Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration.Furthermore,such peripheral nerve allografts undergo immunological rejection by the host immune system.In contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian degeneration.The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study.We hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery.We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion.Ablation-type sciatic nerve injuries in outbred Sprague–Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons.Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively.Other morphological signs of rejection,such as collapsed Schwann cell basal lamina tubes,were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively.Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts.While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts,loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively.MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts,but MHCII expression was modestly lower compared to negative control at 21 days postoperatively.We conclude that,while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts,successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts,and produce recovery of sensory/motor functions and voluntary behaviors.Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.

Percutaneous endoscopic gastrostomy and gastrooesophageal reflux in neurologically impaired children

AIM:To investigate the effects of percutaneous endoscopic gastrostomy(PEG) feeding on gastro-oesophageal reflux(GOR) in a group of these children using combined intraluminal pH and multiple intraluminal impedance(pH/MII) . METHODS:Ten neurologically impaired children underwent 12 h combined pH/MII procedures at least 1 d before and at least 12 d after PEG placement. METHODS:Prior to PEG placement(pre-PEG) a total of 183 GOR episodes were detected,156(85.2%) were non-acidic.After PEG placement(post-PEG) a total of 355 episodes were detected,182(51.3%) were nonacidic.The total number of distal acid reflux events statistically significantly increased post-PEG placement(prePEG total 27,post-PEG total 173,P=0.028) and themean distal pH decreased by 1.1 units.The distal reflux index therefore also significantly increased post-PEG [pre-PEG 0.25(0-2) ,post-PEG 2.95(0-40) ].Average proximal pH was lower post-PEG but the within subject difference was not statistically significant(P=0.058) . Median number of non-acid GOR,average reflux height,total acid clearance time and total bolus clearance time were all lower pre-PEG,but not statistically significant. CONCLUSION:PEG placement increases GOR episodes in neurologically impaired children.

Nutritional support teams increase percutaneous endoscopic gastrostomy uptake in motor neuron disease

AIM:To examine factors influencing percutaneous endoscopic gastrostomy(PEG) uptake and outcomes in motor neuron disease(MND) in a tertiary care centre.METHODS:Case notes from all patients with a confirmed diagnosis of MND who had attended the clinic at the Repatriation General Hospital between January 2007 and January 2011 and who had since died,were audited.Data were extracted for demographics(age and gender),disease characteristics(date of onset,bulbar or peripheral predominance,complications),date and nature of discussion of gastrostomy insertion,nutritional status [weight measurements,body mass index(BMI)],date of gastrostomy insertion and subsequent progress(duration of survival) and quality of life(QoL) [Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised(ALSFRS-R)].In addition,the type of clinician initiating the discussion regarding gastrostomy was recorded as Nutritional Support Team(involved in providing nutrition input viz Gastroenterologist,Speech Pathologist,Dietitian) and other(involved in non-nutritional aspects of patient care).Factors affecting placement and outcomes including length of survival,change in weight and QoL were determined.RESULTS:Case records were available for all 86 patients(49 men,mean age at diagnosis 66.4 years).Thirty-eight patients had bulbar symptoms and 48 had peripheral disease as their presenting feature.Sixty-six patients reported dysphagia.Thirty-one patients had undergone gastrostomy insertion.The major indications for PEG placement were dysphagia and weight loss.Nine patients required immediate full feeding,whereas 17 patients initially used the gastrostomy to supplement oral intake,4 for medication administration and 1 for hydration.Initially the PEG regime met 73% ± 31% of the estimated total energy requirements,increasing to 87% ± 32% prior to death.There was stabilization of weight in patients undergoing gastrostomy [BMI at 3 mo(22.6 ± 2.2 kg/m 2) and 6 mo(22.5 ± 2.0 kg/m 2) after PEG placement compared to weight at the time of the procedure(22.5 ± 3.0 kg/m 2)].However,weight loss recurred in the terminal stages of the illness.There was a strong trend for longer survival from diagnosis among MND in PEG recipients with limb onset presentation compared to similar patients who did not undergo the procedure(P = 0.063).Initial discussions regarding PEG insertion occurred earlier after diagnosis when seen by nutrition support team(NST) clinicians compared to other clinicians.(5.4 ± 7.0 mo vs 11.9 ± 13.4 mo,P = 0.028).There was a significant increase in PEG uptake(56% vs 24%,P = 0.011) if PEG discussions were initiated by the NST staff compared to other clinicians.There was no change in the ALSFRS-R score in patients who underwent PEG(pre 34.1 ± 8.6 vs post 34.8 ± 7.4),although in non-PEG recipients there was a nonsignificant fall in this score(33.7 ± 7.9 vs 31.6 ± 8.8).Four patients died within one month of the procedure,4 developed bacterial site infection requiring antibiotics and 1 required endoscopic therapy for gastric bleeding.Less serious complications attributed to the procedure included persistent gastrostomy site discomfort,poor appetite,altered bowel function and bloating.CONCLUSION:Initial discussion with NST clinicians increases PEG uptake in MND.Gastrostomy stabilizes patient weight but weight loss recurs with advancing disease.

L-carnitine supplementation improves hematological pattern in patients affected by HCV treated with Peg interferon-α 2b plus ribavirin

AIM:To evaluate the efficacy of L-carnitine on alleviating anemia,thrombocytopenia and leukopenia,and minimizing dose reductions in patients with chronic hepatitis C virus(HCV)in treatment with Interferonα(IFN-α)plus ribavirin.METHODS:Sixty-nine patients with chronic hepatitis C were enrolled in the study and divided into two groups.group A(n=35)received Peg-IFN-α2b plus ribavirin plus L-carnitine,and group B(n=34)received Peg-IFN-αand ribavirin for 12 mo.All patients underwent laboratory investigations including:red cell count,he-moglobin,white cell count,platelets,bilirubin,alanine aminotransferase(ALT),aspartate aminotransferase(AST),and viremia.RESULTS:After 12 mo in group A compared to group B we observed significant differences in AST 108.8 vs 76.8(IU/L;P<0.001),ALT 137.vs 112.3(IU/L;P 0.001),viremia 4.04 vs 2.36(106 copies/mL;P< 0.001),Hb 1 vs 3.5(g/dL;P<0.05),red blood cells 0.3 vs 1.1(X1012/L;P0.001),white blood cells 1.5 vs 3(10/L;Pn0.001)and platelets 86 vs 85(×10/L;P0.001).The end treatment responders were 18 vs 12(60%vs>44%)and the non responders were 12 vs 15(40%vs<50%)[odds ratio(OR)1.65,n5%CI =0.65-5.37,P<0.05?.In group A compared to group B there was a significant improvement of sustained vi-rological response in 15 vs 7 patients(50%vs>25%),while the relapsers were 3 vs 5(10%vs<18%)(OR>3.57,n5%CI=0.65-1n.3,Pn0.001).CONCLUSION:L-carnitine supplementations modulate erythropoiesis,leucopoiesis and thrombocytopoiesis,and may be useful in patients treated for HCV.L-carni-tine treatment offers the possibility of achieving a sustained virological response while preventing overtreatment.

Time for the world to move beyond the percutaneous endoscopic gastrostomy

Percutaneous endoscopic gastrostomy (PEG) is a proven feeding tube,just as the nasogastric tube is proven to be able to deliver enteral nutrition.For long-term use,both patient and caregiver want neither.What is desired is the LOOPPEG? 3G tube,more secure than the PEG,and less risky to change than the nasogastric tube.Future clinical research should focus on this high-comfort low-risk tube.

Application and implications of polyethylene glycol-fusion as a novel technology to repair injured spinal cords

Conventional vs. polyethylene glycol （PEG）-fusion tech- nologies to repair severed spinal axons： Most spinal cord injuries （SCIs） involve cutor crush-severance of spinal tract axons in the central nervous system （CNS）. Clinical out- comes after CNS axonal severance is very poor because proximal segments of CNS axons lack a suitable environment for outgrowth （Kakulas, 1999; Fitch and Silver, 2008; Rowland et al., 2008; Kwon et al., 2010） and therefore do not naturally regenerate （Ramon y Caial, 1928）. Current strategies to try to increase behavioral recovery after SCI are focused on en- hancing the environment for axonal outgrowth.

Heterobifunctional PEG-grafted black phosphorus quantum dots: “Three-in-One”nano-platforms for mitochondria-targeted photothermal cancer therapy

Black phosphorus(BP)nano-materials,especially BP quantum dots(BPQDs),performs outstanding photothermal antitumor effects,excellent biocompatibility and biodegradability.However,there are several challenges to overcome before offering real benefits,such as poor stability,poor dispersibility as well as difficulty in tailoring other functions.Here,a“three-in-one”mitochondria-targeted BP nano-platform,called as BPQD-PEG-TPP,was designed.In this nano-platform,BPQDs were covalently grafted with a heterobifunctional PEG,in which one end was an aryl diazo group capable of reacting with BPQDs to form a covalent bond and the other end was a mitochondria-targeted triphenylphosphine(TPP)group.In addition to its excellent near-infrared photothermal properties,BPQD-PEG-TPP had much enhanced stability and dispersibility under physiological conditions,efficient mitochondria targeting and promoted ROS production through a photothermal effect.Both in vitro and in vivo experiments demonstrated that BPQD-PEG-TPP performed much superior photothermal cytotoxicity than BPQDs and BPQD-PEG as the mitochondria targeted PTT.Thus this“three-in-one”nanoplatform fabricated through polymer grafting,with excellent stability,dispersibility and negligible side effects,might be a promising strategy for mitochondria-targeted photothermal cancer therapy.

Effects of NaCl and Iso-Osmotic Polyethylene Glycol Stress on Na^+/H^+Antiport Activity of Three Malus species with Different Salt Tolerance

Salt stress contains osmotic and ionic stress, while iso-osmotic polyethylene glycol （PEG） has only osmotic stress. This study aimed to compare the different effects on the activity of H＋-ATPase, proton pump and Na＋/H＋antiport in Malus seedlings between osmotic and ionic stress. Species of salt tolerant Malus zumi, middle salt tolerant Malus xiaojinensis and salt sensitive Malus baccata were used as experimental materials. Malus seedlings were treated with NaCl and iso-osmotic PEG stress. The activity of H＋-ATPase, proton pump and Na＋/H＋antiport of plasmolemma and tonoplast in Malus seedlings were obviously increased under salt stress, and those in salt-tolerant species increased more. Under the same NaCl concentration, the activity of H＋-ATPase, proton pump and Na＋/H＋antiport of plasmolemma and tonoplast in salt-tolerant species were all obviously higher than those in salt-sensitive one. Higher Na＋/H＋antiport activity of plasmolemma and tonoplast in salt-tolerant species could help to extrude and compartmentalize sodium in roots under salt stress. The ascent rate of activity of H＋-ATPase, proton pump and Na＋/H＋antiport in Malus seedlings under the three salt concentration stress was all obviously higher than that under the iso-osmotic PEG stress. It indicated that the sodium ion effect had more stimulation on the activity of H＋-ATPase, proton pump and Na＋/H＋antiport in salt-tolerant species, and salt-tolerant species has higher capability of sodium extrusion and compartmentalization in roots and is therefore more salt tolerant.

In Vitro Screening of Cactus [Opuntia ficus-indicia (L.) Mill] Genotypes for Drought Tolerance

Drought is one of the complex environmental factors affecting growth and yield of crops in arid and semi-arid areas of the world. In this context, this investigation was carried out to select drought tolerance cactus genotypes under in vitro condition. An experiment was carried out at Laboratory of Mekelle Agricultural Research Center, Northern Ethiopia. Six cactus pear genotypes namely, Gerao, Keyih Beles, Shenkor, Limo, Lemats Beles and Suluhna were used. Areoles were used as explants in tissue culture. The non-ionic water soluble polymer polyethylene glycol (PEG) of molecular weight 6000 was used as osmoticum to simulate water stress. In the first culture, the MS medium was supplemented with (2, 4-D (4 mg/l) and BA (0.5 mg/l) for callus induction. In all cultures MS medium was supplemented with 0, 10, 20 and 40 g/l polyethylene glycol (PEG) and was solidified with 0.8% agar and 30 g of sucrose. Significant differences were observed among the genotypes, PEG levels. In the first culture highest number of explants initiated callus on medium supplemented with no PEG but had not shown significant difference with 10 g/l PEG. At 10 g/l PEG, the callus induction frequency, callus fresh weight and plantlet regeneration were recorded highest for Suluhna (83.3%, 5.5 g and 63.3%), respectively. At 40 g/l PEG, callus induction frequency, callus fresh weight and plantlet regeneration were produced highest for Suluhna (41.7%, 2.75 g and 45%), respectively but no significant difference with Gerao, Limo and Lemats Beles. However, Shenkor and Keyih Beles were induced callus but became reddish black within 35 days supplemented with 40 g/l PEG. Both shoot and root production decreased with increased PEG level in the medium. At 40 g/l PEG in MS medium, the highest shoot number was in Suluhna genotype (4.33) followed by Gerao (3.67). The highest shoot length was in Suluhna (2.11 cm) with no significant difference with Gerao (2.02 cm). Root number (5.00 and root length (1.41 cm) were in the genotype Suluhna. Survival percentage of in vitro regenerated plantlets was 100% during hardening. By taking into consideration, all the growth parameter tested revealed that Suluhna, Gerao, Limo and Lemats Beles showed better drought stress tolerance at the highest level of PEG while Keyih Beles and Shenkor appeared to be drought sensitive at the highest level of PEG.

Separation of a C_(3)H_(6)/C_(2)H_(4) mixture using Pebax^(■) 2533/PEG600 blend membranes

In industry, ethylene(C_(2)H_(4))/propylene(C_(3)H_(6)) separations are usually performed by a cryogenic process,which is energy intensive. Membrane separation technology is an alternative separation process that saves energy and is efficient. In this study, blend membranes were prepared by doping polyethylene glycol(PEG600) into a poly(ether-block-amide)(Pebax^(■) 2533) matrix and were used to separate the C_(2)H_(4)/C_(3)H_(6) mixture. The PEG 600 and Pebax^(■) 2533 polymers have good compatibility because they share hydrogen bonds. The addition of PEG600 is conducive to the hydrophilicity and the free volume of blend membranes, and it is also conducive to the solubility of C_(2)H_(4) and C_(3)H_(6) in the membranes, which improves the ability of the membranes to separate this gas pair. The Pebax^(■) 2533/PEG600 blend membrane with 15%(mass) PEG600 showed the highest separation performance in our investigated membranes, with a C_(3)H_(6)/C_(2)H_(4) selectivity of 8.9 and a C_(3)H_(6) permeability of 196 barrer(1 barrer = 1.33×10^(14)m^(3)(STP)·m·m^(-2)·s^(-1)·kPa^(-1)) at 238 K and 0.2 MPa, which is higher than that of the Pebax^(■) 2533/NaY-6%(mass) membrane(α_(C_(3)H_(6)/C_(2)H_(4)) =6.5, P_(C_(3)H_(6))=211 barrer) reported in our previous work. It is confirmed that incorporating PEG600 into the Pebax^(■) 2533 matrix to fabricate blend membranes is an efficient strategy for separating light olefins.

Polyethylene glycol-fusion retards Wallerian degeneration and rapidly restores behaviors lost after nerve severance

Some biological uses of polyethylene glycol（PEG）：The use of PEG as a membrane fusogen was first reported in 1976with the creation of cell hybrids,formed by suspending two cell lines in a 50%w/w solution of PEG in water.

Transhepatic percutaneous endoscopic gastrostomy

We describe the case of a hepatic injury after the insertion of a PEG. In a cirrhotic woman affected by a locally advanced cancer of the pharynx, the PEG tube was inserted through the edge of the left lobe of the liver. The patient was treated with a conservative approach by managing abdominal pain and the PEG was removed after 4 months without complication. Hepatic injury is a rare complication of PEG placement;in order to avoid it, PEG tube should be inserted to the left of the abdominal midline and the lower edge of the liver should be defined by palpation;in cirrhotic patients, where left hepatic lobe hyper-trophy is common, ultrasound guidance could have been appropriate.

Percutaneous Endoscopic Gastrostomy (PEG) Tube Placement in Patients with Continuous-Flow Left Ventricular Assist Devices (LVAD)

Introduction: Inadequate nutritional support after LVAD placement is known to increase postoperative infections and to decrease survival. LVAD patients with prolonged mechanical ventilation and complicated postoperative recovery requiring prolonged mechanical ventilation may require long-term tube feedings. Placement of a PEG requires knowledge of the location of the LVAD pocket and driveline to avoid device infection and injury. Methods: Between August 2008 and December 2011, 39 patients underwent HeartMate II LVAD placement in our institution. Among them, 5 patients underwent PEG tube placement for long-term nutritional support. Procedure management consisted of cessation of anticoagulation and correction of abnormal coagulation;a cardiothoracic surgeon or intensivist in the operating room to communicate with the surgeon who performed the PEG procedure;and VAD coordinator or perfusionist in the operating room to assist in monitoring the VAD. Data were retrospectively analyzed to investigate complications related to the PEG placement. Results: The studied patients consisted of 3 males and 2 females with mean age of 58 +/﹣5.0. The interval of LVAD to PEG placement was a mean 21 +/﹣8.8 days. PEG was successfully performed in the operating room in all patients. There were no LVAD device or driveline injuries related to the PEG procedure. There were no postoperative short-term or long-term PEG related complications such as acute gastric bleeding or dislodgement of the PEG tube. Conclusions: PEG placement for HeartMate II LVAD patients can be done without increasing the risk of device or intraabdominal organ injury with carefully coordinated efforts from both the mechanical support team and surgical services.

Reduced Fasting Protocol for Endoscopic Percutaneous Gastrostomy in Intubated Patients

Background: Previous studies have shown that ICU patients receive only a fraction of their calculated nutritional goals, and that cumulative caloric deficit in the ICU has been correlated with poor outcome. One reason for this underfeeding is the frequent interruption of enteral nutrition. Many ICU patients receive enteral feeding formula via a nasogastric (NG) tube. Feeding is typically held for several hours prior to procedures due to the theoretical risk of aspiration. An alternative is to continue feeding up until the procedure begins, then stop the feeding and place the NG to suction. This evacuates the contents of the stomach and minimizes the risk of aspiration, while reducing the interruption of feeding that can result in malnutrition. Methods: This study is a review of prospectively gathered data including 55 sequential patients who underwent bedside percutaneous endoscopic gastrostomy (PEG) placement in a mixed ICU under a reduced fasting protocol. This was compared with a historical cohort of 33 critically ill trauma patients who fasted for at least 8 hours prior to the procedure. Under the reduced fasting protocol, enteral feeding via NG was continued up until the time of the procedure. The NG was then placed to suction, and sedation was given. The NG was left in place until the esophagus was cannulated, then it was removed. The PEG was placed in standard fashion, and feeding was resumed via the PEG immediately following the procedure. Results: We have documented no peri-procedural vomiting or aspiration. New diagnosis of pneumonia within 3 days occurred in 2/55 of the feeding group and 4/33 of the fasting group. Overall mortality was higher for the feeding group: 13/55 vs. 1/33, however when adjusted for baseline characteristics, the difference was no longer significant. Under our protocol, the interruption of feeding averaged approximately one hour, rather than the 8 or 9 hour interruption required by standard protocols. This saved an average of approximately 700 kilocalories per patient. Conclusion: We believe that continuing feeding via NG up until the time of bedside PEG is safe and advantageous for intubated patients in the ICU. Since there was minimal gastric content, it may also be safe for other procedures.

Synthesis and Characterization of TiO₂Porous Films for Heterogeneous Photocatalysis

Heterogeneous photocatalysis is one of the advanced oxidation processes (AOP’s). These are very used nowadays for their implementation in tertiary water treatment with solar activation, with very good results. In this study, TiO2 porous films were synthesized by sol-gel method. Polyethylene glycol (PEG) 4000 was used as a templating reagent, which is oxidized at a lower temperature than TiO2. This allows the formation of a “skeleton” of porous TiO2 with increased surface area, resulting in higher photocatalytic activity. The film characterization was made with help of FE-SEM microscope, XRD diffractometer and scotch tape test. Finally, the oxidation experiments were performed using methylene blue as a model pollutant and they revealed an increase in the photocatalytic activity of porous films in comparison with the non-porous films.

Modification of Titanium Surfaces via Surface-initiated Atom Transfer Radical Polymerization to Graft PEG-RGD Polymer Brushes to Inhibit Bacterial Adhesion and Promote Osteoblast Cell Attachment

Implant-related infection is one of the key concerns in clinical medicine, so the modification of titanium to inhibit bacterial adhesion and support osteoblast cell attachment is important. In this article, two strategies were used to examine the above effects. First, modification of titanium via surface-initiated atom transfer radical polymerization（ATRP） was performed. The surface of the titanium was activated initially by a silane coupling agent. Well-defined polymer brushes of poly（ethylene glycol） methacrylate were successfully tethered on the silane-coupled titanium surface to form hydration shell to examine the anti-fouling effect. Second, functionalization of the Ti-PEG surface with RGD was performed to examine the anti-bacterial adhesion and osteoblast cell attachment ability. The chemical composition of modified titanium surfaces was characterized by X-ray photoelectron spectroscopy（XPS）. Changes in surface hydrophilicity and hydrophobicity were characterized by static water contact angle measurements. Results indicated that PEG-RGD brushes were successfully tethered on the titanium surface. And anti-bacterial adhesion ability and osteoblast cell attachment ability were confirmed by fluorescence microscopy and scanning electron microscopy. Results indicated that PEG can inhibit both bacterial adhesion and osteoblast cell attachment, while PEG-RGD brushes can not only inhibit bacterial adhesion but also promote osteoblast cell attachment.

New Approach for the Determination of Tricyclic Antidepressant Amitriptyline Using <i>β</i>-Cyclodextrin-PEG System via Spectrophotomerty

A new and simple procedure for the spectrophotometric determination of the tricyclic antidepressant drug amitriptyline is proposed. The method is based on enhancement of sensitivity of the [AMIYTP]+ β-cyclodextrin and PEG molecules involved in formation of molecules inclusion complex, in presence of polyethylene glycol (PEG) medium. The mole ratio of [AMIYTP]+ β-cyclodextrin and PEG molecules in inclusion complex were determined by the curve fitting method. The value of molar absorptivity of {[AMIYTP: (β CD)] PEG} complex in term of the drug lies in rage of (2.20 - 2.23) × 104 L·mole–1·cm–1 at absorption maximum 242 nm. The slope, intercept and correlation co-efficient were found to be 14.21, 0.0046, and 0.998, respectively. The effect of analytical variables on the determination of the drug and composition of the ion associated complex are discussed in the paper. This method is applicable in the determina-tion of amitriptyline in the pharmaceutical preparations.

干旱指数法综合评价河南烤烟新品种抗旱性

以中烟100、云烟87和NC89为对照品种,采用PEG(聚乙二醇)模拟干旱试验,结合盆栽控水试验研究干旱胁迫对河南省烤烟新品种的影响,采用干旱指数法综合评价新品种的抗旱性。结果表明,河洛1号抗旱性最强;其次是豫浓香201,在中度干旱胁迫条件下抗旱性较强,重度干旱则影响烟叶正常生长;渠首1号抗旱性与对照品种NC89、中烟100和云烟87基本相当。

肺炎克雷伯菌毒力基因检测及新型标志物对高毒力肺炎克雷伯菌的诊断效能

目的探讨肺炎克雷伯菌(KP)毒力基因检测及新型标志物对高毒力肺炎克雷伯菌(HVKP)的诊断效能。方法从2020—2023年住院患者中根据病史和病原学检测结果,挑选出KP阳性患者,从医院菌库里获得对应的非重复KP菌株45株,作为HVKP组;从菌库里随机挑选血液感染患者KP菌株,并按照具体病史剔除伴有其他感染的菌株,最终获取菌株48株,作为普通肺炎克雷伯菌(cKP)组。比较2组血清型和高毒力基因的阳性率,计算2组比较有统计学差异的基因诊断效能。应用多因素Logistic回归分析寻找HVKP诊断分子标志物。结果HVKP组与cKP组相比,K1型比较差异有统计学意义(P<0.01)。HVKP组毒力基因阳性率排名前3种的依次是PEG344、uge、fimH,相较于cKP组,比较存在统计学差异的毒力基因分别是fimH、rmpA2、aero、iutA、kfuBC、PEG344(P<0.01)。诊断效能排序:rmpA2<fimH<aero<K1<kfuBC<iutA<PEG344。多因素Logistic回归分析显示,iutA、PEG344是HVKP的影响因素(P<0.01)。结论HVKP感染以K1血清型为主,rmpA2、fimH、aero、iutA、kfuBC、PEG344基因可作为HVKP诊断的分子生物标志物,且以PEG344、iutA的诊断效能较高。

一种非规则广义LDPC码的构造方法

广义低密度奇偶校验(Generalized Low-Density Parity-Check, GLDPC)码把低密度奇偶校验(Low-Density Parity-Check, LDPC)码中的单奇偶校验(Single Parity-Check, SPC)节点替换为校验能力更强的广义约束(Generalized Constraint, GC)节点,使其在中短码和低码率的条件下具有更低的误码率。传统GLDPC码要求基矩阵的行重等于分量码的码长,这限制了GLDPC码构造的灵活性。另外,相比于传统GLDPC码中GC节点位置的随机选取,GC节点的位置选择在GLDPC码的误码率性能上有一定的优化空间。针对以上两点,提出了一种基于渐进边增长(Progressive Edge-Growth, PEG)算法的非规则GLDPC码构造方法和一种基于Tanner图边数的GC节点位置选择算法。使用PEG算法生成的非规则LDPC码作为本地码,根据本地码的校验节点度使用多种分量码,结合GC节点位置选择算法构造非规则GLDPC码。仿真结果表明,与传统方法构造的GLDPC码相比,基于Tanner图边数的GC节点位置选择算法构造的非规则PEG-GLDPC码在误码率和译码复杂度上均得到明显改善。