From mutations to mechanisms and dysfunction via computation and mining of protein energy landscapes.

BACKGROUND: The protein energy landscape underscores the inherent nature of proteins as dynamic molecules interconverting between structures with varying energies. Reconstructing a protein's energy landscape holds the key to characterizing a protein's equilibrium conformational dynamics and its relationship to function. Many pathogenic mutations in protein sequences alter the equilibrium dynamics that regulates molecular interactions and thus protein function. In principle, reconstructing energy landscapes of a protein's healthy and diseased variants is a central step to understanding how mutations impact dynamics, biological mechanisms, and function. RESULTS: Recent computational advances are yielding detailed, sample-based representations of protein energy landscapes. In this paper, we propose and describe two novel methods that leverage computed, sample-based representations of landscapes to reconstruct them and extract from them informative local structures that reveal the underlying organization of an energy landscape. Such structures constitute landscape features that, as we demonstrate here, can be utilized to detect alterations of landscapes upon mutation. CONCLUSIONS: The proposed methods detect altered protein energy landscape features in response to sequence mutations. By doing so, the methods allow formulating hypotheses on the impact of mutations on specific biological activities of a protein. This work demonstrates that the availability of energy landscapes of healthy and diseased variants of a protein opens up new avenues to harness the quantitative information embedded in landscapes to summarize mechanisms via which mutations alter protein dynamics to percolate to dysfunction.

Sequential recovery of copper and nickel from wastewater without net energy input.

A novel bioelectrochemical system (BES) was designed to recover copper and nickel from wastewater sequentially. The BES has two chambers separated by a bipolar membrane and two cathodes. Firstly, the copper ions were reduced on a graphite cathode with electricity output, and then with an additional bias-potential applied, the nickel ions were recovered sequentially on a copper sheet with electricity input. In this design, nickel and copper can be recovered and separated sequentially on two cathodes. By adjusting the molar ratio of copper and nickel ions to 2.99:1 in wastewater, 1.40 mmol Cu²âº could be recovered with 143.78 J electricity outputs, while 50.68 J electricity was input for 0.32 mmol nickel reduction. The total energy output of copper recovery was far more than the electricity input of nickel reduction. The present technology provides a potential method for heavy metal ion separation and recovery.

A novel suture bridge anchor fixation technique to treat inferior pole fractures of patella: A retrospective clinical study.

The traditional surgical methods to the fracture of the inferior patellar fracture include steel wire tension band fixation and inferior patellar resection, which have many disadvantages. In order to overcome the disadvantages of traditional surgery, we innovated and improved the double row anchor suture bridge technology to the treat the inferior patellar fracture. This study is to investigate the method, technique and clinical efficacy of double-row anchor suture bridge technique in the treatment of inferior pole fractures of patella. Between January 2019 and March 2021, 36 patients with inferior pole fractures of patella underwent the surgery with the double-row anchor suture bridge technique. 28 injury cases were caused by falls while 8 injury cases were from car crashes. The operation time, amount of intraoperative bleeding and complications were recorded. Radiological assessments and Bostman score were performed 1, 3, and 6 months post-operation and at the most recent follow-ups. The study sample consisted of 19 males and 17 females, aged 31 to 72 years old. The operation time was (54-76) minutes. All incisions healed in 1 stage. No complications such as incision infection, flap necrosis and nerve injury occurred. Patients in this group were followed up for 10 to 18 months, with an average follow-up of 12 months. All fractures healed in 10 to 20 weeks, with an average healing time of 12 weeks. At the last follow-up, the Bostman score was (27.5 ± 3.3), excellent in 32 cases and good in 2 cases, with an excellent rate of 94.4%. The range of motion of the knee joint was (-2.6 ± 2.0)° when the knee was extended and (122 ± 5.0)° when the knee was bent. The muscle strength of quadriceps femoris was grade 5. Double-row anchor suture bridge technique is applied to inferior pole fractures of patella by virtue of its various effects, such as the complete preservation of the inferior pole fragments during the operation, satisfactory fracture reduction, firm fixation, and meeting patients' requirements for early postoperative ambulation. In summary, double-row anchor suture bridge technique is an ideal surgical procedure for the treatment of the inferior pole fracture of patella with safety, reliability and high satisfaction.

Effect of Oral Tranexamic Acid on the Blood Transfusion Rate and the Incidence of Deep Vein Thromboembolism in Patients after TKA.

Purpose: To explore the effect of oral tranexamic acid treatment on the blood transfusion rate and the incidence of deep vein thromboembolism after total knee arthroplasty (TKA). Methods: 90 patients undergoing TKA admitted to First People's Hospital of Changshu City from January 2019 to January 2020 were selected and randomized into the control group and the experimental group accordingly (45 cases in each group). The control group intravenously received 20 mL/kg tranexamic acid before the incision was closed. The experimental group was given 1 g of tranexamic acid orally before anesthesia, 6 h and 12 h after the operation. Results: The experimental group witnessed better perioperative indexes in relation to the control group. The experimental group displayed better postoperative coagulation function indexes as compared to the control group (P < 0.05). Remarkably lower postoperative vascular endothelial function indexes in the experimental group than in the control group were observed. The experimental group experienced a markedly lower incidence of deep vein thromboembolism in comparison with the control group (P < 0.05). The postoperative knee society score (KSS) score of the experimental group was significantly higher than that of the control group. A significantly higher postoperative modified rivermead mobility index (MRMI) score was yielded in the experimental group in contrast to the control group (P < 0.05). The experimental group obtained lower numerical rating scale (NRS) scores at T2 and T3 as compared to the control group. Conclusion: Oral tranexamic acid is a suitable alternative for patients undergoing TKA in terms of reducing the blood transfusion rate, relieving pain, and accelerating the recovery of the patient's limbs.

Comparison of Two Surgical Approaches to Supination-External Rotation-Type Ankle Fractures.

Objective: To compare the clinical outcome and postoperative complications of the treatment of supination-external rotation-type ankle fractures using the posterolateral approach in the prone position and the lateral approach in the supine position. Methods: A retrospective cohort study was conducted in our hospital, including a total of 66 patients ranging from January 2013 to February 2016, regardless of age or sex. All the patients were classified as Lauge-Hansen supination-external rotation (SER)-type ankle fractures and were assigned to receive an open reduction and internal fixation (ORIF) through a posterolateral approach performed in the prone position (the "posterolateral approach group," 32 patients), or a lateral approach performed in the supine position (the "Lateral Approach Group," 34 patients). In the posterolateral approach group, 5 patients had Grade II fractures, 8 had Grade III fractures, and 19 had Grade IV fractures; among whom, 12 underwent fixation of the posterior malleolus with hollow screws and 6 with plates, and none of them had fixation of the distal tibiofibular syndesmosis; in the lateral approach group, 4 patients had Grade II fractures, 12 had Grade III fractures, and 18 had Grade IV fractures; among whom, 21 received fixation of the posterior malleolus, and 5 received fixation of the distal tibiofibular syndesmosis. The postoperative complications and ankle scores were recorded. Results: After 1 year of follow-up, in the posterolateral approach group, the incision healed by primary intention and sutures were removed 2 weeks after the operation in all patients; 1 patient had pain in the region posterior to the fibula, presumably peroneal tendon irritation induced by internal fixation, which disappeared after fracture union and fixation device removal; no loosening or breakage of the internal fixation device was reported; the rate of good to excellent results was 96.8% at 12 months. In the lateral approach group: 1 case of wound infection, 1 case of necrosis of lateral skin flap, and 3 cases of lateral skin irritation were reported; the rate of good to excellent results was 94.6% at 12 months. Conclusion: Compared with the traditional lateral approach, the posterolateral approach for the reduction and internal fixation of supination-external rotation-type ankle fractures performed in the prone position has more satisfactory clinical outcomes, with better reduction, more secure fixation, and smaller wound.

Movie Events Detecting Reveals Inter-Subject Synchrony Difference of Functional Brain Activity in Autism Spectrum Disorder.

Recently, movie-watching fMRI has been recognized as a novel method to explore brain working patterns. Previous researchers correlated natural stimuli with brain responses to explore brain functional specialization by "reverse correlation" methods, which were based on within-group analysis. However, what external stimuli drove significantly different brain responses in two groups of different subjects were still unknown. To address this, sliding time windows technique combined with inter-Subject functional correlation (ISFC) was proposed to detect movie events with significant group differences between autism spectrum disorder (ASD) and typical development (TD) subjects. Then, using inter-Subject correlation (ISC) and ISFC analysis, we found that in three movie events involving character emotions, the ASD group showed significantly lower ISC in the middle temporal gyrus, temporal pole, cerebellum, caudate, precuneus, and showed decreased functional connectivity between large scale networks than that in TD. Under the movie event focusing on objects and scenes shot, the dorsal and ventral attentional networks of ASD had a strong synchronous response. Meanwhile, ASD also displayed increased functional connectivity between the frontoparietal network (FPN) and dorsal attention network (DAN), FPN, and sensorimotor network (SMN) than TD. ASD has its own unique synchronous response rather than being "unresponsive" in natural movie-watching. Our findings provide a new method and valuable insight for exploring the inconsistency of the brain "tick collectively" to same natural stimuli. This analytic approach has the potential to explore pathological mechanisms and promote training methods of ASD.

15N and 13C{14N} NMR investigation of the major nitrogen-containing segment in an aquatic fulvic acid: evidence for a hydantoin derivative.

A nitrogen-rich segment in a fulvic acid (FA) from Pony Lake, a coastal pond in Antarctica, was investigated by (15)N and (13)C{(14)N} solid-state NMR techniques. As reported previously, the (13)C{(14)N} spectrum of C bonded to N exhibits a peak at 157 ppm that is assigned to an sp(2)-hybridized carbon bonded to at least two nitrogen atoms. This segment contains 48% of all N in the sample. (15)N NMR shows distinct signals, 20 ppm upfield and downfield from the typical peptide resonance; dipolar dephasing confirmed that they are due to protonated N. The well-resolved downfield peak, which accounts for 1/4 of the spectral area, cannot be assigned to aromatic heterocycles, such as purines, because the fraction of aromatic C bonded to N in this sample is very small. Analysis of (15)N chemical-shift trends and (15)N NMR of model compounds, such as arginine and its derivatives, excludes assignment to a guanidinium ion or to substituted guanidino groups. Similarly, ureido groups, -NH-CO-NH-, that are not bonded to a second C = O do not match the observed (15)N peaks in the FA, since both N resonate upfield from the peptide resonance. On the other hand, all chemical shifts are matched within the observed range by the -C(alkyl)-NH-CO-NH-CO-C structure found in two nonaromatic heterocycles, hydantoin and dihydrouracil. The five-membered hydantoin ring, which is found in the purine metabolite allantoin, provides a better match than the six-membered dihydrouracil ring. Regular uracil or thymine fails to produce adequate agreement with observed chemical shifts.

Clinical analysis of 249 cases of adrenal tumors in a Chinese hospital.

OBJECTIVE: This study was designed to evaluate the clinical and pathological characteristics of adrenal masses. METHODS: The clinical data of 249 cases of adrenal masses which were confirmed at operation and by pathology were analyzed. RESULTS: The series comprised 103 males and 146 females. Overall, females were more commonly represented than males, especially with Cushing's syndrome and typical pheochromocytoma (female:male ratio 3.3:1.9), however the prevalence of adrenal incidentalomas (AIs) in males and females was similar. In our series, 148 (59.4%) were symptomatic, of which 4 (2.7%) were malignant, and 101 (40.6%) were incidental, of which 20 (19.8%) were malignant. Hormonal work-up demonstrated that 30.3% of the AIs were functional. Of 109 adrenocortical adenomas, 47 were primary aldosteronism, 31 were Cushing's syndrome, 30 were AIs, and 1 was adrenal virilization. Of 72 benign pheochromocytomas, 51 were typical pheochromocytomas and 21 were AIs. Of 14 adrenal nodular hyperplasias, 6 were Cushing's syndrome and 8 were primary aldosteronism. Of the remaining 30 benign tumors, all presented as AIs. The diameter of malignant tumors (10.9 ± 5.6 cm) was significantly larger than that of benign tumors (4.5 ± 3.7 cm) (p < 0.001). CONCLUSION: This study shows a high rate of AIs in patients with adrenal masses selected for surgery. Hormone levels should be determined in symptomatic or incidental patients with adrenal masses. Imaging examination (CT and MRI) is the first method used to detect and localize adrenal masses. Tumor size is an important parameter of diagnosis and management of patients with adrenal masses, especially AIs.

Nonaromatic core-shell structure of nanodiamond from solid-state NMR spectroscopy.

The structure of synthetic nanodiamond has been characterized by (13)C nuclear magnetic resonance (NMR) spectral editing combined with measurements of long-range (1)H-(13)C dipolar couplings and (13)C relaxation times. The surface layer of these approximately 4.8-nm diameter carbon particles consists mostly of sp(3)-hybridized C that is protonated or bonded to OH groups, while sp(2)-hybridized carbon makes up less than 1% of the material. The surface protons surprisingly resonate at 3.8 ppm, but their direct bonding to carbon is proved by fast dipolar dephasing under homonuclear decoupling. Long-range (1)H-(13)C distance measurements, based on (13)C{(1)H} dipolar dephasing by surface protons, show that seven carbon layers, in a shell of 0.63 nm thickness that contains approximately 60% of all carbons, predominantly resonate more than +8 ppm from the 37-ppm peak of bulk diamond (i.e., within the 45-80 ppm range). Nitrogen detected in (15)N NMR spectra is mostly not protonated and can account for some of the high-frequency shift of carbon. The location of unpaired electrons (approximately 40 unpaired electrons per particle) was studied in detail, based on their strongly distance-dependent effects on T(1,C) relaxation. The slower relaxation of the surface carbons, selected by spectral editing, showed that the unpaired electrons are not dangling bonds at the surface. This was confirmed by detailed simulations, which indicated that the unpaired electrons are mostly located in the disordered shell, at distances between 0.4 and 1 nm from the surface. On the basis of these results, a nonaromatic core-shell structural model of nanodiamond particles has been proposed.

[Construction of GSK-3beta-targeting RNAi adenovirus vector and the influence of Wnt/beta-catenin pathway in proliferation of human thyrocytes].

OBJECTIVE: To construct RNAi recombinant adenoviral expressive vectors specific to glycogen synthase kinase-3beta (GSK-3beta) and to observe its gene knockdown effect on the expression of GSK-3beta, and to explore the effect of Wnt/beta-catenin pathway on the proliferation of human thyrocytes using the RNAi adenovirus vector. METHODS: An adenovirus plasmid that contained the RNAi cassette targeting the GSK-3beta gene was constructed by homologous recombination and cloning techniques, transfected into human embryo kidney (HEK) 293A cells to product adenovirus, and then was used to infect the HEK293A cells to amplify the adenoviral stock. Plaque forming assay was used to titer the adenoviral stock. Normal human thyrocytes fart from thyroid adenoma were obtained during resection of adenoma, cultured, and infected by the GSK-3beta specific RNAi adenovirus. The GSK-3beta gene silencing effect induced by the RNAi adenovirus was detected by Western blotting 0, 24, 48, 72, 120, and 144 hours later. BrdU method was used to detect the cell proliferation. Another HEK293A cells were divided into 3 groups: infected with recombinant adenovirus plasmid Ad-1457, infected with un-recombinant framework plasmid pAd-DEST, and un-infected. 72 hours later Western blotting was used to examine the level of beta-catenin. RESULTS: The GSK-3beta expression of the thyrocytes infected with the recombinant adenovirus plasmid Ad-1457 were significantly lower than those of the thyrocytes infected with Ad-DEST (all P<0.05). The expression of beta-catenin of the thyrocytes infected with Ad-DEST was significantly higher than those of the Ad-DEST group and un-infected group (both P<0.05). BrdU assay suggested that the proliferation rates 1, 3, 5, and 7 days after infection of the thyrocytes infected with Ad1457 plasmid were significantly higher than those of the thyrocytes infected with the plasmid pAd-DEST (all P<0.05). CONCLUSION: RNAi adenovirus is an important tool inhibiting the expression of target gene efficiently. The Wnt/beta-catenin pathway plays an important role in the regulation of proliferation of human thyrocytes.

[Anti-inflammatory activity and healing-promoting effects of topical application of emu oil on wound in scalded rats].

OBJECTIVE: To investigate the effects of topical application of emu oil on wound healing in scalded rats. METHODS: In 144 male Wistar rats with 10%; total body surface superficial II degree scald treated on a random basis with physiological saline, povidone iodine and emu oil, respectively, the changes of the wound were observed and the wound tissue and blood samples harvested at different times after injury for evaluation of histopathological changes, total tissue water content (measured by wet:dry weight ratios), and tumor necrosis factor (TNF)-alpha levels in the wound tissue and plasma by enzyme-linked immunosorbent assay (ELISA). The general condition of the wound healing was also observed. RESULTS: After application of emu oil, the swelling and effusion of the burn wound were alleviated and evidences of wound infection or adverse effects were not observed. Pathological examination showed that emu oil could alleviate topical inflammation, which was particularly obvious on days 1 and 3 after injury as compared with the other two groups. On day 3 after injury, water content and TNF-alpha level in the tissues was markedly decreased with the application of emu oil (P<0.05), with a significant correlation between their changes (P<0.001) and shortened wound healing time (P<0.05). Pathological examination showed that emu oil could promote epithelialization and differentiation of various epidermal layers. CONCLUSION: Emu oil has topical anti-inflammatory activity in rats with superficial II degree scald, possibly in association with decreased levels of the proinflammatory cytokines in the tissues and can promote wound healing by inhibiting local secondary inflammation.

Spectrally edited 2D 13C-13C NMR spectra without diagonal ridge for characterizing 13C-enriched low-temperature carbon materials.

Two robust combinations of spectral editing techniques with 2D (13)C-(13)C NMR have been developed for characterizing the aromatic components of (13)C-enriched low-temperature carbon materials. One method (exchange with protonated and nonprotonated spectral editing, EXPANSE) selects cross peaks of protonated and nearby nonprotonated carbons, while the other technique, dipolar-dephased double-quantum/single-quantum (DQ/SQ) NMR, selects signals of bonded nonprotonated carbons. Both spectra are free of a diagonal ridge, which has many advantages: Cross peaks on the diagonal or of small intensity can be detected, and residual spinning sidebands or truncation artifacts associated with the diagonal ridge are avoided. In the DQ/SQ experiment, dipolar dephasing of the double-quantum coherence removes protonated-carbon signals; this approach also eliminates the need for high-power proton decoupling. The initial magnetization is generated with minimal fluctuation by combining direct polarization, cross polarization, and equilibration by (13)C spin diffusion. The dipolar dephased DQ/SQ spectrum shows signals from all linkages between aromatic rings, including a distinctive peak from polycondensed aromatics. In EXPANSE NMR, signals of protonated carbons are selected in the first spectral dimension by short cross polarization combined with dipolar dephasing difference. This removes ambiguities of peak assignment to overlapping signals of nonprotonated and protonated aromatic carbons, e.g. near 125 ppm. Spin diffusion is enhanced by dipolar-assisted rotational resonance. Before detection, C-H dipolar dephasing by gated decoupling is applied, which selects signals of nonprotonated carbons. Thus, only cross peaks due to magnetization originating from protonated C and ending on nearby nonprotonated C are retained. Combined with the chemical shifts deduced from the cross-peak position, this double spectral editing defines the bonding environment of aromatic, COO, and C=O carbons, which is particularly useful for identifying furan and arene rings. The C=O carbons, whose chemical shifts vary strongly (between 212 and 165 ppm) and systematically depend on their two bonding partners, show particularly informative cross peaks, given that one bonding partner is defined by the other frequency coordinate of the cross peak. The new techniques and the information content of the resulting spectra are validated on sulfuric-acid treated low-temperature carbon materials and on products of the Maillard reaction. The crucial need for spectral editing for correct peak assignment is demonstrated in an example.

Alkyl and other major structures in (13)C-labeled glucose-glycine melanoidins identified by solid-state nuclear magnetic resonance.

The high molecular weight fraction of melanoidins formed in the Maillard reaction between isotopically labeled glucose and glycine has been characterized comprehensively using advanced (13)C and (15)N solid-state NMR with spectral editing. We have focused on the fate of glucose in a 1:1 molar ratio with glycine, heated as a coprecipitated powder at 125 °C for 2 h. Quantitative (13)C NMR spectra show that aromatic and alkene carbons make up only 40% of the total in the melanoidin. Spectra of melanoidins made from specifically labeled ((13)C1, (13)C2, (13)C3, and (13)C6) glucose are strikingly different, proving that specific structures of various types are formed. More than half of the glucose-C1 carbons form new C-C bonds, not just C-O and C-N bonds. Most C2 carbons are bonded to N or O and not protonated, while C3 shows the reverse trends. C4 and C5 remain significantly in alkyl OCH sites or become part of heterocyclic aromatic rings. C6 undergoes the least transformation, remaining half in OCH(2) groups. Functional groups characteristic of fragmentation are relatively insignificant, except for N/O-C2 ═ O groups indicating some C(1) + C(5) and C(2) + C(4) fragmentation. On the basis of (13)C-(13)C and (15)N-(13)C correlation spectra, 11 "monomer units" have been identified, including several types of alkyl chain or ring segments, furans, pyrroles, imidazoles, and oxazoles; these are mixed on the nanometer scale. This complexity explains why simple models cannot represent the structure of melanoidins. While none of the "monomer units" represents more than 15% of all C, the 11 units identified together account for more than half of all glucose carbon in the melanoidin.

Fate of the amino acid in glucose-glycine melanoidins investigated by solid-state nuclear magnetic resonance (NMR).

The fate of the amino acid in the model Maillard reaction between glucose and glycine in a 1:1 molar ratio has been investigated by applying advanced 13C and 15N solid-state nuclear magnetic resonance (NMR) techniques to 13C- and 15N-labeled melanoidins formed in dry and solution reactions. Quantitative 13C NMR shows that approximately 23% of carbon is from glycine; the approximately 2% loss compared to the 25% glycine C in the reactants is due to the COO moiety being liberated as CO2 (Strecker degradation). 13C J-modulation experiments on melanoidins made from doubly 13C-labeled glycine show that the C-C backbone bond of about two-thirds of the incorporated amino acid stays intact, and about half of all glycine is incorporated as N-CH2-COO without fragmentation. Degradation processes without CO2 loss affect about one-eighth of glycine in dry reaction and about one-fourth in solution. These results indicate that Strecker degradation affects about one-fourth (dry reaction) to one-third (in solution) of all glycine but is not the main pathway of glycine incorporation. Spectra of Strecker degradation products show that C2 of glycine reacts to form N-CH3, C-CHn-C, or aromatic units, but not pyrazines or pyridines. The gycine-C1 carbon incorporated into the melanoidins remains>or=90% part of COO moieties; approximately 5% of amides have also been detected. The C2-N bond stays intact for approximately 70% of the incorporated glycine. The 15N spectra show many peaks, over a 200 ppm range, documenting a multitude of different chemical environments of nitrogen, but no enamines or imines. The majority (>78%) of nitrogen, in particular most pyrrolic N, is not protonated. Because N-H predominates in amino acids and proteins, nonprotonated nitrogen may be a characteristic marker of Maillard reaction products.

Ablation of NF-kappaB expression by small interference RNA prevents the dysfunction of human umbilical vein endothelial cells induced by high glucose.

Diabetes is a major independent risk factor for cardiovascular disease and stroke. High glucose (HG) reduces endothelial cell (EC) proliferation with a concomitant increase in apoptosis. HG also induces the translocation of nuclear factor (NF)-kappaB in human umbilical vein endothelial cells (HUVECs). However, data regarding the relationship between NF-kappaB signaling and HG-induced endothelial dysfunction are limited. In the present study, we constructed an NF-kappaB-targeting RNA interference (RNAi) adenovirus vector and cultured HUVECs in 5.5, 20.5, or 30.5 mM D: -glucose or in daily alternating 5.5 or 30.5 mM D: -glucose. We assessed the effects of the NF-kappaB pathway on proliferation under HG conditions by measuring bromodeoxyuridine incorporation and conducting methyl thiazolyltetrazolium assays. We also tested apoptosis by performing flow cytometry and terminal deoxynucleotidyl transferase nick-end labeling assay. The RNAi adenovirus effectively downregulated expression of the p65 protein in HUVECs for more than 6 days. Blockage of the NF-kappaB pathway with the RNAi adenovirus substantially protected HUVECs from decreased proliferation and reduced cellular apoptosis in HG conditions. These findings may explain how hyperglycemia promotes dysfunction of ECs and could elucidate a potential new target for therapeutic interventions.

Culture differences in design of portal sites.

Two experiments were carried out to examine the effects of cultural differences between the Chinese and the US people on the perceived usability and search performance of World Wide Web (WWW) portal sites. Chinese users in Taiwan and US users in Chicago were recruited to perform searching tasks on two versions of Yahoo! portal site: the standard Yahoo! and Yahoo! Chinese. The layout of Yahoo! Chinese is the same as the layout of Yahoo!, and categories on Yahoo! Chinese have been translated from its US counterpart. A special browser was programmed to record all the keystroke data and participants were asked to fill out a satisfaction questionnaire after finishing the tasks. Significant differences of satisfaction and steps to perform some tasks were found between the two groups. The experiment results also provided more detailed insights into the cultural differences between the Chinese and the US users.