Particle-type dependence of azimuthal anisotropy and nuclear modification of particle production in Au+Au collisions at square root of sNN=200 GeV

We present STAR measurements of the azimuthal anisotropy parameter v(2) and the binary-collision scaled centrality ratio R(CP) for kaons and lambdas (Lambda+Lambda) at midrapidity in Au+Au collisions at square root of s(NN)=200 GeV. In combination, the v(2) and R(CP) particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish p(T) approximately 5 GeV/c as the value where the centrality dependent baryon enhancement ends. The K(0)(S) and Lambda+Lambda v(2) values are consistent with expectations of constituent-quark-number scaling from models of hadron formation by parton coalescence or recombination.

Pion-Kaon correlations in central Au+Au collisions at square root [sNN] = 130 GeV

Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at sqrt[s(NN)]=130 GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.

Three-pion Hanbury Brown-Twiss correlations in relativistic heavy-ion collisions from the STAR experiment

Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at sqrt[s(NN)]=130 GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.

Transverse-momentum and collision-energy dependence of high-pT hadron suppression in Au+Au collisions at ultrarelativistic energies

We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5<p(T)<12 GeV/c. The collision energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.

Evidence from d+Au measurements for final-state suppression of high-p(T) hadrons in Au+Au collisions at RHIC

We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high p(T)) in minimum bias and central d+Au collisions at sqrt[s(NN)]=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high p(T) previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.

Narrowing of the balance function with centrality in Au+Au collisions at the square root of SNN = 130 GeV

The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified charged pion pairs in Au+Au collisions at the square root of SNN = 130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization.

Immunohistochemical evaluation of a malignant intestinal carcinoid in a dog

An intestinal carcinoid with multiple metastases was identified in a 5-year-old male Shih Tzu with a clinical history of anemia, fatigue, anorexia, vomiting, intermittent diarrhea, intestinal bleeding, and progressive emaciation. There was a yellowish-white mass 15 mm in diameter in the anterior jejunum and white nodules consistent with metastases in many organs. Histopathologically, the mass consisted of neoplastic cells arranged in lobules, trabeculae, or closely interdigitating islands of cells. Neoplastic cells were generally polygonal with round hyperchromatic nuclei, modest amounts of eosinophilic cytoplasm, and eosinophilic cytoplasmic granules. Mitoses were common. Rosette formations of tumor cells were apparent in metastatic tumors. Immunohistochemically, tumor cells stained positive for cytokeratin 13, synaptophysin, protein gene product 9.5, neuron-specific enolase, chromogranin A, calcitonin gene-related peptide, serotonin (5-HT), and Leu-7. Serum 5-HT concentrations for this dog were increased 10-fold compared with those of normal dogs. All findings were consistent with a diagnosis of a malignant intestinal carcinoid.

Disappearance of back-to-back high-pT hadron correlations in central Au+Au collisions at sqrt[s NN ] =200 GeV

Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.

Azimuthal anisotropy and correlations in the hard scattering regime at RHIC

Azimuthal anisotropy (v(2)) and two-particle angular correlations of high p(T) charged hadrons have been measured in Au+Au collisions at sqrt[s(NN)]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high p(T) partons. The monotonic rise of v(2)(p(T)) for p(T)<2 GeV/c is consistent with collective hydrodynamical flow calculations. At p(T)>3 GeV/c, a saturation of v(2) is observed which persists up to p(T)=6 GeV/c.

Coherent rho(0) production in ultraperipheral heavy-ion collisions

The STAR Collaboration reports the first observation of exclusive rho(0) photoproduction, AuAu-->AuAurho(0), and rho(0) production accompanied by mutual nuclear Coulomb excitation, AuAu-->Au*Au*rho(0), in ultraperipheral heavy-ion collisions. The rho(0) have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrt[s(NN)]=130 GeV agree with theoretical predictions treating rho(0) production and Coulomb excitation as independent processes.

Centrality dependence of high-p(T) hadron suppression in Au+Au collisions at sqrt[s(NN)]=130 GeV

Inclusive transverse momentum distributions of charged hadrons within 0.2<p(T)<6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at sqrt[s(NN)]=130 GeV. Hadron yields are suppressed at high p(T) in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-p(T) hadron production in heavy-ion collisions at high energy.

Antimicrobial susceptibility of major pathogens of orofacial odontogenic infections to 11 beta-lactam antibiotics

In this study, we evaluated the current effectiveness of 11 beta-lactam antibiotics for treatment of orofacial odontogenic infections by determining the antimicrobial susceptibility of the major pathogens. The antimicrobial susceptibilities of viridans streptococci (n = 47), Peptostreptococcus (n = 67), Porphyromonas (n = 18), Fusobacterium (n = 57), black-pigmented Prevotella (n = 59) and non-pigmented Prevotella (n = 47) isolated from pus specimens of 93 orofacial odontogenic infections to penicillin G, cefmetazole, flomoxef, cefoperazone, cefoperazone/sulbactam, ceftazidime, cefpirome, cefepime, cefoselis, imipenem and faropenem were determined using the agar dilution method. Penicillin G, most cephalosporins, imipenem and faropenem worked well against viridans streptococci, Peptostreptococcus, Porphyromonas and Fusobacterium. Penicillin G and most cephalosporins, including fourth-generation agents, were not effective against beta-lactamase-positive Prevotella, though they were effective against beta-lactamase-negative strains. Cefmetazole, cefoperazone/sulbactam, imipenem and faropenem expressed powerful antimicrobial activity against beta-lactamase-positive Prevotella. In conclusion, penicillins have the potential to be first-line agents in the treatment of orofacial odontogenic infections. Most of the other beta-lactam antibiotics, including fourth-generation cephalosporins, were not found to have greater effectiveness than penicillins. In contrast, cefmetazole, cefoperazone/sulbactam, imipenem and faropenem were found to have greater effectiveness than penicillins.

Azimuthal anisotropy of K(0)(S) and Lambda+Lambda production at midrapidity from Au+Au collisions at sqrt[s(NN)]=130 GeV

We report STAR results on the azimuthal anisotropy parameter v(2) for strange particles K(0)(S), Lambda, and Lambda at midrapidity in Au+Au collisions at sqrt[s(NN)]=130 GeV at the Relativistic Heavy Ion Collider. The value of v(2) as a function of transverse momentum, p(t), of the produced particle and collision centrality is presented for both particles up to p(t) approximately 3.0 GeV/c. A strong p(t) dependence in v(2) is observed up to 2.0 GeV/c. The v(2) measurement is compared with hydrodynamic model calculations. The physics implications of the p(t) integrated v(2) magnitude as a function of particle mass are also discussed.

Midrapidity Lambda and Lambda(macro) production in Au+Au collisions at the square root of [s(NN)]=130 GeV

We report the first measurement of strange (Lambda) and antistrange (Lambda macro) baryon production from square root of [s(NN)]=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Lambda and Lambda; hyperons is found to be approximately proportional to the number of negative hadrons. The production of Lambda; hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone.

Bacteriology and antimicrobial susceptibility of gram-positive cocci isolated from pus specimens of orofacial odontogenic infections

We recently reported the beta-lactamase production and antimicrobial susceptibility of anaerobic gram-negative rods isolated from pus specimens of 93 orofacial odontogenic infections. In this report, we determine the bacteriology and antimicrobial susceptibility of bacteria other than anaerobic gram-negative rods, mainly gram-positive cocci, isolated from the same specimens. Streptococcus constellatus and Peptostreptococcus micros were frequent isolates from all types of infection examined. Peptostreptococcus prevotii, Corynebacterium species, and Eubacterium species were recovered only from dentoalveolar infections, while Gemella morbillorum was found more frequently in periodontitis than in the other infections. beta-Lactamase-positive strains were detected only in staphylococci. Ampicillin, ampicillin/sulbactam, cefazolin, cefotaxime, imipenem, erythromycin, clindamycin and levofloxacin showed high susceptibility rates (> or = 77%) against viridans streptococci, Peptostreptococcus and Gemella. Minocycline showed a high MIC90 value against viridans streptococci (32 microg/ml), and metronidazole was effective against Peptostreptococcus and Gemella. These results provide useful information for the treatment of orofacial odontogenic infections.

Effect of beta-aminopropionitrile and hyaluronic acid on repair of collagenase-induced injury of the rabbit Achilles tendon

Collagenase was injected into the Achilles tendon of both hind legs of 10 clinically normal adult male New Zealand white rabbits. One month after induction of the injury, beta-aminoproprionitrile (BAPN) or hyaluronic acid (HA) was injected into the tendon core of the right hind leg of each rabbit, the left hind leg being left untreated. The treatment effects were evaluated by electron microscopy and analysis of the glycosaminoglycan (GAG) content of samples at 2 and 6 months post-treatment. At 2 months, collagen fibrils in tendons from both hind legs were relatively small in diameter, irregularly arranged, and interspersed with abundant active tenocytes as compared with those in normal tendon uninjured by collagenase. In the matrix, the amount of HA increased, but chondroitin-6-sulphate was eliminated. At 6 months, BAPN-treated tendons had small-diameter, regularly arranged collagen fibrils. HA-treated tendons, on the other hand, had large diameters, as well as regularly arranged collagen fibrils by comparison with non-treated tendon. The results suggest that HA, unlike BAPN, promoted healing.

Measurement of inclusive antiprotons from Au+Au collisions at square root of s(NN) = 130 GeV

We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions at square root of s(NN) = 130 GeV by the STAR experiment at RHIC. The antiproton transverse mass distributions in the measured transverse momentum range of 0.25<p( perpendicular)<0.95 GeV/c are found to fall less steeply for more central collisions. The extrapolated antiproton rapidity density is found to scale approximately with the negative hadron multiplicity density.

d Macro and (3)He macro production in square root of s(NN) = 130 GeV Au+Au collisions

The first measurements of light antinucleus production in Au+Au collisions at the Relativistic Heavy-Ion Collider are reported. The observed production rates for d macro and (3)He macro are much larger than in lower energy nucleus-nucleus collisions. A coalescence model analysis of the yields indicates that there is little or no increase in the antinucleon freeze-out volume compared to collisions at CERN SPS energy. These analyses also indicate that the (3)He macro freeze-out volume is smaller than the d macro freeze-out volume.

Plate fixation after mandibular osteotomy

Skeletal asymmetry in patients who undergo orthognathic surgery is frequently associated with postoperative temporomandibular joint (TMJ) disorders caused by condylar rotation. This study was designed to elucidate the relation between changes in the condylar long axis and TMJ function after bisagittal split osteotomy (BSSO). A total of 42 patients with mandibular prognathism underwent BSSO. Split osseous fragments were secured by standard titanium plates in 22 patients; bent titanium plates were used to secure fragments in 20 patients. The angle of the bent plates was adjusted to avoid displacement of the condyle after osteotomy, as compared with condylar position on preoperative submental-vertical (S-V) cephalograms. The postoperative position of the condyle was assessed on X-ray film, and changes in TMJ function were evaluated. The condylar long axis differed significantly on X-ray film between patients using a standard titanium plate and those using a bent plate (P<0.05), and no sign of TMJ functional impairment was noted in the bent-plate group. Although the use of bent plates requires further study, maintenance of a suitable position of the condyle relative to the condylar axis is one of the conditions for a successful outcome of BSSO.

A model for temporomandibular joint disc repositioning surgery

PURPOSE

The present study establishes a model of reversible anterior disc displacement using the rabbit craniomandibular joint (CMJ) and examines the period required for successful disc repositioning surgery.

MATERIALS AND METHODS

The left CMJ was exposed surgically in 27 animals and a suture positioned at the posterolateral portion of the disc was pulled in an anterior direction causing 7 mm of anterior disc displacement. The suture was then fixed to the zygomatic arch. The changes in the CMJ were observed microscopically in 3 rabbits each at 2, 3, 5, 8, and 24 weeks. Another 12 rabbits underwent secondary disc repositioning surgery either the second and third week after disc displacement, and then 3 rabbits from each group were assessed microscopically at 5 to 6 weeks and 21 to 22 weeks after the first operation. Ten rabbits had a sham operation, and 2 served as unoperated controls. Histomorphometric evaluation included changes in morphology, cartilage, and disc condition.

RESULTS

Progressive osteoarthritic change was induced by disc displacement. Articular disc perforation at 5 weeks after the first operation was accompanied by subchondral bone exposure. The CMJ morphology was almost normal in rabbits that underwent secondary disc repositioning 2 weeks after disc displacement. However, osteoarthritic changes and perforated discs similar to those in rabbits that did not undergo secondary disc repositioning were seen in animals in which repositioning was done in the third week.

CONCLUSION

Artificial disc displacement in the rabbit causes osteoarthritic changes are reversible when the displaced disc is restored within after 2 weeks but not at 3 weeks.

Implantation metastasis of head and neck cancer after fine needle aspiration biopsy

One possible complication of the aspiration biopsy of malignant tumors is dissemination of tumor cells along the needle track. However, a search of the literature revealed few definite reports of implantation metastases of head and neck tumors after fine needle aspiration biopsy (FNAB). Here we report two cases of skin metastasis of head and neck cancer after FNAB, including a patient with papillary adenocarcinoma of the thyroid and one with adenoid cystic carcinoma of the submandibular gland. Surgical treatment prevented the spread of the tumor in both cases and there have been no evidence of recurrence to date. This report should alert head and neck surgeons to the possibility of implantation metastasis after FNAB.

Methylcellulose-immobilized reversed-phase precolumn for direct analysis of drugs in plasma by HPLC

We evaluated a new restricted access media (RAM) precolumn for direct analysis of drugs in plasma using a column switching HPLC system. The new RAM material was prepared by the modification of the external surface of porous silica with hydrophilic methylcellulose (MC), followed by modification of the internal surface with octadecylsilane (ODS). The external surface of the MC-immobilized ODS silica material (MC-ODS) suppressed the adsorption of proteins, while the internal surface of MC-ODS retained various types of drugs, such as ketoprofen, propranolol, caffeine and atenolol in plasma samples. In addition, MC-ODS allowed direct analysis of drugs in a 1000-microL plasma sample to monitor trace amounts of analytes contained. Reduced efficiency and clogging of the MC-ODS precolumn and/or the analytical column were not observed even after the repetitive injection of plasma sample up to 40 mL. Our results indicated that the MC-ODS precolumn could be used in pharmacodynamic and clinical studies.

Abnormalities of gonadotrophs in the adenohypophysis of infertile male PD rats

Male PD strain rats are sterile in the homozygous condition (pd/pd) due to abnormal spermatogenesis detectable at around nine weeks of age. Previous studies have indicated electron microscopic abnormalities in the Sertoli cells of pd/pd males at three and 12 weeks of age. Since spermatogenesis and Sertoli cell function depend on gonadotropins (luteinizing and follicle-stimulating hormones [LH and FSH]) and testosterone, production and/or secretion of these hormones might be altered in pd/pd males. The aim of the study reported here was to investigate the hormonal status of pd/pd males at three, six, and nine weeks of age. Although alteration was not evident in the LH-immunoreactive cells, FSH-immunoreactive cells in pd/pd males were small in size with scant cytoplasm and were reduced in number and area (73 and 51% of phenotypically normal pd/+ males, respectively) at three weeks of age, although serum FSH concentration was similar to that in pd/+ males. At six and nine weeks of age, percentages of the areas occupied by LH- and FSH-immunoreactive cells in pd/pd males were higher than those in pd/+ males. Serum FSH concentration in pd/pd males was significantly high at nine weeks of age, although a difference in serum LH and testosterone concentration was not evident. These results suggest that FSH production in pd/pd males is decreased at three weeks of age. This might be associated with the Sertoli cell abnormalities and subsequent abnormal spermatogenesis seen in adult life.

Multiplicity distribution and spectra of negatively charged hadrons in Au+Au collisions at square root of (sNN) = 130 GeV

The minimum-bias multiplicity distribution and the transverse momentum and pseudorapidity distributions for central collisions have been measured for negative hadrons ( h(-)) in Au+Au interactions at square root of ([s(NN)]) = 130 GeV. The multiplicity density at midrapidity for the 5% most central interactions is dN(h(-))/d(eta)/(eta = 0) = 280+/-1(stat)+/-20(syst), an increase per participant of 38% relative to pp collisions at the same energy. The mean transverse momentum is 0.508+/-0.012 GeV/c and is larger than in central Pb+Pb collisions at lower energies. The scaling of the h(-) yield per participant is a strong function of p( perpendicular). The pseudorapidity distribution is almost constant within /eta/<1.