bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of Emotional Adjustment in Diabetic Patients: Validity and Reliability of ATT39
Authors: Dunn S M , Smartt H H , Beeney L J , Turtle J R
Published: March 2007

The ATT39 scale was developed as a norm-referenced measure of emotional adjustment in diabetic patients. Scores on three parallel forms of the parent scale changed in response to educational intervention, and the change in scores was predictive of subsequent improvement in metabolic control. We describe further reliability and validity studies with six factorially derived subscales of the ATT39, which measured perceived levels of stress, adaptation, guilt, alienation, illness conviction, and tolerance for ambiguity. Internal consistency (Cronbach α) of the unweighted total score was 0.78, and the Guttman lower bound estimate of reliability was 0.86. The test-retest reliability of the total score varied from 0.70 to 0.87, over intervals of 2 wk, 3 mo, and 6 mo, and reliability coefficients for the six factor scores averaged 0.56. ATT39 factor scores, in 134 insulin-dependent diabetes mellitus (IDDM) and 166 noninsulin- dependent diabetes mellitus (NIDDM) patients, were correlated with scores on the Cattell 16 personality factor questionnaire and the locus of control of behavior scale (LCB). In IDDM, age was related to better adaptation, increased feelings of guilt, and a more cooperative attitude to staff and treatment. In NIDDM, age was associated with increasing resignation to a conviction of chronic illness and less tolerance for the ambiguities involved in diabetes. Intelligence was correlated with less guilt and more tolerance. Anxiety was associated with significant diabetes-related stress, regardless of treatment, and with poorer adaptation and guilt in NIDDM. An external LCB was related to increased stress and guilt. The results confirm that emotional adjustment in diabetes involves dynamic interactions among feelings that are relatively stable over periods up to 6 mo and that relate meaningfully to other aspects of personality functioning.
Overnight Interruption of Wearing Insulin Pump: Substitution Dose and Injection Site of Insulin
Authors: Helve E , Pelkonen R , Koivisto V A
Published: March 2007

Discontinuing wear of the insulin pump for short periods enhances the feasibility of continuous subcutaneous insulin infusion (CSII) therapy. Because insulin requirements differ during pump and injection therapy, we studied the optimal substitution dose arid injection site in seven type I diabetic patients to compensate for the overnight (2100–0730 h) interruption of CSII. The missed basal continuous infusion dose was replaced by injecting intermediate-acting insulin subcutaneously in three different ways: 1) 1.5 times the dose in the abdomen, 2) twice the dose in the abdomen, and 3) twice the dose in the buttock.

During CSII, glycemia remained unchanged throughout the night. Both 1.5 times and twice the replacement doses injected in the abdomen resulted in an initial decline in blood glucose with hypoglycemia in two patients followed by a rebound rise. When the replacement dose of 1.5 times was used, blood glucose rose by 4.9 ± 1.2 mM overnight (P < .02). These changes after abdominal injection were associated with a rapid early absorption of injected insulin with hypoinsulinemia in the morning. With twice the replacement dose injected in the buttock, insulin absorption was slower, fluctuations in nocturnal glycemia were minor, and the blood glucose level at 0730 h was similar to that of the previous night. There was a significant inverse correlation between blood glucose and serum free-insulinlevels in the early morning (r = −.60, P < .01). In conclusion, a substitution dose of 1.5 times to twice the missed basal infusion rate injected in the buttock compensates for the overnight interruption of CSII without risk of major fluctuations in blood glucose levels or nocturnal hypoglycemia.
Surveillance in Florida of Continuous Subcutaneous Insulin Infusion Use in Cohort
Authors: Deeb L C , Williams P E
Published: March 2007

Because of concerns about safety and expense associated with continuous subcutaneous insulin infusion (CSII), all people who had used CSII as of July 1982 were identified. Annual follow-up has resulted in data for up to 61 mo. Of the 92 nonpregnant registrees, 31 were <20 yr old, 36 were 20–29, and 25 were 30 yr or older. Two deaths occurred in 1780 person-months of pump use. The cumulative proportion on the pump (CPOP) or actuarial CSII continuance proportion was 11%. There was no significant difference between sexes or between ages for men, but despite eliminating pregnant women, those ≥30 yr old had a CPOP of 0.22, compared with 0.11 for those <30 yr (P = .03). Continuance curves were no different for those beginning CSII with or without complications or for those with or without good glucose control. Those who began at patient request did have better CPOP than thoe who began at physician request (P = .05). Physician perception of clinical, mechanical, or psychosocial problems while on the pump was not predictor of continuance curves as measured by CPOP. Of the 17 physicians queried at the latest update, 9 physicians have 16 current CSII users; these 9 have only 14% of their patients in the original cohort currently on CSII. This is compared with the 3 physicians who have 34 current users and 60% of their original cohort on CSII. Four physicians no longer use CSII. Devices for CSII cost $131/person-month of use. For those discontinuing use within 3 mo of initiation of CSII, per person-month cost is $1517. These population-based data provide further information for use in deciding whether to use CSII as a therapeutic option.
Diabetes in American Indians: A Growing Problem
Authors: Gohdes D M
Published: March 2007

Non-insulin-dependent diabetes mellitus is a major health problem in American Indian communities. Indian Health Service (IHS) collects information about outpatient visits and hospitalizations and analyzes mortality in American Indians and native Alaskans. Between October 1, 1982, and September 30, 1983 (fiscal year 1983), diabetes was the second leading clinical impression for all outpatient visits of patients 15 yr and older. Discharge diagnoses confirm both microvascular and macrovascular complications. Seventy-six percent of all IHS hospitalizations during fiscal year 1983 for lower-extremity amputation also coded diabetes. In 1982, the age-adjusted diabetes death rate per 100,000 was 19.9 for American Indians and native Alaskans, compared with 9.6 for all races in the United States.
Is Islet Transplantation a Realistic Therapy for the Treatment of Type 1 Diabetes in the Near Future?
Authors: Stevens R. Brian , Matsumoto Shinichi , Marsh Christopher L.
Published: March 2007

IN BRIEF

Shapiro and colleagues recently reported a 100% cure rate for type 1 diabetes with their “Edmonton protocol” for islet transplantation. This unprecedented success has caused a groundswell of enthusiasm and an unparalleled effort to replicate their experience. It has also raised questions about the clinical reality of this therapy and sparked a dialog about which patients should benefit from receiving this scarce allocated resource. This article reviews the factors contributing to the Edmonton success and obstacles to immediate and long-term expansion of islet transplantation. The authors argue that use of the two-layered method of pancreas preservation will enable the Edmonton protocol to cure diabetes from single and marginal cadaveric donors. A concerted effort will be required to expedite routing of pancreases to islet processing centers and transplant programs. The long-term success and expansion of islet transplantation will depend on not only safer forms of immunosuppression, but also new sources of islet tissue.
Five Decades of Diabetes Patient Care: The Time of My Life
Authors: Krosnick Arthur
Published: March 2007

In Brief

“To provide clinical care and education to children and adults with diabetes has been a privilege,” says Arthur Krosnick, MD, FACP, CDE. “To observe how such efforts can delay or prevent diabetic complications was an incentive. To have enjoyed 50 years of those adventures has been an unexpected bonus.” Here, Dr. Krosnick looks back on his long career in diabetes and endocrinology, noting the many advances he witnessed and participated in along the way.
“Polypill” for Cardiovascular Disease Prevention
Authors: Narayan K.M. Venkat
Published: March 2007

Objective. To assess the components of, and potential benefit and adverse effects of, a single daily pill (a theoretical “polypill”)to prevent cardiovascular disease (CVD) by simultaneously reducing four CVD risk factors (LDL cholesterol, blood pressure, platelet function, and serum homocysteine).

Design. Meta-analyses of published randomized trials and cohort studies.

End points. Proportional reduction in fatal and nonfatal ischemic heart disease (IHD) and stroke events, life years gained, and prevalence of adverse effects.

Results. A polypill composed of a statin; three pressure-lowering drugs, each at half of its standard dose; aspirin, 75 mg; and folic acid, 0.8 mg, was estimated to potentially reduce IHD events by 88% (95% CI 84-91%) and stroke by 80% (71-87%). One-third of those taking this polypill from age 55 years or from diagnosis of diabetes or CVD would potentially benefit, gaining on average about 11 years of life free from IHD event or stroke. Such a polypill would cause adverse symptoms in 8-15% of those taking it, depending on the specific components in the formulation.

Conclusion. The polypill strategy could prevent IHD and stroke if taken by everyone (without contraindications) aged 55 years and older and everyone with existing CVD or diabetes regardless of their age. This potentially new and different strategy merits further consideration and careful evaluation.
Endoscopic assessment and treatment of lesions of the deep digital flexor tendon in the navicular bursae of 20 lame horses
Authors: SMITH M. R. W. , WRIGHT I. M. , SMITH R. K. W.
Published: March 2007

Reasons for performing study: Clinical lesions of the deep digital flexor tendon and navicular bone are being reported with increasing frequency. However, the role of direct visualisation by navicular bursoscopy in the diagnosis and management of such injuries has not been explored.

Hypothesis: Navicular bursoscopy: 1) corroborates information obtained from other, noninvasive imaging modalities; 2) allows direct visualisation of lesions unidentified by other diagnostic modalities; 3) provides further information on morphology of lesions; and 4) permits minimally invasive surgical access to lesions.

Methods: The case records of all horses that underwent diagnostic navicular bursoscopy for the investigation of lameness admitted to 2 referral clinics (the Royal Veterinary College and Reynolds House Referrals) were evaluated retrospectively. Follow‐up information was obtained by telephone questionnaire.

Results: Twenty‐three bursae were examined endoscopically in 20 horses. Tears of the deep digital flexor tendon were seen in all horses (22 bursae). In 8 bursae, cartilage lesions were also present and in one bursa this was the only abnormal finding. Computed tomography and low field magnetic resonance imaging predicted tendon lesions in most cases, but failed to identify cartilage damage. Greater than 6 month follow‐up information was available for 15 animals of which 11 were sound and 9 had returned to preoperative levels of performance.

Conclusion: Lameness localised to the foot may result from tears of the deep digital flexor tendon and/or navicular fibrocartilage loss. Navicular bursoscopy allows comprehensive evaluation of these changes and also permits appropriate lesion management.

Potential relevance: The diagnostic information obtained from and therapeutic options offered by bursoscopy justify its use in horses with clinical findings localising lameness to the navicular bursa.
Descriptive analysis of retirement of Thoroughbred racehorses due to tendon injuries at the Hong Kong Jockey Club (1992–2004)
Authors: LAM K. H. , PARKIN T. D. H. , RIGGS C. M. , MORGAN K. L.
Published: March 2007

Reasons for performing study: This study was part of a programme to optimise the longevity and maximise the health and welfare of the Thoroughbred racehorses in Hong Kong. Injuries to the superficial digital flexor (SDF) tendon are the most common veterinary reason for premature retirement in this population.

Objective: To describe the frequency and pattern of retirements associated with SDF tendon injuries in Thoroughbred racehorses and to compare the characteristics of these horses with those that retired for other reasons.

Methods: A retrospective analysis of retirement records documented in the Hong Kong Jockey Club clinical database between 1992 and 2004 was conducted. As this is complete census data, no statistical inference to the population is necessary.

Results: The mean annual cumulative incidence of retirements due to tendon injury was 3.2% accounting for 14% of all retirements. The risk of tendon injury increased over the 12 year period from 2.3–4.2%. The racing career, number of starts and earnings of horses retired with tendon injuries were reduced by 25.6, 41.2 and 53.3%, respectively. Thirteen percent of these horses never raced in Hong Kong. A greater proportion of 3‐ and 4‐year‐olds and entire males were retired because of tendon injuries. Ninety‐seven percent of injuries affected the forelimb, the right more frequently than the left. Only 19.7% of retired horses that had received ultrasound examination for SDF tendon injury retired for this reason.

Conclusions: This study provides population based data on the frequency, career and economic losses associated with tendon injury induced retirement.

Potential relevance: This descriptive study has provided a useful resource for further case‐control studies to investigate risk factors for retirement from racing due to tendon injury. This is the first step toward the development of management tools to reduce the incidence of tendon injury related retirement in Hong Kong.
Defocused CO2 laser on equine skin: a histological examination
Authors: BERGH A. , RIDDERSTRÅLE Y. , EKMAN S.
Published: March 2007

Reasons for performing study: No studies have been published on effects of treatment with a defocused beam carbon dioxide (CO2) laser on equine skin histology. A better understanding of this will help to define how lasers should be used, in order to reduce potential side effects.

Objective: To describe the acute effects of different doses of defocused CO2 laser, ranging from therapeutic to surgical levels, on equine skin.

Methods: Defocused CO2 laser was administered to the skin in the hamstrings (91 J/cm2), fetlock (137 J/cm2) and loin (450 J/cm2) areas of 13 Standardbred horses. The acute effects on skin histology were examined 90 min after the end of therapy.

Results: Mild changes with focal spongiosis and subepidermal clefts were found after 91 J/cm2 irradiation and more severe changes with diffuse subepidermal clefts after the 137 J/cm2 dose. A homogeneous eosinophilic acellular zone of dermis and destruction of adnexal structures, and significant thinning of the epidermis was observed after the 450 J/cm2 dose.

Conclusions: The present study indicates acute dose‐dependent changes in equine skin histology after laser treatment. Severe tissue damage was induced using a 450 J/cm2 dose.

Potential relevance: To reduce the potential side effects of defocused CO2 laser treatment, the laser parameters must be carefully evaluated. Caution should be taken if doses higher than 91 J/cm2 (16 W, 4 min, and 42 cm2) are used in irradiation of equine skin.
Retrospective study of dystocia in mares at a referral hospital
Authors: NORTON J. LYNCH , DALLAP B. L. , JOHNSTON J. K. , PALMER J. E. , SERTICH P. L. , BOSTON R. , WILKINS P. A.
Published: March 2007

Reasons for performing study: The period between the onset of dystocia and its resolution has an important bearing on fetal outcome. There are few published data on which to base decisions regarding optimum management of cases in practice.

Objectives: To evaluate and compare the effects of a coordinated dystocia management protocol (CDMP) with that of a previous protocol of random management on time to resolution and outcome in both an emergency dystocia referral population of mares (referred emergency cases: EM) and in a population of mares residing in hospital due to high risk pregnancy (HRP) concerns that then experience dystocia at parturition.

Methods: Retrospective study performed at a university hospital referral centre of cases presenting from 1991–2004 divided intoGroup 1(pre‐CDMP) andGroup 2(CDMP).

Results: Medical records of 71 cases with dystocia were retrieved and data recorded. For referred emergency cases (EM), time from hospital presentation to resolution decreased significantly by 32 min (P = 0.03) after institution of CDMP. Survival rate of mares at discharge was 86%. Survival of EM foals was low, with 10% inGroup 1and 13% inGroup 2, surviving to discharge. For EM foals delivered alive, survival to discharge was 30% and 43% inGroups 1and2, respectively. Median Stage II was significantly (P < 0.001) different at 71 and 282 min for EM foals delivered alive vs. those not alive at delivery, respectively. Median duration of Stage II was also significantly (P < 0.001) different between EM foals surviving and not surviving to discharge, at 44 and 249 min, respectively. Survival of HRP dystocia foals to discharge was 79%.

Conclusions: Although CDMP reduced the time from presentation at the hospital to resolution significantly for EM, total duration of Stage II for EM was unchanged, as was foal outcome.

Potential relevance: Very early referral of mares with dystocia to referral centres with dystocia management protocols may improve fetal outcome as increased duration of Stage II in the horse affects fetal outcome negatively.
Detection of rib trauma in newborn foals in an equine critical care unit: a comparison of ultrasonography, radiography and physical examination
Authors: JEAN D. , PICANDET V. , MACIEIRA S. , BEAUREGARD G. , D'ANJOU M. A. , BEAUCHAMP G.
Published: March 2007

Reasons for performing study: Previous studies have shown that in man ultrasonography is more accurate than radiography for detecting rib fractures.

Objectives: To describe clinical, radiographic and ultrasonographic findings related with rib fractures in newborn foals in an equine critical care unit; and to compare diagnostic accuracy of ultrasonography to radiography.

Methods: A prospective ultrasonographic study was performed on 29 foals presented to the emergency unit. This study was performed at the Centre Hospitalier Universitaire Vétérinaire (CHUV), University of Montreal. Physical examination as well as radiographic and ultrasonographic examinations were performed.

Results: Thoracic radiographs revealed 10 rib fractures in 5 of 26 (19%) foals. Ultrasonography revealed 49 fractures in 19 of 29 (65%) foals of which fillies (n = 13; 68%) were significantly over represented as were fractures to the left thorax (n = 15; 78%). Seventeen of 19 foals (90%) had rib fractures located 3 cm or less from the costochondral junction, the distal part of the rib being displaced laterally in all cases. In 2 foals, where both thoracic radiographs and ultrasonography detected rib fractures, the site of fractures was located on the mid portion of the rib. Rib fractures were detected only by thoracic radiographs in one foal. Sixty‐five percent (32/49) of fractured ribs had a moderate displacement (1–4 mm).

Conclusions: Rib fractures are seen frequently in newborn foals in equine critical care units. Ultrasonography is more accurate than radiography and reveals fractures in most patients presented in emergency. The position (costochondral junction) of rib fractures and of the fragments suggest that most thoracic trauma probably occurs during parturition.

Potential relevance: Ultrasound imaging increases awareness and improves the diagnosis of rib fractures in newborn foals.
Multivariable analysis of factors influencing outcome of 2 treatment protocols in 128 cases of horses responding positively to intra‐articular analgesia of the distal interphalangeal joint
Authors: KRISTIANSEN K. K. , KOLD S. E.
Published: March 2007

Reasons for performing study: There is limited knowledge available of factors influencing response to treatments of the DIP‐joint in horses with lameness responding to diagnostic analgesia of the DIP‐joint. For this reason a multivariable statistical analysis was performed.

Hypothesis: Horses with lameness reduced by ≥75% 10 min after intra‐articular analgesia of the DIP‐joint, can be treated successfully by intra‐articular medication of the joint. Multiple factors influence the response to treatment.

Methods: The study was performed retrospectively based on clinical records of horses treated with either polysulphated glycosaminoglycan (PSGAG) or methylprednisolone acetate (MPA) in the DIP‐joint between January 1996 and January 2003. Information was collected from clinical records and from the owners of the horses via a detailed questionnaire, in which they described their perception of the outcome a minimum of one year after treatment. Allocation of the horses to the 2 treatment groups was done mainly because of a change in treatment policy. In Regime A all horses received 3 intra‐articular injections of PSGAG approximately 8 days apart, whereas in Regime B all horses received a single intra‐articular injection of MPA as a first treatment. If the horse did not improve sufficiently to return to work by 4 weeks, a series of 3 intra‐articular PSGAG injections was administered.

Results: Of the horses receiving Regime A, 67% had a successful outcome, compared with 46% of the group receiving Regime B. A significantly better result was obtained in dressage horses than in jumping horses (eventing and showjumping). Other variables such as age, duration of lameness, distribution of lameness, degree of lameness, response to DIP‐joint analgesia and radiographic observations were also associated with success of treatment.

Conclusions and potential relevance: There is a rationale for using either PSGAG or MPA intra‐articularly in the treatment of lameness, reduced ≥75% within 10 min of analgesia of the DIP‐joint.
New catalyst for the synthesis of poly(butylene terephthalate) with high thermo‐oxidative stability
Authors: Massa Antonio , Scettri Arrigo , Contessa Socrate , Bugatti Valeria , Concilio Simona , Iannelli Pio
Published: March 2007

In this paper we report the employment of Ti(acac)2(O‐iPr)2 (titanium bisacetylacetonate diisopropylate) as a novel catalyst for the synthesis of poly(butylene terephthalate) (PBT). Large scale synthesis of several polymers with the new catalytic system and with the standard catalyst Ti(O‐nBu)4 (titanium tetra‐n‐butylate) have been performed in a 20 L pilot plant. In the optimized reaction conditions, Ti(acac)2(O‐iPr)2 has shown significantly higher activity than standard catalyst, Ti(O‐nBu)4. Furthermore, a stabilized PBT has been synthesized in the presence of Ti(O‐nBu)4 as catalyst with the addition of the stabilizer U626. Then, the stability of the synthesized polymers toward thermo‐oxidation has been tested in a forced circulating air oven. The polymers obtained in the presence of Ti(acac)2(O‐iPr)2 system showed higher stability towards thermo‐oxidation than stabilized and not stabilized PBT, synthesized in the presence of Ti(O‐nBu)4. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis and characterization of novel thermally stable and optically active poly(amide‐imide)s derived from N,N′‐(4,4′‐diphthaloyl)‐bis‐L‐leucine diacid and aromatic diamines
Authors: Liaw Der‐Jang , Chang Feng‐Chyuan , Liu Jui‐Hsiang , Wang Kun‐Li , Faghihi Khalil , Lee Kueir‐Rarn , Lai Juin‐Yih
Published: March 2007

A new diacid containing optically active functional groups, N,N′‐(4,4′‐diphthaloyl)‐bis‐L‐leucine diacid (3), was synthesized and used in a preparation of a series of poly(amide‐imide)s (PAIs) by direct polycondensation with various aromatic diamines in N‐methyl‐2‐pyrrolidinone (NMP). All polymers derived from diacid (3) were highly organosoluble in the solvents like N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, γ‐butyrolactone, cyclohexanone, and chloroform at room temperature or upon heating. Inherent viscosities of the PAIs were found to range between 0.34 and 0.61·dL g−1. All the PAIs afforded flexible and tough films. The glass‐transition temperatures of these PAIs were recorded between 212 and 237°C by differential scanning calorimetry, and the 10% weight loss temperatures were ranging from 372 to 393°C and 336–372°C under nitrogen and air, respectively. The polyimide films had a tensile strength in the range of 63–88 MPa and a tensile modulus in the range of 1.2–1.7 GPa. Optically active PAIs exhibited specific rotations in the range of −10.58° to −38.70°. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Comparison of the effectiveness of four different crosslinking agents with hyaluronic acid hydrogel films for tissue‐culture applications
Authors: Collins M. N. , Birkinshaw C.
Published: March 2007

The effectiveness of four different reagents, glutaraldehyde (GTA), 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC), poly(ethyelene glycol) diglycidyl ether (EX 810), and divinyl sulfone (DVS) as crosslinkers for cast hyaluronic acid (HA) films has been evaluated. Films were prepared by casting from solution and exposed to solutions of the crosslinkers in acetone–water solution. Swelling in water and in phosphate buffered saline (PBS) was then used to assess the effectiveness of the crosslinkers. GTA‐crosslinked films were found to be of low stability compared with those treated with EDC, EX 810, and DVS. Results suggest that instability in GTA‐crosslinked materials arises in part from residual acid catalyst. The effects of polymer molecular weight are not uniform. With GTA‐crosslinked film produced from higher molecular weight HA swells more, and this is attributed to reduced diffusion of the crosslinker, but with EDC, the opposite effect is observed, implying some additional molecular weight dependent mechanism. Differential scanning calorimetry and dynamic mechanical thermal analysis results suggest that there are no significant structural difference between the gels for each crosslinker system and only the crosslink density and moisture content alters the transitions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis, characterization and biological activity of C60 derivative
Authors: Jiang Guichang , Li Guangtao
Published: March 2007

A novel fullerene‐maleic anhydride derivative was synthesized via radical polymerization. It is soluble in polar solvents such as water, dimethyl sulfoxide, and tetrahydrofuran etc. The product was characterized by FTIR, UV‐Vis, GPC, and Transmission electron microscope (TEM). TEM analysis shows that the average particle diameter is about 38 nm. The in vitro antitumor activity of the fullerene‐maleic anhydride derivative has been tested and the result shows that the derivative exhibits better antitumor activity against HeLa cells and bone tumor cells. To prove water‐soluble fullerene derivatives photodynamic effect on tumor cell, i.e., the photodynamic effect on mouse bone tumor in vivo we injected the fullerene ‐maleic anhydride derivatives into the mouse bone tumor body. We found that with I‐W lamp (500 W) illumination the mouse bone tumor body was strongly damaged. The antitumor mechanism of water‐soluble fullerene‐maleic anhydride derivative was investigated for the first time. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Phosphinate Inhibitors of UDP‐N‐Acetylmuramoyl‐L‐Alanyl‐D‐Glutamate: L‐Lysine Ligase (MurE)
Authors: Štrancar Katja , Boniface Audrey , Blanot Didier , Gobec Stanislav
Published: March 2007

The increasing emergence of pathogenic bacterial strains with high resistance to antibiotic therapy has created an urgent need for the development of new antibacterial agents that are directed towards novel targets. We have focused our attention on the Mur ligases (MurC‐F), which catalyze the early steps of bacterial peptidoglycan biosynthesis, and which to date represent under‐exploited targets for antibacterial drug design. We show that some of our phosphinate inhibitors of UDP‐N‐acetylmuramoyl‐L‐alanyl:D‐glutamate ligase (MurD) also inhibits UDP‐N‐acetylmuramoyl‐L‐alanyl‐D‐glutamate:L‐lysine ligase (MurE). To obtain new information on their structure‐activity relationships, three new, structurally related phosphinates were synthesized and evaluated for inhibition of MurD and MurE.
ValC, a New Type of C7‐Cyclitol Kinase Involved in the Biosynthesis of the Antifungal Agent Validamycin A
Authors: Minagawa Kazuyuki , Zhang Yirong , Ito Takuya , Bai Linquan , Deng Zixin , Mahmud Taifo
Published: March 2007

The gene valC, which encodes an enzyme homologous to the 2‐epi‐5‐epi‐valiolone kinase (AcbM) of the acarbose biosynthetic pathway, was identified in the validamycin A biosynthetic gene cluster. Inactivation of valC resulted in mutants that lack the ability to produce validamycin A. Complementation experiments with a replicating plasmid harboring full‐length valC restored the production of validamycin A, thus suggesting a critical function of valC in validamycin biosynthesis. In vitro characterization of ValC revealed a new type of C7‐cyclitol kinase, which phosphorylates valienone and validone—but not 2‐epi‐5‐epi‐valiolone, 5‐epi‐valiolone, or glucose—to afford their 7‐phosphate derivatives. The results provide new insights into the activity of this enzyme and also confirm the existence of two different pathways leading to the same end‐product: the valienamine moiety common to acarbose and validamycin A.
A Novel Inorganic‐Organic Composite Constructed from Cobalt(II)‐Monosubstituted Polyoxometalates and Poly(amidoamine)‐NH2 Dendrimers
Authors: Zhang Xiao‐Feng , Lin Shen , Luo Geng‐Geng , Liu Chun‐Lian
Published: March 2007

An inorganic‐organic composite was prepared by poly(amidoamine) (PAMAM) dendrimer reacting with cobalt(II)‐monosubstituted polyoxometalates Na5CoII(H2O)PW11O39 (PW11Co) in an aqueous solution. The hybrid composite PW11Co/PAMAM was characterized by FT‐IR, UV‐Vis diffuse reflectance spectra (DR‐UV‐Vis), XPS, XRD and TG/DTA, indicating that the PW11Co was chemically anchored to PAMAM. The morphologies of the title composite were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The catalytic activity was evaluated by oxidation of isobutyraldehyde (IBA) to isobutyric acid (IBAc) in MeCN under mild conditions (20 °C, ambient pressure), showing that the title compound is a more effective and recoverable catalyst than corresponding PW11Co.
Non‐polar Solvent Microwave‐Assisted Extraction of Volatile Constituents from Dried Zingiber Officinale Rosc.
Authors: Yu Yong , Wang Zi‐Ming , Wang Yu‐Tang , Li Tie‐Chun , Cheng Jian‐Hua , Liu Zhong‐Ying , Zhang Han‐Qi
Published: March 2007

A new method, non‐polar solvent microwave‐assisted extraction (NPSMAE), was applied to the extraction of essential oil from Zingiber officinale Rosc. in closed‐vessel system. By adding microwave absorption medium‐ carbonyl iron powders (CIP) into extraction system, the essential oil was extracted by the non‐polar solvent (ether) which can be heated by CIP. The constituents of essential oil obtained by NPSMAE were comparable with those obtained by hydrodistillation (HD) by GC‐MS analysis, which indicates that NPSMAE is a feasible way to extract essential oil from dried plant materials. The NPSMAE took much less extraction time (5 min) than HD (180 min), and its extraction efficiency was much higher than that of conventional polar solvent microwave‐assisted extraction (PSMAE) and mixed solvent microwave‐assisted extraction (MSMAE). It can be a good alternative for the extraction of volatile constituents from dried plant samples.
Highly Efficient Regio‐ and Stereoselective Synthesis of β‐(1→6)‐Branched β‐(1→3)‐Linked Glucohexaose and Its Analogue
Authors: Yi Yue‐Tao , Zhao Qian‐Fei , Qian Feng‐Zhen , Ning Jun
Published: March 2007

A β‐(1→6)‐branched β‐(1→3)‐linked glucohexaose (1) and its lauryl glycoside (2), present in many biologically active polysaccharides from traditional herbal medicines such as Ganoderma lucidum, Schizophyllum commune and Lentinus edodes, were highly efficiently synthesized. Coupling of 2,3,4,6‐tetra‐O‐benzoyl‐β‐D‐glucopyranosyl‐ (1→3)‐2‐O‐benzoyl‐4,6‐O‐benzylidene‐α‐D‐glucopyranosyl trichloroacetimidate (7) with 3,6‐branched acceptors 8 and 12 gave β‐(1?3)‐linked pentasaccharides (9) and (13), then via simple chemical transformation 4′,6′‐OH pentasaccharide acceptors 10 and 14 were obtained. Regio‐ and stereoselective coupling of 3 with 10 and 14 gave β‐(1→3)‐linked hexasaccharides (11) and (15) as the major products. Deprotection of 11 and 15 provided the target sugar 1 and 2. Thus, a new method for the preparation of this kind of compounds was developed.
Time averaging. Does the noise really average toward zero?
Authors: Traficante Daniel D.
Published: March 2007

Time averaging is used widely in Fourier transform NMR spectroscopy. Yet there is a popular misconception of how the process increases the overall signal‐to‐noise (S/N) ratio of a spectrum. The common, but incorrect, explanation assumes that when noise is added to noise, the overall result averages toward zero. This article first shows that this explanation cannot be valid and then presents a detailed analysis of time averaging, including a mathematical derivation of the well‐known result that time averaging increases the S/N by the square root of the number of scans averaged.
Whence spin?
Authors: Zumbulyadis Nicholas
Published: March 2007

The concept of angular momentum in quantum mechanics has many counterintuitive aspects, such as assuming only certain discrete values and only certain orientations in space in the presence of external fields. Spin is more esoteric yet; it is hard to imagine how point‐particles with no spatial extent can have an intrinsic angular momentum. Nevertheless, spin is the most fundamental concept in magnetic resonance. Appreciation of the spin concept requires some understanding of the relativistic quantum mechanics developed by P. A. M. Dirac. The history of the evolution of the spin concept is traced—from the turn‐of‐the‐century observation of the Zeeman effect, through the old and new quantum mechanics, and on to Dirac's theory of the electron, which was published in the late 1920s. The special relativity theory is discussed, and there is a brief explanation of how spin emerges naturally in a relativistically correct formulation of quantum mechanics.
A simple, geometrical approach to the steady‐state solution of the Bloch equations
Authors: Szátay Csaba , Kürti Jenö , Janke Frank
Published: March 2007

This article attempts to explain the slow‐passage phenomenon in magnetic resonance from a somewhat unconventional perspective by providing a geometrical interpretation of the Bloch equations. The scope of these equations is also discussed by contrasting them with the spin‐locking experiment. This approach is intended to help newcomers reinforce their understanding of some of the basic principles of magnetic resonance, most notably with regard to the vector model. This presentation is especially useful for chemists, students of chemistry, and those who are more comfortable with a pictorial understanding of physical processes.
The effect of cigarette taxes on smoking among men and women
Authors: Stehr Mark
Published: March 2007

The literature contains numerous studies that estimate the effect of cigarette taxes on smoking across various population groups. Although the conclusions are split, most US studies find that men are more responsive to cigarette taxes than women. This paper shows that these results are due to the failure to control for state‐specific gender gaps in smoking rates that are correlated with cigarette taxes. When gender‐specific state fixed effects are included to control for these gaps, the results indicate that women are nearly twice as responsive to cigarette taxes as are men. Since the econometric specification controls for variation in the tax response by household income, it is unlikely to be responsible for the difference. Copyright © 2007 John Wiley & Sons, Ltd.
Sampling 3‐D seismic data
Authors: Bardan Virgil
Published: March 2007

A 3‐D seismic survey is usually achieved by recording a parallel profile network. The 3‐D data thus obtained are sampled and processed in a cubic grid for which the sampling requirements are generally derived from the usual 1‐D viewpoint. The spectrum of 3‐D seismic data has a support (the region of the Fourier space in which the spectrum is not zero) that can be approximated by a domain bounded by two cones. Considering the particular shape of this support, we use a 3‐D sampling theory to obtain results applicable to the recording and processing of 3‐D seismic data. This naturally leads to weaker sampling requirements than the 1‐D viewpoint does. We define the hexagonal non‐cubic sampling grid and the triangular non‐cubic sampling grid and show that fewer sample points are needed to represent 3‐D seismic data with the same degree of accuracy. Thus, using the hexagonal non‐cubic sampling grid we point out that the maximum value of the spatial sampling interval along the profiles is larger by 15.6% than the one of the cubic sampling grid. We also point out that the triangular non‐cubic sampling grid requires a number of sample points equal to half the number required by a cubic sampling grid.
The use of wiener deconvolution (an optimal filter) in nuclear magnetic resonance imaging
Authors: Letcher John H.
Published: March 2007

A computer software technique has been developed and employed to insert a modified‐Wiener‐deconvolution filter (an optimal filter) immediately following the quadrate detector of a magnetic resonance imager. The purpose of this effort is to try to suppress the undesirable effect of the noise found in the magnetic resonance imaging receiving antenna. This technique convolves the sampled real and imaginary signals taken directly from the antenna quadrature detector with a transfer function which is expressed in terms of the power spectrum of the measured signal with noise and the measured power spectrum of the noise, alone. The latter factor is measured during the dummy cycles which precede a normal scan sequence. Results are presented using data taken with a commercially available phantom.
The detection of transient‐like signals in the presence of a spatially inhomogeneous, nonstationary noise field
Authors: Silvia Manuel T.
Published: March 2007

We will consider the problem of detecting transient‐like signals by means of a spatially distributed array of sensors embedded in an inhomogeneous, nonstationary noise field. If each element of the array has an independent, uncorrupted reference sensor to estimate the noise statistics, then conventional adaptive noise cancellation algorithms can be used to improve the detection process. However, because of practical real‐world constraints, independent, uncorrupted reference sensors for the noise might not be available. Thus, the applicability of conventional adaptive noise cancellation techniques is in question. This paper will discuss the development of a knowledge‐based signal‐processing system that uses Artificial Intelligence (Al) methodologies to adaptively cancel inhomogeneous, nonstationary noise from a distributed array of passive sensors that is constrained to have no noise‐reference sensors.
Solution of convergence problem in ultrasound inverse scattering tomography
Authors: Kwon Sung J. , Park Song B. , Kim Whan W.
Published: March 2007

When the product of contrast and size of an object, which is to be reconstructed by using the ultrasound inverse scattering tomography algorithm, is large, it is well known that those algorithms fail to converge to a unique global minimum. In order to solve this well known and difficult convergence problem, in this paper we present a new method, which converges to the true solution, for obtaining the scattering potential without using the Born or Rytov approximation. This method converts the nonlinear nature of the problem into a linear one. Through computer simulations we will show the validity of the new approach for high contrast two‐dimensional scattering objects which are insonified by an incident ultrasound plane wave. Numerical results show that the reconstruction error is very small for circularly symmetric two‐dimensional cylindrical objects whose refractive indices range from small to even sufficiently large values for which the previous inverse scattering algorithms fail to converge.
Image estimation from scattered field data
Authors: Lin F. C. , Fiddy M. A.
Published: March 2007

The purpose of this paper is to reappraise the linearizing methods frequently used to solve inverse scattering problems. We describe inversion algorithms based on the Born and the Rytov approximations and the nature of the distortions obtained in the reconstructions when using them. We present extensions of these methods, namely, the distorted‐wave Born and the distorted‐wave Rytov approximations, which incorporate prior knowledge about part of the scattering structure. A method for inverting scattered field data using these distorted‐wave approximations is described, which retains the computational simplicity of the Born and the Rytov techniques. Some examples of their use with simulated and real data are given. A further extension of our distorted‐wave formalism, which leads to improvements of the reconstructed image, is suggested. This entails a spectral estimation procedure also based on the incorporation of prior knowledge about the scatterer. This spectral estimation procedure can be useful for interpolation of scattered field data as well as resolution enhancement.
Layer‐Stripping direct traveltime inversion for seismic data
Authors: Justice James H.
Published: March 2007

The problem of determining the velocity and depth structure of a layered earth model from surface seismic data is of considerable interest in exploration seismology, and many variations on ways to pose the problem and solve it have been proposed. One popular approach is based on layer stripping, in which it is assumed that all layers above a given layer whose parameters are to be determined have been inverted. This information is then used, together with seismic reflection data, to invert for the parameters of the given layer. This procedure is repeated until the entire section of interest has been inverted. The problem may be posed as a one‐, two‐, or three‐dimensional problem. The one‐dimensional case has received considerable treatment in the literature. The purpose of this paper is to extend a theoretical result and the corresponding analysis from the 1‐D to the 2‐D case. Specifically, it is shown that for a dipping plane layer 2‐D stratified earth, the depth/dip/velocity structure of the section can be determined by a direct layer‐stripping algorithm in which a system of nonlinear equations is solved for the unknown layer parameters using only traveltime data from three offset locations. This is the minimal information required to solve the problem. In practice, the solution is extremely sensitive to data errors and so a minimum norm implementation would usually be employed, utilizing the redundancy of data available from more than three offsets. It is the theoretical development which is of interest here. Its actual implementation may take many forms.
Tomographic reconstruction of multiple‐layer specimens with the scanning tomographic acoustic microscope
Authors: Lee Hua , Chiao Richard Y.
Published: March 2007

In this article we report the recent results of tomographic image reconstructions of multiple‐layer specimens at 100 MHz with the Scanning Tomographic Acoustic Microscope (STAM) system. The experiment utilizes 12 uniformly spaced projections and the results show significant improvement over the holographic images.
Maximum entropy methods in coherent radar imaging
Authors: Heidbreder G. R.
Published: March 2007

There are some compelling reasons for viewing the problem of image reconstruction from noisy or incomplete data as one of statistical estimation, i.e., of choosing, from the infinity of images consistent with the data, that image which, in some statistical sense, is most plausible. Among these reasons are the soundness of the philosophical underpinning of the resulting image reconstruction process, a greater realization of the image resolution which is inherent in the data, and freedom from many of the artifacts encountered in commonly usedad hocreconstruction schemes. One successful technique employing a principle of statistical inference is the maximum entropy technique, in which the data‐consistent image with maximum configurational entropy is chosen. It is a computationally intensive approach involving a conjugate gradient search over a convex function of a vector in a space of dimensionality equal to the number of image pixels. This technique has been employed with success in situations where the data samples are modeled as linearly related to a real non‐negative object. We investigate application of maximum entropy image reconstruction to the problem of high‐resolution radar diagnostic imaging. The problem differs from others in which maximum entropy has been applied in that the object to be imaged is complex. Although the desired image is of the magnitude of the complex object and is thus real and non‐negative, there is no linear relationship beween object magnitude and data. Rather, the data are linearly related to the complex object. Several earlier proposed methods for applying the maximum entropy principle to this problem are identified and analyzed. A method that more closely approximates true Bayesian estimation is proposed.
Local fractal geometric features for image segmentation
Authors: Keller James M. , Seo Young‐Bo
Published: March 2007

In this article, features based on fractal geometry are used for segmentation of synthetic and natural scenes. Assuming a fractional Brownian motion model of image regions, we extract, at each pixel, small, one‐variable “slices” in each of four directions from which we estimate two features: the fractal dimension and the intercept. While the fractal dimension has received most attention recently as a scale‐invariant feature, we show that the intercept is related to the dimension and possesses even better discriminatory power for segmentation purposes when calculations are made on small, one variable windows. These parameters are studied as segmentation features on both composite images of synthetically generated fractional Brownian motion surfaces and on intensity images of natural scenes.
Knowledge‐Based configuration of image segmentation processes
Authors: Liedtke C.‐E. , Blömer A. , Gahm Th.
Published: March 2007

The solution of an image interpretation problem using digital image analysis methods requires the configuration of an image analysis system to meet the requirements of this specific task the specific data material. This process includes the selection of the appropriate sequence of operators and the adaptation of the free parameters. A system has been developed and is described, which performs this configuration process automatically on the basis of a user‐specified task definition, and general knowledge of an image analysis expert. The latter knowledge has been assessed, stored, and used by employing different paradigms of knowledge representation similar to expert systems.