ライフサイエンスコーパス: reflectivity

1 subretinal fluid, and outer layer disruption/reflectivity.

2 ies, we observed this binding via changes in reflectivity.

3 Japanese Koi fish; one of them with enhanced reflectivity.

4 ing membrane or photoreceptor disruption and reflectivity.

5 on threshold behaviour absent in the optical reflectivity.

6 cted eyes that showed a medium to medium/low reflectivity.

7 eristics included ciliary body thickness and reflectivity.

8 deling was employed to explain the origin of reflectivity.

9 ace plaque, internal structure, and internal reflectivity.

10 All agents provided increased reflectivity.

11 ex refractive index and the normal-incidence reflectivity.

12 ts are specifically chosen to maximize solar reflectivity.

13 onsidered: number per frame, tortuosity, and reflectivity.

14 uced warming by reducing cloud lifetimes and reflectivity.

15 ronous increase in internal ultrasonographic reflectivity.

16 all were significant predictors of choroidal reflectivity.

17 idal reflectivity-vitreous reflectivity)/RPE reflectivity.

18 corresponding oscillations in the transient reflectivity.

19 ) single crystals by ultrafast time-resolved reflectivity.

20 ransmission is generally low due to its high reflectivity.

21 s sits atop a sharp lateral boundary in Moho reflectivity.

22 rysms had an internal lumen with homogeneous reflectivity (109/173; 63%) and moderate reflectivity (8

23 s C and are characterized by AFM, XPS, X-ray reflectivity (2.3 nm repeat spacing), X-ray fluorescence

24 2 tumors (84%) with low to moderate internal reflectivity, 30 tumors (60%) showed an increase in inte

25 ous reflectivity (109/173; 63%) and moderate reflectivity (87/173; 50%).

26 length of 45 cm, bound by mirrors of 99.997% reflectivity, a limit of detection of approximately 180

27 Reconstructing a scene's 3D structure and reflectivity accurately with an active imaging system op

28 ngular distribution, and shortwave radiation reflectivity, all traits available in most major crop ge

29 Interestingly, both EIS and surface reflectivity allowed a film thickness in the nanometer r

30 whereas transmission electron microscopy and reflectivity analysis indicate the two interfaces are ne

31 Moreover, the coupling of the x-ray reflectivity analysis with both highly mobile membrane m

32 brane-bound conformation for effective x-ray reflectivity analysis.

33 bsorbance and show that in the limit of high reflectivities and low absorbances it predicts the same

34 Polarized neutron reflectivity, x-ray reflectivity and aberration-corrected electron microscop

35 highly echogenic prominent tumour with high reflectivity and acoustic shadow.

36 ntained solution using high-resolution X-ray reflectivity and atomic force microscopy.

37 inal hyperreflective flecks and the inherent reflectivity and boundary definition of the subretinal m

38 endently by in situ resonant anomalous X-ray reflectivity and by ex-situ alpha-spectrometry).

39 diffusion MRI, by changes in tissue surface reflectivity and by immunohistochemistry with microtubul

40 was a negative correlation between choroidal reflectivity and choroidal thickness (r = -0.793; P < 0.

41 Choroidal reflectivity and choroidal thickness changes are evident

42 Choroidal reflectivity and choroidal thickness.

43 The homogeneity of the reflectivity and fluorescence spectra, both within and a

44 Using x-ray reflectivity and grazing incidence diffraction, we have

45 ogical membranes, which were probed by x-ray reflectivity and grazing incidence x-ray diffraction.

46 etection limits, even with mirrors of modest reflectivity and inexpensive detectors.

47 Neutron reflectivity and isotopic labeling confirmed the expecte

48 is highly desirable to achieve not only high reflectivity and low absorption, but also good conductiv

49 Higher choroidal reflectivity and lower choroidal thickness were document

50 haped druse with homogeneous medium internal reflectivity and no depolarizing contents (55.3% of drus

51 delity is also shown to be less sensitive to reflectivity and phase errors than the process fidelity.

52 spin state change, as determined by optical reflectivity and photomagnetic measurements.

53 Optical reflectivity and photomagnetic properties of 1 and 3 hav

54 g the advantages of ultra-small pixels, high reflectivity and post-fabrication tuning through control

55 rs of annular lesions with loss of ellipsoid reflectivity and preserved RPE at the lesion center.

56 imate system via its influence on vegetation reflectivity and shortwave surface energy exchange.

57 We show that optical properties such as reflectivity and spectral position of the absorption ban

58 ted using a combination of neutron and X-ray reflectivity and spectroscopic ellipsometry over a wide

59 ore, basal epithelial cells density, stromal reflectivity and sub-basal nerve tortuosity (p = 0.000,

60 tributions at the nanometer scale with X-ray reflectivity and the macroscopic scale with interfacial

61 tinal pigment epithelial detachment internal reflectivity and the presence of subretinal and intraret

62 acteristic of strong coupling is observed in reflectivity and transmission with a Rabi splitting ener

63 iques exploit presumed differences in tissue reflectivity and utilize automated edge detection algori

64 bI3 above 60 GPa was confirmed using both IR reflectivity and variable-temperature dc conductivity me

65 rages on the HfO2 layers, confirmed by X-ray reflectivity and X-ray fluorescence.

66 in the wavefront properties with nearly 100% reflectivity, and as a dynamic diffractive optics they c

67 ur aim is to determine how biology modulates reflectivity, and from this to obtain a mechanistic unde

68 cular traction (P = .037), low vitreous face reflectivity, and maximal foveal thickness <500 mum (P =

69 The VKC patients had increased diameter, reflectivity, and presence of nuclear activation of supe

70 ellipsoid band reflectivity, global retinal reflectivity, and relative inner segment ellipsoid refle

71 inning, as well as a reduced EZ "normalized" reflectivity, and these parameters are correlated.

72 ayer produces a measurable change in optical reflectivity, and this allows label-free quantification

73 sometry, electrochemistry, synchrotron X-ray reflectivity, angle-resolved X-ray photoelectron spectro

74 nificant gains in production, water use, and reflectivity are possible with no additional demand on r

75 gigapascals, hydrogen becomes metallic, with reflectivity as high as 0.91.

76 The nanofiber networks show optical reflectivity as low as 5% and high flexibility; the nano

77 found to be excellent in the "normalized" EZ reflectivity assessment (intraclass correlation coeffici

78 h a concomitant increase in complete loss of reflectivity at 6 (63/99, 63.6%) and 12 months (85/102,

79 resonance (PWR) spectroscopy measures light reflectivity at a waveguide interface as the incident fr

80 helial (RPE) junction layer showed increased reflectivity at the fovea in all patients except patient

81 r inner/outer segment (IS/OS) junctions lost reflectivity at the margins of GA, while visual function

82 ties, including tunable color and asymmetric reflectivity behavior of relevance for thin-film applica

83 A band of reduced reflectivity below the RPE was identified in all three s

84 al variability in size, shape, location, and reflectivity between different eyes.

85 SCO films show no magnetic moment in neutron reflectivity, both above and below Tc.

86 etections to highly accurate scene depth and reflectivity by exploiting both the transverse smoothnes

87 retina, retinal layer location, and internal reflectivity by SD-OCT did not correlate significantly w

88 Significant percentage reflectivity changes (Delta%R) in the SPRi signals and m

89 Associated retinal reflectivity changes are related to lesion stages and ar

90 Photoinduced reflectivity changes distort the shape of transient abso

91 of the optical properties of HFL can explain reflectivity changes imaged in this layer in association

92 free adenovirus antibodies and thus smaller reflectivity changes.

93 omated classification of PEDs using internal reflectivity characteristics appears to be sensitive for

94 uted using the formula: normalized choroidal reflectivity = (choroidal reflectivity-vitreous reflecti

95 potential of gold, carbon, and aluminum low-reflectivity compact discs as a substrate for microassay

96 affected eyes were graded as medium to high reflectivity compared with the unaffected eyes that show

97 ecause of differences in their albedo (solar reflectivity) compared to soils and to natural vegetatio

98 Optical reflectivity complements SEM and demonstrates a vertical

99 Analyzing the whole reflectivity curve at multiple angles of incidence inste

100 processing using integration area under the reflectivity curve is applied for optimum signal to nois

101 obust five parameter fitting of the spectral reflectivity curve which enables monitoring of the refle

102 at quantitative evaluation of the changes in reflectivity curves (shape of the SPR dip) and of the sl

103 The method consists in analysis of the SPR reflectivity curves for several standard solutions (e.g.

104 The experimental results are consistent with reflectivity curves that are theoretically predicted usi

105 Additionally, the ability to measure reflectivity curves with both p- and s-polarized light p

106 ion in the north-eastern USA using nocturnal reflectivity data from 12 weather surveillance radar sta

107 Specular X-ray reflectivity data revealed that superwarfarins, but not

108 s were detected in the high-resolution X-ray reflectivity data with monotonic increase in roughness.

109 resolution from energy-dependent soft X-ray reflectivity data.

110 ificantly improved fit of experimental x-ray reflectivity data.

111 tivity, and relative inner segment ellipsoid reflectivity (defined as the ratio of inner segment elli

112 ted photons per pixel for accurate range and reflectivity determination.

113 ectrum (white electrons) associated with the reflectivity difference between two different substrates

114 se protein probes using an oblique-incidence reflectivity difference scanning optical microscope.

115 d, the sample exhibits a deeper and narrower reflectivity dip at resonance than that obtained under N

116 The LDAS run reproduced reflectivity echoes and associated rainfall bands more e

117 Here we use spin-polarized neutron reflectivity experiments to demonstrate topologically en

118 /absence of the hyperreflective lower border reflectivity feature was assessed.

119 otonic crystal slab reveal that the peaks of reflectivity follow the conical band structure of a Dira

120 By measuring the time evolution of surface reflectivity following the pump pulse of 266 nm light, w

121 Measuring reflectivity for a range of frequencies extends the anal

122 The angles of minimum reflectivity for nickel thin films with 10 nm SiO(x) and

123 subretinal material; and 94% and 87% for low reflectivity from subretinal material.

124 Our technique recovers 3D structure and reflectivity from the first detected photon at each pixe

125 Inner segment ellipsoid band reflectivity, global retinal reflectivity, and relative

126 he GaN/mesoporous GaN DBRs exhibit high peak reflectivities (>96%) across the entire visible spectrum

127 ccording to 5 morphologic parameters: shape, reflectivity, homogeneity, and concurring photoreceptor

128 Significant relations were found between reflectivity, homogeneity, and polarization-sensitive in

129 ns in sequential real-time SPRM differential reflectivity images are counted to create digital adsorp

130 e and experimentally demonstrate a depth and reflectivity imaging system with a single-photon camera

131 rve significant differences in surface radar reflectivity, implying substantial spatial variations in

132 ed in 5 eyes (31%), decreased ellipsoid zone reflectivity in 4 (25%), foveal retinal detachment in 2

133 Confocal microscopy showed areas of altered reflectivity in basal epithelial cells, which appeared h

134 demonstrate advanced applications of neutron reflectivity in resolving Gag conformations on a membran

135 aracterize choroidal thickness and choroidal reflectivity in the eyes of patients with birdshot chori

136 sition of sub-pulse duration range and 4-bit reflectivity information in the presence of high backgro

137 capture three-dimensional (3D) structure and reflectivity information.

138 ata dispersion with respect to the classical reflectivity interrogation mode.

139 The reflectivity is analyzed in terms of the known crystallo

140 ation of PKCalpha-C2 determined by our x-ray reflectivity is consistent with many previous findings,

141 relative to the scale surface is varied when reflectivity is enhanced.

142 We show that enhanced reflectivity is obtained with the same basic guanine cry

143 The nanotexture reflectivity is quantitatively well-modelled after accou

144 I propose that the G reflectivity is regionally enhanced by dynamical process

145 ity in the subablation stroma, lower corneal reflectivity, less stromal regrowth, and lower nonspheri

146 ordinarily sharp photonic bandgaps with high reflectivity, long-range periodicity in all dimensions a

147 nced the light-trapping effect and minimized reflectivity losses from the incident light.

148 ities with thickening/accumulation of varied reflectivities, macrophage infiltration, loss/duplicatio

149 with MAs with hyperreflectivity or moderate reflectivity, MAs with hyporeflectivity on structural SD

150 Novel choroidal parameters such as choroidal reflectivity may warrant further study in the setting of

151 compounds yields a local increase of surface reflectivity measured by a simple imaging system.

152 h ~0.5 A resolution by high-resolution X-ray reflectivity measurement.

153 Monolayers were characterized with X-ray reflectivity measurements and by electronic characteriza

154 High pressure infrared absorption and reflectivity measurements are consistent with closure of

155 X-ray reflectivity measurements are used to determine the conf

156 Time-resolved resonant anomalous X-ray reflectivity measurements at 25 degrees C reveal that Rb

157 Polarized neutron reflectivity measurements confirm the existence of a lay

158 IR reflectivity measurements confirm the predicted metamate

159 Operando high-energy X-ray reflectivity measurements demonstrate that training the

160 X-ray reflectivity measurements establish that this de novo-de

161 Our x-ray and neutron reflectivity measurements indicate that water is prefere

162 Photoluminescence and photomodulated reflectivity measurements of ZnOSe alloys are used to de

163 Magnetic domain structure and spin-dependent reflectivity measurements on cobalt thin films intercala

164 Neutron reflectivity measurements on these polymer:PC(7)(1)BM bl

165 Neutron reflectivity measurements provide insight into the nanom

166 he combined application of X-ray and neutron reflectivity measurements represents a key milestone in

167 Reflectivity measurements show a structural destabilisat

168 X-ray reflectivity measurements showed no clear epitaxial rela

169 an cell toxicity studies, and specular x-ray reflectivity measurements shows that the in vitro activi

170 We present neutron reflectivity measurements that resolve the one-dimension

171 In this work, synchrotron X-ray reflectivity measurements, accompanied by large-scale at

172 igher than those obtained from time-resolved reflectivity measurements, due to large deviations in th

173 n situ specular and resonant anomalous X-ray reflectivity measurements, we investigated the interacti

174 he substitution motif and confirmed by X-ray reflectivity measurements.

175 urrent practice generally involves very high reflectivity mirrors and hence intense light sources (ty

176 repetition rate combined with the superhigh reflectivity mirrors yielded precise isotopic measuremen

177 linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indica

178 opy on sodium shows a transition from a high reflectivity, nearly free-electron metal to a low-reflec

179 direct structural measurements using neutron reflectivity (NR) and conductance measurements using ele

180 earing as multilaminar sub-RPE intense hyper-reflectivity observed in vivo in eyes with regressing dr

181 capture probes were encoded by the different reflectivities of Au and Ag stripe patterns.

182 mpression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd3Ga5O12 (GGG)

183 With an optical cavity mirror reflectivity of 99.994%, a limit of detection of 159 ppb

184 toemission yield is modulated by the Fresnel reflectivity of a multilayer structure and carries struc

185 The reflectivity of dozens of spots is monitored in real tim

186 sing modified pitfall taps that increase the reflectivity of echolocation calls.

187 The reflectivity of HFL was directionally dependent and incr

188 ervers masked to patient groupings evaluated reflectivity of MAs on SDOCT scans, graded as hyporeflec

189 e, as does the plasma motion that causes the reflectivity of metals.

190 The reflectivity of outer retinal layers was measured as a f

191 Drusen that showed a decreased reflectivity of overlying photoreceptor layer (P = .041;

192 SD-OCT) uses infrared light to visualize the reflectivity of structures of differing optical properti

193 They enhance not only the reflectivity of the ant's body surface in the visible an

194 nimum GCC thickness and (2) the "normalized" reflectivity of the ellipsoid zone (EZ) en face image.

195 e spectral signal from the sample due to the reflectivity of the gold surface, which allows forward a

196 taking advantage of the frequency dispersive reflectivity of the metamaterial array, different modes

197 l were segmented to allow the brightness and reflectivity of the pixels in the choroid, RPE band, and

198 airment, (2) drusen-like lesions, (3) normal reflectivity of the RPE line on SD-OCT, and (4) vitellif

199 HRF overlying DLs, a heterogeneous internal reflectivity of these lesions, was found consistently to

200 It relies on the dependence of the electron reflectivity on incidence angle and energy and has a spa

201 period of dark adaptation and examined layer reflectivity on optical coherence tomography in a patien

202 as the ratio of inner segment ellipsoid band reflectivity on overall retinal reflectivity) were measu

203 tumors (60%) showed an increase in internal reflectivity on regression.

204 vitreomacular traction and low vitreous face reflectivity on SD OCT.

205 X-ray reflectivity on selected films provided further insight

206 well preserved and maintained its classical reflectivity on spectral-domain optical coherence tomogr

207 66 mm), with initial atypical medium to high reflectivity on standardized A-scan (100%) and hollownes

208 ong agreement was detected between decreased reflectivity on standardized A-scan and ultrasonographic

209 After 2 to 6 years, decreased internal reflectivity on standardized A-scan and ultrasonographic

210 Outer retinal reflectivity on the transversal optical coherence tomogr

211 the regulating role of the background radar reflectivity on their observed characteristics.

212 as increased thickness and higher ultrasound reflectivity on UBM when compared with the unaffected ey

213 oscopy, polar Kerr effect, and time-resolved reflectivity) on the same optimally doped Bi2201 crystal

214 -D) measurements to maximize the increase in reflectivity or decrease in frequency upon hybridization

215 pression for absorbance regardless of mirror reflectivity or the absorbance and show that in the limi

216 yed fluid, NSD, intraretinal flecks, and low reflectivity or undefined boundaries from subretinal mat

217 create an artificial material with very low reflectivity over a wide spectral range.

218 a surface plaque (P = .07) and the internal reflectivity (P = .77).

219 FD-OCT demonstrated different reflectivity patterns in both calcified and decalcified

220 d be readily separated on the basis of their reflectivity patterns.

221 ctivity, nearly free-electron metal to a low-reflectivity, poor metal in an orthorhombic phase at 118

222 t the retina, shape, homogeneity of internal reflectivity, presence of internal depolarizing characte

223 nd angle-resolved photoemission and infrared reflectivity probes.

224 matrix (TM) treatment is used to derive the reflectivity profile and dispersion curves.

225 PA and LBAT showed a smooth bright reflectivity profile, whereas TA had a granular profile.

226 Each agent had a unique reflectivity profile.

227 the signal peaks and troughs on longitudinal reflectivity profiles.

228 ages using atomic force microscopy and X-ray reflectivity provides information on the surface roughne

229 weight, increases the thickness, or reduces reflectivity, providing clear evidence for the evolution

230 (10 and 50 nm) with resonant anomalous X-ray reflectivity (RAXR) to single crystals expressing the (0

231 evealed a distinctive latticework pattern of reflectivity resembling the spongy bone structure seen h

232 curve, the average single nanoparticle SPRM reflectivity response, Delta%RNP, was measured.

233 orption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface laye

234 lectivity = (choroidal reflectivity-vitreous reflectivity)/RPE reflectivity.

235 al solvents are shown by resonant soft X-ray reflectivity (RSoXR) to be very smooth and sharp.

236 In this regard resonant x-ray reflectivity (RXR) provides a unique experimental tool t

237 face was imaged and graded using a published reflectivity scale.

238 its are preferentially oriented, while X-ray reflectivity scans point to periodic ordering.

239 X-ray reflectivity showed that the drug penetrated the monolay

240 Neutron reflectivity showed, in real time, that OmpF mediates th

241 the butterflies' wings maintained this high reflectivity showing that a single layer of scale cell-l

242 LSCO (x = 0.35) film, the spin asymmetry of reflectivity shows a very small static magnetic moment (

243 X-ray reflectivity shows the adlayer to consist of a stack of

244 clinical cohort, all histologically verified reflectivity signatures were visible and quantifiable.

245 Donor-recipient interface reflectivity significantly influenced scotopic (beta = -

246 A distinctive latticework pattern of reflectivity similar to spongy bone was seen in calcifie

247 In addition, transient analyses of the reflectivity simultaneously recorded with CVs show the f

248 Temperature-dependent hard X-ray reflectivity, small- and wide-angle X-ray scattering, an

249 the particles can be decoded based on their reflectivity spectra and that a multiple analyte assay c

250 Total internal reflection (TIR) Raman and reflectivity spectra were collected for nonresonant anal

251 tivity curve which enables monitoring of the reflectivity spectral shift with a resolution of the ord

252 g) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong o

253 rapid and reproducible change in the optical reflectivity spectrum of the hybrid, allowing for label-

254 shift in wavelength of the main peak in the reflectivity spectrum of the PSi device, which is depend

255 d in momentum resolved photoluminescence and reflectivity studies.

256 ore, basal epithelial cells density, stromal reflectivity, sub-basal nerves tortuosity (p = 0.0000, 0

257 A central core with a reflectivity superficially resembling photoreceptors is

258 ith pump-probe X-ray diffraction and optical reflectivity techniques, and show how trimerons become m

259 The drusen were ovoid regions of lower reflectivity that were bordered by hyperreflective mater

260 azing-incidence x-ray diffraction (GIXD) and reflectivity, the in-plane and out-of-plane structures o

261 protein demonstrates the ability of neutron reflectivity to discern orientation and penetration unde

262 ptide with no such cavity, and applied x-ray reflectivity to monolayers of these peptides to probe th

263 se efficiency, while increasing land-surface reflectivity to offset greenhouse gas warming.

264 gue by using ultrafast time-resolved optical reflectivity to uncover an intimate connection between i

265 stigate these effects we compare the optical reflectivity under resonance excitation in samples prepa

266 er, two major problems with ITO remain: high reflectivity (up to 10%) and insufficient flexibility.

267 nique to calibrate the optical cavity mirror reflectivity using a temperature dependent water vapor s

268 lective spots and complete resolution of all reflectivity using SD-OCT.

269 multiple angles of incidence instead of the reflectivity value at a single incidence angle provides

270 with EM radiation, and their characteristic reflectivity versus incident angle lineshape can be grea

271 rmalized choroidal reflectivity = (choroidal reflectivity-vitreous reflectivity)/RPE reflectivity.

272 The EZ "normalized" reflectivity was 0.67 +/- 0.11 in controls and 0.61 +/-

273 Interface reflectivity was 2.17 +/- 1.2 and significantly correlat

274 In univariate analysis, EZ "normalized" reflectivity was found to have a significant direct rela

275 AOSLO revealed that photoreceptor reflectivity was qualitatively reduced by stage 1 subret

276 segment/outer segment (ellipsoid zone line) reflectivity was reduced significantly at the fovea and

277 ner segment ellipsoid and relative ellipsoid reflectivity were closely correlated with cone density (

278 In decalcified areas 2 patterns of reflectivity were identified: the first consisted of are

279 Corneal thickness and reflectivity were measured by optical coherence tomograp

280 and inner diameters and heterogeneous lumen reflectivity were positively associated with microaneury

281 rusenoid lesions with heterogeneous internal reflectivity were significantly associated with new atro

282 Number per frame and reflectivity were significantly lower in diabetic patien

283 The number of fibers per frame and reflectivity were significantly lower in diabetic patien

284 lipsoid band reflectivity on overall retinal reflectivity) were measured on a longitudinal reflectanc

285 cuit than to small deviations in the coupler reflectivity, which are expected given the tolerance val

286 rcular dichroism and x-ray resonant magnetic reflectivity, which enables magnetic characterizations w

287 plementary to that provided by X-ray Fresnel reflectivity, which presents an advantage to a wide vari

288 Silicone instrumentation showed moderate reflectivity with minimal shadowing.

289 Polyamide material had a moderate reflectivity with subtotal shadowing.

290 ents (e.g., forceps and needles) showed high reflectivity with total shadowing below the instrument.

291 An adjusted or normalized choroidal reflectivity, with the RPE as the bright reference stand

292 omography, epiretinal material of homogenous reflectivity without contractive properties was categori

293 echniques: contact angle measurements, X-ray reflectivity, X-ray photoelectron spectroscopy, ultravio

294 Polarized neutron reflectivity, x-ray reflectivity and aberration-correcte

295 Using x-ray reflectivity (XR) and grazing incidence x-ray diffractio

296 e molecular dynamics (MD) simulations, X-ray reflectivity (XR) and in situ atomic force microscopy (A

297 ng incidence x-ray diffraction (GIXD), x-ray reflectivity (XR), and pressure-area isotherms provides

298 y grazing incidence X-ray diffraction, X-ray reflectivity (XR), and X-ray fluorescence spectroscopy (

299 In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-ang

300 oscopy (TEM), X-ray diffraction (XRD), X-ray reflectivity (XRR), Fourier transform infrared spectrosc