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The densification of parts that are produced by binder jetting Additive Manufacturing (AM; a.k.a. “3D Printing”) is an essential step in making them mechanically useful. By increasing the packing factor of the powder bed by incorporating nanoparticles into the binder has potential to alleviate the amount of shrinkage needed for full densification of binder jet parts. We present preliminary data on the use of 316L Stainless Steel Nanoparticles (SSN) to densify 316L stainless steel binder jet parts. Aqueous solutions of Diethylene Glycol (DEG) or Ethylene Glycol (EG) were prepared at different DEG/water and EG/water molar ratios; pH of the solutions was adjusted by the use of 0.10 M sodium hydroxide. Nanoparticles were suspended in a resulted solution at a volume percentage of SSN/solution at 0.5%. The suspension was then sonicated for thirty minutes. One milliliter of the suspension was added stepwise to a sintered, printed disk with the dimensions: (d = 10 mm, h = 3 mm) in the presence of a small magnet. The 3D part was then sintered again. Moreover, the increase in the mass of the 3D part was used as indication of the amount of nanoparticles that diffused in the 3D part. This mass percent increasemore » was studied as a function of pH of the suspension and as function DEG/water molar ratio. Unlike EG, data show that change in pH affects the mass percent when the suspension was made with DEG. Finally, optical analysis of the discs’ cross sections revealed trends metallic densities similar to trends in the data for mass increase with changing pH and water molar ratio.« less

This paper investigates physicochemical properties of four different types of bio-oil produced through hydrothermal liquefaction (HTL) and vacuum pyrolysis including wood pallet, corn stover, miscanthus and swine manure. It should be noted that the term bio-oil in this paper is used to refer to synthesized oil from post processing of biomass. Accordingly, swine manure was processed under HTL conditions of 340 °C, 10–12 MPa with 15 min residence time. Bio-oils from miscanthus, corn stover and wood pellet were produced at 450 °C under vacuum pyrolysis. Furthermore, in this paper the merit of applying each of these bio-oils as a precursor for producing bio-adhesive was studied using physiochemical and rheological characterization. Chemical functional groups and individual compounds were identified with GC-MS, NMR and FT-IR, while molecular weight distribution determined using GPC showed that wood pellet bio-oil has the lowest molecular weight followed by those from corn stover, miscanthus and swine manure. In addition, boiling point distributions of different fractions of bio-oils were analyzed. Furthermore, TLC-FID was used to determine different fractions of bio-oils based on their solubility in comparison with those of petroleum. It was shown that overall bio-oils from woody bio-mass have higher amount of alcoholic compounds as evidenced by the presence of strong peaks related to ether and alcohols in FTIR spectra; in addition, the TLC-FID analysis showed presence of higher fraction of fused poly aromatic rings referred to “asphaltene” in bio-oils produced from woody biomass compared to bio-oils from swine manure. The results of our characterization show the importance of feedstock composition and their effect on the characteristics of bio-oils as well as their applicability for use in bio-adhesives production.

Pseudouridine at position 39 (Psi(39)) of tRNA's anticodon stem and loop domain (ASL) is highly conserved. To determine the physicochemical contributions of Psi(39)to the ASL and to relate these properties to tRNA function in translation, we synthesized the unmodified yeast tRNA(Phe)ASL and ASLs with various derivatives of U(39)and Psi(39). Psi(39)increased the thermal stability of the ASL (Delta T (m)= 1.3 +/- 0.5 degrees C), but did not significantly affect ribosomal binding ( K (d)= 229 +/- 29 nM) compared to that of the unmodified ASL (K (d)= 197 +/- 58 nM). The ASL-Psi(39)P-site fingerprint on the 30S ribosomal subunit was similar to that of the unmodified ASL. The stability, ribosome binding and fingerprint of the ASL with m(1)Psi(39)were comparable to that of the ASL with Psi(39). Thus, the contribution of Psi(39)to ASL stability is not related to N1-H hydrogen bonding, but probably is due to the nucleoside's ability to improve base stacking compared to U. In contrast, substitutions of m(3)Psi(39), the isosteric m(3)U(39)and m(1)m(3)Psi(39)destabilized the ASL by disrupting the A(31)-U(39)base pair in the stem, as confirmed by NMR. N3-methylations of both U and Psi dramatically decreased ribosomal binding ( K (d)= 1060 +/- 189 to 1283 +/- 258 nM). Thus, canonical base pairing of Psi(39)to A(31)through N3-H is important to structure, stability and ribosome binding, whereas the increased stability and the N1-proton afforded by modification of U(39)to Psi(39)may have biological roles other than tRNA's binding to the ribosomal P-site.

The NMR-derived structure, dynamics and metal binding of a unique 17-residue DNA stem and loop hairpin were determined. The hairpin binds one Mg2+ ion and is a biologically active DNA analogue of the yeast tRNAPhe anticodon domain only when two naturally occurring modified nucleosides, d(m5C) and d(m1G), are site selectively incorporated. The modified nucleosides aided in signal assignments in lieu of isotope labeling. Signal assignments were accomplished for 80% of the exchangeable and non-exchangeable protons. Titration of the DNA with Mn2+, monitored by 1H NMR spectroscopy, indicated that the Mg2+ binding site is located in the loop of the hairpin at the bottom of the stem. The binding of Mg2+ contributed to loop stability. Loop dynamics were evidenced by line broadness on the methyl signal of d(m1G) and were compared with that of an identical tDNA stem and loop hairpin that lacked the d(m1G) modification but contained d(m5U). TDNA hairpin dynamics are discussed in the light of the Mg2+ binding constants for the two tDNAPhe. A highly refined, Mg2+-bound structure of the tDNAACPhe is presented along with computer-simulated effects of Mg2+ on the tDNA's net surface charge and surface of H2O.

In tRNA crystal structures, the only nonaromatic ribonucleoside, dihydrouridine (D) and 3′-adjacent nucleotides adopt the infrequent 2′-endo conformation. Analysis of D, DUA and UUA by circular dichroism (CD) and NMR confirmed that D produces the 2′-endo conformation of the trimer and is responsible for the same in tRNA. The nucleoside, 3-[3-(S)-amino-3-carboxypropyl]uridine (acp3U) occurs in the tRNA sequence D-acp3U-A. CD spectra indicated that D-acp3U-A and U-acp3U-A bind Mg2+, whereas acp3U, D-acp3U, DUA and UUA do not. Ion dependent changes in chemical shifts and paramagnetic broadening of 1H signals indicated that Mg2+ coordination involved the acp3U side chain and the ribose of A. The Mg2+-bound structure was modeled with simulated annealing, molecular mechanics and NMR restraints. Acp3U contributed to local charge density that facilitated Mg2+ coordination. #Present addresses: W. W. S., NMR Facility University of California, Davis, CA; B. F., School of Medicine, University of North Caroli...

Design of biologically active DNA analogues of the yeast tRNA(Phe) anticodon domain, tDNAPheAC, required the introduction of a d(m5C)-dependent, Mg(2+)-induced structural transition and the d(m1G) disruption of an intra-loop dC.dG base pair. The modifications were introduced at residues corresponding to m5C-40 and wybutosine-37 in tRNA(Phe). Modified tDNAPheAC inhibited translation by 50% at a tDNAPheAC:ribosome ratio of 8:1. The molecule's structure has been determined by NMR spectroscopy and restrained molecular dynamics with an overall r.m.s.d. of 2.8 A and 1.7 A in the stem, and is similar to the tRNA(Phe) anticodon domain in conformation and dimensions. The tDNAPheAC structure may provide a guide for the design of translation inhibitors as potential therapeutic agents.

The interactions of arsenate and arsenite with meso-2,3-dimercaptosuccinic acid (DMSA) have been characterized using carbon-13 nuclear magnetic resonance. These studies show that DMSA reduces arsenate to arsenite and complexes arsenite. Monitoring the carbon-13 signals of complexed DMSA and liberated glutathione shows that DMSA readily extracts arsenite from a (glutathione)3-arsenite complex, proving the affinity of arsenite for dithiols is greater than that for monothiols. Competition between DMSA (vicinal thiols) and dithioerythritol (1,4-dimercapto-2,3-butanediol) for binding of arsenite indicates that the binding affinity is inversely related to the distance between the two thiol groups. On the basis of these findings, a model for the interaction of arsenic with mono- and dithiol-containing molecules is proposed.

Coupling constants and chemical shifts were measured for dioctanoylphosphatidylcholine and its thio analogue in a CDCl3/CD3OD solvent mixture. Replacing the bridging oxygen atom of the CH—CH2—O—P portion of the phosphatidylcholine molecule with a sulfur atom affects chemical shifts and coupling constants in the glycerol backbone portion of the molecule as well as in the choline head group region. Preferred conformations about selected bonds in the phospholipids were determined from the vicinal 1H-1H, 31P-1H and 31P-13C coupling constants. A reduction of the 31P T 2 ∗ (effective spin-spin relaxation time) for the thio analogue, as well as changes in the relative chemical shifts of 13C nuclei in the acyl chains, suggest a somewhat greater degree of aggregation for the thio analogue. The quadrupolar coupling constant 1J(14N-13C) for the choline methyls of either analogue, however, indicates that aggregation of these phospholipids in the CDCl3/CD3OD solvent mixture is not significant. Differences in conformation between dioctanoylphosphatidylcholine and its thio analogue may be responsible for their differences in chemical and physical properties.

Laparoscopic deroofing of the solitary non parasitic cysts of the liver is a safe and effective procedure. This technique allows a wide access for surgical treatment of cysts localized in segments II, III, IVb, V, and VIII of the liver. On the contrary, the posterior segments, VI and VII, and the segment IVa, are difficult to approach laparoscopically. This report describes a laparoscopic technique used in treating 3 cases of symptomatic solitary cysts of the posterior segments of the liver. The patients were placed in the left lateral position. The fenestration treatment was easy and the mobilization of the right hepatic lobe was not required. At one year follow-up, neither postoperative complications nor recurring episodes were observed.

This study aimed to compare the safety, efficacy and clinical benefits of laparoscopic splenectomy (LS) to open splenectomy (OS) in patients with hematologic disorders.prospective study;II Department of Surgery, Santa Maria Nuova Hospital, Reggio Emilia and III Department of Surgery, Santo Spirito Hospital Pescara;48 consecutive adult patients underwent splenectomy; 30 patients under-went LS and 18 OS. Perioperative characteristics, outcomes, complications and costs were comparatively analyzed.Mean age was 35.3 years in the LS group, and 40.8 in the OS group. Mean spleen size was 11.7 cm in the LS group and 15.2 cm in the OS group. Accessory spleens were found in 5 patients in the LS group and in 4 patients in the OS group; 4 conversions to laparotomy occurred in the LS group. A total of 4 complications occurred in 3 patients of the LS; 9 complications occurred in 5 patients of OS group. Mean surgical time was 141.5 minutes for LS and 89.7 minutes for OS (p0.005). Mean postsurgical stay was 5.8 days in the LS group and 8.5 days in the OS group (p0.005). Response rates were similar in both groups.LS is comparable to OS in terms of efficacy and safety and it is associated with a shorter hospital stay. LS should become the technique of choice for treatment of intractable benign hematologic disease.

The problems of the surgery of bulky laparoceles began to find concrete solutions with the introduction of materials of synthesis that can be used to reinforce or to substitute the abdominal wall. Despite that, the ideal prosthesis has still not been found, the Dacron (Mersilene), the Polypropylene (Marlex, Prolene) and PTFE (Goretex) are today considered the best materials for the alloplasty. The authors describe their experience in matter of bulky laparocels treated with the technique of Rives. 49 patients have been operated, using Dacron in 44 cases and Polypropylene in 5. They had no mortality and no relapse, while the most frequent complication was 6 seromas, all resolved with conservative therapy. In their series 3 infections of the subcuticular occurred more of which required the removal of the prosthesis.

Carcinoma of the gallbladder is the most frequent neoplasia of the biliary tract with an incidence of 2.5-4.4 cases for every 100,000 inhabitants; it more often affects females and elderly patients (60-70 years). It is an extremely malignant tumour with an often fatal prognosis owing to both its site and the generally late diagnosis; the majority of patients in fact undergo surgery at an advanced stage of the disease when surgery is only palliative. At the Surgical Division of S. Massimo Hospital in Penne (PE) a total of 897 operations on the gallbladder and biliary tract were performed between 1988 and 1994, revealing 21 cases of carcinoma of the cholecyst (2.3%). Sixteen patients were female (male-female ratio 1:3.2) with a mean age of 67.8 years (range 58-83 years). These patients were divided into 5 stages according to the UICC-1992 classification: 80.9% of cases were stage 3-4. Diagnosis was performed intraoperatively in 2 patients, whereas in 3 cases cancer had been diagnosed by the anatomo-pathologist. A total of 3 simple cholecystectomies were performed, 4 were associated with hepatic resection and lymphadenectomy of the hilus and hepatoduodenal ligament; surgery was enlarged in 2 cases due to the involvement of adjacent organs. After exploratory laparotomy, palliative surgery was performed in the remaining 12 patients in the form of biliary and derivation. Four system were implanted for intra-arterial chemotherapy. The most frequently found histological type was adenocarcinoma (76.2%). The mean survival rate of patients who died was 7.6 months. Six of the operated patients are still alive, of whom only one with a follow-up of 4 years. In conclusion, the authors agree with those who consider carcinoma of the gallbladder generally fatal in view of the rarity of early diagnosis and the difficulties of performing radical therapy.

Transfer RNA(Lys)SUU, with a 5-modified-2-thiouridine at wobble position 34, facilitates -1 frameshifts for correct translation of the Escherichia coli DNA polymerase gamma subunit and retroviral polymerases. Peptidyl-tRNA(Lys)SUU prematurely terminates translation more often than other tRNAs. In order to determine if the anticodon structures of bacterial and mammalian tRNA(Lys)SUU species explain these observations, oligonucleotides corresponding to the anticodon regions of mammalian and E. coli tRNA(Lys)SUU were synthesized and their physicochemical properties compared with that of E. coli tRNA(Glu)SUC. The anticodon region of tRNA(Lys)SUU was stabilized by an unusual interaction between the side chains of the 5-modified-s(2)U34 and N-6-threonylcarbamoyl-adenosine-37 (t(6)A37), a combination of modified nucleosides unique to tRNA(Lys)SUU species. This first observation of modified nucleoside side-chain interactions is analogous to the interactions of amino acid side chains in proteins. The tRNA(Lys)SUU anticodon structure was determined from NMR restraints on model oligonucleotides. With only two of three anticodon bases available for codon pairing, this unconventional anticodon structure is a reasonable explanation for the bacterial and mammalian tRNA(Lys)SUU tendency to frameshift. A two-out-of-three reading of coding triplets also explains the increased rate at which peptidyl-tRNA(Lys)SUU prematurely terminates translation. In addition, modified nucleoside interaction distorts the anticodon loop. The distorted loop is a possible structural determinant for the preferential selection of tRNA(Lys3)SUU as primer of HIV-1 reverse transcriptase in vivo.

Intraoperative cholangiography, a diagnostic method through images introduced in to clinical use in 1932, has recently become a different technical support from that attributed by traditional surgery and it has got a different diagnostic meaning with the introduction of video surgery. The authors used it in 54 of 194 patients submitted to a CVL, always making use of the trans-cystic access, with a percentage of success of 82.6%. It was not possible in 8 patients due to the complete section of the cystic duct during the work (3 cases) and the impossibility of introducing the catheter (5 cases). There is still no common agreement about the opportunity to use IC daily: the authors think selective use is better preceded by a careful clinical laboratory instrumental preoperative study to find patients with the common duct stone. Besides, they are of the opinion that a rigorous surgical technique is fundamental to reduce the lesions of the VBP that there are not in their experience.

Meckel's diverticulum is a pathology not rarely found everyday clinical medicine especially when it present with one of its complications. The specific diagnosis is a bit difficult to put because of the low sensibility and specificity of symptoms of diagnostic and instrumental techniques used. The reported case shows a rare type of complication constituted by the phlogosis of Meckel's diverticulum, itself due to an extraneous thing ingested by the patient. The authors discuss the entity of the manifestations of this pathology and highlight every aspects.

The Authors report three cases of epidermoidal carcinoma arising from a congenital cyst of the anterolateral region of the neck. This type of tumor, rarely found in daily practice, arises from a degenerate branchial tissue and differential diagnosis often includes nodal involvement from systemic neoplasias. However, diagnostic criteria of such diseases are well defined; furthermore the rarity of branchial carcinoma is opposed to the high frequency of metastatic lymph nodes deriving from tumors with similar histological aspects located in other sites which could alter the real percentage of branchial tumor manifestation.

The authors describe a case of giant vesical calculus in an 89 year old patient. The diagnosis, as in the other cases reported in the international literature, was made after a series of laboratory and instrumental exams, for groups reported by the patient in the lower abdomen. Operated for the removal of the vesical calculus, he was considered healed after a fortnight. The vesical calculus has a mixed composition and it weighs about 380 grams. The revision of the literature shows the various chemical composition of the vesical calculus that does not permit to identify a common aetiology. It is not possible to demonstrate if the formation of this kind of calculus is primary (in the urinary bladder) or if it is proper of the high urinary tract or mixed. The most recurrent causes being various and different confirm the mixed aetiopathologic theory. The diagnosis, often casual, is made thanks to the most common diagnostic exams; as it is difficult to make a complete cystoscopic control because the bladder is almost completely occupied by the lithiasic formation. The surgical therapy consists of a epicystotomy with a following removal of the calculus. In literature, moreover, cases treated with extra-body lithotripsy are not reported, on the contrary ot happens daily for the lithiasis of the high urinary tract.

The authors present the guidelines which have been followed to introduce into their own Surgical Division an alternative method to cholelithiasis treatment: laparovideocholecystectomy (l.v.c.). They point out how the directions for use of the new surgical method, in place of the traditional laparectomic technique, must be limited to non-complicated cholelithiasis cases, especially in the initial learning stages. That sets the global "morbility" of the above said l.v.c. beneath the cholecystectomy performed with traditional technique. In addition, they point out the sure economic advantages at social and contributions level arriving at the conclusion that l.v.c. is the best treatment for Gallstones.

Although a few modifications are found in DNA, 93 modified nucleosides have been found in the various RNAs. For the most part, the chemistry and structure that modified nucleosides, individually and in combination, uniquely contribute to DNA or RNA function have yet to be explained. However, there are ten physicochemical contributions that can be attributed to modified nucleosides. Of particular interest is the increasingly documented relationship between the presence of modified nucleosides in tRNAs, and the site and affinity of Mg2+ binding to RNA and its effect on function.

The authors describe two cases of recent observed internal-hernia, regarding in the first case the right para-duodenal dimple, and in the second a mesenteric breach. They report the clinic presentation and the diagnostic and therapeutic approach compared with the data deriving from the international literature. A complete clinical classification of the internal-hernia is illustrated showing the different clinical signs. The respective symptomatology that in the initial phases of this pathology is not too evident, shows that the internal hernia should always be held in due consideration at the moment of diagnosis because the consequent mortality due to complications such as intestinal-gangrene is rather high.

The binding of arsenite, As(III), and arsenate, As(V), by molecules in the intracellular compartment of rabbit erythrocytes has been studied by 1H- and 31P-NMR spectroscopy, uptake of 73As, and ultrafiltration experiments. For intact erythrocytes to which 0.1-0.4 mM arsenite was added, direct evidence was obtained for entry of 76% within 1/2 h and subsequent binding of As(III) by intracellular glutathione and induced changes in the hemoglobin structure (NMR), likely due to binding of As(III). These results were compared with the effect of addition of As(V) on intact erythrocytes and revealed that a smaller amount of As(V) (approximately 25%) enters the cells; the main fraction of As(V) enters the phosphate pathway, depletes ATP, and increases Pi. In contrast, As(III) did not affect the ATP level. Both 1H- and 31P-NMR data indicated striking differences between As(III) and As(V) behavior when incubated with rabbit erythrocytes. These differences were confirmed by 73As uptake and binding experiments. meso-2,3-Dimercaptosuccinic acid (DMSA), a dithiol ligand, released glutathione from its arsenite complexes in erythrocytes.

The Chilaiditi syndrome or viscero hepato diaphragmatic interposition is a rare anomaly. The authors describe one case they observed. Even if it is often asymptomatic, it may manifest also by recurrent sub-occlusion or occlusion. Only a few patients need corrective surgical operation. The operation of choice is hepatic extra-peritonealization, which after replacement of the dislocated gastroenteric tract, brings the superior face of the liver again into direct contact with the related diaphragmatic dome.

The authors discuss their experience of six cases of cancer of the gastric stump observed by them in the period from 1988 to 1992 inclusive. All the patients were operated; five total gastrectomies and a gastric re-resection were effected. In association also the spleen was removed in four patients, in one of them a hepatic metastasectomy and a distal pancreasectomy were effected. In the discussion the problems concerning the diagnostic and therapeutic implications with some references to the more likely etiopathogenetic theories were dealt with.

The authors discuss a case of Grynfeltt's quadrilateral lumbar hernia in an 85-year-old patient. These rather rare hernias can be classified as Grynfeltt's hernias of the superior lumbar space, as Petit's inferior lumbar space and as diffused hernias concerning the whole hip. In our case this hernia was located in the superior lumbar space and it was delimited on the upper part by the 12th rib and by the serratus posterior-inferior muscle; in the lower part by the internal oblique muscle and by the lumbar quadratus muscle. Surgical treatment was effected by plastic surgery with synthetic material put in the extra-peritoneum space and fixed by serum-muscular stitches. Postoperative control effected after a month from the operation proves a good keeping of the plastic surgery reconstruction with total disappearance of the hernia.

Following a discussion of the various methods of colorectal anastomosis in cancer surgery, the Authors describe a technical variant using a mechanical stapler in a high rectal location. The rapidity of anastomosis as well as the decreased risk of dehiscence, fistula and stenosis are underlined.

Three cases of chronic gastrointestinal bleeding are described; the Authors emphasize the important role of mesenteric arteriography in establishing site and nature of bleeding. The review of international literature shows a success rate between 41 and 73% of cases studied with this method after negativity of other diagnostic procedures.

Proton lanthanide-induced shifts (LIS) were measured for Yb(fod)3-dibucaine complexes in CDCl3 solution. The data were used in conjunction with empirical energy calculations to determine the preferred conformations of dibucaine. The energy calculations and the LIS analysis were in agreement in showing that the plane of the amide group makes an angle of approximately 60° with the plane of the quinoline ring, and also that the two carbon-carbon bonds between the amide group and the tertiary amine nitrogen are both in gauche configurations. Energy calculations showed that the diethyl tertiary zmine group has very restricted conformational freedom owing to internal steric constraints. The butyl ether group has considerable flexibility but is forced out of the plane of the quinoline ring by steric effects.