bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Insight into Exchange Energy of Covalent Chemical Bonds
Authors: Tang K. T. , Toennies J. P. , Yiu C. L. 
Published: May 2015

AbstractThe exchange energy for the H2 molecule is calculated for a wide range of inter nuclear distance R extending down to R = 0.5 a0 using the surface integral method. This method accounts for the physical exchange of the two electrons between the two nuclei. The good agreement of the present results with the standard Heitler‐London calculation demonstrates that the exchange energy can in deed be described in terms of electrons hop ping back and forth between the nuclei, an interpretation which has been frequently criticized in the past.
Hydrogen‐rare Gas Interactions and Raman Line Shapes
Authors: Waldron Levi , Liu Wing‐Ki 
Published: May 2015

AbstractEmploying the recent XC(fit) intermolecular potential for H2‐Ar, we have presented the results of the spectral parameters for the D2‐Ar Raman Q1 branch, obtained from quantum mechanical close‐coupled calculations. While the theoretical line shifts of the polarized Raman spectra were found to agree with experiments, the corresponding widths were smaller than the measured values by as much as 56%. We observed that the shifts and the widths depend on the vibrational dependence of the potential in their own separate ways, and our results suggested that the anisotropic vibrational dependence of the XC(fit) potential requires improvement, in conjunction with further fine‐tuning of the isotropic part. Even though there is no experimental data for comparison, we have computed the line‐mixing parameters of the polarized Raman Q1 branch, as well as the depolarized line widths and shifts for the Q1(j) lines. These results showed the same trends as the corresponding ones for D2‐He.
Direct Measurement of a Beam Force Exerted to a Foil with a Laser Displacement Meter
Authors: Katayama Ichiro , Jeong Sun‐Chan , Tsuchida Hidetsugu , Ogawa Hidemi , Sakamoto Naoki , Itoh Akio 
Published: May 2015

AbstractThe interaction of a beam with a target foil is studied using a torsion balance. The change in equilibrium angle of the target frame due to momentum transfer of the projectile was measured by a laser displacement meter. The thick foil result can be interpreted in a straight forward way. On the other hand, the thin foil result shows that the momentum transfer to the tar get is 71 +/‐ 10% of that expected from energy loss of a projectile.
Density Functional Theory with Optimized Effective Potential: An Application to Hollow Atoms in the Bulk of Metallic Materials
Authors: Tong Xiao‐Min , Kato Daiji , Watanabe Tsutomu , Shimizu Hiroshi , Yamada Chikashi , Ohtani Shunsuke 
Published: May 2015

AbstractThe local spin‐density functional theory with an optimized effective potential and self‐interaction correction is used to study the energy structure of hollow atoms or ions in the bulk of metallic materials. The energy structure of conduction electrons in the bulk of metallic material is treated by the jellium model. Based on this method, we have studied the emit ted x‐ray spectra of Arq+ hollow atoms and ions in the bulk of Ag as well as in the vacuum. By comparing the energy spectra of Arq+ hollow atoms or ions in the vacuum and in the bulk of Ag, we can illustrate the conduction electron screening effect. Our calculated x‐ray spectra of Arq+ hollow atoms or ions in the bulk of Ag is in reasonable agreement with the experiment.
Single and Multiple Ionization of Atoms by Electron Impact
Authors: Golecki Philip , Klar Hubert 
Published: May 2015

AbstractWe report progress achieved during decades on direct single and multiple ionization of simple atoms by electron collsion. In particular we investigate total cross sections from thresh old to high energies. We show that all experimental data compare favorably with Wannier thresh old theory. A better understanding of the ionization process one gets from the analysis of multiply differential cross sections. To this end we discuss (e, 2e) and (e, 3e) events.
Variational Calculation of the Energy for Helium‐like Ground State from Z = 2 to 5
Authors: Wang Zhi‐Wen , Guan Xiao‐Xu 
Published: May 2015

AbstractThe non‐relativistic energies of the ground states in the helium‐like systems from Z = 2 to 5 are calculated by using three different basis functions, the Slater‐type, the ordered coordinates and the modified angular wave functions in which the angular variational parameters are included. In calculations with the latter two types of basis functions, we only used 168 terms in eight l components. The best value of energy for neutral helium atom in this work is obtained by using the modified angular wave functions. It is determined to be −2.9037161 a.u., which is about 0.00017 a.u. lower than that obtained with the 221‐term Slater‐type expansions. In cases of the helium‐like ions from Z = 3 to 5, the comparison of our calculated results using these three types of basis functions indicates that the results obtained with the modified angular wave functions are better than those with the other two types of basis functions. The convergence pattern in energy with the increasing number of terms in the angular partial wave functions is also analyzed.
X‐ray Spectroscopy of Highly Charged Ions at the Tokyo EBIT
Authors: Nakamura Nobuyuki , Kato Daiji , Nakahara Tetsuro , Ohtani Shunsuke 
Published: May 2015

AbstractRecent results and experimental plans in X‐ray spectroscopic studies of highly charged ions at the Tokyo EBIT (Electron Beam Ion Trap) are presented. We have been using a flat crystal spectrometer to observe X‐ray transitions in the energy range of 3–10 ke V. It has been used to investigate the strong configuration mixing in neonlike ions, the electron‐impact excitation of highly charged ions, the polarization of Ly‐α in hydrogenlike Ti21+, and so on. A Johansson type of spectrometer has been constructed to observe X‐ray transitions in the higher energy range, 10–30 keV. It will be used for high‐resolution spectroscopy of the Lyman series in hydrogenlike medium‐Z ions. In particular, an inter comparison method between Ly‐α of In48+and Ly‐β of Rh44+ is proposed to measure the 1s Lamb shift precisely. It will provide a precise test of the QED theory in the strong field regime.
Cavity Ringdown Spectroscopy: New Approaches and Out Comes
Authors: He Yabai , Orr Brian J. 
Published: May 2015

AbstractCavity ringdown (CRD) absorption spectroscopy provides high sensitivity and photometric precision in the measurement of weak optical absorption spectra. We report several innovations in CRD technique involving either pulsed or continuous‐wave (cw) tunable coherent sources. In the former case, we use narrowband, injection‐seeded optical parametric oscillator (OPO) devices based on quasi phase‐matched nonlinear‐optical media and a novel intensity‐dip cavity control scheme; one such pulsed OPO is pumped by a compact, in expensive multimode laser but still delivers single‐mode OPO signal output. The latter area concerns cw‐CRD spectroscopy with a single‐mode tunable diode laser (TDL) and a rapidly swept ringdown cavity, most recently enhanced by a novel optical heterodyne approach that yields a noise‐limited absorption sensitivity of 3 × 10−9 cm−1. Such pulsed and cw CRD methods are used to record weak rovibrational spectra of carbon dioxide gas (CO2) with high resolution in the 1.5‐μm near‐infrared region. Emphasis is on high‐performance spectroscopic systems with relatively simple, in expensive, compact instrumentation.
Synthesis, Crystal Structure and Magnetic Properties of Zinc (II) Chloride Complexes with Pyridyl‐Substituted Nitronyl Nitroxides
Authors: Lee Chin‐Jhan , Wei Ho‐Hsiang , Lee Gene‐Hsiang , Wang Yu 
Published: May 2015

AbstractZnCl2(NIT‐pPy) 1, (NIT‐pPy = 2‐(4‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide) crystallizes in the orthorhombic space group Pnn2 with the cell parameters a = 9.4083(9), b = 39.686(3), c = 7.4417(14) Å. ZnCl2(NIT‐6M‐oPy) 2, (NIT‐6M‐oPy = 2‐(6‐methyl‐2‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide) crystallizes in the monoclinic space group Pn with a = 7.377(2), b = 19.096(4), c = 11.853(2) Å, β = 95.65(3)°. The temperature dependence magnetic susceptibility of complex 1 revealed an intermolecular ferromagnetic exchange interaction. A simple spin‐polarization model has been used to justify the observed ferromagnetic exchange interaction between the spins of the radical NO group in complex 2.
Synthesis of Thiadiazolinylpyrazolopyridine and Pyridopyrazolotriazine Derivatives
Authors: Attaby Fawzy A. , Elneairy Mohamed A. A. , Eldin Sanaa M. , El‐Louh Ali K. K. 
Published: May 2015

Abstract3‐Diazotized aminopyrazolo[3,4‐b]pyridines 2a,b used as good synthons for the synthesis of 3‐thiadiazolinylpyrazolo[3,4‐b]pyridines 8a,b through their reactions with thiocyanatoacetophenone (6) and pyrido[2,3:3′,4′]pyrazolo[5,1‐c][1,2,4]triazines 5a‐d via their reactions with several active methylene containing reagents: 3a,b, 12, 16, 20, 23a‐d and 26a‐c. All the structures of the newly synthesized heterocyclic compounds were established by considering the data of IR,1H NMR and mass spectra in addition to the synthesis of most newly synthesized heterocyclic compounds via other routes.
A Theory of Coulomb Explosion of Molecules
Authors: Lin S. H. , Mishima K. , Hayashi M. , Chang A. H. H. , Yi J. , Mebel A. M. 
Published: May 2015

AbstractIn this paper, a theory of Coulomb explosion of molecules in intense laser fields based on the Auger effect will be presented. We first show how to calculate the rate of Auger process and then show that multiple ionization processes can be induced by the Auger effect alone or by the Auger effect followed by autoionization. For the case of molecules, multiple ionization is in general followed by dissociation.
Physico‐Chemical Properties of Nb/Ti Binary Oxides and their Photo‐Catalytic Activities
Authors: Tsai Shi‐Jane , Cheng Soofin 
Published: May 2015

AbstractA series of binary Nb/Ti ox ides was prepared by co‐precipitation. Their structure and physico‐chemical properties in term of surface area, surface acidity, bandgap energy and life time of the radiation‐excited electron‐hole pair were examined. These properties were correlated to their catalytic activities in photodegradation of oxygenated organic pollutants in water. The organic pollutants under investigation were phenol, cyclohexanol and tetrahydrofuran (THF). The lab‐made titanium oxide and those doped with a small amount of Nb (molar ratio of Nb/(Nb+Ti) less than 20%) showed higher activities in degradation of the organic pollutants. However, the mineralization efficiencies were different for the three oxygenated organic pollutants. Nearly complete mineralization to form CO2 could be achieved in the degradation of phenol. For cyclohexanol, only ca. 50% selectivity of CO2 was obtained over all the catalysts. Similar low efficiency in complete mineralization was observed in the degradation of THF, but higher selectivity (ca. 65–75%) of CO2 could be obtained on the binary oxide with Nb content less than 4 molar %. In contrast, the binary Nb/Ti oxide with equal Nb and Ti molar content gave the poorest catalytic activity. The photocatalytic activity is generally correlated well to the life time of the radiation‐excited electron‐hole pairs. The contribution of surface acidity to the photocatalytic activity was only demonstrated on the niobia‐dominant oxide catalysts to ward THF. The photocatalytic activity was found to have no correlation with the crystal line structure, the bandgap energy, the surface area or the surface hydroxyl density.
Synthesis and Reactions of Highly Protected Mannosamines
Authors: Smeu Jia‐Cheng , Shaw Yeng‐Jeng , Luh Tien‐Yau 
Published: May 2015

AbstractHighly protected mannosamine derivatives are synthesized from protected glucose derivatives having a free hydroxy group at C2 position. Indium‐mediated allylation of protected mannosamine derivatives is investigated.
Effect of Monomer Sequencing on the Mesophase Behavior of PDPS/PDMS Copolymer
Authors: Yang Mei‐Hui , Hwang Yeun‐Hsing , Liu Jiann Chang , Chou Chyan 
Published: May 2015

AbstractPolydiphenylsiloxane‐co‐polydimethylsiloxane (PDPS/PDMS) statistical and reshuffled copolymers with different compositions have been synthesized and characterized. The phase behaviors of these copolymers are studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Critical compositions for the appearance of the thermal transitions were determined. The thermal transition properties, such as temperature and peak shape, were correlated to the structures of the copolymers. Effect of the monomer sequencing on the mesophase transition behaviors was examined.
Two New Sesquiterpenes and Two New Lignans from the Leaves of Juniperus Chinensis Var. Kaizuka
Authors: Lee Ching‐Kuo , Cheng Yu‐Shia 
Published: May 2015

AbstractTwo new sesquiterpenes, 8,9‐secocedrachinol (1), (+)‐1‐hydroxy‐1,3,5‐bisabolatrien‐10‐one (2) and two new lignans, (7R,8S)‐9′‐(β‐rhamnopyranosyl)‐3‐methoxy‐3′:7,4′:8‐diepoxyneolignan‐4,9‐diol (3), and (7S,8S)‐9′‐(β‐rhamnopyranosyl)‐3‐methoxy‐3′:7,4′:8‐diepoxyneolignan‐4,9‐diol (4), together with eleven known compounds, cedral, sesquichamaenol, caryophylleneoxide, humulenepoxide, benzoic acid benzylester, 4‐hydroxy‐3‐methoxycinnamic acid, 7‐hydroxy‐8‐(3‐methylbut‐2‐enyl)chromen‐2‐one, 2‐[4‐(3‐ hydroxy propyl)‐2‐methoxyphenoxy]propane‐1,3‐diol, luteolin, 3,4‐bis‐(4‐hydroxy‐3‐methoxybenzyl)dihydro‐ furan‐2‐one, and pluviatolide were isolated from the leaves of Juniperus chinensis var. kaizuka. The structures of these compounds were established on the basis of spectroscopic data.
Crown Ether Phase Transfer Catalysts for An Ionic Polymerization of Bisphenol A / 4,4′‐Dichlorodiphenyl Sulfone
Authors: Lue Lie‐Chuan , Shih Jeng‐Shong 
Published: May 2015

AbstractVarious crown ethers were prepared and applied as phase transfer catalysts for the an ionic copolymerization of bisphenol A and 4,4′‐dichlorodiphenyl sulfone monomers with alkali salts, e.g., NaNH2, NaOH and KOH, as initiators. The catalytic abilities of various crown ethers for the an ionic polymerization of bisphenol A / 4,4′‐dichlorodiphenyl sulfone were found to be in the order: 15‐crown‐5 ≅ monobenzo‐15‐crown‐5 > 18‐crown‐6 > Dicyclohexano‐18‐crown‐6 > Dibenzo‐18‐crown‐6 > 12‐crown‐4 with sodium amide (NaNH2) as initiator. Sodium amide was shown to be a better initiator than NaOH or KOH with monobenzo‐ 15‐crown‐5 as a catalyst. Effects of solvents and temperature on the crown ether catalytic polymerization were also investigated. Dimethyl sulfoxide (DMSO) exhibited much better for the polymerization than other organic solvents, e.g., toluene, p‐xylene, dimethyl formamide and dioxane. Higher polymerization was found at higher temperatures and about 100% yield of poly(bisphenol A / sulfone) was obtained at 125 °C in 3 hr. The molecular weight of poly(bisphenol A / sulfone) as a function of reaction time was determined with gel permeation chromatography. Concentration effects of crown ether on % yield and molecular weight of poly(bisphenol A / sulfone) were also investigated and discussed.
De Sign and Synthesis of 1,2,4‐Oxadiazole Derivatives as Non‐Steroidal 5α‐Reductase Inhibitors
Authors: Chang Chih‐Shiang , Kan Wai Ming , Chen Chiu‐Liang , Wang K. C. , Chern Ji‐Wang 
Published: May 2015

AbstractThe purpose of this study was to synthesize compounds in which the 1,2,4‐oxadiazole moiety replaced the amide bond of ONO3805 and to evaluate its 5α‐reductase inhibitory activity as a potential benign prostatic hyperplasia therapeutic target. Four 1,2,4‐oxadiazole derivatives, 1,2,8, and 20, were evaluated in vitro against 5α‐reductase of rat liver microsome. The prepared 1 and 2 possessed similar binding affinity (Ki) to that of ONO3805. Therefore, the use of 1,2,4‐oxadiazole ring as surrogate of the amide bond in ONO3805 has a successful result in this study. It leads not only to enhance chemical stability but also to maintain meaningful inhibitory activity. The butyric acid moiety of these inhibitors is considered to play an important role in mimicing the phosphoric acid portion of coenzyme‐NADPH in interacting with the active site of 5α‐reductase.
Triterpenoids from Rhaponticum Uniflorum
Authors: Zhang Yong‐Hong , Cheng Jie‐Kai , Yang Li , Cheng Dong‐Liang 
Published: May 2015

AbstractThe isolation and identification of twenty‐one components (including four new triterpenoid saponins and one new triterpenoid acid) from the root of Rhaponticum uniflorum (L.) DC. (Compositae) are described. Their structures were determined on the basis of spectral analysis and chemical trans formation. The new compounds were identified as 3‐O‐α‐L‐arabinopyranosyl‐urs‐12,18(19)‐dien‐28‐oic acid β‐D‐glucopyranosyl ester, 3β‐ hydroxyurs‐12,18(19)‐dien‐28‐oic acid β‐D‐glucopyranosyl ester, 3β‐hydroxyurs‐12,19(29)‐dien‐28‐oic acid β‐D‐glucopyranosylester, 3‐O‐α‐L‐arabinopyranosyl‐urs‐9(11),12‐dien‐28‐oic acid β‐D‐glucopyranosyl ester and 2 α,3 α, 19α,25‐tetrahydroxyurs‐12‐en‐23,28‐dioic acid.
Photophysics and Acid‐Base Chemistry of Re(CH3bpyCOOH)(CO)3X (X=Cl−, and Imidazole) Complexes
Authors: Lin Ren‐Jay , Chang I‐Jy 
Published: May 2015

AbstractRheniumtricarbonyl(4′‐methyl‐2,2′‐bipyridine‐4‐carboxylic acid)X (where X is Cl− and imidazole) complexes have been prepared. These two complexes exhibit similar spectroscopic properties. The metal‐ to‐ligand charge‐transfer (MLCT) absorption and the corresponding emission are observed. This charge transfer band is highly solvent dependent. Due to the stronger electron‐withdrawing ability of the ‐COOH (in comparison to the ‐COO− group), the MLCT band has red‐shifted during protonation. Emission quantum yields are dramatically reduced while life time remains similar upon protonation. These behaviors are typical in static quenching mechanism by protons. The ground state pKa of Re(CO)3 (CH3bpyCOOH)Cl obtained from the pH titration curve of the complex absorption at 409 nm was 2.5.
Kinetics of Acid‐Catalyzed Dissociation of Nickel (II) N‐Alkyl‐Substituted Diamino Diamide Complexes
Authors: Chao Min‐Shiun 
Published: May 2015

AbstractThe dissociation kinetics of the nickel (II) complexes of 4‐methyl‐4,7‐diazadecanediamide (4‐Me‐L‐2,2,2), 4,7‐dimethyl‐4,7‐diazadecanediamide (4,7‐N, N′‐Me2‐L‐2,2,2), 4‐ethyl‐4,7‐diazadecanediamide (4‐Et‐ L‐2,2,2), and 4‐methyl‐4,8‐diazaundecanediamide (4‐Me‐L‐2,3,2) have been studied at 25.0 °C and μ = 4.0 M (NaClO4 + HClO4) by the stopped‐flow method. These reactions are specific‐acid catalyzed; however, the rate constants of these reactions do not depend on the concentrations of acetic, chloro acetic, and dichloroacetic acids. At pH values be low 1.0, both the proton‐assisted and the direct protonation path ways make contributions to the rates. The ratios of the rate constant of dissociation by the direct protonation path way to the rate constant by the proton‐assisted path way for the complexes in aqueous solution were measured and discussed.
Formal Synthesis of (±)‐Isodihydronepetalactone
Authors: Chang Meng‐Yang , Chang Bo‐Rm , Chang Chung‐Ho , Chen Shui‐Tein , Chang Nein‐Chen 
Published: May 2015

AbstractA formal synthesis of (±)‐isodihydronepetalactone (1) from cyclobutenone 5 was de scribed. Baeyer‐Villiger lactonization of cyclobutanone 8 followed by decholorination led to lactone 4, which under went a series of functional group trans formations, furnished cyclopentanone derivative 15. Shapiro reaction on hydrazone derivative in the presence of excess dry ice gave lactone 2. Lactone 2 had previously been converted to isodihydronepetalactone (1).
The Constituents and Synthesis of Cryptamygin‐A from the Stem Bark of Cryptocarya Amygadalina
Authors: Charf Yu‐Yi , Wu Chia‐Hung , Wu Shwu‐Jen , Wu Tian‐Shung 
Published: May 2015

AbstractThree new benzenoid compounds, namely cryptamygin‐A, ‐B and ‐C together with eleven known compounds were isolated from the stem bark of Cryptocarya amygadalina. Their structures were elucidated by spectral analysis. The synthesis of cryptamygin‐A is also described.
Role of Nitrite on Nitration of 2′‐Deoxyguanosine by Nitryl Chloride
Authors: Chen Hauh‐Jyun Candy , Wang Tze‐Fan , Chen Yuan‐Mao 
Published: May 2015

AbstractNitryl chloride and peroxynitrite are reactive nitrogen species generated by activated phagocytes against invading pathogens during infections and inflammation. In our previous report, formation of 8‐nitroxanthine and 8‐nitroguanine was observed in reaction of 2′‐deoxyguanosine or calf thymus DNA with nitryl chloride generated by mixing hypochlorous acid (HOCl) with nitrite (NC2−). The present study investigates factors control ling the yields of 8‐nitroxanthine and 8‐nitroguanine formation in nitration of 2′‐deoxyguanosine by nitryl chloride. We found that the yields of 8‐nitroxanthine and 8‐nitroguanine in reaction of 2′‐deoxyguanosine with nitryl chloride were highly dependent on the ratio of NO2− versus HOCl concentration. The yields of 8‐nitroxanthine and 8‐nitroguanine reached a plateau when the ratio of NC2− versus HOCl concentration was higher than 2. A possible mechanism was postulated to explain this observation. While 8‐nitroguanine is not stable in the presence of peroxynitrite, 8‐nitroxanthine is sensitive to HOCl. The stability of these two nitrated ad ducts might be a factor on their final yields in this reaction. Since HOCl is produced by neutrophils at sites of inflammation where the level of NC2− is elevated, it is conceivable that nitryl chloride contributes to DNA base nitration in vivo, forming 8‐nitroxanthine and 8‐nitroguanine.
Raman Spectroscopy of Galactosemic Rat Lens Crystalline: Correlation of Microscopic Changes of Lens Proteins at Molecular Levels with Gross Cataractous Alteration
Authors: Ho Yuh , Huang Fu‐Yung 
Published: May 2015

AbstractNear‐Infrared Fourier trans form (near‐IR FT) Raman spectros copy has been used to study the structural changes of lens proteins both in cortex and nucleus of galactosemic rat lenses. It was found that tyrosine doublet ratio of Raman bands, I832/I855, in creased more rapidly in the cortex than in the nucleus during a 5‐week period of galactose feeding, i.e., from 0.86 to 1.1 for the cortex and 0.88 to 0.92 for the nucleus. The ratio obtained for lens nucleus suggests that a lower ratio of less than 1 does not necessarily reflect the apparent transparent state of lens morphology. More over our results for the in crease of tyrosine doubletratio with the extent of cataract formation in galactosemic lens appear to indicate that there is more hydration in crystallins of the cortex than the nucleus since the in creased ratio of tyro sine doublet has been shown to be due to the hydrogen‐bond formation of hydroxyl groups in various tyrosines of proteins with water. The tryptophan band ratio at 880 cm−1 and 757 cm− (I880/I757) under went a precipitous de crease in the cortex and a rather gradual de crease in the nucleus, suggesting buried tryptophan residues become more exposed in the cortex than in the nucleus during galactose‐induced cataractogenesis. Based on the changes of the two ratios, I832/I855 and I880/I757, the change of lens protein environment induced by galactosemic feeding appeared to take place in the cortex first, which was consistent with the observation that the development of an opaque lens be gins in the cortex. While no sulfhydryl (‐SH) signal was detected, there was a slow in crease of disulfide (‐S‐S‐) signal in the cortex of galactose‐fed lenses as compared to control lenses with out galactose. This suggested that a loss of lens glutathione occurred early and oxidation of cysteines in crystallins started in the first week, i.e., be fore the onset of cortical cataract. In contrast, for nucleus of galactosemic lenses the signal of the‐SH group was detected and yet the ‐S‐S‐signal of crystallins could not be found. In this study, we have conclusively demonstrated using Raman vibrational band shift that galactosemic cataract be gins in the cortex, and that the lens cortex suffers more structural alteration in crystallins than the nucleus.