Pretreatment of corn stover by aqueous ammonia

Corn stover was pretreated with aqueous ammonia in a flow-through column reactor, a process termed ammonia recycled percolation (ARP). This method was highly effective in delignifying of the biomass, reducing the lignin content by 70-85%. Most lignin removal occurred within the first 20 min of the process. Lignin removal by ARP was further confirmed by FTIR analysis and lignin staining. The ARP process solubilized 40-60% of the hemicellulose but left the cellulose intact. The solubilized carbohydrate existed in oligomeric form. Carbohydrate decomposition during the pretreatment was insignificant. Corn stover treated for 90 min exhibited enzymatic digestibility of 99% with 60 FPU/g of glucan enzyme loading, and 92.5% with 10 FPU/g of glucan. The digestibility of ARP treated corn stover was substantially higher than that of alpha-cellulose. The enzymatic digestibility was related with the removal of lignin and hemicellulose, perhaps due to increased surface area and porosity. The SEM pictures indicated that the biomass structure was deformed and its fibers exposed by the pretreatment. The crystallinity index increased with pretreatment reflecting removal of the amorphous portion of biomass. The crystalline structure of the cellulose in the biomass, however, was not changed by the ARP treatment.

HLA-B27 polymorphism in the Malays

The frequency of HLA-B27 and its subtypes was determined in 878 Malay subjects. Thirty-five of the subjects typed for HLA-A, -B and -DR were found to be positive for HLA-B27. The frequency of this allele in the Malay population was found to be 3.99%. The subtypes observed and their frequencies are: HLA-B*2704 (19.4%), HLA-B*2705 (5.6%), HLA-B*2706 (72.2%) and HLA-B*2707 (2.8%).

Heterogeneous aspects of acid hydrolysis of alpha-cellulose

Hydrolysis of alpha-cellulose by H2SO4 is a heterogeneous reaction. As such the reaction is influenced by physical factors. The hydrolysis reaction is therefore controlled not only by the reaction conditions (acid concentration and temperature) but also by the physical state of the cellulose. As evidence of this, the reaction rates measured at the high-temperature region (above 200 C) exhibited a sudden change in apparent activation energy at a certain temperature, deviating from Arrhenius law. Furthermore, alpha-cellulose, once it was dissolved into concentrated H2SO4 and reprecipitated, showed a reaction rate two orders of magnitude higher than that of untreated cellulose, about the same magnitude as cornstarch. The alpha-cellulose when treated with a varying level of H2SO4 underwent an abrupt change in physical structure (fibrous form to gelatinous form) at about 65% H2SO4. The sudden shift of physical structure and reaction pattern in response to acid concentration and temperature indicates that the main factor causing the change in cellulose structure is disruption of hydrogen bonding. Finding effective means of disrupting hydrogen bonding before or during the hydrolysis reaction may lead to a novel biomass saccharification process.

A comprehensive kinetic model for dilute-acid hydrolysis of cellulose

Acid-catalyzed hydrolysis is controlled not only by temperature and acid concentration but also by the physical state of the cellulose. Under low temperature and acid condition the cellulose structure stays in stable crystalline form. Therefore, the prevailing reaction mode is endwise hydrolysis. Glucose then becomes the main sugar product. However, when temperature and/or acid concentration is raised to a certain level, the cellulose structure becomes unstable by breakage of hydrogen bonding, the primary force that holds the cellulose chains. Once the crystalline structure of the cellulose is disrupted, acid molecules can penetrate into the inner layers of the cellulose chains. In support of this hypothesis, we have experimentally verified that a substantial amount of oligomers is formed as reaction intermediates under extremely low-acid and high-temperature conditions. We also found that the breakage of hydrogen bonds occurs rather abruptly in response to temperature. One such condition is 210 degrees C, 0.07% H2SO4. Glucose, once it is formed in the hydrolysate, interacts with acid-soluble lignin, forming a lignin-carbohydrate complex. This occurs concurrently with other reactions involving glucose such as decomposition and reversion. On the basis of these findings, a comprehensive kinetic model is proposed. This model is in full compliance with our recent experimental data obtained under a broad range of reaction conditions.

Simplistic modeling approach to heterogeneous dilute-acid hydrolysis of cellulose microcrystallites

The classic kinetic model for cellulose hydrolysis is often referred to as pseudo-homogeneous, a term revealing the insight that the process is actually heterogeneous. During the past 10-15 yr, the shortcomings of this model have been demonstrated in various studies and the interest in the heterogeneous aspects has increased. The present work presents a simplistic model in which the intrinsic, heterogeneous hydrolysis and transport rates are coupled by the assumption of a constant glucosidic surface concentration. The mechanisms affecting these two rates are largely unknown, but the model serves as a guideline for further exploration of the process.

Measurement of the positive muon anomalous magnetic moment to 0.7 ppm

A higher precision measurement of the anomalous g value, a(mu)=(g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron, based on data collected in the year 2000. The result a(mu(+))=11 659 204(7)(5)x10(-10) (0.7 ppm) is in good agreement with previous measurements and has an error about one-half that of the combined previous data. The present world average experimental value is a(mu)(expt)=11 659 203(8)x10(-10) (0.7 ppm).

Fermentation of xylose into acetic acid by Clostridium thermoaceticum

For optimum fermentation, fermenting xylose into acetic acid by Clostridium thermoaceticum (ATCC 49707) requires adaptation of the strain to xylose medium. Exposed to a mixture of glucose and xylose, it preferentially consumes xylose over glucose. The initial concentration of xylose in the medium affects the final concentration and the yield of acetic acid. Batch fermentation of 20 g/L of xylose with 5 g/L of yeast extract as the nitrogen source results in a maximum acetate concentration of 15.2 g/L and yield of 0.76 g of acid/g of xylose. Corn steep liquor (CLS) is a good substitute for yeast extract and results in similar fermentation profiles. The organism consumes fructose, xylose, and glucose from a mixture of sugars in batch fermentation. Arabinose, mannose, and galactose are consumed only slightly. This organism loses viability on fed-batch operation, even with supplementation of all the required nutrients. In fed-batch fermentation with CSL supplementation, D-xylulose (an intermediate in the xylose metabolic pathway) accumulates in large quantities.

Production of oxychemicals from precipitated hardwood lignin

Lignin is a major byproduct in the biomass-to-ethanol process. The lignin produced from acid treatment of biomass has characteristics suitable for further conversion to organic chemicals. It is free of contaminants and has a relatively low molecular weight. In this study, catalytic oxidative conversion of the acid-soluble lignin precipitated from acid hydrolysates of hardwood was investigated. The process is based on aqueous alkaline oxidation of lignin with dissolved O2 in the presence of Fe3+ and Cu2+ catalysts at moderate reaction temperatures (160-180 degrees C). Aromatic aldehydes, ketones, and organic acids are found to be the primary products identifiable on extraction with ether. The combined weight yield of the total ether extractable products is about 20-25% of the initial lignin. The yield of the aldehydes (vanillin + syringaldehyde) is in the vicinity of 15% with an additional 3 to 4% of aromatic ketones. The yields of aldehydes plus ketones observed in this work far exceeded those obtainable from the conventional alkaline air oxidation of spent sulfite liquors. This article also provides comprehensive batch reaction data on conversion and product distribution.

Cellulose hydrolysis under extremely low sulfuric acid and high-temperature conditions

The kinetics of cellulose hydrolysis under extremely low acid (ELA) conditions (0.07 wt%) and at temperatures >200 degrees C was investigated using batch reactors and bed-shrinking flow-through (BSFT) reactors. The maximum yield of glucose obtained from batch reactor experiments was about 60% for alpha-cellulose, which occurred at 205 and 220 degrees C. The maximum glucose yields from yellow poplar feedstocks were substantially lower, falling in the range of 26-50%. With yellow poplar feedstocks, a large amount of glucose was unaccounted for at the latter phase of the batch reactions. It appears that a substantial amount of released glucose condenses with nonglucosidic substances in liquid. The rate of glucan hydrolysis under ELA was relatively insensitive to temperature in batch experiments for all three substrates. This contradicts the traditional concept of cellulose hydrolysis and implies that additional factors influence the hydrolysis of glucan under ELA. In experiments using BSFT reactors, the glucose yields of 87.5, 90.3, and 90.8% were obtained for yellow poplar feedstocks at 205, 220, and 235 degrees C, respectively. The hydrolysis rate for glucan was about three times higher with the BSFT than with the batch reactors. The difference of observed kinetics and performance data between the BSFT and the batch reactors was far above that predicted by the reactor theory.

Diffusion of sulfuric acid within lignocellulosic biomass particles and its impact on dilute-acid pretreatment

Intra-particle diffusion of sulfuric acid into sugarcane bagasse, corn stover, rice straw and yellow poplar was investigated to determine the effective diffusivity of sulfuric acid within the porous biomass structure. Diffusion experiments were conducted over 25-75 degrees C for two different biomass sizes using dynamic diffusion test cells. Diffusivities of sulfuric acid in agricultural residues were significantly higher than those of hard wood. Diffusivity data for each biomass were fitted into the Arrhenius equation for extrapolation to higher temperatures. The diffusivity data were subsequently incorporated into a theoretical model to determine acid profile within the biomass matrix. The modeling results indicate that intra-particle diffusion of acid influences the rate of dilute-acid pretreatment if unground biomass feedstock is used under normal pretreatment conditions. A criterion was set up to determine the critical biomass size at which the intra-particle acid diffusion becomes a rate-influencing factor for a given pretreatment condition.

Video-assisted endoscopic lumbar discectomy

BACKGROUND

The optimal management of symptomatic lumbar disc herniations (LDH) remains controversial. This study examines the feasibility and safety of a video-assisted endoscopic intracanalicular technique for managing symptomatic LDH.

METHODS

From September 1999 to June 2000, we used the current technique, the Vertebroscope System, on 11 patients (six men, five women), aged from 18 to 61 years (mean, 45), who had suffered symptomatic LDH. The disc levels involved were at L4-L5 (n = 8), and L5-S1 (n = 3). The Vertebroscope, which has a 30 degrees viewing angle and a working channel 1.7 cm in diameter, was used for the minimally invasive endoscopic procedures. The mean follow-up period was 12 months (range, 6-15).

RESULTS

The operating time ranged from 60 to 335 min (mean, 136.5), and the estimated blood loss during operation was minimal to 200 ml. The mean length of the paramedian skin incisions was 2 cm. No drainage tube was used postoperatively. The mean hospital stay was 3 days (range, 2-5), with five patients discharged on the 1st postoperative day. Complications included one superficial wound infection, one conversion to an open procedure when muscle herniation into the working channel created a technical difficulty in approaching the ligamatum flavum, and one minor tear of the nerve root sleeve that did not require further surgery. In the first five patients studied herein, the mean operating time was significantly longer than that for the later five patients (201 vs 72 min, p < 0.001).

CONCLUSIONS

The advantages of the current endoscopic disectomy technique include its minimally invasive character, with less paraspinal muscle trauma, direct address to the lesion site that resembles the open technique, and enhanced operative field visualization with a paramedian skin incision of just 2 cm. Practice is needed to perfect such an endoscopic approach for lumbar disc excision, so the operating time decreased significantly as the surgeons became more familiar with this endoscopic technique. It has proved to be safe and effective for treating patients with symptomatic LDH.

Selective termination of aneuploidy utilizing rapid fluorescence in situ hybridization detection techniques

Twin pregnancy following assisted reproductive technology with a euploid fetus and a coexisting aneuploid co-twin constitutes a conflicting situation; therefore, it is important for the genetic constitution of each co-twin to be diagnosed accurately and promptly for parental genetic counseling and subsequent aggressive management. A 35-year-old woman, gravida 1, with a 2-year history of infertility, presented bilateral fallopian tubal obstruction at her infertility workups, for which she received in vitro fertilization; subsequently she conceived a twin pregnancy. She underwent genetic amniocentesis at 16 weeks' gestation, as indicated by an advanced maternal age. Presented with the diagnosis of twin pregnancy with discordancy for trisomy 21, a rapid fluorescence in situ hybridization (FISH) technique for aneuploidy mapping was applied for subsequent abdominal selective fetal reduction. The FISH technique facilitates the rapid analysis of uncultured amniocytes. Normal (disomic) and trisomic samples can be distinguished clearly and rapidly for subsequent selective fetocide. The FISH technique is an important tool in prenatal diagnosis and clinical applications.

Minimal access surgery in managing anterior lumbar disorders

Traditional anterior lumbar surgery usually requires a long and sometimes painful skin incision. The current study evaluated the feasibility and safety of minimal access surgery for anterior lumbar disorders, emphasizing indications, operative technique, and the minimum 2-year followup results. From May 1996 to December 1997, the authors used this technique on 25 patients whose indications for surgery included syndromes of failed back surgery, selected cases of lumbar disc herniations, tuberculous or pyogenic spondylitis, selected spondylolisthesis, and vertebral tumors. In 23 of 25 patients, the site of interest was approached through a left flank incision, regardless of the laterality of the lesion. The mean length of the main incision was 5 cm. There were no injuries to great vessels or any neurologic deterioration after the procedures. Solid interbody fusion could be identified radiographically between 3 and 6 months after surgery. At a mean followup of 39.6 months, nine patients had excellent clinical outcomes, 11 patients had good outcomes, two patients had fair outcomes, and one patient had a poor outcome. The authors think such minimal access surgery is simple, effective, and safe for anterior lumbar disorders. The merits of the current technique include no need for endoscopic, microscopic, or complex surgical instruments, a lower amount of radiation exposure during surgery, and a shortened learning curve because the approach is similar to the anterior open lumbar technique, although the skin incision is only 5 cm in length.

Potential role of caspase-3 and -9 in arsenic trioxide-mediated apoptosis in PCI-1 head and neck cancer cells

Arsenic trioxide (As2O3) has been shown to inhibit the proliferation of hematologic malignant cells. Previously, we reported that As2O3 had an antitumoral effect in head and neck cancer. Here, we investigated the induction of apoptosis and its mechanism in PCI-1 head and neck squamous carcinoma cells, after treatment with As2O3. Treatment with 2 microM of As2O3 caused apoptosis in PCI-1 cells following 3 days of exposure, which was detected by the annexin V-PI and DAPI staining methods. The cell death population was markedly increased, being 88% larger than the As2O3-untreated control cells. To address the mechanism of apoptosis, a Western blot assay was performed, showing that Bax was up-regulated without a change in Bcl-2. Activation of caspase-9 during As2O3-induced apoptosis was substantiated by monitoring the proteolysis of the caspase-9, which was associated with an increase of Apaf-1 and cytochrome c protein. PCI-1 cells rapidly changed the mitochondria membrane potential (DeltaPsim) after addition of As2O3. Furthermore, activation of caspase-3 was demonstrated by monitoring the proteolysis of the caspase-3 and by measuring caspase-3 activity with a fluorogenic substrate, which was associated with the cleavage of poly(ADP-ribose) polymerase. To examine the in vivo effect of As2O3, C3H mouse inoculated with syngenic SCC7 cells was treated by intratumoral injection of As2O3 (300 microg) every day, demonstrating that tumor mass was dramatically reduced on day 4, and revealed induction of apoptosis by TUNEL assay. These results suggest that apoptosis of PCI-1 cells by As2O3 is induced by activation of caspase-3 via cytochrome c, caspase-9 and Apaf-1 complex.

Clinical impacts of tumor cell contamination of hematopoietic stem cell products in metastatic breast cancer patients undergoing autologous peripheral blood stem cell transplantation: multicenter trial

To determine whether the tumor cell contamination of peripheral blood stem cells influences clinical impacts on high-dose chemotherapy in patients with metastatic breast cancer, we analyzed carcinoembryonic antigen (CEA) mRNA in the apheresis products by nested RT-PCR (reverse transcriptase-polymerase chain reaction). A total of 38 metastatic breast cancer patients and ten normal healthy subjects as a negative control were included. Twenty out of 38 (51.3%) apheresis products from patients with metastatic breast cancer were positive for CEA mRNA. CEA mRNA was noted in 54.8% (17/31) of patients mobilized with chemotherapy plus G-CSF and 42.8% (3/7) of patients with G-CSF alone. There was no significant difference in age, estrogen receptor, menopausal status, mobilization method, disease free interval, or number of metastasis sites (1 vs > or = 2) between positive and negative groups. The presence of CEA mRNA in apheresis products did not influence the time to progression and overall survival in both groups. However, both the univariate and the multivariate analysis disclosed that the number of metastasis was associated with survival significantly. We suggest that the tumor cell contamination does not predict poor treatment outcome in patients with metastatic breast cancer.

Identification of stress-responsive genes in Streptococcus mutans by differential display reverse transcription-PCR

Streptococcus mutans, which causes dental caries in the human oral cavity and occasionally causes infective endocarditis in the heart, withstands adverse environmental stress through diverse alterations in protein synthesis. Differential gene expression in response to environmental stress was analyzed by RNA fingerprinting using arbitrarily primed PCR with a panel of 11mer primers designed for differential display in Enterobacteriaceae. Dot and Northern blot hybridization confirmed that the transcription of several genes was up- or down-regulated following exposure to acid shock from pH 7.5 to 5.5. RNA of a gene designated AP-185 (acid-stress protein) was induced specifically by acid treatment, while RNA of GSP-781 (general-stress protein) was up-regulated significantly when bacteria were exposed to high osmolarity and temperature, as well as low pH. The deduced amino acid sequence of AP-185 shares homology (78% identity) with branched-chain amino acid aminotransferase. Cloning and sequence analysis of GSP-781 revealed a potential secreted protein of a molecular mass of about 43 kDa and with a pI predicted to be 5.5. Transcriptional levels of another gene, designated AR-186 (acid-repressed protein), which encodes putative aconitase, were repressed by acid treatment but were enhanced by plasma or serum components. Analogous results were identified in icd and citZ genes, and repression of these genes, along with AR-186, was also observed when they were exposed to high osmolarity and temperature. These results indicate that differential regulation of specific genes at the transcriptional level is triggered by different stress and that genes responsible for glutamate biosynthesis in the citrate pathway are coordinately regulated during the stress response of S. mutans.

Precise measurement of the positive muon anomalous magnetic moment

A precise measurement of the anomalous g value, a(mu) = (g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron. The result a(mu+) = 11 659 202(14) (6) x 10(-10) (1.3 ppm) is in good agreement with previous measurements and has an error one third that of the combined previous data. The current theoretical value from the standard model is a(mu)(SM) = 11 659 159.6(6.7) x 10(-10) (0.57 ppm) and a(mu)(exp) - a(mu)(SM) = 43(16) x 10(-10) in which a(mu)(exp) is the world average experimental value.

Detection of malignant cells in pleural fluid or ascites by CD44v8-10/CD44v10 competitive RT-PCR

BACKGROUND

CD44 is a cell surface adhesion molecule which has been implicated in various biologic functions as lymphocyte homing and activation, cellular migration and extracellular matrix adhesion. Over-expression of CD44v8-10 has been found in several cancers and is considered to be associated with tumor progression and metastasis. Recently, a novel molecular method, CD44v8-10/CD44v10 competitive reverse transcription-polymerase chain reaction(RT-PCR) has been developed for detecting cancer cells over-expressing CD44v8-10.

METHODS

We analyzed from benign and malignant pleural effusion and ascites by CD44 competitive RT-PCR and compared to the conventional cytology.

RESULTS

The CD44 competitive RT-PCR analysis showed that all the 24 samples associated with benign disease presented a predominant expression of the CD44v10 transcript (v8-10/v10 ratio: 0.126-0.948), whereas 6 of 7 malignant pleural samples associated with cytology positive cancer expressed the CD44v8-10 transcript (v8-10/v10 ratio > 1.00).

CONCLUSION

These results indicate that CD44 competitive RT-PCR assay is a useful and adjunct to cytological examination in cancer diagnosis, especially in detecting exfoliated cancer cells in pleural effusion.

Potential role of caspase-3 and -9 in arsenic trioxide-mediated apoptosis in PCI-1 head and neck cancer cells

Arsenic trioxide (As2O3) has been shown to inhibit the proliferation of hematologic malignant cells. Previously, we reported that As2O3 had an antitumoral effect in head and neck cancer. Here, we investigated the induction of apoptosis and its mechanism in PCI-1 head and neck squamous carcinoma cells, after treatment with As2O3. Treatment with 2 microM of As2O3 caused apoptosis in PCI-1 cells following 3 days of exposure, which was detected by the annexin V-PI and DAPI staining methods. The cell death population was markedly increased, being 88% larger than the As2O3-untreated control cells. To address the mechanism of apoptosis, a Western blot assay was performed, showing that Bax was up-regulated without a change in Bcl-2. Activation of caspase-9 during As2O3-induced apoptosis was substantiated by monitoring the proteolysis of the caspase-9, which was associated with an increase of Apaf-1 and cytochrome c protein. PCI-1 cells rapidly changed the mitochondria membrane potential (DeltaPsim) after addition of As2O3. Furthermore, activation of caspase-3 was demonstrated by monitoring the proteolysis of the caspase-3 and by measuring caspase-3 activity with a fluorogenic substrate, which was associated with the cleavage of poly(ADP-ribose) polymerase. To examine the in vivo effect of As2O3, C3H mouse inoculated with syngenic SCC7 cells was treated by intratumoral injection of As2O3 (300 microg) every day, demonstrating that tumor mass was dramatically reduced on day 4, and revealed induction of apoptosis by TUNEL assay. These results suggest that apoptosis of PCI-1 cells by As2O3 is induced by activation of caspase-3 via cytochrome c, caspase-9 and Apaf-1 complex.

Clinical significance of microvessel density in multiple myeloma patients

To investigate the role of angiogenesis in multiple myeloma (MM), bone marrow biopsy from 75 adults with newly diagnosed, untreated MM were evaluated. Microvessels were scored in at least 3 areas ( x 200 fields) of the highest microvessel density in representative sections of each bone marrow specimen using immunohistochemistry for CD34. Prognostic variables were also evaluated for the overall survival. Microvessel counts were significantly higher in patients with MM (n=69.42+/-9.67), compared with control (n=26.81+/-2.85). Microvessel density had a weak correlation with percentage of bone marrow plasma cells. By univariate analysis, age, beta2-microglobulin, serum albumin, serum creatinine, serum calcium, hemoglobin, platelet count, and bone marrow plasma cell percentage were correlated with survival. By multivariate analysis, age, serum albumin, serum creatinine, hemoglobin, platelet count and bone marrow plasma cell percentage were correlated with overall survival, whereas microvessel density was not. In summary, microvessel density in bone marrow of MM is significantly increased compared to control, but was not correlated with overall survival. Further studies regarding angiogeneic molecules are needed to determine the functional role of angiogenesis in MM.

A case of primary intestinal T-cell lymphoma involving entire gastrointestinal tract: esophagus to rectum

Primary intestinal T-cell lymphoma is a rare disease entity, which is approximately 10% to 25% of intestinal lymphomas, and most of the lymphomas occur in the small intestine. We report here a case of a 56-year-old woman who has been suffering from chronic diarrhea and weight loss for 6 months. Abdominal CT scan and small bowel series showed diffuse wall thickening of the small bowel. Gastroscopic examination showed diffuse erythematous lesions on the esophagus and small gastric ulcerations on the antrum of the stomach, and colonoscopic examination also showed multiple punched-out ulcerations and erosions on the entire colon, including the sigmoid colon to the terminal ileum. Diffuse infiltration of CD 3 positive lymphoma cells was found on biopsy. The patient was diagnosed as primary intestinal T-cell lymphoma with diffuse involvement of the entire gastrointestinal tracts from the esophagus to the rectum. Although the patient received systemic combination chemotherapy and achieved partial response initially, the lymphoma relapsed repeatedly.

Three-pion interferometry results from central Pb+Pb collisions at 158A GeV/c

Three-particle correlations have been measured for identified pi(-) from central 158A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.

Ontogeny of natural killer cells and T cells by analysis of BCR-ABL rearrangement from patients with chronic myelogenous leukaemia

Chronic myelogenous leukaemia (CML) is a haematological malignant disorder characterized by the Philadelphia chromosome (Ph) and BCR-ABL gene rearrangement. This abnormal fusion gene can be considered to serve as a marker for the transformed cell clone in CML and is found in all cells arising from the same malignant precursor cell. It has been detected in CML cells of the myeloid, monocytic, erythroid and B-lymphocytic lineages. However, it is still arguable as to whether T lymphocytes or natural killer (NK) cells carry this marker. Answering this question would clarify the ontogenic relationship between NK cells and T cells. We examined 12 CML patients and studied the expression of BCR-ABL rearrangement by fluorescence in situ hybridization (FISH) in both NK cells and T cells sorted by flow cytometry. The purity of T cells was 95.6-99.8% and that of NK cells was 95.3-99.3% after sorting. Neither NK cells nor T cells showed any positive BCR-ABL signal with the exception of one patient who recovered from a lymphoid blastic crisis. We speculate that T cells and NK cells originate from BCR-ABL-negative stem cells.

Pretreatment of wastepaper and pulp mill sludge by aqueous ammonia and hydrogen peroxide

Pretreatment of two different softwood-based lignocellulosic wastes (newsprint and Kraft pulp mill sludge) was investigated. Pretreatment was done by aqueous ammonia and hydrogen peroxide (H2O2), two delignifying reagents that are environmentally benign. Three different treatment schemes were employed: aqueous ammonia alone (ammonia recycled percolation [ARP]), mixed stream of aqueous ammonia and H2O2, and successive treatment with H2O2 and aqueous ammonia. In all cases there was a substantial degree of delignification ranging from 30 to 50%. About half of the hemicellulose sugars were dissolved into the process effluent. Retention of cellulose after pretreatment varied from 85 to 100% for newspaper feedstock and from 77 to 85% for the pulp mill sludge. After treatment with aqueous ammonia alone (ARP), the digestibility of newspaper and the pulp mill sludge was improved only by 5% (from 40 to 45% for the former and from 68 to 73% for the latter), despite a substantial degree of delignification occurring after the ARP process. The lignin content thus did not correlate with the digestibility for these substrates. Simultaneous treatment with H2O2 and aqueous ammonia did not bring about any significant improvement in the digestibility over that of the ARP. A successive treatment by H2O2 and ARP showed the most promise because it improved the digestibility of the newspaper from 41 to 75%, a level comparable to that of alpha-cellulose.

Simultaneous saccharification and fermentation of cellulosic biomass to acetic acid

A strain of Clostridium thermoaceticum (ATCC 49707) was evaluated for its homoacetate potential. This thermophilic anaerobe best produces acetate from glucose at pH 6.0 and 59 degrees C with a yield of 83% of theoretical. Enzyme hydrolysis of two substrates, a-cellulose and a pulp mill sludge, yielded 68% and 70% digestion, respectively. The optimum conditions for the simultaneous saccharification and fermentation (SSF) were substrate dependent: 55 degrees C, pH 6.0 for alpha-cellulose, and 55 degrees C, pH 5.5 for the pulp mill sludge. In the SSF with alpha-cellulose, the overall yield of acetate was strongly influenced by the enzyme loading. In a fed-batch operation of SSF with alpha-cellulose, an overall acetic acid yield of 60 wt% was obtained. Among the factors limiting the yields were incomplete digestion by the enzyme and the end-product inhibition. In the SSF of pulp mill sludge, inhibitors present in the sludge severely limited bacterial action. A large accumulation of glucose developed over the entire process, changing the intended SSF operation into a separate hydrolysis and fermentation operation. Despite a long lag phase of microbial growth, a terminal yield of 85% was obtained with this substrate.