bluuebunny/crossref_metadata_2025 huggingface dataset:
Rate‐determining step of butyrylcholinesterase‐catalyzed hydrolysis of benzoylcholine and benzoylthiocholine
Authors: Masson Patrick , Bec Nicole , Froment Marie‐Thérèse , Nachon Florian , Balny Claude , Lockridge Oksana , Schopfer Lawrence M.
Published: April 2004

The rate‐limiting step for hydrolysis of the positively charged oxoester benzoylcholine (BzCh) by human butyrylcholinesterase (BuChE) is deacylation (k3), whereas it is acylation (k2) for hydrolysis of the homologous thioester benzoylthiocholine (BzSCh). Steady‐state hydrolysis of BzCh and BzSCh by wild‐type BuChE and its peripheral anionic site mutant D70G was investigated at different hydrostatic pressures, which allowed determination of volume changes associated with substrate binding, and the activation volumes for the chemical steps. A differential nonlinear pressure‐dependence of the catalytic parameters for hydrolysis of both substrates by both enzymes was shown. Nonlinearity of the plots may be explained in terms of compressibility changes or rate‐limiting changes. To distinguish between these two possibilities, enzyme phosphorylation by diisopropylfluorophosphate (DFP) in the presence of substrate (BzSCh) under pressure was studied. There was no pressure dependence of volume changes for DFP binding or for phosphorylation of either wild‐type or D70G. Analysis of the pressure dependence for steady‐state hydrolysis of substrates, and for phosphorylation by DFP provided evidence that no enzyme compressibility changes occurred during the catalyzed reactions. Thus, the nonlinear pressure dependence of substrate hydrolysis reflects changes in the rate‐limiting step with pressure. Change in rate‐determining step occurred at a pressure of 100 MPa for hydrolysis of BzCh by wild‐type and at 75 MPa for D70G. For hydrolysis of BzSCh the change occurred at higher pressures because k2 << k3 at atmospheric pressure for this substrate. Elementary volume change contributions upon initial binding, productive binding, acylation and deacylation were calculated from the pressure differentiation of kinetic constants. This analysis shed light on the molecular events taking place along the hydrolysis pathways of BzCh and BzSCh by wild‐type BuChE and the D70G mutant. In addition, volume change differences between wild‐type and D70G provided new evidence that residue D70 in the peripheral site controls hydration of the active site gorge and the dynamics of the water molecule network during catalysis. Finally, a steady‐state kinetic study of the oxyanion hole mutant (G117H) showed that substitution of the ethereal sulfur for oxygen in the substrate alters the final adjustment of substrate in the active site and stabilization of the acylation transition state.
Lipids and glycosphingolipids in caveolae and surrounding plasma membrane of primary rat adipocytes
Authors: Örtegren Unn , Karlsson Margareta , Blazic Natascha , Blomqvist Maria , Nystrom Fredrik H. , Gustavsson Johanna , Fredman Pam , Strålfors Peter
Published: April 2004

We have made a comprehensive and quantitative analysis of the lipid composition of caveolae from primary rat fat cells and compared the composition of plasma membrane inside and outside caveolae. We isolated caveolae from purified plasma membranes using ultrasonication in carbonate buffer to disrupt the membrane, or extraction with nonionic detergent, followed by density gradient ultracentrifugation. The carbonate‐isolated caveolae fraction was further immunopurified using caveolin antibodies. Carbonate‐isolated caveolae were enriched in cholesterol and sphingomyelin, and the concentration was three‐ and twofold higher, respectively, in caveolae compared to the surrounding plasma membrane. The concentration of glycerophospholipids was similar suggesting that glycerophospholipids constitute a constant core throughout the plasma membrane. The composition of detergent‐insoluble fractions of the plasma membrane was very variable between preparations, but strongly enriched in sphingomyelin and depleted of glycerophospholipids compared to carbonate‐isolated caveolae; indicating that detergent extraction is not a suitable technique for caveolae preparation. An average adipocyte caveola contained about 22 × 103 molecules of cholesterol, 7.5 × 103 of sphingomyelin and 23 × 103 of glycerophospholipid. The glycosphingolipid GD3 was highly enriched in caveolae, whereas GM3, GM1 and GD1a were present inside as well as outside the caveolae membrane. GD1b, GT1b, GM2, GQ1b, sulfatide and lactosylceramide sulfate were not detected in caveolae.
Acute abdomen in Henoch–Schonlein purpura: A case report and literature review
Authors: Wong Siu‐Wang , Lee Kit‐Fai , Lai Paul Bo‐San
Published: April 2004

Henoch–Schonlein purpura (HSP) is characterized by vasculitis affecting small vessels. Typically, it would involve the skin, gut, and kidney and is associated with arthraglia or arthritis. In children, HSP may be complicated by intussusception, perforation and infarction of the gut, requiring surgical intervention. However, in adults, surgical intervention is seldom necessary. Sometimes, HSP may cause diagnostic confusion and results in unnecessary operation in children. This case report documents an adult patient who suffered from HSP who presented with acute abdomen that caused diagnostic confusion. In conclusion, high index of suspicion and early diagnosis of HSP may avoid unnecessary surgery.
Recent advances in neuro‐endovascular therapy
Authors: Yu Simon Chun‐Ho , Cheng Harold Kin‐Ming
Published: April 2004

The current article aims to provide a technology‐based overview of the recent advances in endovascular treatment approaches that have been developed for the management of intracranial aneurysms and intracranial arteriovenous malformations. Technologies such as detachable coils, protective devices for wide‐neck aneurysms, and liquid embolic agents are introduced.
The use of chromoendoscopy in the surveillance and detection of lesions of the upper gastrointestinal tract
Authors: CHOI C.Y. , CHIU P.W.Y. , KWONG K.H. , LAM S.H.
Published: April 2004

Aim: Chromoendoscopy is recently employed in the surveillance and detection of early cancers and dysplasia of the upper gastrointestinal tract. This study aims to investigate the efficacy of chromoendoscopy in the surveillance and detection of pathology in the upper gastrointestinal tract.

Method: We performed selective chromoendoscopy in patients with either high risk of early cancers or those with suspicious pathology of the upper gastrointestinal tract detected on primary endoscopy. The diagnosis of these lesions was confirmed with histology. We compared the findings before and after chromoendoscopy.

Results: From June 2202 to October 2003, we performed chromoendoscopy on 104 patients (72 males, 32 females). The mean age was 66 (range: 27–87). Seventy‐four chromoendoscopies were performed for the purpose of ‘suveillance’ which included: (i) screening for synchronous esophageal tumour; (ii) Barrett's esophagitis; (iii) reflux esophagitis; (iv) esophageal dysplasia or neoplasia; and (v) gastric intestinal metaplasia or epithelial dysplasia. Thirty were performed for ‘detection’ of new lesions which included: (i) suspicious esophageal or gastric lesions; (ii) gastric ulcer with suspicious endoscopic appearance; and (iii) gastric malignancy. In the surveillance group, new pathological findings were detection by chromoendoscopy in 12.2% patients (9/74). In the detection group, clinically important new findings were detected in 67% patients (20/30). The overall rate of new findings by chromoendoscopy is 27.9% (χ2P=0.0001).

Conclusions: Chromoendoscopy significantly delineates more pathology in upper gastrointestinal tract when compares to conventional upper endoscopy.
Loop ileostomy as temporary faecal diversion following total mesorectal excision
Authors: JEONG H.K.M. , LAM S.C.W. , LAM C.Y.W. , LAM S.H.
Published: April 2004

Aim: Anastomotic leakage following low anterior resection with total mesorectal excision carries a significant morbidity and mortality. Both loop ileostomy and loop transverse colostomy are common options of temporary faecal diversion to reduce the severity of anastomotic leakage. We use loop ileostomy routinely because of its ease of construction and closure, and low complication rate. Here, we reviewed our result of loop ileostomy.

Methods: We reviewed the medical records of all patients who had temporary loop ileostomy constructed following low anterior resection with total mesorectal excision for CA rectum, from 1.1999 to 12.2003. Stoma related morbidity pre and post–closure of loop ileostomy were recorded.

Results: Eighty‐eight patients had loop ileostomy constructed and later closed from 1.1999 to 12.2003. Seventeen of them required small bowel resection during closure of the loop ileostomy. Three patients (3.4%) had skin excoriation and one patient (1.1%) had prolonged ileus after the construction of ileostomy (3.4%). After closure of ileostomy, two patients (2.2%) had wound infection and two patients (2.2%) had anastomotic leakage. Six patients (6.8%) developed intestinal obstruction later. Post‐closure intestinal obstruction and anastomotic leakage were found to be associated with small bowel resection during the closure of ileostomy (P=0.042).

Conclusion: Loop ileostomy and its closure are associated with low complication rates. We therefore continue to advocate the use of loop ileostomy as a temporary diversion procedure after total mesorectal excision.
The use of fillet limb to reconstruct huge defect post trunk tumor excision
Authors: PANG P.C.W. , LAM S.C.K. , CHENG L.H.W. , KUMTA S. , BURD A.
Published: April 2004

Post girdle excision (forequarter amputation and hemi‐pelvectomy) for bone or soft tissue tumours result in extensive defects exposing bone and major neurovascular structures. Large flaps are necessary to reconstruct the defect and protect the underlying structures. Total thigh flap was first described in 1956 by Georgiade et al. for the treatment of large trochanteric ulcers with osteomyelitis of femur. Free fillet flaps from the amputated limb provides a large amount of soft tissue coverage without additional donor site morbidity and hence it is ideal in major reconstruction for these trunk defect. We had five patients with major excision of girdle tumour with two forequarter amputation, three hemipelvectomy (two osteosarcoma, three soft tissue sarcoma). Four fillet limbs were used (two upper limbs, two lower limbs, one multiple local transposition flaps). The clinical course, morbidity and mortality were discussed in this paper.
The results of pelvic muscle biofeedback exercise in children with faecal incontinence after surgery for severe anorectal malformation
Authors: CHAO N.S.Y. , LEUNG M.W.Y. , LEUNG A.K.P. , CHO J.S.Y. , KWOK E.C.H. , CHUNG K.W. , LIU K.K.W.
Published: April 2004

Purpose: Children with severe anorectal malformation, after anorectoplasty, frequently have faecal soiling, which is disruptive functionally and psychosocially. Post‐operative bowel management program involves multimodality treatment including drug manipulation, laxative enema and pelvic muscle training. The results of pelvic muscle biofeedback exercise are reviewed.

Methods: Patients with anorectal malformation after anorectoplasty were followed‐up at continence clinic with symptom scoring (Rintala score). Co‐operative patients with problematic soiling were selected for biofeedback treatment program. Pelvic musculature anatomy and physiology were assessed by anorectal manometry, magnetic‐ resonance imaging and transrectal ultrasonography. They received active pelvic musculature stimulation and biofeedback training of pelvic muscle (Myoexorciser 1000 Biofeedback System – VERIMED, Florida, USA). Duration of treatment ranged from 3 to 6 months. Outcome was measured by incontinence score, manometry and electromyogram of pelvic muscle.

Results: Eight boys, aged 5–11 years, completed the biofeedback program. Soiling frequency dropped significantly post treatment (P=0.0431). Electromyogram of pelvic muscle improved (P < 0.05). Overall symptom‐score confirmed functional improvement.

Conclusions: Biofeedback training program benefits children with intractable soiling after surgery for severe anorectal malformation. Follow up studies are required to confirm whether the benefit is sustained in the long term.
Pancreatic cystic tumour: A local regional hospital experience
Authors: LI W.H. , CHAN C.K. , CHEUNG M.T. , HWANG J.S.T.
Published: April 2004

Aim of study: To review the management of patients with pancreatic cystic tumour.

Method: Retrospective review of patients with pancreatic cystic tumours who has either cytological or histological diagnosis made from 1994 to 2003

Results: There were total 16 patients who had the diagnosis of pancreatic cystic tumour. The male/female ratio was 1 : 4.5 (5/11). Median of age was 51 (2–76).There were 6 (37%) serous cystadenoma, 4 (25%) mucinous cystic tumour, 3 (19%) intraductal papillary mucinous tumour and 3 (19%) solid and cystic papillary tumour. All tumours were located in the head or tail of pancreas. Median size of the tumour was 6 cm (1–15 cm). Majority of patients presented incidentally or with abdominal pain. All patients had CT scan done (except one who had only USG), and imaging was either inconclusive or incorrect in 80% of the patients. Fine needle aspiration (FNA) was performed only in seven (40%) patients. FNA result was inconclusive in six (85%) patients. A total 13 resections were performed which included seven distal pancreatectomy, four pancreaticoduodenectomy and two total pancreatectomy. There were two (15%) patient complicated with postoperative intra‐abdominal abscess and postoperative bleeding and one (7%) patient die with postoperative multiorgan failure. The median FU period was 24 months, and there were no tumour recurrence noted.

Conclusion: In this review, nature of the lesions was difficult to establish in majority of the cases preoperatively. Surgical resection seems to be a safe and viable option for the management of pancreatic cystic tumour.
Experience of breast sentinel ln biopsy in QEH
Authors: LO I. , HO P.K. , POON M. , TONG K.L. , HWANG S.T.
Published: April 2004

Background: Routine axillary dissection in breast cancer carries morbidity. Sentinel lymph node biopsy has been shown to predict axillary status. The experience of SLN biopsy in QEH is reviewed.

Materials and methods: We included all patients with unifocal, palpable T1 or T2 tumour without palpable axillary LN from January 2001 to January 2004. Those who had previous excisional biopsy were also included. We excluded patients who had previous neoadjuvant chemotherapy or previous axillary surgery. Same‐day subdermal injection of C1Tc99m sulphur colloid and peritumoral patent blue injection technique was employed. SLN detected were removed, followed by formal axillary clearance.

Outcome: The endpoint is to evaluate pathological result of SLN and remaining axillary content.

Results: Forty‐three patients had SLN biopsy. Mean age was 51.2. Mean tumour size was 2.2 cm. Dye identification rate was 86%. Isotope identification rate was 97.7%. Mean no. of SLN harvested was 1.3. Sensitivity of SLN biopsy is 95.2%. Specificity is 100%. False negative rate is 4.76%. Negative predictive value is 95.7%. Accuracy is 97.7%. 57% of axilla‐involved patients had SLN as the only LN involved. Five out of 21 SLN metastasis were micrometastasis. 60% of micrometastasis were diagnosed by immunohistochemistry.

Conclusion: Results of breast SLN biopsy in QEH is comparable to other centres and is feasible.
Treatment of genuine stress incontinence with tension free vaginal tape: five years experience in tuen mun hospital
Authors: MAH I.S.F. , YUNG Y.P. , AU W.H. , CHAN W.H. , CHIU L.P. , MAN C.W.
Published: April 2004

Aim: Tension free vaginal tape (TVT) is a minimal invasive treatment for genuine stress incontinence by providing a mid‐urethral support. The aim of this study is to review our experience in using the TVT in the treatment of stress incontinence in our hospital since 1999.

Patients and methods: Twenty‐three patients with genuine stress incontinence were treated with the TVT between March 1999 and January 2004. The mean age was 50. The preoperative investigations included history, physical examination, and aerodynamic study. Patients with derisory instability or significant cystoscoele were excluded. They were followed up after the operation and the outcome of procedure including improvement in symptoms and number of pads used were assessed.

Results: Operative time ranged from 25 to 50 min with a mean of 29. Blood loss was minimal and the hospital stay ranged from 1 to 4 days (mean 1.9 days). They were followed up for a period ranging from 2 to 60 months with a median of 62 months. 95.6% of the patients are completely dry and do not require the use of pad anymore. 91.3% of the patients are very satisfied with the result of the operation.

Conclusion: TVT is a safe and effective procedure for stress incontinence. The short‐term good results have been documented in various studies. This study shows that the mid‐term results are very promising as well as the dryness is well sustained in our patients with a median follow up of 32 months.
Comparison of systemic responses of radiofrequency ablation, cryotherapy and surgical resection in a porcine liver model
Authors: NG K.K.C. , LAM C.M. , POON R.T.P. , SHEK T.W.H. , FAN S.T.
Published: April 2004

This is an in vivo study on 23 domestic pigs to compare the systemic responses of hepatic radiofrequency ablation with those of cryotherapy and resection. Different hepatic procedures were carried on the medial lobe of liver (30% of the liver volume). Systemic responses in terms of systemic inflammatory marker changes and end‐organ functions were determined. During the early postoperative period, the systemic inflammatory markers concentration in radiofrequency ablation group was significantly lower than cryotherapy group but it was significantly higher than the control group. The corresponding concentration in hepatectomy group remained similar to the control group. Liver function, renal function and coagulation profile remained normal in radiofrequency ablation group. However, the renal function deteriorated in cryotherapy group on day 1. Both platelet count and activated clotting time showed significant derangement in cryotherapy group, compared with the control group. There was more severe interstitial pneumonitic change of porcine lung after cryotherapy than radiofrequency ablation. The systemic responses of radiofrequency ablation were significantly less severe than cryotherapy. However, the increase in serum inflammatory markers and pneumonitis after radiofrequency ablation was substantial, when compared with hepatectomy.
Laparoscopic exploration of common bile duct in difficult choledocholithiasis
Authors: TANG C.N. , TSUI D.K.K. , TAI C.K. , HA J.P.Y. , LI M.K.W.
Published: April 2004

This is a retrospective review of the role of laparoscopic exploration of common bile duct (LECBD) in the management of difficult choledocholithiasis performed in our centre during the period 1995–2003. 97 LECBDs were performed during this period. Twenty‐five of them were performed for difficult choledocholithiasis. Difficult choledocholithiasis was defined as those which ERCP failed to retrieve because of various reasons including access and cannulation difficulty (7), difficult nature of the common bile duct (CBD) stones (16) and presence of endoscopic retrograde cholangiopancreatography (ERCP) related complications (2). Altogether 2 transcystic duct explorations and 23 choledochotomies were performed. Mean operative time was 149.4 ± 49.3 min and there were three conversions (12%). Stone clearance rate was 100% and no recurrence was detected upon a mean follow‐up of 16.8 months. Only five complications were encountered which included three bile leak and two wound infections. When the results were compared to the remaining 72 LECBD for non‐difficult stone during the same period, the complication rate, conversion rate and residual stone rate were similar despite longer operation time (149.4 ± 49.4 min vs 121.6 ± 50.5 min, P=0.025)

Conclusion: LECBD is the solution to difficult CBD stones where ERCP is impossible or stone retrieval is incomplete.
The clinical efficacy of intensive chemoradiation for inoperable squamous esophageal cancer: case‐controlled study
Authors: WONG S.K.H. , CHAN A.C.W. , LEUNG S.F. , GRIFFITH J.F. , NG E.K.W. , CHUNG S.C.S.
Published: April 2004

Aims: We evaluated the role of intensive chemoradiation regimen for patients with inoperable T4 or cervical nodal metastatic squamous esophageal cancer.

Methods: From 1996 to 2003, patients with histologically proven, inoperable, squamous cell esophageal carcinoma who received intensive chemoradiation therapy of two 3‐weekly cycles of continuous infusion of 5‐fluorouracil, day 1 and 22 cisplatin and concurrent radiotherapy 50–60 Gy were recruited for analysis. Efficacy of treatment was analysed by endoscopy, biopsy, computerized axial tomography before and 8 weeks after completion of treatment. Median survival and the need palliative esophageal stenting were compared with the matched control group during the same period that decline chemoradiation therapy. Both groups were comparable in demographic characteristics, pretreatment dysphagia score, comorbidity, tumour differentiation, location, staging and size.

Results: Thirty‐six consecutive patients (33 male, mean age 63.2, S.D.9.5) with either T4 (81%) and/or cervical nodal metastatic (50%) tumour had received chemoradiotherapy. Treatment was completed in 32 patients (89%). Grade II neutropenia occurred in 8 patients (22%) and the incidence of febrile neutropenia was 11%. There was no therapy‐related mortality. Tumor volume as measured by CT scan was significantly reduced after treatment with a major clinical response (>*Τ*50% reduction in tumour volume) observed in 18 patients (50%). Four patients (11%) received salvage esophagectomy for local recurrence 1–3 years after initial complete response. As compared to the matched controlled patients, chemoradiation therapy had significantly improved the 5‐year survival (0 vs 19%, P=0.01), median survival (4.0 months vs 9.5 months, P < 0.005) and the need of palliative stenting (100 vs 22%, P=0.005).

Conclusions: Although prognosis of patients with inoperable and cervical nodal metastatic esophageal cancer is extremely poor, this study confirms the efficacy and good tolerance of radiochemotherapy in these patients which can both improve their overall survival and reduce the need of esophageal stenting.
Free Jejunal Interposition following Pharyngolaryngectomy: Report on 25 Consecutive Cases
Authors: CHENG M.S. , CHEUNG W.Y. , HO C.M.
Published: April 2004

Free jejunal interposition has become a common procedure for reconstruction of circumferential defects following pharyngolaryngectomy.

Methods: Retrospective analysis of 25 consecutive free jejunal interposition grafts performed in the Department of Surgery, Kwong Wah Hospital between 1995 and 2002. The median age was 65 (range 45–74). There were 22 men and three women. The median follow up was 20 months. The most common site was the hypopharynx (n=17), followed by larynx (n=2), neopharynx (n=2), tongue base (n=2), recurrent carcinoma thyroid (n=1) and intractable gastritis post PLO secondary to radiotherapy (n=1). They were all either T3 or T4 tumours. Three patients had received prior radiotherapy as initial treatment or for another previous primary. Twenty patients received postoperative radiotherapy. The jejunum interposition grafts were harvested from the second or third arcade. Esophago‐jejunal and pharyngo‐jejunal anastomoses were performed in sequence and in the end to end manner. Sentinel loops were used to monitor flap viability in the majority of cases.

Results: There was no peri‐operative mortality. Major complications include six anastomotic leakages treated conservatively, one delayed flap failure(1/25) due to infection and one post operative myocardial infarction. Donor site morbidity includes one intra‐abdominal haemorrhage due to slipped mesenteric ligatures and one jejuno‐jejunal anastomotic stricture. There was no fistula or stricture formation. Nineteen patients were available for assessment and 94% were able to maintain solid (11/18) and soft diet (7/18) at 1 year postoperatively. Voice rehabilitation includes electrolaryx (6), pneumatic devices (3) and Provox (5). Kaplan‐Meyer was used to estimate survival and the 1‐ and 3‐year survival rates were 70 and 46.9%, respectively. Nine patients died of loco‐regional recurrence; one with carotid blowout. One patient died of systemic metastases. Two patients succumbed to another aero‐digestive primary tumour and two to unrelated medical problem.

Conclusion: In conclusion, the free jejunal interposition graft is a safe and predictable method of reconstruction following total pharyngolaryngectomy and expeditiously providing return of function in patients with late stage disease.
221 Breast Reconstructions in 12 years – How to select options among Implants, Pedicled TRAM, Free TRAM and DIEP flaps?
Authors: CHEUNG W.Y. , LEUNG M.Y. , LEUNG M.Y. , CHENG M.S. , HO C.M.
Published: April 2004

This is a report of 221 breast reconstructions performed after total mastectomy for the treatment of breast tumour in Kwong Wah Hospital between 1991 and 2003. In these 12 years, there was a trend of increasing options among various methods of breast reconstructions. Three distinct periods: 1991–1994, 1994–2001, and 2001–03 were categorized. In the first period (91–94), 27 pedicled TRAM flap had been the workhorse for the postmastectomy reconstruction. In the second period (1994–2001), pedicled TRAM flap had dropped to 41% (52/126) while free TRAM flap that were transferred for larger breasts became equally important 45% (57/126). Latissimus Dorsi flap with mammary implant (4/126) was also used in selected patients who accepted foreign body implantation. In the third period (01–03), the concept of functional preservation of the rectus abdominus muscle had brought in a major change in autologous tissue transfer in breast reconstruction. Thereafter, a series of 43 perforator flaps (DIEP: Deep Inferior Epigastric Perforator flap) had been performed with a high success rate (100%). In the same period, 25 other options (37%) continued to be selected for appropriate patients. In the selection among various options, breast size and donor flap matching, postoperation radiation and foreign body fibrosis, donor site morbidity and free flap success rate were the major determining factors.
Interanal stool bag for the bedridden elderly with pressure ulcer
Authors: Fujii M. , Sato T.N. , Ohrui T. , Sato T. , Sasaki H.
Published: April 2004

Elderly bedridden patients with decubitus suffer from infection by decubitus contamination from stools. We developed a disposable interanal stool bag that collects stools without contamination. The interanal stool bag attaches perianally and detaches easily, similar to an artificial anal bag. Since the new bag keeps the perineum clean, it is accepted not only by patients with bed sores but also by caregivers.
Proton magnetic resonance spectroscopy in corticobasal degeneration and progressive supranuclear palsy
Authors: Negoro Kiyoshi , Tada Yukiko , Ogasawara Jun‐ichi , Kawai Motoharu , Morimatsu Mitsunori , Hashida Masahiro , Yamauchi Syu‐ichi
Published: April 2004

Background:  Corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) each have distinctive clinical features, but diagnosis is often uncertain. Our purpose was to evaluate whether localized, single‐voxel proton magnetic resonance spectroscopy (1H‐MRS) could distinguish between typical CBD and PSP patients.

Methods:  The study included 10 patients with CBD, nine with PSP and eight age‐matched normal healthy subjects. A single‐voxel method of 8 cm3 (2 × 2 × 2 cm) was used for 1H‐MRS. The volume of interest was selected at the frontoparietal cortex and the lentiform nucleus.

Results:  Patients with CBD had significantly reduced ratios of N‐acetylaspartate to choline‐containing compounds (NAA/Cho), N‐acetylaspartate to creatine and phosphocreatine (NAA/Cr) in the frontoparietal cortex and lentiform nucleus compared with the normal subjects. Patients with PSP had significantly reduced NAA/Cho and NAA/Cr ratios in the lentiform nucleus, but not in the frontoparietal cortex compared with normal subjects. There was a significant difference in the NAA/Cho in the frontoparietal lobe between CBD and PSP patients.

Conclusion:  1H‐MRS may indicate different regional patterns of neuronal involvement in CBD and PSP. We suggest that this could be helpful in the differentiation and diagnostic evaluation of CBD and PSP patients.
Root resorption and its association with alterations in physical properties, mineral contents and resorption craters in human premolars following application of light and heavy controlled orthodontic forces
Authors: Darendeliler MA , Kharbanda OP , Chan EKM , Srivicharnkul P , Rex T , Swain MV , Jones AS , Petocz P
Published: April 2004

Structured Abstract

Authors – Darendeliler MA, Kharbanda OP, Chan EKM, Srivicharnkul P, Rex T, Swain MV, Jones AS, Petocz P

Objectives – To study the effect of different orthodontic force levels on cementum, investigating from the point of view of its physical properties, alterations in the mineral components, type and location of the resorption craters and the exploration in 3D of space.

Design – In vivo human premolars subjected to heavy and light forces were employed for this study. After a period of movement they were analyzed for hardness and elasticity. Also, the mineral composition measuring Ca, P and F of the cementum root surface was investigated. A new method for volumetric analysis of resorption craters was developed.

Results – There were no significant differences for hardness and elastic modulus between the light and heavy force groups and no significant effects for different tooth positions. Significant inter‐individual variation in the Ca, P and F concentrations was noted. Force‐related data showed that mean volume of the resorption crater in light‐force group was 3.49‐fold greater than the control group, and the heavy‐force group 11.59‐fold more than control group. The heavy force group had 3.31‐fold greater total resorption volume then light force group. Buccal cervical and lingual apical regions demonstrated significantly more resorption craters than the other regions. The 2D measurements were strongly correlated to 3D measurements.

Conclusion – The application of light and heavy forces did not show any statistically significant differences in hardness and elastic modulus when compared with untreated teeth. The inconsistent increase or decrease of Ca, P and F contents between control and experimental teeth at sites of compression and tension were difficult to explain. There was more resorption by volume in the heavy force group as compared with the light group and controls. Our data also suggested that the high‐pressure zones might be more susceptible to resorption after 28 days of force application.
The Moulded Electronic Package (MEP)
Authors: Lowrie David J. J.
Published: April 2004

Two high profile goals of the electronics industry today are lead free and embedded passives. The following describes the design and construction of a populated and planarized “PCB” which accomplishes these goals. The Moulded Electronic Package also integrates bare die and other components without the use of solder, wire bonding or flip chip attach. The result is a completely populated package including EMI shielding without the need for expensive metal packages. The technology described is fully additive, using both readily available, Polymer Thick Film materials and a new, high conductivity material. High Density Interconnection is accomplished either by direct printing of 75 micron conductor traces or, for smaller dimensions, conductive ink deposited in specially “patterned” dielectric.
Temperature Dependent Deformation Analysis of Ceramic Ball Grid Array Package Assembly Under Accelerated Thermal Cycling Condition
Authors: Cho Seungmin , Han Bongtae , Joo Jinwon
Published: April 2004

A robust scheme of moire´ interferometry for real-time observation is employed to study the temperature dependent thermo-mechanical behavior of a ceramic ball grid array package assembly. The scheme is implemented with a convection-type environmental chamber that provides the rapid temperature control required in accelerated thermal cycling. Thermal deformations are documented at various temperatures. Thermal-history dependent analyses of global and local deformations are presented. A significant nonlinear global behavior is documented due to complete stress relaxation at the maximum temperature. An analysis of solder interconnections reveals that inelastic deformation accumulates at the bottom eutectic solder fillet only at high temperatures.
A Highly Reliable Design for a Nonmetallurgical Contact-Joint Structure Consisting of an Adhesive Film
Authors: Tanaka Naotaka , Kawano Kenya , Miura Hideo , Kado Yoshiyuki , Yoshida Ikuo
Published: April 2004

The interconnection reliability of a contact-joint structure with anisotropic conductive film (ACF) or non-conductive film (NCF) was evaluated in terms of stability of the compressive force at the contact face between a chip bump and a substrate pad. The key factor that dominates the interconnection reliability during temperature cycling is the amount of plastic strain in the chip bump (gold bump) at the contact face. The plastic deformation of the chip bump must therefore be controlled by selecting the appropriate mechanical properties of the adhesive film (ACF or NCF) and the build-up substrate material. Moreover, the interconnection reliability during moisture-resistance tests deteriorates because of stress relaxation near the glass-transition temperature of the commonly used build-up material. It is therefore concluded that a new material system, which includes the mechanical property of the build-up material for preventing stress relaxation, should be developed
Air Flow and Heat Transfer in Fan Cooled Electronic Systems
Authors: Grimes Ronan , Davies Mark
Published: April 2004

In this paper, measurements of surface temperature and air velocity are presented for the case of a printed circuit board with heated metal elements in a fan-induced flow. Surface temperature measurements were performed using infra red thermography, while air flow measurements were performed using Particle Image Velocimetry (PIV). The aim is firstly to provide a physical explanation of the heat transfer process for the board situated in the inlet and exit air flow from the fan, and secondly to provide a set of data to test predictive methods. The results are presented in two parts: first, surface temperature distribution and velocity field data are presented for the case of the fan drawing air from the system. The flow was found to be parallel and uniform. There were symmetrical temperature gradients across the board that were readily explained in terms of board conduction and boundary layer growth. This data set is in strong contrast to that presented in the second part of the paper, which deals with the board mounted in the fan exit flow. In this case, both the flow and the heat transfer changed dramatically. The flow here is unsteady and swirling, giving rise to significantly higher Nusselt numbers over the whole of the board. A simple method of understanding these flows is presented to help the system designer to use them to advantage. The implications for increased system reliability, due to both the measured low component temperatures and the lower operational temperature of the fan are significant.
SCHEDULING ISSUES IN SURVIVABILITY APPLICATIONS USING HYBRID FAULT MODELS
Authors: KRINGS AXEL W. , HARRISON WILLIAM S. , AZADMANESH AZAD , McQUEEN MILES
Published: April 2004

This research addresses scheduling issues in networked computer systems with survivability requirements, i.e. systems in which essential services must survive malicious acts. In order to achieve survivability based on spatial redundancy, agreement algorithms are needed as a mechanism to consolidate results of individual replicas. The potentially enormous overhead associated with communication and voting schemes of the algorithms put unique burdens on the scheduler as the efficiency of scheduling determines the suitability of the agreement algorithm. This paper derives agreement task graphs, representing computations, and inter-process communication based on phantom tasks. Task graph primitives are identified and it is shown how their scheduling directly influences the performance of the agreement algorithm. Finally, the notion of dynamic k-of-N precedence is introduced and its impact on resource reclaiming for early stopping algorithms is discussed.
CASE STUDY: APPLYING DATA MINING TO DEFECT DIAGNOSIS
Authors: JOTHISHANKAR M. C. , WU TONG (TERESA) , ROBERTS JOHNIE , SHIAU JIUN-YAN
Published: April 2004

One of the defects during the re-flow soldering in printed circuit boards is the defect of tombstone. It is a chip component that has partially or completely lifted off one end of the surface of the pad. Tombstones may be caused by several factors. In this paper, a description of the problem is presented with the factors that cause tombstones. Data mining approaches are presented to identify the factors that are significant. Data was collected over a period of one year to study this problem. Results are presented with suggested improvements.
PERFORMANCE VALUE ANALYSIS FOR THE JUSTIFICATION OF WORLD-CLASS MANUFACTURING SYSTEMS
Authors: KODALI RAMBABU , SANGWAN KULDIP SINGH , SUNNAPWAR VIVEK K.
Published: April 2004

World-class manufacturing systems (WCMS) has attracted the attention of industries all over the world. The perceptible impact of WCMS lies in attaining the far reaching world-class standards. Attempts have been made to examine WCMS for the feasibility in Indian industries. The present work describes a performance value analysis for the justification of WCMS for Indian industries.
SENSORY INFORMATION ACQUISITION FOR MONITORING AND CONTROL OF INTELLIGENT MECHATRONIC SYSTEMS
Authors: DE SILVA C. W.
Published: April 2004

Mechatronic systems are electromechanical systems where an integrated design procedure is used with respect to mechanical and electrical aspects. These systems possess computational intelligence with capabilities such as perception, learning, reasoning, and making inferences (or, decisions) from incomplete information. Concepts of sensing and information acquisition are crucial for mechatronic systems in all stages of design, development, testing, operation, and maintenance. This paper outlines the considerations of sensing and information acquisition for intelligent mechatronic systems. A typical mechatronic system operates as a self-contained unit and involves direct information acquisition. There are situations, however, where a group of mechatronic systems have to operate in a coordinated manner, as in a mechatronic workcell. Also it may be necessary to monitor a mechatronic system remotely and to share common resources between several applications. Networked control is needed then. This issue is also addressed in the paper. Several industrial applications of intelligent mechatronics have been developed in our Industrial Automation Laboratory. Some of them involve cutting, inspection, and grading of fish products. The paper presents a representative application, by highlighting information acquisition and the integration of sensing and control.
Scheduling Transportation of Live Animals to Avoid the Spread of Diseases
Authors: Sigurd Mikkel , Pisinger David , Sig Michael
Published: April 2004

In the classical vehicle-routing problem (VRP) the objective is to service some geographically scattered customers with a given number of vehicles at the minimal cost. In the present paper, we consider a variant of the VRP where the vehicles should deliver some goods between groups of customers. The customers have an associated time window, a precedence number, and a quantity. Each vehicle should visit the customers within their time windows, in nondecreasing order of precedence respecting the capacity of the vehicle. The problem will be denoted the pickup-and-delivery problem with time windows and precedence constraints (PDPTWP). The PDPTWP has applications in the transportation of live animals where veterinary rules demand that the livestocks are visited in a given sequence in order not to spread specific diseases. We propose a tighter formulation of the PDPTWP based on Dantzig-Wolfe decomposition. The formulation splits the problem into a master problem, which is a kind of set-covering problem, and a subproblem that generates legal routes for a single vehicle. The LP-relaxation of the decomposed problem is solved through delayed column generation. Computational experiments show that the obtained bounds are less than 0.24% from optimum for the considered problems. As solving the pricing problems takes up the majority of the solution time, a reformulation of the problem is proposed that makes use of the precedence constraints. By merging customers having the same precedence number into “super nodes,” the pricing problem may be reformulated as a shortest-path problem defined on an acyclic layered graph. This makes it possible to solve the pricing problem in pseudopolynomial time through dynamic programming. The paper concludes with a comprehensive computational study involving real-life instances from the transportation of live pigs. It is demonstrated that instances with up to 580 nodes can be solved to optimality.
Economies of Scale in Empty Freight Car Distribution in Scheduled Railways
Authors: Joborn Martin , Crainic Teodor Gabriel , Gendreau Michel , Holmberg Kaj , Lundgren Jan T.
Published: April 2004

In this paper, we consider empty freight car distribution in a scheduled railway system. We analyze the cost structure for the repositioning of empty cars, and conclude that the distribution cost shows an economy-of-scale behavior. In addition to the cost proportional to the number of cars sent from origin to destination, there is a cost related to car-handling operations at yards, which depends on the number of car groups that are handled. Thus, if we can find a transportation pattern in which fewer but larger groups of cars are built, the total distribution cost can be decreased.

The objective of the paper is to propose an optimization model that explicitly takes this economy-of-scale effect into account. We use a time-dependent network to describe the possible car movements in time and space, and show how this network can be transformed into a network with fixed costs on links representing movements of cars with identical origin and destination terminals. The resulting optimization model is a capacitated network design model, where each capacity constraint limits the flow on several arcs. We describe a tabu heuristic for solving the model, and present computational results.
Real-Time Multivehicle Truckload Pickup and Delivery Problems
Authors: Yang Jian , Jaillet Patrick , Mahmassani Hani
Published: April 2004

In this paper we formally introduce a generic real-time multivehicle truckload pickup and delivery problem. The problem includes the consideration of various costs associated with trucks' empty travel distances, jobs' delayed completion times, and job rejections. Although very simple, the problem captures most features of the operational problem of a real-world trucking fleet that dynamically moves truckloads between different sites according to customer requests that arrive continuously.

We propose a mixed-integer programming formulation for the offline version of the problem. We then consider and compare five rolling horizon strategies for the real-time version. Two of the policies are based on a repeated reoptimization of various instances of the offline problem, while the others use simpler local (heuristic) rules. One of the reoptimization strategies is new, while the other strategies have recently been tested for similar real-time fleet management problems.

The comparison of the policies is done under a general simulation framework. The analysis is systematic and considers varying traffic intensities, varying degrees of advance information, and varying degrees of flexibility for job-rejection decisions. The new reoptimization policy is shown to systematically outperform the others under all these conditions.
Survey of Clinical Pharmacists' Knowledge of Appropriateness of Antimicrobial Therapy for Upper Respiratory Infections and Acute Bronchitis
Authors: Mainous Arch G. , MacFarlane Lori L. , Connor Margaret K. , Green Lucy A. , Fowler Kenneth , Hueston William J.
Published: April 2004

We conducted a survey to assess clinical pharmacists' recommendation of antibiotics for upper respiratory infections (URIs) and acute bronchitis. A random sample of 752 members of the American College of Clinical Pharmacy were mailed a multiple‐choice survey that presented four examples consistent with clinical symptoms of the two disorders. Respondents were asked what treatment they would recommend for each example. The response rate was 59%. Pharmacists recommended antibiotics for the treatment of both URIs and acute bronchitis significantly more if patients' symptoms included discolored discharge or sputum as opposed to clear discharge. Those who were board certified were less likely than nonboard‐certified pharmacists to recommend antibiotics for URIs with discolored discharge. Pharmacists who specialized in either ambulatory care or infectious disease were less likely than those in other specialties to recommend antibiotics for acute bronchitis with discolored sputum. Clinical pharmacists are similar to patients and physicians in their belief that antibiotics are appropriate for URIs and acute bronchitis with discolored discharge. Considering the role that pharmacists play as clinical consultants to physicians, greater efforts should be made to educate them regarding appropriate prescription of antibiotics.
Review and Comparison of Advanced‐Generation Macrolides Clarithromycin and Dirithromycin
Authors: McConnell Scott A. , Amsden Guy W.
Published: April 2004

We reviewed English‐language clinical studies, abstracts, and review articles identified from MEDLINE searches from January 1966–August 1998, and bibliographies of identified articles to compare advanced‐generation macrolides dirithromycin and clarithromycin and their use for respiratory tract infections. Both agents have superior adverse effect profiles compared with erythromycin, the original macrolide. Both have broad antibacterial coverage, but clarithromycin usually has a lower MIC90 to susceptible organisms than dirithromycin; for most isolates this difference is not clinically significant. Clarithromycin has better in vitro coverage of Haemophilus influenzae, but this activity varies with formation of its bioactive metabolite, 14‐hydroxyclarithromycin. Neither agent is ideal for H. influenzae eradication. The agents differ markedly in terms of pharmacokinetics, pharmacodynamics, metabolism, and cost, and thus with respect to drug interaction profiles and dosages. Dirithromycin's drug interaction profile is markedly better than clarithromycin's. Clarithromycin is dosed twice/day; dirithromycin's pharmacokinetics allow once/day dosing. Dirithromycin is less expensive with regard to both cost/day and cost/treatment regimen. Clarithromycin has been studied and approved for administration to children. In adults with respiratory tract infections who are receiving drugs that would interact with clarithromycin, and in those with renal dysfunction with or without coexisting hepatic dysfunction, dirithromycin appears to be superior in terms of safety and equivalent to clarithromycin in terms of efficacy.