bluuebunny/crossref_metadata_2025_split huggingface dataset:
Necessary and Sufficient Conditions for Delay Moments in FIFO Multiserver Queues with an Application Comparing s Slow Servers with One Fast One
Authors: Scheller-Wolf Alan 
Published: December 2003

In this paper we establish the weakest known sufficient conditions for the existence of stationary delay moments in FIFO GI/GI/s queues, for s≥2. These conditions involve not only the service time distribution, as in the classic Kiefer and Wolfowitz conditions, but also the interplay of the traffic intensity and the number of servers in the queue. We then prove the necessity of our conditions for a large class of service times having finite first, but infinite αth, moment for some finite α. Such service time distributions include many, but not all of, the class of heavy-tailed distributions: The Pareto and Cauchy are members; the Weibull is not.Our results are then applied to provide one answer to the classic question: When are s slow servers (operating at rate 1/s) better than one fast server (operating at rate 1)? We consider this question with respect to the rate of decay of the tail of stationary customer delay. In a system characterized by service times that have finite mean but lack some higher moments, such as are often used to model telecommunications traffic, for s greater than a traffic-related constant, the answer is always. Our results help to quantify the benefits of extra servers, while also pointing the way towards the derivation of bounds and asymptotics for the stationary delay distribution of multiserver queues having these types of service times. Such queues are attracting a great deal of academic research, motivated by their practical use modeling telecommunications systems.
The Dynamics of Alignment: Insights from a Punctuated Equilibrium Model
Authors: Sabherwal Rajiv , Hirschheim Rudy , Goles Tim 
Published: December 2003

Several prior articles have emphasized the importance of alignment between business and information system (IS) strategies, and between business and IS structures. Seeking to advance our understanding of alignment, we examine the dynamics of changes in alignment through strategy/structure interactions in the business and IS domains. More specifically, we address the following question: In what ways does alignment evolve over time?Changes in the strategic IS management profile (which includes business strategy, IS strategy, business structure, and IS structure) over time are examined using a punctuated equilibrium model, involving long periods of relative stability, or evolutionary change, interrupted by short periods of quick and extensive, or revolutionary, change. Case studies of changes in business and IS strategies and structure over long time periods in three organizations suggest that the punctuated equilibrium model provides a valuable perspective for viewing these dynamics.The cases suggest that a pattern of alignment may continue over a long period, because either the level of alignment is high or the managers do not recognize the low alignment as a problem. Revolutions, involving changes in most or all dimensions of the strategic IS management profile, interrupt the evolutionary changes. However, organizations hesitate to make such revolutionary changes in strategic IS management profiles. Complete revolutions apparently require a combination of strong triggers. Finally, post-revolution adjustments to one dimension of the strategic IS management profile seem to follow revolutionary changes.
Scheduling Trains and Containers with Due Dates and Dynamic Arrivals
Authors: Yano Candace A. , Newman Alexandra M. 
Published: December 2003

We consider the problem of scheduling trains and containers (or trucks and pallets) between a depot and a destination. Goods arrive at the depot dynamically over time and have distinct due dates at the destination. There is a fixed-charge transportation cost for each vehicle, and each vehicle has the same capacity. The cost of holding goods may differ between the depot and the destination. The goal is to minimize the sum of transportation and holding costs. For the case in which all goods have the same holding costs, we consider two variations: one in which the holding cost at the destination is less than that at the origin, and one in which the relationship is reversed. For the first variation, we derive properties of the optimal solution which provide the basis for an O(T 2) solution procedure. For the second variation, we introduce a new definition of a regeneration state, derive strong characterizations of the shipment schedule within a regeneration interval, and develop an O(T 4) procedure. We also analyze two multi-item scenarios. In the first, for each item, the holding cost at the origin is less than that at the destination; in the second, the relationship is reversed for all items. We generalize several of the structural results for the single-item problem to the corresponding multi-item case. We also show that the optimal vehicle schedule can be obtained by solving a related single-item problem in which the item demands are aggregated in a particular way. The optimal assignment of customer orders to vehicles can then be found by solving a linear program.
Advances in Dental Imaging
Authors: Brown Jackie E 
Published: December 2003

The number of dental radiographs taken in the UK has steadily increased over the past 20 years—recently estimating around 18 million taken in the general dental services alone, and dental radiographs now account for nearly 25% of all medical radiographic exposures.1 Radiographs remain our most useful diagnostic aid. Their strength is in demonstrating hard tissue pathology, which makes radiographs particularly effective in the maxillofacial region. Although well accepted in this capacity, there remain a number of limitations and drawbacks to conventional radiographs which recent developments have begun to overcome. There have been improvements in the scope and capabilities of dental imaging equipment. There has also been a continuing effort to reduce radiation-induced harm by limiting our exposure to it. This has been possible both through the introduction of new methods and protocols for reducing individual radiation exposures and by the creation of guidelines for selecting radiographs more effectively and thereby reducing the total number of radiographs taken.
Is the Current Access to Health Information Helping or Hindering Effective Decision-making for Dentists and Patients? Guidelines for Dental Practice
Authors: Best Helen A , Bedi Raman 
Published: December 2003

With the introduction of the Internet there has been a growth both in the quantity and accessibility of information to the public concerning health issues. This improved availability of information does not always lead to a more informed public since there is no quality control of information but it can lead to a public that takes a more active role in their own health and thus is involved in shared decision-making. In order to develop a more informed public in the future, systems for quality control of information have been addressed. These systems can range from the present state of uncontrolled information (no quality control) to full-centralised control (censored information). Between these extremes lie two, more appropriate, decentralised filtering approaches—'upstream filtering’ (where third parties set quality criteria and evaluate information) and ‘down-stream filtering’ (where data are rated, labelled and weighted according to consumers’ criteria). These systems of filtering are discussed along with recommendations for those using the Internet as a source of information. The paper also documents reliable sources of information for the public, highlights the current concepts of shared decision-making, and provides some guidelines for developing an effective decision-making strategy.
Crystal structures of hydrofluorocarbons from powder X-ray diffraction data: HFC-134a and HFC-152a
Authors: Brunelli M. , Fitch A. N. 
Published: December 2003

Abstract
High-resolution powder X-ray diffraction measurements have been used to determine the low-temperature crystal structures of the hydrofluorocarbons 1,1,1,2-tetrafluoroethane (HFC-134a) and 1,2-difluoroethane (HFC-152a). Below their melting points both compounds form body-centred-cubic orientationally-disordered phases with a = 5.7606(2) Å for HFC-134a and a = 5.5433(1) Å for HFC-152a, at 120 K. These transform to ordered structures on cooling, which were solved by autoindexing, intensity extraction and direct methods with the EXPO program, and refined via the Rietveld method. HCF-134a is monoclinic, space group P21/c, a = 8.7569(4) Å, b = 9.3523(1) Å, c = 9.0784(4) Å , β = 106.479(5)°, at 80 K, Z = 8. HFC-152a is monoclinic, space group Pc, a = 8.6417(2) Å, b = 7.6748(1) Å, c = 7.9123(2) Å, β= 113.367(1)º, at 90 K, Z = 6. The packing of the molecules in the low-temperature phases is influenced by the formation of weak C-H···F interactions.
Arylisocyanide derivatives of iron(0): crystal and molecular structures of Fe(CO)2[P(OPh)3]2(CNR) (R = phenyl, para-tolyl, mesityl)
Authors: Cromhout N. L. , Gallagher J. F. , Lough A. J. , Manning A. R. 
Published: December 2003

Abstract
The iron(0) isocyanide derivatives Fe(CO)2[P(OPh)3]2(CNR), where R = phenyl, para-tolyl and mesityl, respectively, are obtained upon photolysis of Fe(CO)3[P(OPh)3]2 and reaction of the resulting photoproduct, HFe(CO)2[P(OPh)3][(PhO)2P(o-OC6H4)], with CNR. All three molecular structures possess a similar trigonal bipyramidal geometry about the iron metal core, with trans apical phosphite ligands and a trigonal planar arrangement of CO and isocyanide ligands. The phenyl isocyanide complex crystallises with two molecules per asymmetric unit (in P21/a) comprising one ordered molecule with a bent isocyanide ligand C=N-CPh 163.5(3)° and a second molecule which is disordered with two components of equal site occupancy. The para-tolyl and mesityl isocyanide derivatives (both in C2/c) have two-fold crystallographic symmetry, with the iron atom and the isocyanide ligands residing on the two-fold axes.
Form and folding of pentameric human serum Amyloid P component
Authors: Janner A. 
Published: December 2003

Abstract
The molecular prismatic forms which enclose the tertiary and the quaternary structure of the human serum Amyloid P component show remarkable ratios expressible in terms of the golden mean. A scale-rotation crystallographic point group, leaving these forms invariant, allows to explain these golden mean proportions and to assign integer indices to the vertices of the molecular forms. Cα
-positions at form-confined folding points are identified and discussed on the basis of scale-rotations relating a number of corresponding ideal positions indexed by rational numbers.
Structure and transport properties of the R2Co2Al compounds (R=Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y)
Authors: Pani M. , Merlo F. , Fornasini M. L. 
Published: December 2003

Abstract
The new R2Co2Al compounds (R=Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y), studied by single crystal and powder X-ray diffraction, crystallize with the W2CoB2 structure type. Pr2Co2Al is dimorphic, showing also its own monoclinic structure (a=9.595 Å, b=5.602 Å, c=7.753 Å, β=103.89°), which is closely related to the W2CoB2 type. Both structures are based on different packing of chains of cobalt-centred double trigonal prisms formed by rare earth and aluminum atoms. The electrical resistivity, measured in the 13-300K temperature range for all phases (save Y2Co2Al), always shows a transition point at temperatures going from 14K for Tm2Co2Al to 94K for Tb2Co2Al. As already found for Gd2Co2Al, these points should correspond to an order-disorder magnetic transition, and the deviations from de Gennes scaling indicate the influence of both the crystalline electric field and the strong coupling between 4f and conduction electrons.
'Size-effect'-like distortions in quasicrystalline structures
Authors: Welberry T. R. , Honal M. 
Published: December 2003

AbstractWe show in this paper that by applying size-effect distortions to a perfect Penrose tiling, on the basis that rhomb-edges which connect different types of vertices assume different lengths, we can obtain a diffraction pattern which shows remarkable similarity to the zero-level (h5=0) section observed in decagonal Al71Co13Ni16. In particular a central clearly delineated decagon is observed, on the inside of which there is reduced intensity, and on the outside of which there is enhanced intensity. Such a transfer of intensity is characteristic of size-effect distortions in crystals but for these systems it is necessary to have disorder involving (at least) two types of atoms. In the present case the effect is observed with all vertices occupied by a single scatterer and the system remains topologically equivalent to the Penrose pattern with long range quasicrystallinity.
Crystallographic software for the new generation
Authors: Watkin D. , Cooper R. , Prout C. K. 
Published: December 2003

Abstract
We see the current generation of area detector diffractometers as the heralds of a crystallographic revival, launching the renewal and revitalisation of the subject. Coupling these machines to appropriate software will enable chemists to undertake some of their own analyses, releasing structure analysts and crystallographers from the burden of routine tasks. Their skills can then be turned to the innumerable unsolved problems that can be called 'crystallographic' in the widest sense. CRYSTALS is a software suite that offers help and support to beginners, and still retains a rich wealth of crystallographic functionality.
Sodium-Glucose Cotransporter 2 Inhibitors and Nephrolithiasis Risk in Patients With Type 2 Diabetes
Authors: Paik Julie M. , Tesfaye Helen , Curhan Gary C. , Zakoul Heidi , Wexler Deborah J. , Patorno Elisabetta 
Published: January 2024

ImportanceType 2 diabetes (T2D) is associated with an increased risk of kidney stones. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) might lower the risk of nephrolithiasis by altering urine composition. However, no studies have investigated the association between SGLT2i use and nephrolithiasis risk in patients receiving routine care in the US.ObjectiveTo investigate the association between SGLT2i use and nephrolithiasis risk in clinical practice.Design, Setting, and ParticipantsThis new-user, active comparator cohort study used data from commercially insured adults (aged ≥18 years) with T2D who initiated treatment with SGLT2is, glucagon-like peptide 1 receptor agonists (GLP-1RAs), or dipeptidyl peptidase 4 inhibitors (DPP4is) between April 1, 2013, and December 31, 2020. The data were analyzed from July 2021 through June 2023.ExposureNew initiation of an SGLT2i, GLP-1RA, or DPP4i.Main Outcomes and MeasuresThe primary outcome was nephrolithiasis diagnosed by International Classification of Diseases codes in the inpatient or outpatient setting. New SGLT2i users were 1:1 propensity score matched to new users of a GLP-1RA or DPP4i in pairwise comparisons. Incidence rates, rate differences (RDs), and estimated hazard ratios (HRs) with 95% CIs were calculated.ResultsAfter 1:1 propensity score matching, a total of 716 406 adults with T2D (358 203 pairs) initiating an SGLT2i or a GLP-1RA (mean [SD] age, 61.4 [9.7] years for both groups; 51.4% vs 51.2% female; 48.6% vs 48.5% male) and 662 056 adults (331 028 pairs) initiating an SGLT2i or a DPP4i (mean [SD] age, 61.8 [9.3] vs 61.7 [10.1] years; 47.4% vs 47.3% female; 52.6% vs 52.7% male) were included. Over a median follow-up of 192 (IQR, 88-409) days, the risk of nephrolithiasis was lower in patients initiating an SGLT2i than among those initiating a GLP-1RA (14.9 vs 21.3 events per 1000 person-years; HR, 0.69 [95% CI, 0.67-0.72]; RD, −6.4 [95% CI, −7.1 to −5.7]) or a DPP4i (14.6 vs 19.9 events per 1000 person-years; HR, 0.74 [95% CI, 0.71-0.77]; RD, −5.3 [95% CI, −6.0 to −4.6]). The association between SGLT2i use and nephrolithiasis risk was similar by sex, race and ethnicity, history of chronic kidney disease, and obesity. The magnitude of the risk reduction with SGLT2i use was larger among adults aged younger than 70 years vs aged 70 years or older (HR, 0.85 [95% CI, 0.79-0.91]; RD, −3.46 [95% CI, −4.87 to −2.05] per 1000 person-years; P for interaction &amp;lt;.001).Conclusions and RelevanceThese findings suggest that in adults with T2D, SGLT2i use may lower the risk of nephrolithiasis compared with GLP-1RAs or DPP4is and could help to inform decision-making when prescribing glucose-lowering agents for patients who may be at risk for developing nephrolithiasis.
Unveiling the Pivotal Parameters for Advancing High Energy Density in Lithium‐Sulfur Batteries: A Comprehensive Review
Authors: Fei Yue , Li Ge 
Published: January 2024

AbstractThe lithium‐sulfur (Li‐S) battery stands as a strong contender for the next‐generation energy storage system, characterized by abundant sulfur resources, environmental sustainability, and high specific capacity. However, its energy density remains constrained by factors such as low sulfur loading and fraction in the cathode, excessive electrolyte, and an excess of anode. These mild conditions significantly limit the energy density of Li‐S batteries, making them less competitive. To achieve higher energy density, harsh operation conditions are necessary, but these remain challenging to implement, even in a lab‐scale production. In this comprehensive review, the emphasis will be on recent advancements in Li‐S batteries, specifically in the realm of designing high sulfur loading, high sulfur fraction, lean electrolyte, and low limited negative electrode Li‐S batteries. A visualizable model that illustrates the relationship between cell energy density and various cell parameters, underscoring the importance of exploring Li‐S batteries under extreme operating conditions for further development is provided. Furthermore, it will discussed the possibilities of achieving even higher energy density in Li‐S batteries and the challenges that need to be addressed to make them practical for real‐world applications.
Coumarin‐Based Light‐Responsive Composite Nanochannel Membranes for Precise Controlled Release of Pesticides
Authors: Gong Jue‐Ying , Zhou Xing‐Long , Faraj Yousef , Zou Lin‐Bing , Zhou Chang‐Hai , Xie Rui , Wang Wei , Liu Zhuang , Pan Da‐Wei , Ju Xiao‐Jie , Chu Liang‐Yin 
Published: January 2024

AbstractThe precise, controllable, and safe application of pesticides can effectively reduce pesticide consumption and minimize chemical pollution at the source. Here, a light‐responsive controlled‐release system with flexible control, precise release, easy recovery, and suitability for future pesticide application in aquatic environments is proposed. The system precisely controls the release of pesticides through a light‐responsive composite nanochannel membrane (CTC@SNM/PET) with reactive coumarin derivatives (CTC) as gating molecules. The prepared nanochannel membrane has an ultrathin thickness of 67.5 nm and well‐ordered vertical nanochannels with a uniform size of 1.9 nm, providing a prerequisite for precise molecular gating and high permeability for mass transport. CTC monomers can realize cycloaddition/cyclocracking and nanochannel closing/opening to control the release of pesticides by controlling 365/254 nm ultraviolet light irradiation. As a proof of concept, the light‐responsive controlled‐release system based on CTC@MSF/PET against Saprolegnia parasitica achieves an inhibition rate of more than 95% and reduces pesticide residues by 56.5% compared to the control group. The proposed membrane system has great application potential to easily enable remote, quantitative, timed, and positioned pesticide application, thereby reducing pesticide residues and providing a prospective approach to reducing environmental and human risks.
Breaking‐Down Tumoral Physical Barrier by Remotely Unwrapping Metal‐Polyphenol‐Packaged Hyaluronidase for Optimizing Photothermal/Photodynamic Therapy‐Induced Immune Response
Authors: Sun Quanwei , Li Yunlong , Shen Wei , Shang Wencui , xu Yujing , Yang Jinming , Chen Jie , Gao Wenheng , Wu Qinghua , Xu Fan , Yang Ye , Yin Dengke 
Published: January 2024

AbstractThe therapy of solid tumors is often hindered by the compact and rigid tumoral extracellular matrix (TECM). Precise reduction of TECM by hyaluronidase (HAase) in combination with nanotechnology is promising for solid tumor therapeutics, yet remains an enormous challenge. Inspired by the treatment of iron poisoning, here a remotely unwrapping strategy is proposed of metal‐polyphenol‐packaged HAase (named PPFH) by sequentially injecting PPFH and a clinically used iron‐chelator deferoxamine (DFO). The in situ dynamic disassembly of PPFH can be triggered by the intravenously injected DFO, resulting in the release, reactivation, and deep penetration of encapsulated HAase inside tumors. Such a cost‐effective HAase delivery strategy memorably improves the subsequent photothermal and photodynamic therapy (PTT/PDT)‐induced intratumoral infiltration of cytotoxic T lymphocyte cells and the cross‐talk between tumor and tumor‐draining lymph nodes (TDLN), thereby decreasing the immunosuppression and optimizing tumoricidal immune response that can efficiently protect mice from tumor growth, metastasis, and recurrence in multiple mouse cancer models. Overall, this work presents a proof‐of‐concept of the dynamic disassembly of metal‐polyphenol nanoparticles for extracellular drug delivery as well as the modulation of TECM and immunosuppressive tumor microenvironment.
Advanced Effect of the Substitution of Zn2+ on the Solid‐State Synthesis of Red Phosphor, High Temperature Phase NaMgPO4:Eu2+
Authors: Du Yuze , Seto Takatoshi , Liu Wenjing , Wang Yuhua , Ma Xiongbo 
Published: January 2024

AbstractIt is known that high‐temperature phase (olivine structure) of NaMgPO4:Eu2+ (NMP:Eu2+) is a precious oxide phosphor suitable for LED devices, emitting red at 625 nm under blue excitation. However, mainly due to the stable glaserite structure in the wide range of low temperature, pure olivine‐phase NMP:Eu2+ is obtained only by using melt‐quenching and arc‐imaging furnace so far, which is inconvenient for the purpose of mass‐production or industry. Generally, a traditional solid‐state method is simpler and pollution‐free, which is more favorable in phosphor‐industry. Here, it is found that when quite small amount of Zn2+ is substituted for NMP:Eu2+ in solid‐state method, the purity of olivine phase is much improved and the luminescence intensity is significantly improved. For the Na(Mg,Zn)PO4:Eu2+ having new composition, crystal structure, optical properties, and color properties are investigated. The phase transition temperature before and after doping with Zn2+ are calculated by combining TG/DSC experimental measurements and first‐principles calculations. In addition, other characteristics related to the phosphor, such as structure, morphology, luminescence lifetime, thermal quenching properties, and quantum efficiency, are also studied in detail. Finally, it is demonstrated that this phosphor can be utilized in various applications through the manufacturing of LED devices, fluorescent pigments, and plant growth.