An SIS epidemic model with the standard incidence rate and saturated treatment func- tion is proposed. The dynamics of the system are discussed, and the effect of the capacity for treatment and the recruitment of the ...An SIS epidemic model with the standard incidence rate and saturated treatment func- tion is proposed. The dynamics of the system are discussed, and the effect of the capacity for treatment and the recruitment of the population are also studied. We find that the effect of the maximum recovery per unit of time and the recruitment rate of the popula- tion over some level are two factors which lead to the backward bifurcation, and in some cases, the model may undergo the saddle-node bifurcation or Bogdanov-Takens bifurca- tion. It is shown that the disease-free equilibrium is globally asymptotically stable under some conditions, Numerical simulations are consistent with our obtained results in the- orems, which show that improving the efficiency and capacity of treatment is important for control of disease.展开更多
A mathematical model describing the epidemic interactions between humans and blackflies in the transmission of onchocerciasis is considered.In this model,the onchocerciasis infected human individuals are divided into ...A mathematical model describing the epidemic interactions between humans and blackflies in the transmission of onchocerciasis is considered.In this model,the onchocerciasis infected human individuals are divided into two classes of infected humans with high and low microfilarial output incorporating saturated treatment function,which caters for high saturation of onchocerciasis disease.We analyze the model feasible region and obtain the basic reproduction number(R_(hb))using the next generation matrix method.Also,we obtain the onchocerciasis-free and onchocerciasis endemic equilibrium solutions and show that if R_(hb) is less than unity,the onchocerciasis-free equilibrium is locally and globally asymptotically stable.Furthermore,we employed a Lyapunov function to analyze the global asymptotic stability of the onchocerciasis—endemic equilibrium whenever Rhb is greater than unity.In addition,data on mass drug distribution of ivermectin drug to combat onchocerciasis prevalence in Ekiti state of Nigeria were fitted to the model.Graphical results reveal that consistent annual or bi-annual distribution of ivermectin drug in the region is effective in reducing the disease menace.Further simulations also show that public health control measures are needed to minimize infectious contact between humans and blackflies which leads to onchocerciasis infections and visual blindness.展开更多
In this paper,we study a network-based SIR epidemic model with a saturated treatment function in which a parameterαis introduced to measure the extent of the effect of the infected being delayed for treatment.Our aim...In this paper,we study a network-based SIR epidemic model with a saturated treatment function in which a parameterαis introduced to measure the extent of the effect of the infected being delayed for treatment.Our aim is to present a global analysis and to investigate how the parameterαaffects the spreading of diseases.Our main results are as follows:(1)In the case of the threshold value R_(0)<1,there exist two values of α:α_(c) and α_(0),such that the disease-free equilibrium is globally asymptotically stable when α≤α_(0) and multiple endemic equilibria exist when α≥α_(0).This means that the parameterαhas an essential infuence on the spreading of the disease.(2)In the case of the threshold value R_(0)>1,if the model has only one endemic equilibrium,then the unique endemic equilibrium is globally attractive.In this case,it is also proved that if α≤α_(c),then the endemic equilibrium has only one,so is globally attractive,In addition,numerical simulation is performed to illustrate our theoretical results.展开更多
Objective:To compare the effect of surgical intervention on functional treatment.Methods: By searching the MEDLINE(1966 to October 2011),EMBASE(1980 to October 2011),the Chinese Biomedical Database Databases(1980 to O...Objective:To compare the effect of surgical intervention on functional treatment.Methods: By searching the MEDLINE(1966 to October 2011),EMBASE(1980 to October 2011),the Chinese Biomedical Database Databases(1980 to October 2011),a total of 9 related RCT studies comparing surgical intervention with functional treatment were included in our study.RevMan software was taken to analyze the data.Results:These 9 studies Involved a total of 1 268 mostly young adults,including 580 patients with surgical treatment and 688 patients with functional treatment.The results showed the stability of ankle activity in surgical treatment group was better than that in functional treatment group,with the OR and 95%CI of 0.72(0.52-0.99).No significant difference was found in the recurrence of the surgical and functional group.However, the movement disorder in the surgical treatment suggested increased risk than that in functional group,with the OR and 95%CI of 2 39(0.98-5.85).Surgical group found more complication than the function group,such as deep vein thrombosis,deep venous thrombosis,tenderness of scar and sensory loss.Conclusions:In conclusion,our finding showed that surgical treatment could gain better efficacy than functional treatment,but may bring more complication.Therefore,further large sample size RCT is warranted.展开更多
Congenital cataract is a common cause of childhood low vision or blindness worldwide..Early surgery should be performed in sensitive vision development period to avoid vision deprivation in cases of strabismus and nys...Congenital cataract is a common cause of childhood low vision or blindness worldwide..Early surgery should be performed in sensitive vision development period to avoid vision deprivation in cases of strabismus and nystagmus development. Postoperative recovery of visual function is of great significance for these patients and should include proper postoperative aphakia correction by the application of a contact lens and secondary implantation of an intraocular lens(IOL). Patients should receive amblyopic training after surgery to improve their postoperative visual acuity..Although recent advances in surgery techniques and materials have brought better postoperative visual acuity and less complications, a few postoperative complications can still hamper vision condition and vision development,.including posterior capsule opacification and secondary glaucoma. Surgery in early infancy are risk factors for these two complications..Life-long follow-up is essential for these patients..Further study will continue to address the surgery timing issue and methods that prevent postoperative complications.展开更多
Acupuncture at the Taichong (LR 3), Sanyinjiao (SP 6) and Ciliao (BL 32) points combined with TCM drugs for soothing the liver, replenishing the kidney, freeing the seminal passage, and eliminating the stasis showed e...Acupuncture at the Taichong (LR 3), Sanyinjiao (SP 6) and Ciliao (BL 32) points combined with TCM drugs for soothing the liver, replenishing the kidney, freeing the seminal passage, and eliminating the stasis showed effective for functional retrograde ejaculation in 25 cases. The total effective rate of 68.0% was significantly better than imipramine used in the control group (P<0.05).展开更多
Low-level laser therapy(LLLT) may have an effect on the pain associated with orthodontic treatment. The aim of this study was to evaluate the effect of LLLT on pain and somatosensory sensitization induced by orthodont...Low-level laser therapy(LLLT) may have an effect on the pain associated with orthodontic treatment. The aim of this study was to evaluate the effect of LLLT on pain and somatosensory sensitization induced by orthodontic treatment. Forty individuals(12–33 years old; mean ± standard deviations: 20.8 ± 5.9 years) scheduled to receive orthodontic treatment were randomly divided into a laser group(LG) or a placebo group(PG)(1:1). The LG received LLLT(810-nm gallium-aluminium-arsenic diode laser in continuous mode with the power set at 400 mW, 2 J·cm–2) at 0 h, 2 h, 24 h, 4 d, and 7 d after treatment, and the PG received inactive treatment at the same time points. In both groups, the non-treated side served as a control. A numerical rating scale(NRS) of pain, pressure pain thresholds(PPTs), cold detection thresholds(CDTs), warmth detection thresholds(WDTs), cold pain thresholds(CPTs), and heat pain thresholds(HPTs) were tested on both sides at the gingiva and canine tooth and on the hand. The data were analysed by a repeated measures analysis of variance(ANOVA). The NRS pain scores were significantly lower in the LG group(P = 0.01). The CDTs,CPTs, WDTs, HPTs, and PPTs at the gingiva and the PPTs at the canine tooth were significantly less sensitive on the treatment side of the LG compared with that of the PG(P < 0.033). The parameters tested also showed significantly less sensitivity on the nontreatment side of the LG compared to that of the PG(P < 0.043). There were no differences between the groups for any quantitative sensory testing(QST) measures of the hand. The application of LLLT appears to reduce the pain and sensitivity of the tooth and gingiva associated with orthodontic treatment and may have contralateral effects within the trigeminal system but no generalized QST effects. Thus, the present study indicated a significant analgesia effect of LLLT application during orthodontic treatment.Further clinical applications are suggested.展开更多
Traumatic spinal cord injury （SCI） causes motor paralysis, sensory anesthesia and autonomic dysfunction below the le- sion site and additionally some SCI patients refer neuropathic pain together with these signs and...Traumatic spinal cord injury （SCI） causes motor paralysis, sensory anesthesia and autonomic dysfunction below the le- sion site and additionally some SCI patients refer neuropathic pain together with these signs and symptoms. Clinical and experimental studies have revealed the main pathological changes of injured spinal cord implicated in all these signs and symptoms, including neuropathic pain. After few hours of traumatic SCI, it is usual to observe broken blood brain barrier with plasma and blood cells extravasation, cell necrosis, disruption of ascending and descending spinal cord pathways and increased potassium and glutamate. Glutamate contributes to excitotoxicity of neurons whereas potassium facilitates ectopic depolarization of survival neurons and activation of resident microglia.展开更多
Purpose: To research the mechanism of neurophysiological treatment of amblyopia by observing the visual cortex activation under rotating grating stimulus with functional magnetic resonance imaging (MRI), and identify ...Purpose: To research the mechanism of neurophysiological treatment of amblyopia by observing the visual cortex activation under rotating grating stimulus with functional magnetic resonance imaging (MRI), and identify the components of the activation. Methods: Nine healthy volunteers were examined using gradient-recalled echo and echo-planar imaging (GRE-EPI) pulse sequence performed at the 1.5 Tesla MRI scanner. In the block designing, rotating grating, stationary grating and luminance were plotted as task states, stationary grating, luminance and darkness as control states, respectively. The tasks of stimuli included 6 steps. Imaging processing and statistical analysis were carried out off-line using statistical parametric mapping (SPM99) software in single-subject. Results: Some individual areas of visual cortex were activated by various stimuli information supplied by rotating grating. The strong activation in the middle of occipital lobe related to the stimuli of luminance, bilateral activation of Brodmann’s 19th area related to visual motion perception, and the mild activation in the middle of occipital lobe related to form perception. Conclusion: The plotting of control state is important in bock design. The effective visual information of rotating grating includes components of luminance, visual motion perception and form perception. Functional MRI has potential as a tool for studying the physiological mechanism of visual cortex.展开更多
Recent developments in magnetic resonance(MR) functional quantitative imaging have made it a potentially powerful tool to assess treatment response in radiation therapy. With its abilities to capture functional inform...Recent developments in magnetic resonance(MR) functional quantitative imaging have made it a potentially powerful tool to assess treatment response in radiation therapy. With its abilities to capture functional information on underlying tissue characteristics, MR functional quantitative imaging can be valuable in assessing treatment response and as such to optimize therapeutic outcome. Various MR quantitative imaging techniques, including diffusion weighted imaging, diffusion tensor imaging, MR spectroscopy and dynamic contrastenhanced imaging, have been investigated and found useful for assessment of radiotherapy. However, various aspects including data reproducibility, interpretation of biomarkers, image quality and data analysis impose challenges on applications of MR functional quantitative imaging in radiotherapy assessment. All of these challenging issues shall be addressed to help us understand whether MR functional quantitative imaging is truly beneficial and contributes to future development of radiotherapy. It is evident that individualized therapy is the future direction of patient care. MR functional quantitative imaging might serves as an indispensable tool towards this promising direction.展开更多
经颅交流电刺激(transcranial alternating current stimulation,tACS)是一种非侵入性的电神经调控技术,它通过向头皮施加特定频率的周期性微电流,调节大脑特定脑区的神经振荡,从而改变个体的特定认知功能或改善临床症状。自2008年以来...经颅交流电刺激(transcranial alternating current stimulation,tACS)是一种非侵入性的电神经调控技术,它通过向头皮施加特定频率的周期性微电流,调节大脑特定脑区的神经振荡,从而改变个体的特定认知功能或改善临床症状。自2008年以来,心理学研究者们利用tACS揭示了大脑不同神经振荡频段与特定认知活动的因果性联系。我们首先介绍tACS技术调控神经振荡的作用机制,接着分别介绍tACS在改变单脑和双脑认知功能研究中的应用。未来研究需精确控制tACS施加电流与大脑自发脑电节律间的相位关系、考虑脑神经节律等方面的个体差异,实现精准的tACS神经调控,从而更好地揭示不同认知功能的神经电机制。同时需系统评估tACS在临床应用研究中的施治方案和疗效持续性,为临床治疗提供科学指导。展开更多
This paper describes the electroless Ni or Cu plating of some fiuoropolymer substrates through a tin-free activation process. Materials subjected to surface metallization are commercial Teflon() FEP, Nafion(), ACLAR()...This paper describes the electroless Ni or Cu plating of some fiuoropolymer substrates through a tin-free activation process. Materials subjected to surface metallization are commercial Teflon() FEP, Nafion(), ACLAR() and LaRCTM-CP1 thin films which have recently gained a large scientific and technological interest due to their excellent thermal, chemical, mechanical and dielectric properties. The original approach implemented in the present work involves: (i)the grafting of nitrogen-containing functionalities on the polymer surfaces through plasma treatments in ammonia, (ii) the direct catalysis of the so-modified surfaces via their immersion in a simple acidic PdCl2 solution (i.e. without using a prior surface sensitization in an acidic SnCl2 solution), and finally (iii) the electroless metallization itself. However, prior to the immersion in the industrial plating baths, the chemical reduction of the Pd+2 species (species covalently tethered on the nitrogen-containing groups) to metallic palladium (PdO) is shown to be a key factor in catalyzing the electroless deposition initiation. This is made by immersion in an hypophosphite (H2PO2-) solution. Wettability measurements and X-ray photoelectron spectroscopy (XPS) experiments are used to characterize every surface modification step of the developed process. A cross-hatch tape test was used to asses the adhesion strength of the electroless films that is shown qualitatively good. In addition, a fragmentation test was developed in combination with electrical measurements. Its use allows to distinguish different adhesion levels at the metal/polymer interface and to evidence the influence of some processing parameters.展开更多
文摘An SIS epidemic model with the standard incidence rate and saturated treatment func- tion is proposed. The dynamics of the system are discussed, and the effect of the capacity for treatment and the recruitment of the population are also studied. We find that the effect of the maximum recovery per unit of time and the recruitment rate of the popula- tion over some level are two factors which lead to the backward bifurcation, and in some cases, the model may undergo the saddle-node bifurcation or Bogdanov-Takens bifurca- tion. It is shown that the disease-free equilibrium is globally asymptotically stable under some conditions, Numerical simulations are consistent with our obtained results in the- orems, which show that improving the efficiency and capacity of treatment is important for control of disease.
文摘A mathematical model describing the epidemic interactions between humans and blackflies in the transmission of onchocerciasis is considered.In this model,the onchocerciasis infected human individuals are divided into two classes of infected humans with high and low microfilarial output incorporating saturated treatment function,which caters for high saturation of onchocerciasis disease.We analyze the model feasible region and obtain the basic reproduction number(R_(hb))using the next generation matrix method.Also,we obtain the onchocerciasis-free and onchocerciasis endemic equilibrium solutions and show that if R_(hb) is less than unity,the onchocerciasis-free equilibrium is locally and globally asymptotically stable.Furthermore,we employed a Lyapunov function to analyze the global asymptotic stability of the onchocerciasis—endemic equilibrium whenever Rhb is greater than unity.In addition,data on mass drug distribution of ivermectin drug to combat onchocerciasis prevalence in Ekiti state of Nigeria were fitted to the model.Graphical results reveal that consistent annual or bi-annual distribution of ivermectin drug in the region is effective in reducing the disease menace.Further simulations also show that public health control measures are needed to minimize infectious contact between humans and blackflies which leads to onchocerciasis infections and visual blindness.
基金The research was supported in part by the NNSFC(grant 12071058)the Applied Basic Research Program of Department of Science and Technology of Liaoning Province of China(grant 2023JH2/101300095).
文摘In this paper,we study a network-based SIR epidemic model with a saturated treatment function in which a parameterαis introduced to measure the extent of the effect of the infected being delayed for treatment.Our aim is to present a global analysis and to investigate how the parameterαaffects the spreading of diseases.Our main results are as follows:(1)In the case of the threshold value R_(0)<1,there exist two values of α:α_(c) and α_(0),such that the disease-free equilibrium is globally asymptotically stable when α≤α_(0) and multiple endemic equilibria exist when α≥α_(0).This means that the parameterαhas an essential infuence on the spreading of the disease.(2)In the case of the threshold value R_(0)>1,if the model has only one endemic equilibrium,then the unique endemic equilibrium is globally attractive.In this case,it is also proved that if α≤α_(c),then the endemic equilibrium has only one,so is globally attractive,In addition,numerical simulation is performed to illustrate our theoretical results.
文摘Objective:To compare the effect of surgical intervention on functional treatment.Methods: By searching the MEDLINE(1966 to October 2011),EMBASE(1980 to October 2011),the Chinese Biomedical Database Databases(1980 to October 2011),a total of 9 related RCT studies comparing surgical intervention with functional treatment were included in our study.RevMan software was taken to analyze the data.Results:These 9 studies Involved a total of 1 268 mostly young adults,including 580 patients with surgical treatment and 688 patients with functional treatment.The results showed the stability of ankle activity in surgical treatment group was better than that in functional treatment group,with the OR and 95%CI of 0.72(0.52-0.99).No significant difference was found in the recurrence of the surgical and functional group.However, the movement disorder in the surgical treatment suggested increased risk than that in functional group,with the OR and 95%CI of 2 39(0.98-5.85).Surgical group found more complication than the function group,such as deep vein thrombosis,deep venous thrombosis,tenderness of scar and sensory loss.Conclusions:In conclusion,our finding showed that surgical treatment could gain better efficacy than functional treatment,but may bring more complication.Therefore,further large sample size RCT is warranted.
基金National Nature Science Foundation of China(Grand Number30973276)
文摘Congenital cataract is a common cause of childhood low vision or blindness worldwide..Early surgery should be performed in sensitive vision development period to avoid vision deprivation in cases of strabismus and nystagmus development. Postoperative recovery of visual function is of great significance for these patients and should include proper postoperative aphakia correction by the application of a contact lens and secondary implantation of an intraocular lens(IOL). Patients should receive amblyopic training after surgery to improve their postoperative visual acuity..Although recent advances in surgery techniques and materials have brought better postoperative visual acuity and less complications, a few postoperative complications can still hamper vision condition and vision development,.including posterior capsule opacification and secondary glaucoma. Surgery in early infancy are risk factors for these two complications..Life-long follow-up is essential for these patients..Further study will continue to address the surgery timing issue and methods that prevent postoperative complications.
文摘Acupuncture at the Taichong (LR 3), Sanyinjiao (SP 6) and Ciliao (BL 32) points combined with TCM drugs for soothing the liver, replenishing the kidney, freeing the seminal passage, and eliminating the stasis showed effective for functional retrograde ejaculation in 25 cases. The total effective rate of 68.0% was significantly better than imipramine used in the control group (P<0.05).
基金funded by the Priority Academic Program Development of Jiangsu Higher Education Institution(Grant No.2014-37)the Jiangsu Provincial Health and Family Planning Commission(No.H201535)Orofacial Pain and TMD Research Unit,Institute of Stomatology,Affiliated Hospital of Stomatology,Nanjing Medical University,for their support
文摘Low-level laser therapy(LLLT) may have an effect on the pain associated with orthodontic treatment. The aim of this study was to evaluate the effect of LLLT on pain and somatosensory sensitization induced by orthodontic treatment. Forty individuals(12–33 years old; mean ± standard deviations: 20.8 ± 5.9 years) scheduled to receive orthodontic treatment were randomly divided into a laser group(LG) or a placebo group(PG)(1:1). The LG received LLLT(810-nm gallium-aluminium-arsenic diode laser in continuous mode with the power set at 400 mW, 2 J·cm–2) at 0 h, 2 h, 24 h, 4 d, and 7 d after treatment, and the PG received inactive treatment at the same time points. In both groups, the non-treated side served as a control. A numerical rating scale(NRS) of pain, pressure pain thresholds(PPTs), cold detection thresholds(CDTs), warmth detection thresholds(WDTs), cold pain thresholds(CPTs), and heat pain thresholds(HPTs) were tested on both sides at the gingiva and canine tooth and on the hand. The data were analysed by a repeated measures analysis of variance(ANOVA). The NRS pain scores were significantly lower in the LG group(P = 0.01). The CDTs,CPTs, WDTs, HPTs, and PPTs at the gingiva and the PPTs at the canine tooth were significantly less sensitive on the treatment side of the LG compared with that of the PG(P < 0.033). The parameters tested also showed significantly less sensitivity on the nontreatment side of the LG compared to that of the PG(P < 0.043). There were no differences between the groups for any quantitative sensory testing(QST) measures of the hand. The application of LLLT appears to reduce the pain and sensitivity of the tooth and gingiva associated with orthodontic treatment and may have contralateral effects within the trigeminal system but no generalized QST effects. Thus, the present study indicated a significant analgesia effect of LLLT application during orthodontic treatment.Further clinical applications are suggested.
基金funded by Accions Singulars de R+D(Sing 12/17)del Vicerectorat de Recerca de la Universitat de Girona,Girona,Spain
文摘Traumatic spinal cord injury （SCI） causes motor paralysis, sensory anesthesia and autonomic dysfunction below the le- sion site and additionally some SCI patients refer neuropathic pain together with these signs and symptoms. Clinical and experimental studies have revealed the main pathological changes of injured spinal cord implicated in all these signs and symptoms, including neuropathic pain. After few hours of traumatic SCI, it is usual to observe broken blood brain barrier with plasma and blood cells extravasation, cell necrosis, disruption of ascending and descending spinal cord pathways and increased potassium and glutamate. Glutamate contributes to excitotoxicity of neurons whereas potassium facilitates ectopic depolarization of survival neurons and activation of resident microglia.
基金supported by Nanjing Jinling Hospital ( 2004082) Basic application grant supported by The Department ofEducation of Jiangsu Province
文摘Purpose: To research the mechanism of neurophysiological treatment of amblyopia by observing the visual cortex activation under rotating grating stimulus with functional magnetic resonance imaging (MRI), and identify the components of the activation. Methods: Nine healthy volunteers were examined using gradient-recalled echo and echo-planar imaging (GRE-EPI) pulse sequence performed at the 1.5 Tesla MRI scanner. In the block designing, rotating grating, stationary grating and luminance were plotted as task states, stationary grating, luminance and darkness as control states, respectively. The tasks of stimuli included 6 steps. Imaging processing and statistical analysis were carried out off-line using statistical parametric mapping (SPM99) software in single-subject. Results: Some individual areas of visual cortex were activated by various stimuli information supplied by rotating grating. The strong activation in the middle of occipital lobe related to the stimuli of luminance, bilateral activation of Brodmann’s 19th area related to visual motion perception, and the mild activation in the middle of occipital lobe related to form perception. Conclusion: The plotting of control state is important in bock design. The effective visual information of rotating grating includes components of luminance, visual motion perception and form perception. Functional MRI has potential as a tool for studying the physiological mechanism of visual cortex.
文摘Recent developments in magnetic resonance(MR) functional quantitative imaging have made it a potentially powerful tool to assess treatment response in radiation therapy. With its abilities to capture functional information on underlying tissue characteristics, MR functional quantitative imaging can be valuable in assessing treatment response and as such to optimize therapeutic outcome. Various MR quantitative imaging techniques, including diffusion weighted imaging, diffusion tensor imaging, MR spectroscopy and dynamic contrastenhanced imaging, have been investigated and found useful for assessment of radiotherapy. However, various aspects including data reproducibility, interpretation of biomarkers, image quality and data analysis impose challenges on applications of MR functional quantitative imaging in radiotherapy assessment. All of these challenging issues shall be addressed to help us understand whether MR functional quantitative imaging is truly beneficial and contributes to future development of radiotherapy. It is evident that individualized therapy is the future direction of patient care. MR functional quantitative imaging might serves as an indispensable tool towards this promising direction.
文摘经颅交流电刺激(transcranial alternating current stimulation,tACS)是一种非侵入性的电神经调控技术,它通过向头皮施加特定频率的周期性微电流,调节大脑特定脑区的神经振荡,从而改变个体的特定认知功能或改善临床症状。自2008年以来,心理学研究者们利用tACS揭示了大脑不同神经振荡频段与特定认知活动的因果性联系。我们首先介绍tACS技术调控神经振荡的作用机制,接着分别介绍tACS在改变单脑和双脑认知功能研究中的应用。未来研究需精确控制tACS施加电流与大脑自发脑电节律间的相位关系、考虑脑神经节律等方面的个体差异,实现精准的tACS神经调控,从而更好地揭示不同认知功能的神经电机制。同时需系统评估tACS在临床应用研究中的施治方案和疗效持续性,为临床治疗提供科学指导。
文摘This paper describes the electroless Ni or Cu plating of some fiuoropolymer substrates through a tin-free activation process. Materials subjected to surface metallization are commercial Teflon() FEP, Nafion(), ACLAR() and LaRCTM-CP1 thin films which have recently gained a large scientific and technological interest due to their excellent thermal, chemical, mechanical and dielectric properties. The original approach implemented in the present work involves: (i)the grafting of nitrogen-containing functionalities on the polymer surfaces through plasma treatments in ammonia, (ii) the direct catalysis of the so-modified surfaces via their immersion in a simple acidic PdCl2 solution (i.e. without using a prior surface sensitization in an acidic SnCl2 solution), and finally (iii) the electroless metallization itself. However, prior to the immersion in the industrial plating baths, the chemical reduction of the Pd+2 species (species covalently tethered on the nitrogen-containing groups) to metallic palladium (PdO) is shown to be a key factor in catalyzing the electroless deposition initiation. This is made by immersion in an hypophosphite (H2PO2-) solution. Wettability measurements and X-ray photoelectron spectroscopy (XPS) experiments are used to characterize every surface modification step of the developed process. A cross-hatch tape test was used to asses the adhesion strength of the electroless films that is shown qualitatively good. In addition, a fragmentation test was developed in combination with electrical measurements. Its use allows to distinguish different adhesion levels at the metal/polymer interface and to evidence the influence of some processing parameters.
