[The surgical management of benign tumors of the lateral skull base with intracranial invasion: experience from a single centre over ten years].

Objective: To investigate the clinical features, pathological types, imaging features, and surgical strategies of lateral skull base benign tumors with intracranial invasion. Methods: From January 2011 to March 2021, 36 patients of lateral skull base benign tumors with intracranial invasion were included in this retrospective study. Among the 36 patients, 14 cases were male, 22 cases were female, the aged range from 20-67, with the median age of 48. The clinical manifestations, characteristic imaging findings, pathological types, surgical approach selection, and prognosis were analyzed. Results: 36 cases of lateral skull base tumors with intracranial invasion were all accepted surgeries. 23 cases were neurogenic tumors, facial nerve tumors (n=8), neurogenic tumors in jugular foramen with unknown origin(n=6), hypoglossal schwannoma (n=3), transotic intralabyrinthine schwannoma (n=3), vestibular schwannoma involving the middle ear(n=2), vagal nerve schwannoma(n=1). Other types of tumors included meningioma (n=10) and paraganglioma (Di 1 or 2,n=3). Different pathological types of tumors had different clinical manifestations and imaging manifestations. Sixteen cases were subjected to primary resection, while, other 20 cases underwent staged operation. Among the patients with staged operation, 10 patients had completed the second stage operation, five patients were waiting for the second stage operation, the other five patient's residual intracranial tumor were significantly reduced and the space between tumor and brain tissues widened after the first stage operation, so, the following up with "wait and scan"policy was suggested. The total resection rate of tumors was related to the pathological nature, in which neurogenic tumors were 15/17, and meningiomas were 5/8. The main postoperative complications were cerebrospinal fluid leakage and infection in the operation area. There were two cases of postoperative intracranial infection, and three cases of cerebrospinal fluid leakage occurred in non staged operation cases. Conclusions: Lateral skull base tumors with intracranial invasion are rare. The most common pathological type is schwannoma, followed by meningioma and paraganglioma. For this type of tumor, if there is infection in the operation area and neck invasion is large, it is suggested to choose staged surgery, which can reduce the risk of intracranial infection and the incidence of cerebrospinal fluid leakage. Staged surgery strategy can also reduce the difficulty of second stage surgery, so the operation is much safer than non staged surgery.

[Application of 3D-CT simulation image in the description of gastric artery variation to guide laparoscopic total gastrectomy].

Objective: Anatomic variations in the perigastric vessels during laparoscopic radical gastrectomy often affect the operator's judgment and prolong the operation time, and even cause accidental injury and surgical complications, and hence the safety and quality of the operation cannot be ensured. In this study, multiple slice CT was reconstructed by 3-dimensional CT simulation software (3D-CT), and 3D-CT images were used to describe the variation of celiac trunk and splenic artery before surgery. The guiding role of the different variation of vessels was analyzed for laparoscopic total gastrectomy+D2 lymph node dissection (LTG+D2LD). Methods: A retrospective cohort study was conducted. Case inclusion criteria: (1) Gastric cancer was at an advanced stage. All the patients were preoperatively examined by digestive endoscopy and 64-row enhanced CT scan, and were histopathologically diagnosed with gastric adenocarcinoma. (2) 3D-CT simulation images were reconstructed to guide the operation. (3) LTG+D2LD surgery was performed by the same surgical team. (4) Clinical data were complete, and all the patients had signed the informed consent. From 2014 to 2018, 98 patients with gastric cancer at the Gastrointestinal Surgery Department of Henan Provincial People's Hospital were enrolled. According to the Adachi classification, celiac trunk variation was divided into common type (Adachi type I) and rare type (Adachi type II-VI). According to the Natsume classification, splenic artery was classified into "flat type" and "curved type". Based on 3D-CT simulation images, variation of celiac trunk and splenic artery was described, and the differences in operation time, intraoperative blood loss and the number of postoperative retrieved lymph nodes were compared between groups with different types of arterial variation. Results: For celiac trunk, common type was found in 84 cases (86%) and rare type was found in 14 cases, including 6 cases (6%) of type II, 2 cases (2%) of type III, 2 cases (2%) of type IV, 3 cases (3%) of type V, 1 case (1%) of type VI. No other types were found. There were no statistically significant differences in clinical characteristics and number of retrieved lymph nodes between patients of the common type group and rare type group (all P>0.05). Compared with common type patients, those of rare type had longer operative time [(321.1±29.0) minutes vs. (295.1±46.5) minutes, t=2.081, P=0.040] and more intraoperative blood loss (median: 66.0 ml vs. 32.0 ml, Z=-4.974, P=0.001). For splenic artery, 41 patients (42%) were flat type and 57 patients (58%) were curved type. There were no statistically significant differences between the two groups in terms of clinical characteristics, intraoperative blood loss, operative time and number of retrieved lymph nodes (all P>0.05). Conclusions: The method of describing the variation in the perigastric vessels by 3D-CT simulation has certain clinical value in laparoscopic radical gastrectomy. The duration of LTG+D2LD is prolonged and the intraoperative blood loss is increased with the variation of celiac trunk, while the variation of splenic artery has no effect on LTG+D2LD.

[Changes of insulin secretion and its signal transduction mechanism at early stage of severe scald in rats].

Objective: To observe the changes of insulin secretion in the early stage of severe scald in rats, and to explore its signal transduction mechanism. Methods: Twenty-four male Wistar rats aged 7 weeks were divided into sham injury alone (SIA) group, sham injury+ BPV (HOpic) (SIB) group, scald alone (SA) group, and scald+ BPV (HOpic) (SB) group using the random number table, with 6 rats in each group. Full-thickness scald of 50% total body surface area was inflicted in rats of SA and SB groups by a 6-s immersion of the abdomen and a 12-s immersion of the back in 94 ℃ hot water. Rats in SIA and SIB groups received sham injuries through immersion of the back and abdomen in 37 ℃ warm water for 6 and 12 seconds respectively. From 0 (immediately) to 2 day (s) after injury, the rats in groups SB and SIB were intraperitoneally injected with the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway enhancer BPV (HOpic) solution (0.5 mg/mL) at the dosage of 0.6 mg/kg once a day, and the rats in groups SA and SIA were intraperitoneally injected with the same volume of dimethyl sulfoxide once a day. At post injury hour (PIH) 72, the tail blood of rats was sampled for measuring fasting blood glucose (FBG) with a glucometer, and the pancreatic tissue samples of rats was harvested for observing the pathological manifestations of islets by hematoxylin-eosin staining, counting the docked granules per 10 µm membrane of islet beta cells and calculating the proportion of insulin vesicles through the observation of the ultrastructure of islet beta cells by transmission electron microscope, and detecting the phosphorylation level of Akt in the pancreatic PI3K/Akt signaling pathway by Western blotting. Data were statistically analyzed with one-way analysis of variance and least significant difference test. Results: (1) At PIH 72, the rat FBG levels in SIA and SIB groups were normal and similar (P>0.05). Compared with the levels of those two groups, the rat FBG level in SA group was increased significantly (P<0.01), while the level in SB group showed no obvious change (P>0.05). Compared with that in SA group, the rat FBG level in SB group was decreased significantly (P<0.01). (2) At PIH 72, the morphology of rat islets was complete and the islet cells distributed regularly in SIA and SIB groups. Compared with those in SIA and SIB groups, the morphology of rat islets was incomplete, the insulin vesicles in islets were common, the islet cells distributed irregularly, and the cytoplasm of some islet beta cells was lightly stained or translucent in SA group; the morphology of islets in SB group did not change obviously. Compared with those in SA group, the morphology of islets was comparatively complete, the insulin vesicles in islets were less common, the islet cells distributed comparatively regularly, and the lightly stained or translucent cytoplasm of islet beta cells was less in SB group. (3) At PIH 72, the number of docked granules per 10 µm membrane of rat islet beta cells and the proportion of insulin vesicles in SIA and SIB groups were similar (P>0.05). Compared with those in SIA and SIB groups, the number of docked granules per 10 µm membrane of rat islet beta cells in SA group was decreased significantly (P<0.01), while the proportion of insulin vesicles was increased significantly (P<0.01); the number of docked granules per 10 µm membrane of rat islet beta cells in SB group was obviously decreased (P<0.05), while the proportion of insulin vesicles did not change obviously (P>0.05). Compared with those in SA group, the number of docked granules per 10 µm membrane of rat islet beta cells in SB group was significantly increased (P<0.01), while the proportion of insulin vesicles was significantly decreased (P<0.01). (4) At PIH 72, the phosphorylation levels of Akt in SIA, SIB, SA, and SB groups were 0.91±0.03, 0.98±0.03, 0.78±0.08, and 0.87±0.08, respectively. Compared with that in SIA group, the phosphorylation level of Akt was increased obviously in SIB group (P<0.05) but was decreased significantly in SA group (P<0.01), while the level in SB group did not change obviously (P>0.05). Compared with the level in SIB group, the phosphorylation levels of Akt in SA and SB groups were decreased significantly (P<0.01). Compared with that in SA group, the phosphorylation level of Akt in SB group was increased significantly (P<0.05). Conclusions: At the early stage post severe scald in rats, the activity of the pancreatic PI3K/Akt signaling pathway and the function of insulin secretion are reduced. Improving the activity of the pancreatic PI3K/Akt signaling pathway in rats can ameliorate the function of insulin secretion and recover the physiological level of blood glucose.

[Clinical outcomes of gastric cancer patients received capecitabine based adjuvant chemotherapy and the corresponding pharmacogenomics analysis].

Objective: To investigate the association between Thymidine phosphorylase(TYMP)genetic variation and clinical outcomes of postoperative gastric cancer (GC) patients received capecitabine based regimens. Methods: A total of 198 GC patients underwent surgical treatment and received capecitabine based adjuvant chemotherapy were included in this retrospective study. Peripheral blood and the postoperative tissue specimen of the GC patients were collected for the genotyping of polymorphism and TYMP mRNA expression, respectively. The correlation between polymorphism and clinical outcomes and safety of postoperative GC patients were analysed. Results: Located in the upstream, rs11479 was of clinical significance. The prevalence of rs11479 in TYMP among the GC patients were as follows: CC genotype 125 cases (63.13%), CT genotype 65 cases (32.83%), TT genotype 8 cases (4.04%), minor allele frequency of rs11479 is 0.20. The distribution of three genotypes were in accordance with Hardy-Weinberg Equilibrium (P=0.901). The analysis results of patients with different genotypes found that the 3-year disease free survival rate of the patients with CT/TT genotype and CC genotype were 73.97% and 65.60%, respectively, which was statistically significant (P=0.003). In terms of overall survival, the 3-year overall survival rate of the two genotypes were 83.56% and 72.80% (P=0.012), respectively. Adjusted in multivariate Cox regression analysis, CT/TT genotype was an independent favorable factor for disease free survival (OR=0.55, P=0.011). Safety analysis indicated that there was no significant association between genotypes and grade 2 adverse reaction. Additionally, of the 79 postoperative tissue specimens, the results showed that the expression of TYMP in cancer tissues of the patients with CT/TT genotypes were significantly higher than those of the wild type CC genotype patients (P<0.001). Conclusion: The polymorphism rs11479 of TYMP have favorable influence on the clinical outcomes of gastric cancer patients received capecitabine based adjuvant chemotherapy treatment through changing the mRNA expression of TYMP.

[Diagnosis and treatment of labyrinthine fistula caused by chronic otitis media].

Objective:To evaluate the clinical features diagnostic experience and the surgical management of labyrinthine fistula in chronic suppurative otitismedia.Method:Twenty-four cases(24 ears)of labyrinthine fistula caused by chronic suppurative otitis media that were treated from 2006 to 2013 were reviewed.The fistula test and temporal bone CT scan were performed before the operation, then compare the positive rates between them.In all of these cases, the lesion tissue of fistula is cleaned. Then the fistula was repair of through fascia sealing by temporal myofascial or mastoid periosteum in type Ⅰ and Ⅱ fistula.Semicircular canal occlusion was used in type Ⅲ fistula.Comparison of the effect of fistula typing on preoperative and postoperative hearing.Result:The fistulae were located at the lateral semicircular canal in 23 ears, at the lateral semicircular canal in 1 ears.Temporal bones was positive in 10 cases(41.66％) while fistula test was positive in 9 cases(37.5％). There was no statistically significant difference between the diagnosis of the labyrinthine fistula(P=0.50).The effect of fistula typing on postoperative auditory changes was not statistically significant (P=0.73).Conclusion:In the preoperative diagnosis of the fistula,the use of fistula test and CT scan simultaneously may increase the accuracy of the diagnostic. However the test results are not reliable when is negative results,intraoperative exploration is the most important method for the diagnosis of labyrinth fistula.Surgery should be based on the type of fistula,size,hearing levels and operation experience.

Characterizing Ni(II) hydration in aqueous solution using DFT and EXAFS.

In the present work, a detailed investigation of Ni(II) hydration in water solutions was carried out using density functional theory (DFT) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The hydrated characteristics of [Ni(H2O)n](2+) clusters, such as energy parameters, atomic charge distributions, and bond parameters, were explored using DFT with Becke's three-parameter exchange potential and the Lee-Yang-Parr correlation functional (B3LYP). DFT calculations indicated that the preferred structure of the first hydration shell of Ni(II) generally has a coordination number of six and is almost unaffected by the water molecules in the outer solvation shell, whereas the structure of the second solvation shell varies as the hydration proceeds. EXAFS measurements are reported for aqueous NiSO4 and Ni(NO3)2 solutions and the Ni(NO3)2·6H2O crystal. Analysis of the EXAFS spectra of these three systems using a multiparameter fitting procedure showed that, in each case, the first coordination shell consists of six water molecules with a Ni-O coordination distance of 2.04 Å, and that there is no Ni-S or Ni-N coordination in the first shell. There was no evidence of outer-shell SO4(2-) or NO3(-) ions substituting inner-sphere water molecules in NiSO4 and Ni(NO3)2. The characteristics of Ni(II) hydration obtained from DFT calculations agreed well with those obtained experimentally using EXAFS.

A Novel Submicron Emulsion System Loaded with Doxorubicin Overcome Multi-Drug Resistance in MCF-7/ADR Cells.

The purpose of the present study was to develop the Solutol HS15-based doxorubicin submicron emulsion with good stability and overcoming multi-drug resistance. In this study, we prepared doxorubicin submicron emulsion, and examined the stability after autoclaving, the in vitro cytotoxic activity, the intracellular accumulation and apoptpsis of doxorubicin submicron emulsion in MCF-7/ADR cells. The physicochemical properties of doxorubicin submicron emulsion were not significantly affected after autoclaving. The doxorubicin submicron emulsion significantly increased the intracellular accumulation of doxorubicin submicron emulsion and enhanced cytotoxic activity and apoptotic effects of doxorubicin. These results may be correlated to doxorubicin submicron emulsion inhibitory effects on efflux pumps through the progressive release of intracellular free Solutol HS15 from doxorubicin submicron emulsion. Furthermore, these in vitro results suggest that the Solutol HS15-based submicron emulsion may be a potentially useful drug delivery system to circumvent multi-drug resistance of tumor cells.

Meta-analysis of the differentially expressed colorectal cancer-related microRNA expression profiles.

OBJECTIVES: Unique microRNAs (miRNAs) have been identified in colorectal cancer in recent studies which can be used to accurately diagnose the presence of colorectal cancer and help predict disease recurrence. Differential expression of specific miRNAs in tissues or blood offers the prospect of their use in early detection and screening for colorectal cancer. However, the experiments under different environments would produce different results. The purpose of this study was to get a reliable result on differentially expressed miRNAs related to colorectal cancer by integrating different studies. MATERIALS AND METHODS: A meta-analysis was performed to review three miRNA microarray datasets from three published literatures that compared the microRNAs expression profiles in colorectal cancer tissues with those in normal colorectal tissues. The R VennDiagram package was applied to identify the overlapping miRNAs with differential expression among these three studies. RESULTS: A total of 175 differentially expressed miRNAs were reported in the three miRNA expression profiling studies that compared colorectal cancer tissues with normal tissues, of which 25 miRNAs were reported at least by two studies including 15 up-regulated miRNAs and 10 down-regulated miRNAs. Among the 25 miRNAs, 15 ones were differentially expressed between early stage colorectal cancer and normal tissues including 11 up-regulated miRNAs and 4 down-regulated miRNAs, of which hsa-miR-195 (down-regulated) and hsa-miR-20a (up-regulated) were shared by these three studies. CONCLUSIONS: The 15 differentially expressed miRNAs, especially hsa-miR-195 and hsa-miR-20a may be used as potential biomarkers for early detection and screening of colorectal cancer.

Room temperature electrical and thermal switching CNT/hexadecane composites.

A large contrast in the electrical and thermal conductivities via a first order phase transition in surface-functionalized carbon nanotube(CNT)/hexadecane composites is reported. Surface modification of the CNTs improves the electrical conductivity contrast and the stability of the composites. We demonstrate that, with these composites, the electrical conductivity changes above 10(5) times and the thermal conductivity varies up to 3 times at 18 °C.

Thermoregulatory sudomotor dysfunction and diabetic neuropathy develop in parallel in at-risk feet.

AIMS: To establish the longitudinal relationship of foot complications to neuropathy based on a 4-year follow-up of diabetic patients stratified by sudomotor dysfunctions. METHODS: One hundred and nineteen Type 2 diabetic patients and 36 non-diabetic subjects were initially registered in the prospective cohort study. Plantar skin temperature and sympathetic skin response (SSR) were used to monitor sympathetic mediated thermoregulation and sudomotor function. Peripheral somatic and central autonomic functions were studied using clinical, nerve conduction and cardiovascular reflex tests. At enrolment, the diabetic patients were classified into one of three groups by the progressive stages of sudomotor dysfunction: SSR+ (SSR present; 49 patients), SSR- (SSR absent; 41 patients) and at-risk group (SSR absent but with cracked skin involving partial thickness of the dermis; 29 patients). RESULTS: The at-risk group had 13.4 times (95% confidence interval 1.4-125.7) higher plantar ulceration rates than the other two patient groups during the 4 years. Skin temperature elevation occurred in parallel with development of foot sweating problems. There were no significant differences between the three patient groups in the ratios of abnormal heart rate variation, orthostatic test and clinical neuropathy score at follow-up. After 4 years of follow-up, nerve conduction abnormalities were more frequent in the at-risk and SSR- groups than in the SSR+ group. CONCLUSIONS: Early deterioration of small sympathetic fibres could not be quantified accurately by the clinical, somatic and autonomic tests. Assessing skin integrity and sudomotor function in at-risk individuals identifies early peripheral sympathetic neuropathy, even if the patients have no overt clinical symptoms.

Retinal imaging with a low-cost micromachined membrane deformable mirror.

PURPOSE: To study the retina in normal subjects with a high-resolution imaging system using adaptive optics for wave front aberration correction. METHODS: We used a low-cost 37-element micromachined membrane deformable mirror (MMDM) with a continuous membrane as the reflective surface. A Hartmann-Shack wave front sensor with cooled charge coupled device camera was used to measure the wave front aberration. Zernike polynomials were used to describe the wave front shape. We developed a mirror control system to compensate for wave aberrations. We tested this instrument in normal subjects. RESULTS: We were able to image the retina in monochromatic laser light and document the increase in resolution. While it is hard to estimate the exact size of the smallest structures in the image, we were able to subjectively grade the image quality. The system is able to compensate for higher order aberrations present in the human eye. CONCLUSION: The capabilities of correcting ocular aberrations are limited by the number of adjustable elements in the mirror and the deflection range of the surface. The advantage of the MMDM system is its low cost when compared with other adaptive optics solutions such as piezodriven mirrors and spatial light modulators. This technique may allow for improved resolution for clinical fundus photography.

Simian virus 40 Vp1 DNA-binding domain is functionally separable from the overlapping nuclear localization signal and is required for effective virion formation and full viability.

A DNA-binding domain (DBD) was identified on simian virus 40 (SV40) major capsid protein Vp1, and the domain's function in the SV40 life cycle was examined. The DBD was mapped by assaying various recombinant Vp1 proteins for DNA binding in vitro. The carboxy-terminal 58-residue truncated Vp1DeltaC58 pentamer bound DNA with a K(d) of 1.8 x 10(-9) M in terms of the protein pentamer, while full-length Vp1 and carboxy-terminal-17-truncated Vp1DeltaC17 had comparable apparent K(d)s of 5.3 x 10(-9) to 7.3 x 10(-9) M in terms of the protein monomers. Previously identified on Vp1 was a nuclear localization signal (NLS) consisting of two N-terminal basic clusters, NLS1 (4-KRK-6) and NLS2 (15-KKPK-18). Vp1DeltaC58 pentamers harboring multiple-point mutations in NLS1 (NLSm1), NLS2 (NLSm2), or both basic clusters (NLSm1. 2) had progressively decreased DNA-binding activity, down to 0.7% of the Vp1DeltaC58 level for NLSm1. 2 Vp1. These data, along with those of N-terminally truncated proteins, placed the DBD in overlap with the bipartite NLS. The role of the Vp1 DBD during infection was investigated by taking advantage of NLS phenotypic complementation (N. Ishii, A. Nakanishi, M. Yamada, M. H. Macalalad, and H. Kasamatsu, J. Virol. 68:8209-8216, 1994), in which an NLS-defective Vp1 could localize to the nucleus in the presence of wild-type minor capsid proteins Vp2 and Vp3. This approach made it possible to dissect the role of the bifunctional Vp1 NLS-DBD in virion assembly in the nucleus. Mutants of the viable nonoverlapping SV40 (NO-SV40) DNA NLSm1, NLSm2, and NLSm1. 2 replicated normally following transfection into host cells and produced capsid proteins at normal levels. All mutant Vp1s were able to interact with Vp3 in vitro. The mutants NLSm1 and NLSm1. 2 were nonviable, and the mutant Vp1s unexpectedly failed to localize to the nucleus though Vp2 and Vp3 did, suggesting that the mutated NLS1 acted as a dominant signal for the cytoplasmic localization of Vp1. Mutant NLSm2, for which the mutant Vp1's nuclear localization defect was complemented by Vp2 and Vp3, displayed a 5,000-fold reduced viability. Analysis of NLSm2 DNA-transfected cell lysate revealed a 10-fold reduction in the level of DNase I-protected viral DNA, and yet virion-like particles were found among the DNase I-resistant material. Collective results support a role for Vp1 NLS2-DBD2 in the assembly of virion particles. The results also suggest that this determinant can function in the infection of new cells.

Transcript map of the 8p23 putative tumor suppressor region.

Cancers of the head and neck, prostate, liver, and bladder exhibit minimal regions of deletion within chromosomal band 8p23 that either overlap or map very close to one another. We previously refined a minimal region of deletion in squamous cell carcinomas to a 112-kb interval within 8p23. There seems to be only a single gene within this region that is expressed in normal upper aerodigestive tract epithelium. This candidate for the squamous cancer suppressor, CUB and sushi multiple domains-1 (CSMD1), extends into the minimal regions of deletions defined for the other types of cancer with 8p23 deletions. RT-PCR and EST data indicate that CSMD1 is also expressed in those organs,making this gene a candidate for a suppressor of multiple types of cancer. Both the sequence of the gene and the organization of the protein are highly conserved in the mouse.

Ultrashort pulse propagation in near-field periodic diffractive structures by use of rigorous coupled-wave analysis.

We present a method for near-field analysis of ultrashort optical pulse propagation in periodic structures-including subwavelength and resonant grating structures-based on the integration of Fourier spectrum decomposition and rigorous coupled-wave analysis (RCWA). We discuss the spectral decomposition, including considerations for computational efficiency, the application of the RCWA method to compute the internal and external fields of the structure, and the synthesis of the resulting fields to obtain the time-domain solution. We apply this tool to the analysis of two photonic structures: (1) a nanostructured polarization-selective mirror that exhibits the desired broadband performance characteristics when operated at the design wavelength but yields strongly diminished polarization selectivity and modulation of the pulse envelope at an offset wave-length and (2) a two-mode coupled waveguide structure that produces from one incident pulse two transmitted pulses whose temporal separation depends on the waveguide geometry. In both examples, we apply our new modeling tool to investigate the near fields and find that near-field effects are critical in determining the performance characteristics of nanostructured devices. Furthermore, detailed observation and understanding of near-field phenomena in nanostructures may be applied to the design of novel photonic devices.

Linear and nonlinear operation of a time-to-space processor.

The operational characteristics of a time-to-space processor based on three-wave mixing for instantaneous imaging of ultrafast waveforms are investigated. We assess the effects of various system parameters on the processor's important attributes: time window of operation and signal conversion efficiency. Both linear and nonlinear operation regimes are considered, with use of a Gaussian pulse profile and a Gaussian spatial mode model. This model enables us to define a resolution measure for the processor, which is found to be an important characteristic. When the processor is operated in the linear interaction regime, we find that the conversion efficiency of a temporal signal to a spatial image is inversely proportional to the resolution measure. In the nonlinear interaction regime, nonuniform signal conversion due to fundamental wave depletion gives rise to a phenomenon that can be used to enhanced the imaging operation. We experimentally verify this nonlinear operation.

Study of spatial-temporal characteristics of optical fiber based on ultrashort-pulse interferometry.

We demonstrate a method for reconstruction of the modal intensity distribution of light at the output of an optical fiber. Spatial modes of the optical fiber are separated in time as a result of differences in group velocity and are detected experimentally by observation of the interference of the modal field distribution with the time-gating reference field. The detected interference patterns of the modal fields are analyzed, providing the spatial impulse response of the fiber. We also use interferometric correlation to determine the spatiotemporal characteristics of the fiber modes, such as pulse width, linear chirp, and group velocity, for each mode.

Time reversal of ultrafast waveforms by wave mixing of spectrally decomposed waves.

Two different realizations of time-reversal experiments of ultrafast waveforms are carried out in real time by use of four-wave mixing arrangements of spectrally decomposed waves. The first, conventional, method is based on phase conjugation of the waveform's spectrum and achieves time reversal of real amplitude waveforms. The second arrangement of the spectrally decomposed waves spatially inverts the waveform's spectrum with respect to the optical axis of the processor and achieves true time reversal for complex-amplitude ultrafast waveforms. We compare and contrast these two real-time techniques.

Reply to "Comment on 'Time reversal of ultrafast waveforms by wave mixing spectrally decomposed waves'".

In response to a comment on our Letter [Opt. Lett. 25, 132 (2000)], we reiterate the distinction between the spectral inversion and the spectral phase conjugation processing techniques. The former achieves time reversal of the complex amplitude waveform, whereas the latter performs time reversal of the real electric field.

Interference microscopy for three-dimensional imaging with wavelength-to-depth encoding.

A novel interference microscope for three-dimensional (3D) imaging based on a wavelength-to-depth encoding technique is presented. Wavelength-to-depth encoding is realized by use of a diffractive lens and wavelength tuning. A high depth resolution of 0.71 mum is obtained with 0.90-N.A. objective lenses. Experimental measurements of a four-level grating are presented, and the results are found to be comparable with those obtained with a Dektak profilometer and a similar interference microscope that uses mechanical depth scanning. The system is promising for fast, noncontact, high-resolution 3D imaging.

Nontranslational three-dimensional profilometry by chromatic confocal microscopy with dynamically configurable micromirror scanning.

A confocal microscope profilometer, which incorporates chromatic depth scanning with a diffractive optical element and a digital micromirror device for configurable transverse scanning, provides three-dimensional (3D) quantitative measurements without mechanical translation of either the sample or the microscope. We used a microscope with various objective lenses (e.g., 40x, 60x, and 100x) to achieve different system characteristics. With a 100x objective, the microscope acquires stable measurements over a 320 microm x 240 microm surface area with a depth resolution of 0.39 microm at a 3-Hz scan rate. The total longitudinal field of view is 26.4 microm for a wavelength tuning range of 48.3 nm. The FWHM value of the longitudinal point-spread function is measured to be 0.99 microm. We present 3D measurements of a four-phase-level diffractive element and an integrated-circuit chip. The resolution and the accuracy are shown to be equivalent to those found with use of conventional mechanical scanning.