular investigations of CBP are in process in our series to clarify the cause of RTS.

UV resonance Raman spectroscopy of DNA and protein constituents of viruses: assignments and cross sections for excitations at 257, 244, 238, and 229 nm

Ultraviolet resonance Raman (UVRR) spectra of H2O and D2O solutions of the nucleoside (dA, dG, dC, dT) and aromatic amino acid (Phe, Trp, Tyr) constituents of DNA viruses have been obtained with laser excitation wavelengths of 257, 244, 238, and 229 nm. Using the 981 cm-1 marker of Na2SO4 as an internal standard, Raman frequencies and scattering cross sections were evaluated for all prominent UVRR bands at each excitation wavelength. The results show that UVRR cross sections of both the nucleosides and amino acids are strongly dependent on excitation wavelength and constitute sensitive and selective probes of the residues. The results provide a library of UVRR marker bands for structural analysis of DNA viruses and other nucleoprotein assemblies.

18p monosomy with midline defects and a de novo satellite identified by FISH

We report a girl with an 18p deletion and showing a total GH deficiency, a single central maxillary incisor, and a pituitary dysplasia. This suggests that del(18)(p) could be involved in pituitary dysplasia. We review the association between midline developmental defects and chromosome 18 anomalies. This case is due to a de novo satellite resulting from an unbalanced translocation t(18p;13p) identified by FISH. This is the first case of this cytogenetic mechanism in the 18p monosomy.

Structure and interactions of the single-stranded DNA genome of filamentous virus fd: investigation by ultraviolet resonance raman spectroscopy

The filamentous bacteriophage fd is a member of the Ff class of Inovirus, which includes phages f1 and M13. Ultraviolet resonance Raman (UVRR) spectra of fd have been obtained using excitation wavelengths of 257, 244, 238, and 229 nm. Excitation at 257 nm selectively enhances Raman markers of the packaged single-stranded (ss) DNA genome, while excitation at the shorter wavelengths favors the detection of Raman signals from coat protein aromatics, particularly tryptophan (W26) and tyrosine residues (Y21 and Y24) of the viral coat subunit (pVIII). The principal findings are the following: (1) Distinctive markers of dA, dC, dG, and dT residues of the packaged genome are identified in UVRR spectra of fd excited at 257 and 244 nm, despite the low DNA mass composition (12%) of the virion. (2) Raman bands of the bases of packaged ssDNA show extraordinary resonance Raman hypochromism. Raman intensity losses as large as 80% of the parent DNA nucleotide intensities are observed. This is interpreted as evidence of extensive short-range interactions involving bases of the packaged genome. (3) Conversely, Raman bands of tryptophan and tyrosine residues of the coat protein generally exhibit strong hyperchromism. Typically, Raman markers of the aromatic amino acids are about 3-fold more intense in the UVRR spectrum of fd than in spectra of the free amino acids. The very high Raman cross sections for residues Y21, Y24, and W26 are indicative of unusual hydrophobic environments in the viral assembly. (4) UVRR band shifts that accompany the transfer of fd from H2O to D2O solution indicate that bases of the packaged ssDNA are readily exchanged by the solvent. Similarly, the indole N1H group of W26 is accessible to solvent, as shown by N1H --> N1D exchange in D2O solution. (5) The UVRR markers of the packaged fd genome confirm the conclusion reached previously from off-resonance Raman studies that fd DNA nucleosides favor the C3'-endo/anti conformation, rather than the C2'-endo/anti conformation that is characteristic of the lowest energy structure of DNA. We conclude that nucleoside conformations of the packaged fd genome are influenced by the specific organization of ssDNA and coat protein subunits in the native virion assembly.

Vibrational Raman optical activity of alpha-lactalbumin: comparison with lysozyme, and evidence for native tertiary folds in molten globule states

Proteins in aqueous solution are now accessible to Raman optical activity (ROA) measurements, which provide an incisive new probe of secondary and tertiary structure illustrated here by a study of bovine alpha-lactalbumin. The room-temperature ROA spectrum of native bovine alpha-lactalbumin is similar to that of native hen egg-white lysozyme except for features attributable to differences in the loop regions: in particular, a positive ROA band at approximately 1338 cm-1 assigned to conformationally homogeneous loop structure, possibly with local order corresponding to 3(10)-helix, has more than double the intensity in alpha-lactalbumin compared with lysozyme. This is consistent with the two proteins having similar secondary structure but different local details in the tertiary fold. ROA measurements on alpha-lactalbumin at pH 2.0 over a range of temperatures have provided a new perspective on the molten globule state. Thus at 35 degrees C ROA reveals the presence of some secondary structure but an almost complete loss of the tertiary loop structure; whereas at 2 degrees C the ROA spectrum is almost identical with that of the native protein, which is strong evidence that virtually all of the secondary structure and the tertiary backbone fold persist, albeit within a looser framework associated with increased solvent exposure and change of environment of many of the side-chains as evidenced by an increase in noise and bandwidth of some of the ROA signals together with aromatic fluorescence and near-UV circular dichroism signals characteristic of the molten globule state. Our sample of acid alpha-lactalbumin at 2 degrees C therefore appears to be an archetypal example of Ptitsyn's "native-like" molten globule, having a fixed native-like tertiary fold but with loss of tight packing of the side-chains; whereas at 35 degrees C it is a "disordered" molten globule. At 20 degrees C the acid molten globule appears to retain highly native-like secondary structure but with most of the tertiary fold already lost. A calcium-free sample of alpha-lactalbumin at neutral pH displayed a broad cooperative transition between native and molten globule states at approximately 15 degrees C, with the latter state showing similar but somewhat degraded tertiary loop ROA signatures to the native protein. In both the acid and apo molten globule states the ROA signatures of the secondary structure and the tertiary loops showed a gradual change with temperature.

Prenatal diagnosis of trisomy 9. Six cases and a review of the literature

Six prenatally diagnosed cases of trisomy 9 are reported and 22 previously reported cases are reviewed; the difficulty of genetic counselling for such cases and the variation in the percentage of trisomic cells in different tissues, thus making accurate diagnosis of trisomy 9 difficult, are emphasized. In addition to karyotyping results, ultrasound findings are important in achieving diagnoses. Finally, a course of action when prenatal trisomy 9 is detected is proposed.

Beta-sheet and associated turn signatures in vibrational Raman optical activity spectra of proteins

We have measured the aqueous solution vibrational Raman optical activity (ROA) spectra of concanavalin A, alpha-chymotrypsin, and beta-lactoglobulin, all of which are rich in beta-sheet, together with that of the model beta-turn peptide L-pro-L-leu-gly-NH2. Possible ROA signatures of antiparallel beta-sheet include a strong sharp positive band at approximately 1,313 cm-1 associated with backbone amide III C alpha H and NH deformations, and an amide I couplet, negative at low wavenumber and positive at high, centered at approximately 1,658 cm-1. Negative ROA bands in the range approximately 1,340-1,380 cm-1, which might originate in glycine CH2 deformations, appear to be characteristic of beta-turns. Our results provide further evidence that ROA is a more incisive probe of protein conformation than conventional vibrational spectroscopy, infrared, or Raman, because only those few vibrational coordinates within a given normal mode that sample the skeletal chirality directly contribute to the corresponding ROA band intensity.

Vibrational Raman optical activity of enzymes

Advances in Raman optical activity (ROA) instrumentation, based on the employment of a backscattering geometry together with a back-thinned CCD detector and a single-grating spectrograph with a holographic edge filter, have now enhanced the sensitivity to the level necessary to provide vibrational ROA spectra of proteins in aqueous solution. Early results show at least four separate regions in protein ROA spectra associated with vibrations of the backbone which appear to characterize the alpha-helix, beta-sheet, reverse turn and random-coil secondary conformation content. Side-group ROA features also appear, with tryptophan particularly prominent in lysozyme and alpha-lactalbumin. ROA should become a sensitive new probe of protein folding and ligand-induced conformational change in aqueous solution.

Hydroxyurea versus interferon alfa-2b in chronic myelogenous leukaemia: preliminary results of an open French multicentre randomized study

In order to compare the effects of interferon versus hydroxyurea for the treatment of chronic myelogenous leukaemia (CML), 58 CML patients, having received no previous treatment, were randomized into two treatment groups (hydroxyurea or interferon) for an open multicentre study from 1 May 1987 until 1 July 1990. Fifty patients were evaluable: 24 in the interferon group and 26 in the hydroxyurea group. Haematological response was obtained in 16/24 interferon-treated patients and 23/26 hydroxyurea patients. Failure to obtain haematological remissions occurred in eight of 24 interferon-treated patients and in three of 26 hydroxyurea patients. Four interferon-treated patient failures and one hydroxyurea-treated failure were due to drug intolerance. Progression occurred in one interferon-treated patient and in three patients given hydroxyurea. Fourteen of 16 patients in the interferon group and 17/23 in the hydroxyurea group continue on study and show no progression.

Vibrational Raman optical activity of carbohydrates

Vibrational Raman optical activity (R.o.a.) spectra of a range of carbohydrates in aqueous solution, measured in back-scattering between 700 and 1500 cm-1, are presented. Features were revealed that appear to be characteristic of details of the stereochemistry. Effects associated with the glycosidic linkage in di- and oligo-saccharides are prominent.