Objective To gain insights into the biological characteristics of different populations of Culex tritaeniorhynchus within and around the Yellow Sea wetland from the perspective of the occurrence of resistance, we investigated the levels of resistance to deltamethrin and kdr gene mutation in the wetland and its peripheral areas. Methods Specimens were collected from Cx. tritaeniorhynchus populations at two monitoring sites in the Rare Bird National Nature Reserve and Tiaozi Ni Wetland Scenic Area, and also from two populations in Yancheng City and the Liuhe District of Nanjing, and the resistance of these mosquitoes to deltamethrin was determined using the CDC biotest bottle method. For each concentration of deltamethrin assessed, a random subset of exposed specimens was selected for amplification of the kdr gene fragment, followed by Sanger sequencing to identify and analyze resistance-associated mutations. Results The LC50 levels of deltamethrin among mosquitoes from the four populations in Luhe, Yancheng, the Rare Bird National Nature Reserve and the Tiaozi Ni Wetland Scenic Area were 2.048 5, 7.798 2, 3.473 3, and 17.695 5 mg/mL, respectively, with corresponding concentrations of deltamethrin ranging from 0.005 to 5.000,0.050 to 50.000,0.050 to 25.000 and 0.050 to 50.000 mg/mL, respectively. Furthermore, the ranges of the KT50 values were 11.76-107.43, 67.05-216.30,29.77-107.43 and 28.40-329.51 min; the 1-h knockdown rates were 34.58%-99.15%, 9.52%-43.80%, 55.09%-73.01%, and 10.09%-68.07%; and the 24-h mortality rates were 12.15%-67.52%,9.52%-79.56%,13.17%-82.21%, and 11.01%-78.99%, respectively. With respect to kdr gene mutation, we assayed a total of 63,70,59, and 57 mosquitoes for the four populations, for which we detected L1014F mutation frequencies of 14.29%, 35.00%, 20.34%, and 31.58%, respectively, with a majority of these mutations being heterozygous for resistance. In addition, five adult mosquitoes were identified has having synonymous mutations at site 1011[i. e. , AAT(asparagine)mutation to AAC(asparagine)]. Conclusions Our findings revealed the clear resistance of Cx. tritaeniorhynchus to deltamethrin in the Yancheng region of the Yellow Sea wetland, and the resistance phenotype and kdr frequency of Cx. tritaeniorhynchus in the wetland environment were comparable to those of Cx. tritaeniorhynchus in the wetland environment, thereby indicating that the resistance of different populations of Cx. tritaeniorhynchus was homogeneous under the pressure of different insecticide selection within and around the wetland. However, the underlying mechanisms need to be further studied.

Objective To analyze the global burden of occupational noise-induced hearing loss (ONHL) from 1990 to 2021 and to predict its trends for 2025 to 2035. Methods Data on disability-adjusted life years (DALYs), age-standardized DALYs rates, and summary exposure values for ONHL were extracted from the Global Burden of Disease database. An age-period-cohort model was used to assess age, period, and cohort effects. Joinpoint regression was applied to calculate the annual percentage change in ASDRs. An autoregressive integrated moving average (ARIMA) model was employed to forecast DALY trends from 2025 to 2035. Results Global DALYs attributable to ONHL increased from 3.838 1 million person-years in 1990 to 7.847 4 million person-years in 2021, representing a 104.46% increase. DALYs attributable to ONHL increased by 64.93%, 94.30%, 111.51%, 114.64%, and 129.08% in high-, high-middle-, middle-, low-middle-, and low-Socio-demographic Index (SDI) regions, respectively. DALYs counts were consistently higher in males than in females. DALYs counts peaked in the older age group (60-64 years), whereas the DALYs rate of peaked in the older age group (70-74 years). Age-period-cohort model analysis revealed significant overall age effects in all five SDI regions (all P<0.01). There were a significant overall period and cohort effects in the high-middle SDI region (all P<0.01), but not in the other regions (all P>0.05). The ARIMA model projected that global DALYs due to ONHL would reach 9.650 0 million person-years by 2035, an increase of 22.97% compared with 2021, with the largest increase expected among individuals aged 55-59 years. Conclusion The global burden of ONHL has continuously increased from 1990 to 2021, particularly among male workers in low-SDI regions. This burden is expected to continue rising over the next decade.

OBJECTIVE: To compare the short-term clinical efficacy and safety of closed reduction with Kirschner wire fixation versus open reduction with plate fixation for treating osteoporotic Colles' fractures in middle-aged and elderly patients. METHODS: Between January 2018 and January 2023, 119 patients with Colles fractures were retrospectively analyzed, including 39 males and 80 females, aged from 48 to 74 years old with an average of(60.58±6.71) years old. The time from injury to operation ranged 1 to 13 days with an average of (5.29±2.52) days. According to the surgical method, they were divided into Kirschner wire fixation group (Kirschner wire group) and plate internal fixation group (plate group). In Kirschner wire group, there were a total of 68 patients, comprising 21 males and 47 females. The average age was (61.15±6.24) years old, ranged from 49 to 74 years old. Among them, 41 cases involved the left side while 27 cases involved the right side. In the plate group, there were a total of 51 patients, including 18 males and 33 females. The average age was (59.78±5.71) years old ranged from 48 to 72 years old. Among them, there were 31 cases on the left side and 20 cases on the right side. The following parameters were recorded before and after the operation:operation time, intraoperative blood loss, hospitalization days, hospitalization expenses, postoperative complications, and radiographic parameters of distal radius (distal radius height, ulnar deviation angle, palmar tilt angle). The clinical efficacy was evaluated at 3 and 12 months after the operation using Gartland-Werley and disabilites of the arm shoulder and hand (DASH) scores. RESULTS: The patients in both groups were followed up for a duration from 12 to 19 months with an average of(13.32±2.02) months. The Kirschner wire group exhibited significantly shorter operation time compared to the plate group 27.91(13.00, 42.00) min vs 67.52(29.72, 105.32) min, Z=-8.74, P=0.00. Intraoperative blood loss was also significantly lower in the Kirschner wire group than in the plate group 3.24(1.08, 5.40) ml vs 21.91(17.38, 26.44) ml, Z=-9.31, P=0.00. Furthermore, patients in the Kirschner wire group had a shorter length of hospital stay compared to those in the plate group (8.38±2.63) days vs (11.40±2.78) days, t=-3.12, P=0.00. Additionally, hospitalization cost was significantly lower in the Kirschner wire group than in the plate group 10 111.29(6 738.98, 13 483.60) yuan vs 15 871.11(11 690.40, 20 051.82) yuan, Z=-5.62, P=0.00. The incidence of complications was 2 cases in the Kirschner wire group and 1 case in the plate group, with no statistically significant difference(P>0.05). At 3 months postoprative, the radial height of the Kirschner wire group was found to be significantly smaller than that of the plate group, with measurements of (11.45±1.69) mm and (12.11±1.78) mm respectively (t=-2.06, P=0.04). However, there were no statistically significant differences observed in ulnar deviation angle and palmar tilt angle between the two groups (P>0.05). The DASH score and Gartland-Werley score in the Kirschner group were significantly higher than those in the plate group at 3 months post-operation (19.10±9.89) vs (13.47±3.51), t=4.34, P=0.00;(11.15±3.61) vs (6.41±2.75), t=8.13, P=0.00). However, there was no significant difference between the two groups at 12 months post-operation (P>0.05). CONCLUSION Compared to plate internal fixation, closed reduction with Kirschner wire support fixation yields a slightly inferior recovery of radial height;however, there is no significant disparity in the functional score of the affected limb at 12 months post-operation. Nonetheless, this technique offers advantages such as shorter operation time, reduced intraoperative blood loss, decreased hospitalization duration, and lower cost.
Humans ; Female ; Male ; Middle Aged ; Aged ; Fracture Fixation, Internal/instrumentation* ; Bone Wires ; Bone Plates ; Retrospective Studies ; Colles' Fracture/surgery* ; Minimally Invasive Surgical Procedures/methods* ; Open Fracture Reduction/methods* ; Osteoporotic Fractures/surgery*

OBJECTIVE: To explore clinical effect of bone cement-strengthened pedicle screw technique in the correction of stage Ⅲ asymptomatic Kümmell disease with kyphosis. METHODS: A retrospective analysis was conducted on clinical data of 40 asymptomatic stage Ⅲ Kümmell disease patients admitted between March 2019 and December 2021, including 15 males and 25 females, aged from 61 to 81 years old with an average of (67.4±5.2) years old;according to different surgical methods, they were divided into percutaneous kyphoplasty group (PKP) and reinforced screw group. There were 18 patients in PKP group, including 7 males and 11 females, aged from 61 to 78 years old with an average of (66.2±5.5) years old;the courses of disease ranged from 5 to 12 months with an average of (7.33±1.78) months;bone mineral density(BMD) T values ranged from -2.45 to -4.00 with an average of (-3.08±0.46);2 patients with T₈-T₉, 10 patients with T₁₀-T₁₂, and 6 patients with L₁-L₂;treated with PKP. There were 22 patients in reinforced screw group, including 8 males and 14 females, aged from 65 to 81 years old with an average of (68.5±3.8) years old;the courses of disease ranged from 4 to 15 months with an average of (7.86±2.73)months;bone mineral density(BMD) T values ranged from -2.40 to -4.50 with an average of (-3.18±0.54);3 patients with T₈-T₉, 12 patients with T₁₀-T₁₂, and 7 patients with L₁-L₂;treated with bone cement reinforced pedicle screw internal fixation combined with kyphoplasty. Cobb angle and anterior margin height of the injured vertebra were compared before operation, 3 d and 12 months after operation. Visual analogue scale (VAS) and Oswestry disability index (ODI) were compared between two groups before operation and 12 months after operation. The incidence of postoperative complications was compared between two groups. RESULTS: All patients were followed up, PKP group followed up for 11 to 14 months with an average of (11.97±0.96) months and 10 to 14 months with an average of (12.05±1.09) months in reinforced screw group;there was no significant difference between two groups (P>0.05). Postoperative Cobb angle at 3 days and 12 months in reinforced screw group were (7.34±2.26) ° and (18.86±1.96) °, while in PKP group were (18.88±1.89) ° and (23.28±1.90) °;there were statistical difference between two groups (P<0.05). The anterior margin height of the injured vertebra in reinforced screw group were (25.28±1.33) mm and (19.62±2.22) mm at 3 days and 12 months after operation, while in PKP group were (18.61±2.16) mm and(15.93±1.34) mm;there were statistical difference between two groups (P<0.05). Cobb angle and the anterior margin height of the injured vertebra were significantly improved at 3 days and 12 months after operation between two groups (P<0.05). Postoperative VAS and ODI at 12 months in PKP group were (2.00±0.69) score and (13.44±4.02)%, while in reinforced screw group were(1.91±0.61) score and (10.18±4.26)%;which were significantly lower than (6.89±0.76) score and (36.33±3.40)% in PKP group, (7.23±0.75) score and (37.09±3.73) % in reinforced screw group before operation. There were no difference in postoperative VAS between two groups at 12 months (P>0.05);postoperative ODI in reinforced screw group at 12 months was lower than that in PKP group(P<0.05). There was no significant difference in complications between two groups (χ²=0.071, P>0.05). CONCLUSION PKP and bone cement reinforced nail combined with PKP could improve kyphotic deformity and postoperative function, and relieve pain. The application of bone cement-reinforced nail fixation technology could provide a more stable support, more obvious functional recovery, lower the risk of re-collapse of the injured vertebra, and maintain the long-term stability of spine.
Humans ; Male ; Female ; Aged, 80 and over ; Kyphosis/surgery* ; Aged ; Bone Cements ; Middle Aged ; Retrospective Studies ; Pedicle Screws ; Spinal Fractures/surgery* ; Fracture Fixation, Internal/methods* ; Bone Screws ; Kyphoplasty

OBJECTIVE: To retrospectively analyze the clinical characteristics, co-mutated genes in newly diagnosed acute myeloid leukemia (AML) patients with NRAS and KRAS gene mutations, and the impact of NRAS and KRAS mutations on prognosis. METHODS: The clinical data and next-generation sequencing results of 80 newly diagnosed AML patients treated at our hospital from December 2018 to December 2023 were collected. The clinical characteristics, co-mutated genes of NRAS and KRAS , and the impact of NRAS and KRAS mutations on prognosis in newly diagnosed AML patients were analyzed. RESULTS: Among 80 newly diagnosed AML patients, NRAS mutations were detected in 20 cases(25.0%), and KRAS mutations were detected in 9 cases(11.3%). NRAS mutations predominantly occurred at codons 12 and 13 of exon 2, as well as codon 61 of exon 3, while KRAS mutations were most commonly occurred at codons 12 and 13 of exon 2, all of which were missense mutations. There were no statistically significant differences observed in terms of age, sex, white blood cell count(WBC), hemoglobin(Hb), platelet count(PLT), bone marrow blasts, first induction chemotherapy regimen, CR1/CRi1 rates, chromosome karyotype, 2022 ELN risk classification and allogeneic hematopoietic stem cell transplantation(allo-HSCT) among the NRAS mutation group, KRAS mutation group and NRAS/KRAS wild-type group (P >0.05). KRAS mutations were significantly correlated with PTPN11 mutations (r =0.344), whereas no genes significantly associated with NRAS mutations were found. Survival analysis showed that compared to the NRAS/KRAS wild-type group, patients with NRAS mutation had a relatively higher 5-year overall survival (OS) rate and relapse-free survival (RFS) rate, though the differences were not statistically significant (P =0.097, P =0.249). Compared to the NRAS/KRAS wild-type group, patients with KRAS mutation had a lower 5-year OS rate and RFS rate, with no significant differences observed (P =0.275, P =0.442). There was no significant difference in the 5-year RFS rate between the KRAS mutation group and NRAS mutation group (P =0.157), but the 5-year OS rate of patients with KRAS mutation was significantly lower than that of patients with NRAS mutation (P =0.037). CONCLUSION In newly diagnosed AML patients, KRAS mutation was significantly correlated with PTPN11 mutation. Compared to patients with NRAS/KRAS wild-type, those with NRAS mutation showed a more favorable prognosis, while patients with KRAS mutation showed a poorer prognosis; however, these differences did not reach statistical significance. Notably, the prognosis of AML patients with KRAS mutation was significantly inferior compared to those with NRAS mutation.
Humans ; Leukemia, Myeloid, Acute/diagnosis* ; Mutation ; Prognosis ; Proto-Oncogene Proteins p21(ras)/genetics* ; GTP Phosphohydrolases/genetics* ; Retrospective Studies ; Membrane Proteins/genetics* ; Female ; Male ; Middle Aged ; Adult ; Aged

Objective To investigate the effect of dorsal repulsive axon guidance protein(Draxin)on the migration of trunk neural crest cells during the early development of embryonic mouse spinal cord.Methods Immunohistochemistry and in situ hybridization were used to detect the expression characteristics of Draxin in early embryonic spinal cord(8 mice each group);In situ hybridization was used to detect the change of migration characteristics of trunk neural crest cells in early embryonic spinal cord of different types of mouse(5 mice each group);in vitro culture method was used to check the effect of Draxin on the migration characteristics of embryonic mouse trunk neural crest cells(16 mice each group).Resultsβ-galactosidase gene Z(LacZ)gene was introduced when Draxin gene was knocked out to produce Draxin gene knockout mice.β-galactosidase staining was used to detect LacZ gene expression in Draxin knockout embryonic mice,and the result showed that Draxin expression was observed in the spinal cord of early embryonic mice since 9.5 days(E9.5).Draxin expression was obvious in the embryonic mice spinal cord in E10.5 period.In situ hybridization was used to detect the expression of Draxin gene in the spinal cord of wild type embryonic mice,and the result further verified the obvious expression of Draxin in the early embryonic mice spinal cord in El0.5 period.Sox10 in situ hybridization was used to detect neural crest cell migration in the spinal cord of embryonic mice in E10.5 period.The result showed that segmental migration of neural crest cells in the early embryonic spinal cord of some Draxin knockout mice was delayed compared with the wild type mice.The effect of Draxin on the migration of wild type early embryonic mice trunk neural crest cells in vitro was tested.The result showed that Draxin reduced the migration distance of neural crest cells in vitro.Conclusion In the early developmental stage of embryonic spinal cord(E9.5-E10.5),neural crest cells migrated exuberant.At the same time,Draxin plays an important inhibitory function in the formation of the specific migration pathways of trunk neural crest cells by promoting neural crest cells migrating away from Draxin expressing regions.

The purpose of the present study was to investigate the effects of resistance combined with aerobic chrono-exercise on the common carotid artery elasticity and hemodynamics. 24 healthy young men (21.96±0.43 years old) underwent a single acute resistance combined with aerobic exercise intervention at eight time periods (6, 8, 10, 12, 14, 16, 18, and 20 o'clock). The axial flow velocity and diameter waveforms of the common carotid artery were measured, and the hemodynamics were calculated using the classical hemodynamic theory before exercise, immediately after exercise, 10 min and 20 min after exercise. The results showed that during exercise recovery, systolic and mean pressures decreased more markedly after exercise at 8 o'clock (P < 0.05); At 20 min post-exercise, arterial stiffness index and pressure-strain elastic modulus after exercise at 6 o'clock were reduced compared with the resting state, but were significantly elevated after exercise at 20 o'clock (P < 0.05). Immediately after exercise, the pressure rise was higher after exercise at 6 o'clock and the mean wall shear stress was higher after exercise at 20 o'clock (P < 0.05). These results suggest that resistance combined with aerobic chrono-exercise produces different effects on common carotid artery hemodynamics in young men. A single acute session of resistance combined with aerobic exercise at 8 o'clock is more effective in lowering blood pressure. Exercise at 6 o'clock is beneficial to improve arterial elasticity but is not recommended for young male individuals with cardiovascular disease risks because of the excessive increase in blood pressure immediately after exercise. Exercise at 20 o'clock is more effective in improving wall shear stress but is accompanied by elevated arterial stiffness indices and pressure-strain elastic modulus. These results provide a scientific basis for healthy young men in choosing the time of exercise by exploring the common carotid artery elasticity and hemodynamic-related indices.
Humans ; Male ; Young Adult ; Exercise/physiology* ; Carotid Artery, Common/physiology* ; Hemodynamics/physiology* ; Vascular Stiffness/physiology* ; Elasticity ; Resistance Training ; Adult

Jiuwei Xifeng Granules have become a Chinese patent medicine in the market. Because the formula contains Os Draconis, a top-level protected fossil of ancient organisms, the formula was to be improved by replacing Os Draconis with Ostreae Concha. To evaluate whether the improved formula has the same effectiveness and safety as the original formula, a randomized, double-blind, parallel-controlled, equivalence clinical trial was conducted. This study enrolled 288 tic disorder(TD) of children and assigned them into two groups in 1∶1. The treatment group and control group took the modified formula and original formula, respectively. The treatment lasted for 6 weeks, and follow-up visits were conducted at weeks 2, 4, and 6. The primary efficacy endpoint was the difference in Yale global tic severity scale(YGTSS)-total tic severity(TTS) score from baseline after 6 weeks of treatment. The results showed that after 6 weeks of treatment, the declines in YGTSS-TSS score showed no statistically significant difference between the two groups. The difference in YGTSS-TSS score(treatment group-control group) and the 95%CI of the full analysis set(FAS) were-0.17[-1.42, 1.08] and those of per-protocol set(PPS) were 0.29[-0.97, 1.56], which were within the equivalence boundary [-3, 3]. The equivalence test was therefore concluded. The two groups showed no significant differences in the secondary efficacy endpoints of effective rate for TD, total score and factor scores of YGTSS, clinical global impressions-severity(CGI-S) score, traditional Chinese medicine(TCM) response rate, or symptom disappearance rate, and thus a complete evidence chain with the primary outcome was formed. A total of 6 adverse reactions were reported, including 4(2.82%) cases in the treatment group and 2(1.41%) cases in the control group, which showed no statistically significant difference between the two groups. No serious suspected unexpected adverse reactions were reported, and no laboratory test results indicated serious clinically significant abnormalities. The results support the replacement of Os Draconis by Ostreae Concha in the original formula, and the efficacy and safety of the modified formula are consistent with those of the original formula.
Adolescent ; Child ; Child, Preschool ; Female ; Humans ; Male ; Double-Blind Method ; Drugs, Chinese Herbal/therapeutic use* ; Tic Disorders/drug therapy* ; Treatment Outcome

This paper aimed to explore the intestinal toxicity of Euphoriae Ebracteolata Radix(EER) before and after being processed with Mongolian medicine Hezi Decoction(HZD) and the toxicity-reducing mechanism of this processing method. The intestinal toxicity in rats treated with unprocessed EER and HZD-processed EER extracts via 95% ethanol was compared. The comparison was based on several indicators, including fecal volume, serum diamine oxidase(DAO) and D-lactate(D-LA) levels, the water content of various intestinal segments and their contents, and inflammatory factor levels in intestinal segments. Tandem mass tag(TMT) quantitative proteomics technology was employed to analyze the key proteins associated with changes in intestinal toxicity between unprocessed EER and HZD-processed EER. The results indicated that compared with the blank group, unprocessed EER significantly increased the fecal volume, serum DAO and D-LA levels, water content of the ileal segment and its contents, as well as the release levels of inflammatory factors, including tumor necrosis factor(TNF-α) and interleukin-1 beta(IL-1β) in the ileal segment of rats(P<0.05), indicating that EER can cause diarrhea, increase intestinal permeability, and induce intestinal inflammation. Compared with those in the unprocessed EER group, all indicators in the HZD-processed EER group were significantly reduced(P<0.05). The TMT quantitative proteomics analysis revealed that a total of 6 487 proteins were identified in the rat ileum tissue. Compared to the blank group, 182 proteins exhibited significant changes in the unprocessed EER group, while 907 proteins in the HZD-processed EER group showed significant changes. The intersection of the differential proteins between the two groups identified 38 common proteins. Among them, the protein levels of intestinal barrier tight junction protein claudin3, squalene monooxidase(Sqle), clusterin, Na~+/H~+ exchange regulatory cofactor NHE-RF3(Pdzk1), and Y+L amino acid transporter 1(Slc7a7) exhibited significant changes before and after processing, and these changes were closely related to intestinal barrier function. Compared with the blank group, the expression of claudin3, Pdzk1, and Slc7a7 in the raw product group was significantly down-regulated(P<0.05),while the expression of Sqle and clusterin was significantly up-regulated(P<0.05).Compared with the raw product group, the expression of claudin3, Pdzk1, and Slc7a7 in the processed product group of HZD was significantly up-regulated(P<0.05), while the expression of Sqle and clusterin was significantly down-regulated(P<0.05). Western blot was used to detect the expression level of claudin 3 in the ileum of rats in each group. The results show that compared to that in the blank group, the expression level of claudin 3 in the unprocessed EER group was significantly reduced(P<0.01); compared to that in the unprocessed EER group, the expression level of claudin 3 in the HZD-processed EER group was significantly increased(P<0.01). This finding aligned with the proteomic outcomes, indicating that claudin 3 protein levels could serve as a crucial indicator for intestinal damage caused by EER. In summary, HZD-processed EER can reduce EER's intestinal toxicity, and the primary mechanism for its alleviation of intestinal barrier damage is the regulation of the intestinal barrier tight junction protein claudin 3 and other intestinal-related proteins.
Animals ; Drugs, Chinese Herbal/adverse effects* ; Proteomics ; Rats ; Male ; Rats, Sprague-Dawley ; Intestines/drug effects* ; Intestinal Mucosa/drug effects* ; Tumor Necrosis Factor-alpha/metabolism*

By employing the analytic hierarchy process(AHP), the CRITIC method(a weight determination method based on indicator correlations), and the AHP-CRITIC hybrid weighting method, the weight coefficients of evaluation indicators were determined, followed by a comprehensive score comparison. The grey correlation analysis was then performed to analyze the results calculated using the hybrid weighting method. Subsequently, a backpropagation-artificial neural network(BP-ANN) model was constructed to predict the extraction process parameters and optimize the extraction process for Shenxiong Huanglian Jiedu Granules(SHJG). In the extraction process, an L_9(3~4) orthogonal experiment was designed to optimize three factors at three levels, including extraction frequency, water addition amount, and extraction time. The evaluation indicators included geniposide, berberine, ginsenoside Rg_1 + Re, ginsenoside Rb_1, ferulic acid, and extract yield. Finally, the optimal extraction results obtained by the orthogonal experiment, grey correlation analysis, and BP-ANN method were compared, and validation experiments were conducted. The results showed that the optimal extraction process involved two rounds of aqueous extraction, each lasting one hour; the first extraction used ten times the amount of added water, while the second extraction used eight times the amount. In the validation experiments, the average content of each indicator component was higher than the average content obtained in the orthogonal experiment, with a higher comprehensive score. The optimized extraction process parameters were reliable and stable, making them suitable for subsequent preparation process research.
Drugs, Chinese Herbal/analysis* ; Neural Networks, Computer